Lithium-ion battery manufacturing process

The production process of lithium-ion batteries is relatively complicated, and the important production process mainly covers the stirring and coating stage (front stage) of electrode production, the winding liquid injection stage (middle stage) of cell synthesis, and the packaging inspection stage of chemical formation and packaging (post stage) .
The lithium battery equipment corresponding to the front-end process of lithium battery production mainly includes vacuum mixers, coating machines, roller presses, etc.; the middle-end process mainly includes die-cutting machines, winding machines, stacking machines, liquid injection machines, etc.; the back-end process includes chemical forming machines. , capacity testing equipment, process warehousing and logistics automation, etc. In addition, the production of battery packs requires Pack automation equipment.

Lithium battery front-end production process
Electrode manufacturing is related to the core performance of the battery
The result of the lithium-ion battery front-end process is the preparation of the positive and negative electrodes of the lithium-ion battery. The first process is stirring, that is, mixing the positive and negative solid-state battery materials evenly, adding a solvent, and stirring them into a slurry by a vacuum mixer. The stirring of ingredients is the basis of the subsequent process of lithium batteries, and high-quality stirring is the basis for the high-quality completion of subsequent coating and rolling processes.
The coating and rolling process is followed by slitting, that is, the coating is subjected to a slitting process. If burrs appear during the slitting process, there will be safety hazards in the subsequent assembly, electrolyte injection and other procedures, and even the battery use process. Therefore, the front-end equipment in the lithium battery production process, such as mixers, coating machines, roller presses, and slitting machines, are the core machines of battery manufacturing, which are related to the quality of the entire production line. Therefore, the value (amount) of front-end equipment accounts for the entire lithium battery. The proportion of automated production lines is the highest, about 35%.

Lithium battery middle section process
Efficiency comes first, winding goes before lamination
In the manufacturing process of lithium-ion batteries, the middle process is mainly to complete the forming of the battery. The important process includes sheet production, pole piece winding, die-cutting, cell winding forming and lamination forming, etc., which is currently a relatively fierce competition among domestic equipment manufacturers. An area of China, accounting for about 30% of the value of lithium-ion battery production lines.
At present, there are mainly two types of cell manufacturing processes for power lithium-ion batteries: winding and stacking. The corresponding battery structures are mainly cylindrical, square, and soft-packed. Cylindrical and square batteries are mainly produced by winding processes, and soft-packed batteries The lamination process is mainly used. The cylinder is mainly represented by 18650 and 26650 (Tesla has independently developed the 21700 battery, which is being promoted in the whole industry). Mainly, the aluminum shell is mainly based on the winding process.

The structure of soft packs is mainly aimed at the high-end digital market, and the profit margin per unit product is relatively high. Under the same output conditions, the relative profit is higher than that of aluminum shell batteries. Since aluminum-cased batteries are easy to form scale effect, product qualification rate and cost are easy to control, both currently have considerable profits in their respective market fields, and it is difficult for both of them to be completely replaced in the foreseeable future.
Since the winding process can achieve high-speed production of battery cells through the speed, and the speed that can be increased by the stacking technology is limited, the current domestic power lithium-ion batteries mainly use the winding process, so the shipment volume of winding machines is currently greater than Stacking machine.
The previous process corresponding to winding and lamination production is the production and die-cutting of pole pieces. Sheet production includes welding pole pieces/tabs after slitting, dedusting pole pieces, pasting protective tape, tab wrapping and winding or cutting to length, in which the winding pole pieces are used for subsequent fully automatic winding, The fixed-length cutting pole piece is used for subsequent semi-automatic winding; the die-cut pole piece is to punch and shape the slit pole piece winding for subsequent lamination process.
In terms of lithium battery packaging and welding, Lianying, Han's, and Everbright's mainstream laser technology integration and application manufacturers are all involved, which can meet the demand and do not need to import.

Lithium battery back-end process flow
Volume separation is the core link
The post-production process of lithium batteries mainly includes four processes of capacity separation, formation, testing, and packaging and storage, accounting for about 35% of the value of the production line. Formation and capacity separation are the most important links in the back-end process, and the formed battery is activated and tested. Due to the long charge and discharge test cycle of the battery, the value of the equipment is the highest. The important purpose of the formation process is to charge and activate the battery cells after liquid injection packaging, and the capacity separation process is to test the battery capacity and other electrical performance parameters after the battery is activated and classify it. Formation and volume separation are performed by the formation machine and the volume separation machine, usually by an automated volume separation and formation system.