During the industrial button battery processing process, uneven thickness of the electrode sheet during rolling is a key issue affecting consistent battery performance. As a core component of the battery, the uniformity of the electrode sheet's thickness directly affects the distribution of active materials, ion transport efficiency, and the overall charge and discharge performance of the battery. Excessive thickness variation during rolling can lead to battery capacity degradation, shortened cycle life, and even increased safety risks. Therefore, optimizing rolling process parameters, improving equipment precision, and establishing an effective quality monitoring system are key approaches to addressing this issue.
In the rolling process, the stability of rolling pressure is the primary factor affecting the target thickness. In industrial button battery processing, the roller press uses upper and lower rollers to compress the electrode sheet to achieve the target thickness. If the pressure distribution is uneven, such as greater pressure at the ends of the rollers than in the middle, or if the pressure fluctuates over time, the electrode sheet's thickness will fluctuate due to the force differential. In this case, the roller press's hydraulic system or mechanical transmission components should be inspected to ensure accurate pressure sensor feedback and synchronized hydraulic valve operation. A pre-loading device should be used to balance the initial pressure and minimize thickness variations before the electrode sheet enters the main rollers. Furthermore, the parallelism and hardness of the rollers should be regularly calibrated to prevent localized pressure abnormalities caused by roller deformation. The roller surface condition has a direct impact on the uniformity of electrode thickness. In industrial button battery processing, rollers can develop unevenness due to wear and tear over time, or surface roughness changes due to residual electrode material. These defects are transmitted to the electrode through contact pressure, resulting in periodic thickness fluctuations. Addressing this issue requires establishing a roller surface maintenance system, such as using high-precision grinders to regularly repair the roller surface or applying a wear-resistant coating to extend its service life. Furthermore, cleaning tools should be used to thoroughly remove impurities from the roller surface before production to prevent hard particles from embedding in the electrode and causing indentations.
Variations in the quality of incoming electrode material are an indirect cause of uneven thickness during rolling. In the industrial button battery processing process, the slurry uniformity and drying level during the coating process, as well as substrate tension control, all affect the initial condition of the electrode before entering the roller press. If streaks or particle accumulation occur in the coating layer, thickness variations in certain areas during rolling can occur due to varying compression ratios. Therefore, it's necessary to add an online inspection step after the coating process. Using a laser thickness gauge or vision system to screen out unqualified electrodes, feedback is then provided to adjust parameters such as the coating machine's slurry supply speed and scraper gap to ensure consistent initial electrode thickness.
The matching of roller speed and temperature is also critical. In industrial button battery processing, excessively fast roller speeds can result in insufficient contact time between the electrode and the roller, leading to insufficient compression in some areas. Excessively slow roller speeds can increase the electrode temperature, causing changes in material fluidity and resulting in thickness rebound. Furthermore, the roller temperature must be controlled within an appropriate range. Excessively high temperatures can soften the binder in the electrode, leading to thickness rebound after rolling. Excessively low temperatures can increase material brittleness and cause cracks. In actual operation, the optimal speed-temperature combination must be determined through experimentation, and both ambient temperature and electrode surface temperature must be monitored in real time during production.
Equipment vibration and transmission accuracy are often overlooked process variables. During the roller pressing process of industrial button battery processing, looseness or wear in the roller press's motor, bearings, or couplings can cause periodic vibration, leading to regular fluctuations in electrode thickness. Addressing this issue requires regular inspection of the equipment's transmission components, replacement of aging parts, and the addition of shock absorbers to the roller press base. Furthermore, high-precision encoders are used to monitor roller speed to ensure synchronized operation of both rollers, preventing uneven stretching or compression of the electrode sheets due to speed differences.
Establishing a closed-loop quality control system is fundamental to ensuring uniform electrode sheet thickness. In industrial button battery processing, an online thickness gauge is installed after the roller pressing process to provide real-time feedback to the control system regarding electrode sheet thickness. If thickness deviations exceed the allowable range, the system automatically adjusts the roller pressing pressure, speed, or temperature parameters, creating a dynamic correction mechanism. Furthermore, regular offline sampling of electrode sheets is conducted, combined with X-ray diffraction or scanning electron microscopy to observe changes in material structure. This verifies the effectiveness of process adjustments at a microscopic level and provides data support for continuous optimization.
