Non-Destructive Detection of Local Aging in Lithium-Ion Pouch Cells by Multi-Directional Laser Scanning

Previous studies of lithium-ion pouch cells [B. Rieger et al., Journal of Energy Storage, 8, 1 (2016)] have shown non-uniform swelling with local displacement overshoots during charging. In this experimental work, a novel three-dimensional laser scanning method is used to investigate local reversible and irreversible thickness changes of six commercial LiCoO2/graphite cells during a cyclic aging experiment.

Three cycle scenarios were included and two cells each were exposed to a specific temperature and charging rate. The cells showing local displacement overshoots also exhibit non-uniform distributions of irreversible thickness change. Post-mortem analysis showed largely inhomogenously degraded surfaces of the single anode layers.