Lithium-ion batteries are everywhere. They power our phones, laptops, electric bikes, power tools and even our cars. As useful as they are, they come with a risk that’s becoming harder to ignore: fire.
With incidents on the rise, understanding what causes lithium-ion batteries to catch fire and how you can protect yourself has never been more important.
That is what we are going to explain today. In this article, we will take a detailed look at Lithium-ion batteries and explain why they catch fire and how you can mitigate the risk, while also answering some common Lithium-ion battery fire-related questions.
Why do Lithium-ion batteries catch fire?
Let’s start by looking at the science behind why these batteries catch fire.
Lithium-ion batteries store a large amount of energy in a compact space. If you look at your mobile phone or a toy, for example, they’re not big devices – they can probably fit in the palm of your hand. Yet within that device is a rechargeable battery that is designed to store energy in the most efficient way possible to give you maximum use time before recharging.
The way a rechargeable battery works is actually quite simple: there are 2 different chemicals inside the battery, separated by a barrier through which the energy passes from one side to the other as it’s used or recharged. The only catch is that the 2 chemicals actually react with each other when they are in direct contact – that’s why the barrier is in place. When the barrier is compromised (usually through overheating, physical damage, or manufacturer failure), the outcome is a dangerous process known as thermal runaway. Once thermal runaway begins, the battery heats up rapidly, creating toxic gases, explosions and flames, often igniting nearby flammable materials.
At what temperature does a Lithium-ion battery explode?
There is no set temperature at which lithium-ion batteries explode. The precursors to thermal runaway can start from around 60°C (140°F), but thermal runaway generally begins at temperatures exceeding 100°C (212°F). In some scenarios, batteries can reach more than 1,000°C during thermal runaway, posing a serious threat to life and property.
How common are Lithium-ion battery fires?
Fire incidents involving lithium-ion batteries have increased steadily over the past few years. In 2023 alone, UK fire services responded to 46 per cent more fires linked to Lithium-ion batteries than in 2022, with data showing that services attended a total of 921 fires, of which e-scooters made up 125 and electric vehicles were linked to 118.
Why the spike, though?
As these batteries become more widespread in devices like e-scooters, e-bikes and power banks, the potential for misuse, damage, or failure increases. Add in substandard chargers or counterfeit batteries, and the risks multiply rapidly.
The adoption of electric vehicles and devices places pressure on manufacturers to deliver high quality products and this can be seen reflected in their pricing, but where cost is the decisive factor, it can lead to a rise in sub-standard products flooding the market, increasing the risk of fires caused by malfunctioning, overheating or overcharging.
Is it safe to leave a Lithium-ion battery on charge overnight?
It might be convenient, but it’s not safe.
Given the length of time it can take for some batteries to recharge (such as those used in mobile phones or cordless tools, for example), it might seem logical to charge the battery overnight, so it is fully charged and ready for use the next morning. However, this presents an issue whereby any early warning signs, such as odours or swelling, are much more likely to go undetected and survival chances of a fire when sleeping are much lower than when people are awake.
Fortunately, most high-quality lithium-ion battery devices include built-in overcharge protection. This doesn’t mean that they are safe to charge overnight, but they are safer to charge generally than cheaper models or counterfeit chargers that have eliminated this technology to reduce their costs.
Is it safe to store Lithium-ion batteries indoors?
In most cases, yes, but you must follow safety precautions.
Best practice suggests that Lithium-ion batteries should be stored:
- In a dry, cool, well-ventilated space
- Away from direct sunlight, radiators, or heaters
- On a non-flammable surface
- Out of reach of children and pets
Damaged, leaking, or swollen batteries should never be stored indoors and must be disposed of safely according to local guidelines (something we will come to shortly).
How are Lithium-ion battery fires extinguished?
These fires aren’t like regular fires. Traditional extinguishers like CO2, water, dry powder or foam extinguishers won’t work, and (especially in the case of water and water mist) can even make things worse.
