Failure and hazard characterisation of high-power lithium-ion cells via coupling accelerating rate calorimetry with in-line mass spectrometry, statistical and post-mortem analyses. (15th August 2023)

• Record Type: Journal Article
• Authors: Buckwell, Mark; Kirchner-Burles, Charlie; Owen, Rhodri E.; Neville, Tobias P.; Weaving, Julia S.; Brett, Daniel J.L.; Shearing, Paul R.
• Is Part Of: Journal of energy storage. Volume 65(2023)
• Publication Date: 2023-08-15
• Subjects: Lithium ion batteries -- Mass spectrometry -- Accelerating rate calorimetry -- Thermal runaway -- Onset -- Mitigation; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2023.107069
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Lithium-ion battery safety continues to be an obstacle for electric vehicles and electrified aerospace. Cell failure must be studied in order to engineer improved cells, battery packs and management systems. In this work, the thermal runaway of commercially available, high-power cells is studied, to understand the optimal areas to develop mitigation strategies. Accelerating rate calorimetry is coupled with mass spectrometry to examine self-heating and the corresponding evolution of gases. A statistical analysis of cell failure is then conducted, combined with post-mortem examinations. The methodology forms a robust assessment of cell failure, including the expected worst- and best-cases, and the associated real-world hazards. Cells produce a highly flammable, toxic gas mixture which varies over the course of self-heating. Failure also produces particulate matter which poses a severe health hazard. Critically, the onset of self-heating is detectable more than a day in advance of full thermal runaway. Likewise, voltage drops and leaks are detectable prior to venting, highlighting the potential for highly effective early onset detection. Furthermore, the behaviour of the cap during thermal runaway indicates that ejection of material likely reduces the chance of thermal runaway propagation to neighbouring cells. These findings also emphasise that research must be conducted safely. Graphical abstract: Unlabelled Image Highlights: Cell failures signals detectable more than a day in advance of thermal runaway. Cap is most likely to heat rapidly and unpredictably. Post-mortem demonstrates that inefficient ejection of material leads to ruptures. Gaseous and particulate emissions pose a significant health hazard. Emergency response and research work must be carried out safely.