Voltage drop screening for defective cells during the battery formation process

초록

Foreign metallic particles frequently contaminate lithium-ion battery (LIB) manufacturing processes, posing a serious risk of internal short circuits that compromise battery safety and performance. Voltage drop screening, conducted during the formation process by monitoring subtle changes in open circuit voltage (OCV), is used to identify such defective cells. However, this method is operationally demanding, and frequent OCV drops caused by internal defects can significantly reduce production efficiency and yield. To mitigate these issues, proactive contamination control through stringent technical cleanliness is critical for minimizing early-stage particle intrusion and reducing dependence on extensive screening. In this study, we analyze key aspects of the formation process and evaluate the effectiveness of voltage drop screening, with particular focus on the electrochemical behavior and risk profiles of various metallic contaminants. Our findings demonstrate how metallic particle contamination affects defect rates across different manufacturing stages. By integrating robust contamination control with optimized screening protocols, we propose practical strategies for enhancing LIB production efficiency, yield, and safety.

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