Anode Redundancy Failure Diagnosis of Commercial Lithium–Ion Batteries Based on Synergistic 2D/3D X-ray and High-Resolution Computed Tomography

Failure mechanisms in lithium-ion batteries (LIBs) often originate from subtle structural defects that are challenging to detect with conventional methods. This study employs an integrated 2D/3D X-ray computed tomography (CT) approach to investigate the failure of commercial pouch LIBs caused by electrode redundancy fluctuations and insufficient redundancy. Through nondestructive multiscale imaging, critical manufacturing defects such as electrode misalignment, localized poor redundancy (cathode electrode sheet is higher than anode electrode sheet), and internal deformation are identified. These defects induce the lithium precipitation, promote the formation of deleterious byproducts, and ultimately cause the batteries to develop hard bulges and experience performance degradation. Post-mortem analysis validates the nondestructive findings, correlating structural anomalies with electrochemical degradation. This work underscores the necessity of precision electrode assembly and presents a robust nondestructive framework for root-cause diagnosis in battery failures, which is applicable to diverse cell architectures and emerging battery chemistries.