Comparison of lithium-ion battery performance at beginning-of-life and end-of-life. (September 2018) - Stroe, A.-I.
Abstract: In this paper, a comparison between the performance of a Lithium-ion battery at beginning-of-life (BOL) and at two increased degradation levels is presented. The capacity, internal resistance, and open circuit voltage of a 13 Ah high-power Lithium-ion battery had been measured at BOL for different temperatures, C-rates, and state-of-charge (SOC) levels. Then, two battery cells were aged at two different cycle aging conditions until they lost 40% and 60% of their initial capacity, respectively. At that moment, the two battery cells were removed from the aging processes and were subjected to characterization measurements similar to the ones performed at BOL. The obtained results shown that besides the expected capacity fade and internal resistance increase, there is a dramatic change in the variation of the battery performance parameters with the temperature, C-rate, and/or SOC, between a fresh cell and the two heavily degraded cells. Highlights: Accelerated cycle aging tests of high-power LTO/NMC-based Lithium-ion battery cells; The capacity of the studied LTO/NMC Lithium-ion batteries follows a three-stage degradation behavior. The dependence of the battery capacity and resistance on the C-rate, temperature, and SOC changes dramatically during aging.