Lithium battery fires

We’ve seen an increase in the number of fires caused by lithium-ion batteries. See how you can use and store them safely to reduce your fire risk.

What is a lithium-ion battery?

They are the rechargeable batteries in electrical items such as mobile phones, laptops, e-scooters, e-bikes and e-cigarettes. The device you’re reading on right now is probably powered by a lithium-ion battery.

The dangers

These batteries are safe during normal use, but present a fire risk when over-charged, short-circuited, submerged in water or damaged.

They are a main cause of waste fires and can be extremely dangerous when thrown away with general rubbish, or mixed with recyclable materials like card, metal and plastic. Lithium-ion batteries are extremely sensitive to high temperatures and inherently flammable. These fires quickly spread and are hard to put out, causing a lot of damage.

Causes of battery fires

  • Rapid overheating (a process called thermal runaway) leading to fire or explosion.
  • Overcharging – if you charge too long or with too much voltage, it can cause overheating and fires.
  • Damaged batteries - may release flammable electrolytes, increasing the risk of fire.
  • Exposure to high temperatures – high temperatures speed up battery ageing and increase the chance of battery failure.

Our safety advice

  • Keep batteries in a cool, dry place away from flammable materials and direct sunlight.
  • Recycle damaged or swollen batteries at designated recycling points.
  • Always use the charger supplied with the device or recommended by the manufacturer.
  • To prevent overcharging, use a charger that automatically shuts off or has a timer.
  • Never leave batteries unattended while charging and do not charge them overnight.
  • If a battery shows signs of swelling, overheating, or emitting smoke, safely remove it and report the incident to appropriate authorities.

How to safely store and charge lithium-ion batteries

Watch this video to learn how to store and charge the lithium-ion battery in you e-bike or e-scooter.

Read a transcript of the video

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How to store and charge lithium-ion batteries safely

Electric bikes and scooters are changing the way we travel, but if not used correctly, they come with risks including severe fires. E bikes and E scooters are powered by electric motors using lithium-ion batteries. Lithium-ion batteries hold more energy than other batteries, but they must be stored and charged properly to reduce the risk of fire. A fire could start due to a substandard battery, charging the battery incorrectly or damage to the battery.

If one cell of a lithium-ion battery overheats, it can enter a state of thermal runaway which can quickly spread to other cells in the battery. This is an explosive chemical reaction similar to several fireworks going off at once. With such ferocity and intense heat, it cannot be put out easily.

Here's some advice to reduce the risks of a fire.

  • Buy your E bike or E scooter from a reputable retailer that you know and trust. If you need a replacement charger or battery, get it from the original manufacturer. Fake or substandard chargers can cause fires. Avoid buying from market stalls or from third party sellers on online marketplaces. There is no guarantee the product has been through Product Safety testing.
  • To charge your E bike or E scooter safely, follow the manufacturer's charging instructions and regularly check the battery and charger for damage. 
  • Once charged, unplug the charger so you don't leave the battery on a continuous charge.
  • It's never a good idea to charge an electrical product overnight, especially ones containing lithium-ion batteries. Fires occurring at night when people are sleeping are particularly dangerous as your reaction time is massively reduced.
  • Don't charge your E bike or E scooter in an exit route like a hallway, landing or stairwell. If a fire breaks out, it can block your ability to escape.
  • Don't try to modify your battery pack as these modifications can cause fires. So, charge batteries in a safe place from a socket that is RCD protected, and in an area with working smoke alarms.

An RCD is a lifesaving device designed to prevent fatal electric shock if you touch something live. They can be plugged into a wall socket, be part of the wall socket, or added to your fuse box.

  • Charge, preferably outside, in an enclosed space like a detached garage, shed or a designated charging area for high rise flats. If you cannot avoid charging indoors, make sure you don't do it in an escape route. This is particularly important in shared housing and high-rise flats.
  • Avoid charging batteries in strong sunlight or anywhere there is a high temperature or flammable materials.

Converting pedal bikes into E bikes using DIY kits bought online can be very dangerous and pose a higher risk of fires as they may not be safe. If you want to convert your bike, go to a reputable retailer and have it fitted by a professional.

If your battery catches fire, do not attempt to put it out yourself, get out and call the fire service.

If you follow these tips, you can enjoy your E bike or E scooter while keeping yourself, your neighbours and your loved ones safe.

E-bikes and e-scooters

This image was taken at a fire we attended involving an electric bike. Our crews had to rescue five people from a building due to the escape route being blocked by the fire.

If you use rechargeable bikes, scooters, motorbikes or mobility scooters make sure you follow our safety advice.

  • Make sure you have working smoke alarms on every floor of your home and in the room where you charge the bike/scooter.
  • Always use the charger supplied with the device or recommended by the manufacturer
  • If you spot signs of wear and tear or damage, buy an official replacement charger for your product from a reputable seller.
  • Keep escape routes clear so you can evacuate quickly and safely.
  • Do not charge the battery overnight.
  • Do not charge the batteries for any longer than they need to fully charge.
  • Plug the cable into a mains socket rather than an extension lead.
More safety advice for e-bikes and e-scooters can be found on the NFCC website
Charred and fire damaged walls and floor following a fire involving an e-bike