Lifecycle Extensions for Large-Scale Retired Lithium-Ion Batteries

Abstract

Lifecycle extensions of retired lithium-ion batteries are essential for reducing clean energy system costs, conserving resources, and promoting sustainability. In the early stages of extensions, estimating the degradation of these batteries is crucial for assessing their reutilization potential. Yet, long-term degradation data and insights for retired batteries remain unavailable. The absence of historical data and long-term degradation knowledge limits the research and application of lifecycle extensions for retired batteries. This study conducts degradation experiments of retired lithium-ion batteries across three retirement scenarios. The degradation characteristics of these batteries are observed while constructing datasets comprising 352 samples. For reutilization assessment, this study introduces a sawtooth charging strategy during the initial charging phase, enriching the battery state information carried by voltage data. Internal hidden states of batteries are then captured to estimate current and future degradation. Through validation, the method accomplishes degradation assessment using 30 seconds of voltage data. The datasets and methods of this study hold promise for scientific research and practical application in assessing reutilization potential, thereby contributing to the standardization and scaling of lifecycle extension industries for retired batteries.

Keywords: Retired Batteries, Lifecycle Extensions, Internal Hidden States