Determination of Electrode Balancing in Multilayer Pouch Cells Through Tracking and Tracing in Lithium-Ion Battery Production

Manufacturing lithium-ion batteries is a complex procedure with interconnected process steps. Unknown interdependencies lead to production deviations, which, in combination with expensive materials, result in costly rejects. To gain better insight into the processes, tracking and tracing systems are increasingly being established in battery cell production. This improves the database and enhances transparency, as quality-critical production data is already recorded during electrode production and specifically assigned to individual intermediate products. The data assignment aids in characterizing intermediate products properties to identify correlations and defects. An important parameter is the balancing from cathode to anode, which has a crucial influence on cell performance. Therefore, this paper demonstrates the determination of the balancing between all electrode layers in a lithium-ion pouch cell using a traceability system. The traceable areal mass loading was determined for each electrode sheet. After the stacking process, the opposing electrode areal mass loadings of the cathodes and anodes were used to calculate the electrode balancing. Subsequently, their influence on the cycling performance of the cells was investigated. Battery cells with areal mass loadings within the permissible tolerances showed no abnormalities, whereas cells with production fluctuations exhibited rapid ageing.