How lithium batteries go up in flames

Lithium batteries are all around us, but did you know that charging them can pose a fire risk?

With life being so electrified that it’s fully ingrained in our everyday devices, from vapes to toothbrushes, to electric bikes and vehicles, it’s important to understand the potential hazards.

The Guardian recently reported a statistic that certainly sets off sirens: UK firefighters are called out to a lithium-caused fire every 5 hours.

When devices sit idly in bedrooms, hallways, kitchens, and anywhere in between, charging comes at the expense of safety, prioritizing convenience.

“When firefighters are attending these incidents often, the problem has moved beyond rare product failures,” says Brian Dunagan, managing consultant and chief investigator at IFO Group, an occupational health and safety company.

Disproportionate findings

QBE Insurance Group found that e-bike fires account for up to a third of lithium-ion battery fires in the UK each year, which is a sizable share.

And with the slang term “frankenbike” doing the rounds, meaning a bike put together from mismatched parts, poorly produced bits of kit can easily overheat and cause the flames to rip roar.

Alarmingly, equipment purchased on mainstream platforms like Amazon, including complete e-bikes made in China, has been known to explode, even mid-ride.

“This is particularly hazardous for electrified bicycles that have been converted because of the battery, motor, controller, and charger,” explained Dunagan, adding that they “all need to work in unison as a system, and are not necessarily designed to work together.”

With e-bike branding positioned as sleek and appealing, the city commuter is tempted to plug and play, without considering the safety implications.

E-bike-related fire callouts more than tripled from 2022 to 2025 in the UK, climbing from 149 to 520.

The process is a bit like a blowtorch effect, in that a damaged battery can overheat in a process dubbed thermal runaway. In turn, toxic gas is produced before the battery finally explodes.

Better battery hygiene is encouraged, including not charging devices overnight or when you leave the house. And, as Dunagan pointed out, devices should simply be unplugged if they overheat, and be properly disposed of if faulty – not just thrown in the trash.

Meanwhile, the spotlight needn’t be on the end-user alone. It’s an industry-level issue in Dunagan's eyes, who forecasts that “The future is safer batteries, which means better chemistry, smarter chargers, strong certification, clearer labels and greater accountability throughout the supply chain.”