Abstract: Orthogonal experiments were utilized to explore the characteristics and distribution of degradation of lithium ion batteries cycled at low temperature. The main aging factors and internal lithium plating distribution were investigated with the statistical method and post-mortem physical-chemical analysis, respectively. The results showed that the order of the 3 important aging factors are the ambient temperature > charge current > charge cut-off voltage. The amount of lithium plated in center electrodes is greater than that in the outer electrodes. The amount of lithium plated in central area and the area near the negative tab is greater than that on other areas in the same electrode layer. The main reason for such lithium plating distribution is attributed to the non-uniformity in the current density in the battery, as the voltage at areas with larger current density reaches the lithium plating potential easier. Therefore, to alleviate degradation from lithium plating, an effective measure is to design battery with more uniform current density distribution.

Key words: lithium-ion batteries, cycling at low temperature, lithium plating, main factor analysis, degradation distribution