Investigating the Thermal Runaway Behaviour of Fresh and Aged Large Prismatic Lithium-Ion Cells in Overtemperature Experiments

Abstract

When using lithium-ion batteries (LiBs) with nickel-rich cathodes, safety issues such as thermal runaway (TR) propagation must be considered. To design safe LiBs, effective countermeasures against TR propagation must be developed. For this purpose, knowledge about the TR behaviour, especially the TR onset temperature, of fresh and aged lithium-ion cells is required. Therefore, the aim of this work is to investigate the TR behaviour of several fresh and aged lithium-ion cells with different cathode chemistries in overtemperature tests using an oven test setup to determine changes in the TR behaviour due to cyclisation. For the investigation of the TR behaviour of large format lithium-ion cells, the oven test setup turns out to be an effective alternative to the accelerating rate calorimetry test. Analysing the results shows that the initial TR temperature after cyclisation for one cell chemistry is significantly decreased due to the failure of one cell component. In addition, from a series of tests and the measured TR onset temperatures it can be deduced that an underlying probability distribution should be taken into account when designing safe LiBs.

Keywords

• lithium-ion battery
• thermal runaway
• battery safety
• battery ageing
• thermal runaway propagation