A Framework for Assessing the Second-Life Potential of Lithium-Ion Batteries Using Tomographic and Electrochemical Parameters

Driven by increasing environmental awareness and the demand for emission-free energy sources, electromobility has become a central focus of sustainable transport development. The widespread adoption of light electric vehicles (LEVs) is expected to contribute significantly to achieving global climate goals. Lithium-ion batteries (LIBs) serve as their primary energy source but typically reach the end of their first life cycle after a capacity loss of 20-30%. A second-life application in stationary energy storage systems with lower functional demands is only feasible if the degradation state of each battery is accurately assessed and quantified. Such evaluation enables reliable conclusions about remaining performance capability and safety-related aspects. Electrochemical impedance spectroscopy (EIS) provides quantifiable indicators of degradation. However, future aging behavior is difficult to predict due to limited usage data. A complementary, non-destructive approach is the visual inspection of internal structures using computed tomography (CT). Tomographic analyses reveal and quantify additional degradation symptoms that can enhance predictive aging models. This paper introduces a novel methodological framework that correlates electrochemically measurable indicators with visually observable anomalies to forecast the reliability of LIBs in second-life applications. The framework, developed within an ongoing research project, outlines all implementation phases and associated methods. Initially, reference measurements of newly produced LIBs using EIS and CT are conducted to enable automated detection of visual error appearances through artificial intelligence (AI)-based anomaly detection. Subsequently, defined aging cycles are performed under continuous monitoring of electrochemical and structural parameters. By combining the acquired data, the relationship between degradation mechanisms and visual manifestations is established. Finally, the proposed methods are evaluated with respect to their diagnostic efficiency and economic viability, providing a foundation for reliable and sustainable second-life utilization of lithium-ion batteries.

Keywords: Battery cells, computer tomography, functional- and safety related failures, degradation, Second-Life.