That’s why Lith-Ex extinguishers were developed. Specifically designed for the complex, unique nature of lithium-ion battery fires, they:
- Cool the fire
- Suppress flammable vapours
- Prevent re-ignition
They're especially useful in workplaces or transport settings where larger batteries are in use, but are available in sizes ranging from handheld 500ml Lith-Ex extinguishers for the home right up to wheeled 50ltr Lith-Ex extinguishers.
Can a fire blanket put out a Lithium-ion battery fire?
Yes, but it must be the right kind. Standard fire blankets often found in kitchens aren’t effective against battery fires due to the extreme heat and toxic off-gassing.
Our range of Lithium-ion battery fire blankets, however, are designed to contain, isolate and suppress battery fires - even at temperatures up to and exceeding 1,000°C. (2000°C in the case of our LithShield® Ultra+ battery fire blankets).
Achieving DIN SPEC 91489 certification, our LithShield™ Tough EV fire blankets are independently tested in extreme temperatures such as those generated by electric vehicle fires, meaning they provide vital peace of mind for EV owners.
How to dispose of Lithium-ion batteries
A major fire risk involving Lithium-ion batteries comes AFTER people have used them. A common mistake is to simply throw them away or to put them into a battery recycling point, often found in supermarkets. However, the unique nature of Lithium batteries often means that there is still the potential for thermal runaway.
Putting them in the bin can mean that, when taken to a recycling centre with the rest of your rubbish, they can be damaged or compressed, leading to an explosion which then spreads throughout the recycling centre – or even in the lorry en route.
Used Lithium-ion batteries should be taken to specialist battery recycling facilities where they will be safely discharged and dismantled, enabling the mechanical and chemical elements of the battery to be sorted and recycled correctly.
More information on how and where to recycle or dispose of used Lithium-ion batteries can be found online through experts such as Veolia.
How to prevent Lithium-ion battery fires
Of course, in an ideal world, we would never experience the majority of the issues we’ve talked about here. However, as we’ve discussed, incidents continue to rise.
Education is an incredibly powerful tool in the fight against Lithium-ion battery fires, and a lot of information can be found through the Firechief® Academy and our range of webinars, which you can book a place on to improve your knowledge and understanding of the risks and how to mitigate them.
In the meantime, there are some key points that you can take with you to help to prevent Lithium-ion battery fires:
Remember, the most common causes of fire include:
- Overcharging
- Exposure to high temperatures
- Impact or puncture
- Using incompatible chargers
- Manufacturing faults
Here are some essential tips to reduce the risk:
- Only use certified chargers and batteries from reputable brands (ideally, the manufacturer of the device)
- Avoid overcharging. Always unplug the battery and charger once fully charged. The optimum charge range for most lithium-ion batteries is between 20% and 80%
- Inspect batteries regularly for any signs of swelling, leaks or damage
- Do not try to repair a battery or charger that seems to be faulty. The safest way is always to replace
- Always store devices in a cool, dry place, away from flammable items
- Never charge a battery under your pillow or on your bed
In summary
Lithium-ion batteries are incredibly powerful, and we’re becoming increasingly reliant on them. As more and more of us switch to electric vehicles and technologies advance, education and understanding of how to mitigate the risk of fires become even more important.
Hopefully, this article has gone some way to doing that, and you can take the first steps now by equipping yourself with fire safety products from our Lithium-ion battery safety range.
In addition to our Lithium-ion battery fire extinguishers and blankets, the Firechief® range of fire safety products also includes extinguisher stands, suppression systems, signage and fire safety products for all types of fires. For information, call us on +44 (0)330 999 0019 or email sales@firechiefglobal.com.
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Disclaimer
The information contained within this blog is provided solely for general informational and educational purposes and is not intended as a substitute for professional advice. Before taking any actions based upon this information, we advise the reader to consult all relevant statutory or regulatory guidance and, where necessary, to consult a qualified fire or industry regulation professional. The use or reliance on any information contained herein is solely at the reader's risk.