Characterization of Second-Life Lithium-Ion Batteries from a Solar-Powered Electric Bus for Stationary Applications
Abstract
This work presents the electrical and thermal characterization of second life lithium-ion battery modules from the solar electric bus (eBus) of the Federal University of Santa Catarina (UFSC), with the aim of assessing their feasibility for applications in transportable storage systems within the CELESC and UFSC project. In total, 149 modules were analyzed under controlled charge and discharge tests to determine state of health (SoH), direct current internal resistance (DCIR), and the electrical characteristic curves of these battery modules. The results indicated a strong negative correlation between SoH and DCIR R² = 0.80, validating DCIR as an effective parameter for estimating the level of degradation and the remaining capacity of the batteries. Modules that remained in continuous operation in the e-Bus exhibited greater degradation SoH between 58% and 64%, whereas the reserve modules maintained better conditions SoH between 66% and 69%. The results confirm the technical potential for repurposing these batteries in stationary energy storage systems, provided they undergo appropriate requalification and balancing processes. The study contributes to advancing the circular economy applied to electric mobility and to the development of standardized methodologies for evaluating second life batteries.
Keywords
Second-life lithium-ion batteries, Battery repurposing, State of Health (SoH), Direct current internal resistance (DCIR), Electric Bus, Transportable battery energy storage systems