Lithium ion batteries
Lithium ion batteries power a variety of everyday devices such as phones, laptops and also vehicles from scooters to cars and as part of solar panel systems on houses.
When we buy a re-chargeable "battery" in say a supermarket, we are usually looking for the AA or AAA size individual cells. Tesla manufactures it's own bigger individual cells 70mm x 21mm. So when car manufacturers talk about a "battery", they usually mean the powerpack that (in the Tesla example) contains 690 - 828 of these individual cells.
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| Energy.gov lithium battery |
What happens when Lithium batteries are damaged?
- First there is a popping sound and hissing , or high pitched screaming as gas expands making the cells / battery explode. More likely to be immediate fire than vapour if battery is fully charged.
- Black cloud - next there is likely to be a black cloud of heavy metal materials from the battery terminals
- White vapour cloud - Next is white vapour which lasts seconds up to 12minutes , and which is LIGHTER than air and produced in very large volumes. -Contains all sorts of nasty gases eg Hydrogen cyanide, Ethan, Methane and other hydrocarbons, sulphur and nitrogen oxides. This is NOT steam and NOT normal smoke though it may easily be mistaken as such with potentially fatal consequences.
- Additional vapour - Sometimes there is also a HEAVIER than air toxic inflammable vapour cloud which will roll across the ground like dry ice on a dance floor . In a USA factory fire, the cloud rolled across the prairie and was reported as a brush fire.
- Thermal runaway - Damage to cell / battery causes uncontrollable overheating which is impossible to stop. You have to let it burn out. Sometimes immediate ignition and long rocket like flames 2000 degrees celcius. If the device is an Escooter or above, then sometimes it'll be a delayed vapour cloud explosion.
Examples of Lithium battery fires
This YouTube video from the Firechief global website shows a selection of lithium fires involving different devices.
Lecture about lithium battery fires
At 11mins 35seconds in the following Youtube video, Prof Christensen is very emphatic that the trade in second hand electric vehicle batteries, especially if they are re-purposed for homes, should stop immediately.
Paul Christensen is a professor of pure and applied electrochemistry at Newcastle University, UK. His Linkedin profile says that he is a consultant on all aspects of Lithium-ion battery safety including fire detection and suppression. He is easy to find on Google and Youtube because he regularly speaks on those subjects.
Prof Christensen says that when first manufactured, the cells have to be charged slowly at the factory to create a "solid electrolyte interface" - this is a sort of protective barrier that is created inside the cell when first charged, to stop it overheating (2mins 10 secs into the video).
Any subsequent problems are usually caused when there is damage or erosion of the protective solid electrolyte interface. Examples would be prolonged overcharging (cheap scooter with no protective circuit) , or maybe a car accident which punctures, splits or crushes the cells might cause thermal runaway (ie uncontrolled overheating).
Safety advice
Lancashire fire & rescue advice -
Do NOT - Charge devices whilst you are asleep, or charge devices in any area used as an escape route area.keep them out of direct sunshine or extremes of hot or cold. Puncture or damage may cause immediate fire or explosion.
DO - charge in a safe area meaning on a solid surface away from flammable items.
According to Suffolk Fire & Rescue Service, there were 5 Escooter fires in the 3yrs 2020 - 2022 inclusive . No stats given for total lithium battery fires from all types of devices or cars.