Circular economy metrics for batteries: Enhancing sustainability in energy storage systems

The transition to a circular economy (CE) is critical for mitigating the environmental impacts of industrial processes and products. Electric vehicles (EVs), a key segment of the mobility sector, play a pivotal role in this transition. Effectively managing EV batteries through their entire life cycle is essential, given their potential for reuse before disposal. This study investigates various circularity indicators and frameworks introduced in recent research, proposing a novel framework aimed at managing the sustainable lifespan of EV batteries on a mesoscale (industrial) level. The developed framework comprehensively addresses material flow, end-of-life management, and energy flow throughout the service life of EV batteries. The framework was developed and validated through interviews with stakeholders and academic experts, employing Structural Self-Interaction Matrix (SSIM) and Matrice d'Impacts Croisés Multiplication Appliquée à un Classement (MICMAC) analyses. Fifteen circularity indicators were identified and applied to a case study of an EV product using the gathered data and assumptions based on scientific and grey literature. Quantified CE scores show progress in collaboration and renewable energy use but highlight challenges like material outflows, insufficient inflows, and poor end-of-life management. The framework offers a robust approach to improving circular economy practices and fostering a more sustainable automotive industry.