Correlation of Health Indicators on Lithium‐Ion Batteries

Abstract

Herein, a detailed correlation index of health indicators for lithium‐ion batteries is presented. Identifying potential correlations of health indicators is of high importance with regard to the cell selection process and to minimize the occurring cell‐to‐cell spread within the lifetime. Health indicators that are taken into account are among others impedance measurements of different pulse lengths, capacity values at different discharge procedures and checkups, weight, and initial voltage. Herein, the work is based on four different aging datasets covering variations in cell chemistry (NMC, LFP, NCA), cell type (round, prismatic), as well as the size and designated application (consumer, automotive). A publicly available dataset is included to allow for an easy reproduction of the results.

Evaluating Frequency Domain Reflectometry as a Tool for Lithium-Ion Battery Health Prognosis

“…In automative applications, cells whose capacity has fallen below 70% at a given state of charge are considered aged [26]. However, no generalised ESR threshold has been established in the literature that universally indicates a battery problem, although different values and descriptions, such as a 20-30% increment; slight changes; and double initial values have been suggested [27][28][29][30]. ESR increases with age and varies based on battery type and operating conditions.…”