Analysis of the Remaining Useful Life of Electric Vehicle Batteries and Development of Second-Life Solutions

When batteries used in electric vehicles reach the end of their useful life in this application, they still have a high potential for reuse in other less demanding applications regarding power and cycling, such as stationary energy storage systems with renewable energy. This concept is called second-life. In this context, the pioneering Research and Development (R&D) project "CPFL Second-Life" of the Electricity Utility Company CPFL Energia is under development in Brazil, in cooperation with CPQD (Telecommunications Research and Development Center) andBYDBrazil. The objective is the development of energy storage solutions using second-life batteries. This article presents methodologies andmain results obtained through the realization of this project, aiming to evaluate the actual performance of EV batteries in second-life. To this end, cell reconditioning and remanufacturing techniques are being developed and improved, from disassembly to reconfiguration in new systems, considering mechanical, thermal, electronic, and systemic developments necessary for this. Simultaneously, several laboratory tests are being carried out to characterize the remaining useful life of these batteries in second-use applications; both to understand their behavior and to support the development of algorithms, which will be used in newsystems to monitor their main operating parameters and which will also identify the remaining lifetime given the future operating conditions of the batteries. The development of an energy storage solution from degraded cells during application in EVs used in the country will strengthen the technological advancement of the national EV and battery industry. Additionally, this project is fully aligned with the concept of circular economy, providing the reuse of elements thatwould initially be discarded or sent for recycling.