Combined dilatometry and voltage analysis for a reliable detection of lithium deposition on graphitic anodes

Lithium deposition (LD) is a parasitic, detrimental side reaction during the charging of lithium-ion batteries with graphite anodes. The kinetic limitations of the intercalation of lithium ions into the host lattice lead to over-potentials, making the metallic deposition thermodynamically favourable. These limitations are especially crucial at low temperatures, high states of charge, and high currents. Hence, lithium deposition becomes the major mechanism for accelerated ageing during fast charging. In our work, the effects of LD on the cell's voltage and thickness are analysed in detail. We show that the dilation behaviour of pouch cells during the charge subsequent relaxation phase can be used to detect LD. A yet undescribed feature in the differential dilation even provides information about the severity of the LD. These findings are verified with the established method of differential voltage analysis during relaxation. Additionally, we propose a Bayes algorithm for the combined use of voltage and dilation data to detect LD even for dilation measurements with strong noise and limited resolution.

Automated summary

The study uncovers the impact of lithium deposition on cell voltage and thickness, demonstrating that dilation behavior and voltage analysis can be used to detect LD, proposing a Bayes algorithm for combined data detection.