I believe that buyers who have purchased lithium batteries have had a curious idea and want to know how the process of lithium battery manufacturers is different. At this accidental time, I would like to share with you a new sharing of battery manufacturing from the CATL.
<Battery Manufacturing Basics from CATL’s Cell Production Line (Part 1)>
This summary of the battery production process of CATL, collected from open sources in Chinese media, shares 3 main production stages and 14 key processes for the world’s largest battery manufacturer.
Although different lithium battery manufacturers have certain differences in the production process of lithium batteries, because of the same principle, the main production processes of lithium batteries are basically the same, generally including: batching, coating, rolling, cutting, slitting, Welding tabs, winding, packaging, baking, liquid injection, formation, molding, volumetric testing and other processes.
Lithium battery production process
In the necessary steps of the above-mentioned lithium battery production process, five aspects should be paid attention to from material selection to volume distribution testing after molding:
1. Improve the physical and chemical structure of positive and negative active materials, which is the basic link of the lithium battery production process:
- Appropriate ion doping of the material,
- Improve the particle size distribution of the active material and avoid the particle size distribution of the active material being too wide,
- Try to use materials with disordered layered structure or thin layer structure,
- Improve the surface structure of electrode materials;
2. The high bonding strength of the electrode coating is conducive to reducing the rate of decrease in cycle capacity. This is the most technical process in the production process of lithium batteries. For this reason, we should pay attention to:
- The binder and solvent forming the adhesive material should be pure, and the coated pole piece should not be stored for too long.
- The ratio of adhesive and active material used in the mixture of positive and negative coating films should be appropriate to ensure that no powder or powder is removed after coating;
3. Optimization of the composition of the electrolyte, the requirement of the lithium battery production process for the electrolyte is to maintain the capacity and prolong the battery life:
- Through the optimization of lithium salts, solvents and additives, the conductivity of the electrolyte is improved, and the polarization is reduced.
- Inhibit the reaction between the positive electrode material and the electrolyte,
- Improve the surface structure of the negative electrode material by controlling the appropriate specific surface area and surface treatments such as coating, film formation and surface chemical reaction of the carbon negative electrode material;
4. After the battery material preparation is completed, the lithium battery production process enters the assembly process. At this time, we should pay attention to:
- The negative electrode capacity is slightly larger than the positive electrode capacity.
- After winding the positive and negative electrodes and the diaphragm, the gap size between the formed positive and negative electrode sheets and the diaphragm should not exceed 0.5mm, and the upper and lower deviation should not exceed 0.5mm.
5. When dividing the capacity, it is advisable to charge at a low rate in accordance with national standards, generally 0.2C.
In general, the following proportional relationships should be paid attention to in the process manufacturing stage: the compaction density of the pole piece and the pole piece, the excess rate of the negative electrode, the formulation process, and the appropriate amount of the electrolyte and the positive and negative electrodes.
The time for each step in the production process of lithium batteries is different. In general, the ingredients, baking, and formation take a long time, ranging from about 10 hours to two days and two nights; other processes are faster, with an average of 5 or 6 Hour. The entire lithium battery production process takes about 15 days.
