Lithium-ion battery fires on the rise as experts warn of explosion risks

The number of fires caused by lithium-ion batteries has nearly doubled in Denmark over three years, according to emergency services, who attribute the increase to the growing use of battery-powered devices in households.

National emergency response agency Danske Beredskaber reports that battery fires jumped from 75 incidents in 2021 to 143 in 2024, with e-bikes, power tools, and even mobile phones posing significant risks. Bjarne Nigaard, head of secretariat at Danske Beredskaber, describes the fires as particularly dangerous due to their ability to reignite and spread rapidly.

“These batteries can act like small explosives,” Nigaard warns. “They’re difficult to extinguish and can quickly ignite surrounding materials, making containment challenging.”

Emergency services and retailers share key advice to prevent battery fires and mitigate risks:

Safe charging practices

Where and when you charge devices can make a critical difference. Per Vedsted, emergency chief at Nordjyllands Beredskab, stresses that batteries should never be left unattended while charging—especially overnight or when no one is home. His agency responded to 31 battery fires in 2023, up from just six the previous year.

Nigaard adds that charging stations should be placed away from flammable materials and never near exits, as fires in entryways can block escape routes. “Avoid charging in hallways or near doors,” he advises. “If a fire starts there, you could be trapped.”

Maintenance matters

Anders Isgaard, manager at FriBikeshop in Aalborg, recommends avoiding extreme charge levels to prolong battery safety. “Never let the battery drain completely, and don’t leave it plugged in overnight,” he says. “Overcharging or deep discharging stresses the battery and increases fire risks.”

If a fire starts

In the event of a battery fire, Nigaard underscores the importance of prior planning: “Your ability to escape depends on where the battery is located. Keep it away from your primary exit path.” Lithium-ion fires can reignite even after appearing extinguished, requiring professional intervention.