Overcharged Li-Polymer Batteries: A Post-Mortem Analysis

Since safety hazards can occur during the life of a Li-ion battery, understanding its behaviour under abusive conditions is important for the development of a safe cell. In this work, overcharge tests on commercial Li-polymer cells were conducted, resulting in gas evolution. A comprehensive postmortem analysis of the abused cells was planned to be carried out by means of several analytical techniques: gas phase chromatography for the identification of the exhaust gases, scanning electron microscopy and energy X-ray spectrometry for the investigation of the cathode and anode materials, Fourier-transform infrared spectroscopy for the study of the electrolyte composition, etc.). First interesting results, regarding the characterization of a high temperature overcharged cell and the detection of flammable and toxic species produced by the cell, are presented in this paper.