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05.1 Categorising lithium-ion batteries

What's most likely to catch fire? An electric car, energy storage system or an ebike?

We know from our research that battery fires in road-going EVs are rare.

However, the rate of battery fires in personal mobility devices (PMDs) - ebikes, escooters, eskateboards, hoverboards and unicycles - is increasing alarmingly.

This is due to a range of factors, but primarily the quality of the lithium-ion battery cells & battery management system; in EVs they're high quality & subject to stringent regulation, in PMDs they're often very low quality & unregulated.

How does this knowledge assist emergency response?

We found the difference in fire likelihood between EVs and PMDs adds to community & emergency responder confusion about the level of risk to life & property safety.

So, for clarity, we have created the following categorisation of lithium-ion batteries, based on how they're used & what our research says about the risk of a fire (thermal runaway) occurring.

Please see the bottom of the page for a full explainer for this graphic.

EV FireSafe EV LiB Categories.png

How did we build our LiB categorisation?

We've known for some time that PMDs pose a far higher risk of battery fire than other devices & vehicles where lithium-ion batteries are used.

But to quantify this, for the first 6 months of 2023 we tracked incidents involving road registered electric vehicles (cars, buses, trucks), VS personal mobility devices (ebikes, escooters, eskateboards, unicycles, hoverboards).

Here's what we found:

EV vs PMD battery fires.png

We looked for the number of overall incidents, injuries (requiring hospitalisation), fatalities & whether there was a property loss.


Not so fun fact; there were so many PMD incidents in the 6 month period that our researcher couldn't keep up, & we had to stop counting at 500 PMD battery fires.

The message? The risk of battery fire is NOT the same across all categories

Our research, & testing programs being conducted around the world, prove that.

We are often approached by responders & businesses concerned about their EV fire risk, while having absolutely no awareness of the PMDs & other smaller devices that pose a far greater risk to their safety.

This means homes, properties & lives are being threatened due to an unnecessary singular focus on one risk & not others.

This lack of awareness contributed to approximately 206 injuries & at least 47 deaths in 2023. Over an 18 month period in 2022/2023, four whole families were killed by PMDs that went into thermal runaway in their homes.

We cannot compare battery fire risk in electric vehicles to personal mobility devices. 

EV FireSafe EV vs PMD battery fire.png
4 families lost to PMD fires_edited.jpg

EV FireSafe LiB Categorisation explainer:

EV FireSafe EV LiB Categories.png

Categories - items that contain lithium-ion batteries:


Smaller Devices (SD): 

  • Phones, laptops, earbuds, tablets

  • Drones, cameras and microphones

  • Vapes (e-cigarettes)

  • Torches, power tools, handheld radios

Personal Mobility Devices (PMD):

  • Electric bicycles

  • Electric scooters

  • Electric skateboards

  • Hoverboards

  • Unicycles

Utility Task Electric Vehicle (UTEV):

  • Electric Tuk Tuks

  • Electric Golf Buggies (using lithium-ion, not lead acid, batteries)

  • Small Electric Delivery Vans:

    • May have a limited road registration

    • Often used on campuses, such as shopping centres, hospitals, universities to transport gardening or cleaning equipment

Road-Registered Electric Vehicles (RREV):

  • Electric motorbikes

  • Electric passenger cars

  • Electric buses 

  • Electric trucks 

Battery Energy Storage Systems (BESS):

  • Residential battery storage (often connected to PV)

  • Commercial battery storage

  • Grid scale battery storage

What's meant by OEM guidance & ERG?

OEM Guidance & Emergency Response Guides:


This refers to a set of instructions written by the Original Equipment Manufacturer (OEM) that lists out steps on how to manage an incident involving their product.

For Road-Registered Electric Vehicles, this should be in the form of an Emergency Response Guide (ERG) written to international standard ISO 17840. This is important as it sets out a standardised set of steps that greatly assist responders managing any incident involving lithium-ion batteries.

Responders can access ERGs via:

  • ANCAP Rescue app (free)

  • EURO Rescue app (free)

  • Modietech CRS (paid subscription)

  • By Googling

  • NFPA AFV Guide

EV FireSafe EV emergency response guides.png

How have we determined the level of risk of battery fire?

Level of risk:


We have based risk ratings on our global database of incidents through a variety of sources, contacts & conversations.

How can emergency responders manage a battery fire in lithium-ion batteries?

Emergency Response:


There are three main firefighting responses to lithium-ion battery fires; cool, burn or submerge.

The following graphic is from our online training pack for firefighters, & refers to road-registered electric cars, however these methods are applicable to all lithium-ion batteries in any application.

EV Fire Cool Burn Submerge Firefighting Electric Vehicle battery fires.png
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