Computed Tomography Analysis of Li-Ion Battery Case Ruptures

Battery explosion incidents hinder the development and application of Li-ion batteries. This paper describes the use of nondestructive computed tomography (CT) to analyze cylindrical Li-ion battery samples that underwent thermal runaway and exploded. Unlike destructive analysis methods, which can lead to a loss of battery structural information, CT scan allows direct observation of a battery's internal structure without disassembly. In this study, two case studies of 20700 and 18650 batteries show that sidewall and bottom case rupture was caused by blockage of the battery vent region, which prevented the release of the generated gas. This work demonstrates the ability of CT for post-mortem incident analysis and the limitations of current vent design, and also gives insight to a safety issue with some cylindrical batteries.