Volume Change from Materials to Cell Level and Its Influence on Battery Lifetime

摘要

1 Volume change by intercalation on crystal level has an significant impact on: 1.1 Forces in electrode and between electrode and current collector 1.2 Thickness change of electrodes and cells, even inhomogeneous 2 Volume is also increased by temperature and by Li-plating 3 Inhomogeneous compression, as seen in cylindrical cells, result in inhomogeneous Li-plating inside the cell. 4 Li-plating starts first in areas with higher compression 5 Volume change can be represented by simplified Electrode models 6 Inhomogeneous current distribution results in inhomogeneous SoC, followed by inhomogeneous volume change and mechanical stress. 7 During charging, inhomogeneous charge currents result in inhomogeneous li-plating, including overshooting in thickness. 8 First 3D coupled mechanical-chemical-thermal model shows good results 9 Further model improvement necessary, taking Li-plating into account.