Date: 2024-05-25 hits: 363
In the manufacturing process of lithium-ion battery, roll technology, as a key process, has an irreplaceable role in improving the performance of the battery. The main objective of roller pressing is to increase the compaction density of the battery electrode sheet, enhance the bonding strength of the active substance and the foil, and thus ensure the stability of the battery during electrolyte immersion and use. In addition, the roller technology can also effectively compress the cell volume, improve the energy density of the cell, and reduce the internal resistance of the battery to extend the cycle life of the lithium battery.
A. Key points of roll control
1. Thickness control: uniformity of electrode thickness is crucial to battery performance.
During the rolling process, it is necessary to ensure the consistency of the thickness of the pole sheet to avoid uneven thickness caused by overpressure or underpressure. Uneven thickness may lead to increased internal resistance of the battery, affecting the energy density and discharge performance of the battery.
Therefore, it is necessary to accurately control the thickness of the pole plate by precisely controlling the pressure and speed of the rolling equipment.
2. Compaction density: Compaction density is another key factor affecting battery performance.
Appropriate compaction density helps to improve battery capacity and energy density, but too large compaction density may lead to an increase in the diffusion resistance of lithium ions in the electrode, which in turn affects the rate performance of the battery.
Therefore, during the rolling process, the compaction density should be reasonably adjusted according to the specific application scenarios and performance requirements of the battery.
3. Tension control: Appropriate tension should be maintained during the rolling process to prevent breakage or deformation of the pole sheet.
Excessive tension may lead to excessive stretch of the pole sheet, or even tear; Too little tension may result in corrugation or wavy edges during rolling.
Therefore, it is necessary to adjust the tension control system of the rolling equipment to ensure that the pole plate maintains a stable tension during the rolling process.
4, roller speed: roller speed is an important factor affecting the quality and production efficiency of the pole sheet.
Too fast rolling speed may lead to insufficient compaction of the pole plate and affect the performance of the battery. Too slow rolling speed may reduce production efficiency and increase manufacturing costs.
Therefore, it is necessary to choose the appropriate roller speed according to the material characteristics of the pole sheet and the equipment capacity.
5, environmental humidity: the humidity of the rolling environment has a significant impact on the moisture content of the pole sheet, which in turn affects the thickness of the pole sheet rebound and battery performance.
In the rolling process, it is necessary to strictly control the ambient humidity to avoid excessive thickness rebound due to moisture absorption.
6, rolling temperature: temperature is one of the important factors affecting the rolling effect.
The appropriate roll temperature helps to reduce the rebound of the pole sheet and improve the adhesion between the active substance and the foil, thus enhancing the stability of the battery. However, too high a temperature may lead to thermal deformation or thermal decomposition of the electrode material, affecting the battery performance.
Therefore, it is necessary to select the appropriate roller temperature according to the thermal properties of the electrode sheet material.
B. Notice
1. Maintenance of rolling equipment: The accuracy and stability of rolling equipment have a direct impact on the quality of the pole sheet.
Therefore, it is necessary to regularly maintain and maintain the rolling equipment to ensure the normal operation and accuracy of the equipment.
At the same time, it is also necessary to keep the roller surface clean and smooth to avoid damage to the pole sheet caused by impurities and scratches.
2. Post-roll test: After rolling is completed, a series of quality tests should be carried out on the pole sheet, including thickness, peel strength, arc height and elongation.
These tests help to evaluate the roller effect and ensure that the pole sheet meets quality requirements. For the pole plate that does not meet the requirements, it needs to be reworked or scrapped.
3. Process optimization and innovation: With the continuous development of lithium battery technology, the rolling process is also constantly optimized and innovative.
New techniques such as differential drawing and hot roll pressing are used to improve the quality of the electrode and the performance of the battery.
At the same time, through the introduction of automation and intelligent control system, the precise control and monitoring of the rolling process can be achieved, and the production efficiency and product quality can be improved.
4, safe operation and protection: the rolling process involves high-speed rotation of the roller wheel and high temperature environment, there are certain safety risks.
Therefore, you need to strengthen safety operation training to ensure that operators are familiar with the operating rules and safety precautions of the equipment.
At the same time, it is also necessary to equip with necessary safety protection devices and emergency measures to deal with possible accidents.
C. Summary
The key points and precautions of lithium battery roll control cover many aspects from equipment maintenance, process parameter adjustment to safe operation. By precisely controlling the parameters and precautions in the rolling process, the quality of the battery electrode and the overall performance of the battery can be improved.
In addition, with the continuous progress of lithium battery technology and changes in market demand, the rolling process also needs to continue to innovate and optimize to adapt to new challenges.
