With the emergence and popularity of lithium-ion batteries as a power source in the last decade, a growing number of concerns over how firesafe the batteries are have arisen. From everyday household electronics such as laptops, mobile phones, and tablets, to large-scale energy storage systems and electric vehicles (EVs), lithium-ion batteries are commonplace, and in the case of a fire event, these types of fire can be very difficult to extinguish.
This advice and guidance article covers what causes lithium battery fires and how lithium-ion battery fires are successfully controlled.
What causes lithium-ion battery fires?
Like many other forms of technology that routinely transform, store, and use energy, there is a small chance of malfunction, which for lithium-ion batteries may occur, for example, following physical damage or heat exposure, and while the chance of a li ion battery fire is extremely rare, these adverse conditions can lead to fire.
Lithium-ion battery fires are commonly caused by a chain reaction known as ‘thermal runaway’, which occurs when a lithium-ion battery cell produces more heat than is being dispersed. Lithium-ion batteries contain flammable materials such a flammable electrolyte which breaks-down into various flammable and toxic gases, along with some oxygen, during ‘thermal runaway’, that can result in fire or explosion.
Thermal runaway can be caused by a number of reasons. As mentioned above, malfunction from physical damage to battery cells, such as damage leading to short circuits, and heat exposure (high temperatures) from an external source, as well as manufacturing defects and over-charging, can all lead to ‘thermal runaway’.
Due to lithium-ion batteries generating their own oxygen during thermal runaway, it is worth noting that lithium-ion battery fires or a burning lithium ion battery can be very difficult to control. For this reason, it is worth understanding how lithium-ion fires can be controlled should a fire scenario happen.
How to extinguish lithium-ion battery fires?
In all circumstances, only suitably trained personnel/emergency-responders should attempt to extinguish early-stage lithium-ion battery fires, when it is safe to do so.
As lithium-ion battery fires create their own oxygen during thermal runaway, they are very difficult for fire and rescue services to deal with. Lithium-ion battery fire control is normally only achieved by using copious amounts of water to cool battery cells.
For small lithium-ion battery fires, specialist fire extinguishers are now available, that can be applied directly to the battery cells, to provide both cooling and oxygen depletion, with the aim to control fire and reduce temperature to below the level where there is sufficient heat to re-ignite the fire. Also, some smothering systems, e.g. specially constructed fire blankets and specially formulated fire suppression granules, are now available to help control lithium-ion battery fires.
In the case of fires involving large arrays of lithium-ion battery cells, like those used in electric vehicles, lithium-ion battery fires are normally only controlled and extinguished when the fire and rescue service deliver a large amount of water to the burning materials for a significant amount of time.
It may be necessary to continue to supply cooling water to the extinguished fire for hours, or even days after, to prevent reignition. The fire and rescue service may also use specially designed car fire blankets to help control EV (electric car) car fires.
Due to the difficult nature of lithium-ion battery fires, it is recommended that you do whatever you can to minimize the risk of a lithium-ion battery fire occurring, despite how rare they are. You can find out more about steps to take in minimizing the risk through our advice and guidance article “Why do lithium-ion batteries catch fire?”.
You can also find further information about lithium-ion batteries in the guidelines below:
Please be aware that considerable efforts have been made to ensure the accuracy of the information contained within this article at the time of publication, however any legislative (or other) changes that come into effect after this may render the information out of date until it is reviewed and updated as part of the FPA’s content review cycle.