SafeBatt – Science of Battery Safety
Whilst lithium-ion cell fires are rare, they can occur under various conditions of mechanical, thermal or electrical stress or abuse. As the use of lithium-ion batteries expands into automotive, stationary storage, aerospace and other sectors, there is a need to further decrease the risk associated with battery usage to enable the optimisation of safety systems.
This project is improving the fundamental understanding of the root causes of cell failure and the mechanisms of failure propagation. Working closely with industry partners, a multi-scale approach is being taken, from the material to the cell and module scale. Whilst the nucleation of failure may be a microscopic event, the propagation of failure, in particular cell-to-cell propagation, is macroscopic. Research spans time frames from the degradation of materials over hundreds of charging cycles, down to the nucleation and propagation of thermal runaway with characteristically sub-second events.
The project is also developing an improved understanding of processes occurring during real world failure, including the environmental consequences of lithium-ion battery fires, which will inform the further development of fire sensing and protection systems for lithium-ion battery energy storage systems and help inform first responders.
Timeline with milestone/deliverables (March 2025)
- Investigate materials driven safety issues, detecting early signatures of failure and how these may change as the cell ages.
- Investigate the effect of fast charging and operation under extreme conditions on the safety response at a cell level.
- Understand cell failure modes and how they translate to multi-cell clusters and modules, using advanced instrumentation and high-speed characterisation and imaging techniques.
- Develop and demonstrate detection methods and mitigation strategies to prevent thermal runaway and propagation.
- Develop a model to infer reaction kinetics and predict thermal runaway, simulating the external flow of gas, heat and ejecta during failure.
- Conduct tests in larger format cells and at module level to help industry and other stakeholders understand how EV and micro-mobility battery packs and static energy storage systems fail in real-world scenarios.
- Continue international dissemination activities, providing a central point of access for industry, government bodies and fire services seeking knowledge on safety related battery issues.
Project innovations
Large scale experiments at module level include further investigating fire extinguisher efficacy and the toxicity of fumes and run-off. Previous large scale work has been instrumental in highlighting the potential explosion hazard of the vapour cloud, which is produced by cells under certain failure conditions. This ground-breaking work is informing best practice and providing knowledge to numerous stakeholders internationally (including first responders and government working groups) on real-world lithium-ion battery failure hazards in EVs and micro-mobility devices, recycling facilities, and domestic and industrial energy storage facilities. This knowledge is being used to influence British and international standards, and produce safe practices for storing and charging devices such as e-scooters and e-bikes.
2D spatiotemporal cross-correlation mapping as a quantitative technique to track failure propagation; this image shows the spatiotemporal map where a ball compresses the electrode structure. The map indicates that the centre of the ball, x ≈ 3.45 mm, starts displacing the electrodes from t ≈ 0.04 s, where the extent of displacement reduces radially due to the circular profile of the ball.
Project funding
£4.3m
1 April 2021 – 31 March 2025
Principal Investigator
Professor Paul Shearing
University of Oxford
Project Leader
Dr Julia Weaving
University College London
University Partners
University College London (Lead)
University of Oxford
University of Cambridge
Kings College London
Newcastle University
University of Sheffield
University of Warwick
+ 2 Industry Partners
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