17th May 2022
Electrical Engineer Richard Heath recently presented a webinar to the Association of Insurance Surveyors. His presentation on lithium-ion battery fires was part of series of talks, which also included a presentation from Hawkins’ Managing Director Andrew Moncrieff in January.
Richard spoke to members of the of the AIS about the composition, prevalence, and dangers of lithium-ion batteries. With increasingly high usage of our mobile phones, tablets, laptops, headphones, and even ‘robot hoovers,’ it’s worth knowing what’s inside. A lithium-ion battery is a rechargeable battery that comes in several forms, including small or large cylindrical cells, pouch cells and prismatic cells. Lithium ions flow through these batteries from negative electrodes to positive electrodes, and back again, during the charging process.
Non-energetic battery failures can result from ‘ageing’ or loss of capacity within the battery, as well as from an increase in internal resistance, which causes a lower current output. This is the benign way that most batteries tend to fail over time. An energetic failure, also known as thermal runaway, is what can cause rapid self-heating and lead to fires. This can happen when the internal cell temperature increases, the cell contents are ejected, or gas venting from the cell occurs—with one failure often leading to damage that will cause further failures. The more charge a cell has, the more energetic the runaway; cells are also most likely to fail during or shortly after charging. Most cell designs ensure that exothermic reactions do not occur, but when they do, the resulting fires can be difficult to extinguish and so can cause extensive damage.
Hawkins can determine whether thermal runaway was caused by defects in manufacturing (poor electrochemical design, cell faults, or battery faults), or whether the failure was due to a defect in use (mechanical, thermal or electrical abuse/misuse).
Important lessons to take away from Richard’s webinar include:
- Beware of the ‘bargain battery’
- Always use the charger that was provided with the device.
To learn more about lithium-ion batteries, you can read this article by Richard Heath & Jake Irwin.
If you would like us to schedule a presentation for your company, please contact us.