Development and implementation of in-line segmentation for continuous electrode production in lithium-ion battery cell manufacturing for traceability applications

Abstract

One of the biggest challenges in battery cell production is reducing manufacturing costs. Production errors and manufacturing inaccuracies due to a complex process chain and cost-intensive material flows lead to high scrap rates and costs. In order to detect and eliminate production errors early in the manufacturing process, traceability approaches have been increasingly referred to in the literature. Here, process and product parameters are already assigned to the individual intermediate products and used to evaluate whether further processing is possible. When transferring traceability concepts to battery cell production, the challenge is to identify individual sections in the continuous processes of electrode production. These process steps have a decisive influence on the later electrochemical performance of the battery cells and have so far only been performed in batches to reduce possible defects. This paper presents two approaches to segmenting the produced electrodes in-line in the coating process to provide discrete sections for tracking and tracing applications. Production data are allocated to single electrodes instead of the entire electrode coil. Laser and ink marking systems are used to apply unique markings that are subsequently read out for product and process data assignment. Appropriate integration requirements must be met for both marking systems to apply readable markings. The requirements are derived for both marking systems from the respective mode of operation and compared with each other. It is shown that laser systems are more technically challenging and cost-intensive to integrate than ink systems but offer greater geometrical flexibility. Furthermore, it is shown how both marking technologies are integrated into the respective coating lines for lithium-ion battery electrodes within the pilot production lines at two research facilities. The traceability of product data to individual electrode sections is demonstrated using in-line and hand-measured electrode areal mass loading data.