(Invited) The Path to Vapour Cloud Explosions and Lithium-Ion Batteries

Abstract

The lecture will cover the research that led to the realisation that vapour cloud explosion was and is the understated hazard of lithium-ion batteries, commencing with work in January and March 2020 and leading up to the present day. The research was initiated with an exploration of the effect of various abuse methods on 1.7 kWh Envision-AESC modules, followed by investigating the effect of State-of-Charge on the manifestation of thermal runaway, the latter leading to the realisation of the vapour cloud and its potential consequences. This was followed by experiments on the larger scale to analyse the vapour cloud composition and to trigger deflagration: these suggested the possibility that arc plasma may have a role in the production of the vapour cloud. Later, experiments on the suppression of thermal runaway clearly showed the risks associated with the suppression of fire without the suppression of thermal runaway, as the hazard flips from fire to explosion. This was a key finding, as was the large volume of vapour cloud produced by lithium-ion batteries (i.e. at least 500 L/kWh and up to 5500 L/kWh), causing the routinely observed rocket-like flames when the cloud ignites immediately, and the fact that even small lithium-ion batteries (e-bikes, e-scooters) are causing vapour cloud explosions.As well as academic research, the concepts and ideas discussed will be illustrated with information and videos from a wide range of sources including first responder reports from across the world.Finally, the possible risks and hazards of the use of electric vehicle batteries in 2nd life applications will be addressed