Lithium-ion batteries often suffer from coating tailing during the production process, which adversely affects the performance and life of the battery. The impact of coating tailing on lithium-ion batteries is now analyzed and corresponding solutions are proposed.
1. The influence of coating tailing phenomenon
Coating tailing refers to the defect caused by the tail of the coating material being dragged on the coating machine during the coating process, which appears at the end of the coated sample. There are many reasons for coating tailing. For some reasons, the coating material forms an uneven thickness distribution on the electrode. This uneven distribution will cause uneven current distribution inside the battery, thus affecting the performance and life of the battery.
1. Battery performance decreases:
Coating tailing will cause uneven current distribution inside the battery. Some electrodes are under an excessively thick coating layer, and the current inside the battery cannot be fully transmitted, resulting in reduced battery performance. Battery capacity, discharge performance and cycle life will all be affected.
2. Shortened battery life:
Coating tailing will lead to uneven temperature distribution inside the battery, and some electrodes are prone to local overheating due to excessive coating. This overheating will accelerate the aging rate of the battery, resulting in shortened battery life.
2. Analysis of the causes of coating tailing
There are many reasons for coating tailing, including coating process parameters, electrode material properties, equipment conditions and other factors.
1. Coating pressure does not match
Process parameters such as coating speed, coating pressure and coating head design have an important impact on the coating tailing phenomenon. Too high a coating pressure will result in a coating layer that is too thick, and a coating pressure that is too low will result in a coating layer that is too thin.
2. Coating speed does not match
When the coating speed does not match the conveying speed of the coating machine, it will cause the coating material to stretch and squeeze, resulting in coating tailing. This is usually caused by an erratic material supply or improper machine tuning.
3. Electrode material properties:
The surface tension of the electrode material and the adhesion of the coating substance will also affect the coating tailing phenomenon. Excessive surface tension will cause the coating material to be unable to be evenly distributed on the electrode surface, and too low adhesion will cause the coating material to fall off easily.
4. Equipment condition:
The state of the coating equipment will also have an impact on coating tailing. Wear of the coating head of the equipment, wear of the coating roller and contamination of the coating medium will all lead to coating tailing.
3. Solutions
In order to solve the coating tailing phenomenon, the following measures can be taken:
1. Optimize coating process parameters
By rationally adjusting the coating speed, coating pressure and coating head design, the thickness distribution of the coating layer is more uniform. The optimal coating process parameters can be determined through experiments and simulation analysis.
2. Improve electrode material properties
Changing the surface properties of electrode materials, such as adjusting surface tension and increasing adhesion, can improve the uniform distribution of coating substances on the electrode surface. The properties of electrode materials can be improved through surface treatments or the addition of special coatings.
3. Maintain equipment regularly
Regularly inspect and maintain coating equipment, including cleaning and replacement of coating heads, coating rollers and coating media. Ensure that the equipment is in good working condition and reduce the occurrence of coating tailing.
4. Introduce online monitoring system
An online monitoring system is introduced to monitor the coating thickness distribution in real time during the coating process. By monitoring data, coating process parameters can be adjusted in a timely manner to achieve better coating effects.
4. Conclusion
Coating tailing adversely affects the performance and life of lithium-ion batteries. By optimizing coating process parameters, improving electrode material properties, regularly maintaining equipment, and introducing online monitoring systems and other solutions, the occurrence of coating tailing can be effectively reduced and the performance and life of lithium-ion batteries can be improved.
