Measuring Li-ion battery film thickness after coating and calendering

Measuring film thickness after coating and calendering

With increasing production of high-performance lithium-ion batteries for a growing number of purposes such as electric cars and numerous devices across the globe, precise quality and process control of the battery production process is key to deliver high-performance, reliable and safe products. Hammer-IMS enables battery manufacturers to monitor film thickness, leading edge, and heavy edge, after the coating and calendering process with Marveloc-CURTAIN systems, as well as detecting and classifying pinholes and other anomalies with Edge-Vision-4.0.

An essential step in the manufacturing process of lithium-ion batteries is applying electrode coatings on copper (anode) or aluminum (cathode) films. The film is continuously or intermittently coated with the isolation substance using an application tool, such as a slot die, a doctor blade or an anilox roller. After coating, the wet foil is transferred to the dryer stages.

Hammer-IMS offers quality control systems that gauge wet coated films to identify sections where the coating layer is too thin or missing. Such deficiencies potentially lead to degraded battery performance and short circuits. The thickness measurement system with one or multiple sensors scans the entire width of the wet coated films. Dynamic graphic displays with underlying reporting data allow operators and production supervisors to monitor wet coated film thickness. Optionally, it is possible to use the reporting data to automatically control the electrode coating step in closed loop.

The Hammer-IMS systems are equally suitable to measure the thickness of the coated film after the upstream calendering stage. The coated film is then compressed by a rotating pair of rollers. This step is essential in obtaining the required line pressure, to ensure the subsequent wetting properties of the electrodes and the energy density of the cells. Accurate thickness measurement of the coated film after calendering is an important quality indication in battery production lines.

The leading edge in battery coating refers to the portion of the electrode where the coating material first makes contact with the substrate. Monitoring the leading edge is crucial because it impacts the initial adhesion of the coating material to the substrate. If there are issues with the leading edge, it can lead to uneven coating thickness, poor adhesion, or defects in the electrode structure.

The heavy edge refers to the opposite end of the coating, where more coating material accumulates, resulting in a thicker section compared to the rest of the coated electrode. Keeping track of the heavy edge is important because an excessively thick region can affect the overall performance of the battery. It can lead to non-uniform electrode thickness, which in turn can cause variations in battery capacity and efficiency. Uniform coatings minimize the risk of defects and performance variations in the final battery products, enhancing their reliability and lifespan. Get in touch with Hammer-IMS to discuss your case.