Abstract:
Millions of electric vehicle (EV) batteries are projected to retire over the next decade, often retaining substantial capacity left. Repurposing these batteries offers a promising solution to address challenges in the battery industry, including raw material scarcity, supply chain constraints, and the need for a circular economy. However, current EV batteries mainly retire after their performance becomes unsatisfactory, leading to heterogeneous health conditions that diversify lifetime during second use. There is a clear need for guidance on reuse strategies to maximize their whole-lifecycle value, including reuse in lower-demand applications. Here, we assess over 101,000 active retirement-reuse-retirement scenarios for EV batteries across popular stationary energy storage applications. The whole-lifecycle value of EV batteries is quantified using real-world data from EV batteries and their digital twins. For EV batteries retired at different mileages, we simulated their remaining useful life under realistic second-use applications. The tradeoff between first-life benefits and second-lifetime benefits is analyzed, and recommendations for selecting second-use applications based on first-life usage conditions are investigated. Our results demonstrate the feasibility of repurposing retired EV batteries and underscore the importance of whole-lifecycle management to enhance circular economy.

Biography:
Ziyou Song is an Assistant Professor in the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. He earned his bachelor’s degree with honors and Ph.D. degree with the highest honors in Automotive Engineering from Tsinghua University, China, in 2011 and 2016, respectively. Prior to joining the University of Michigan, Dr. Song served as an Assistant Professor at the National University of Singapore and worked as a battery algorithm engineer at Apple. Dr. Song’s research focuses on modeling, estimation, optimization, and control of energy storage systems, especially for the electrified transportation and renewable energy sectors. Dr. Song has received several paper awards, including Automotive Innovation Best Paper Award, Applied Energy Highly Cited Paper Award, NSK Outstanding Paper Award of Mechanical Engineering, and IEEE VPPC Best Student Paper Award. Dr. Song serves as an Associate Editor and Editorial Member for IEEE Transactions on Transportation Electrification, IEEE Transactions on Power Electronics, Applied Energy, and eTransportation, and received the Outstanding Associate Editor award from IEEE Transactions on Transportation Electrification.