Investigation of lithium-ion polymer battery cell failure using X-ray computed tomography

The paper presents the first application of laboratory X-ray μCT for post-mortem analysis of a failed lithium-ion polymer battery pouch cell. Analysis of the μCT data allowed quantification of the physical distortion within the individual cell layers of both an untested and failed cell. In the failed cell, the maximum separation of the electrode assemblies was measured in each direction (XY = 833 μm, YZ = 787 μm), representing a significant increase from the untested cell, where the spacing was below 43 μm. Deformation was more prominent in the central region of the cell since both ends of the battery electrodes remained tightly clamped even after failure. Based on the visually observed volume expansion and the deformation of the cell architecture observed by μCT we conclude that the deformation was caused by pressure build up as a result of gas generation, which could have arisen from a short circuit in the cell. © 2011 Elsevier B.V. All Rights Reserved.