Understanding lithium battery risks and safety measures

Experts generally agree that lithium batteries are inherently safe during manufacturing, with over 10 billion cells produced annually. However, when failures occur, they can be dramatic. Consumer lithium batteries typically include safety features like temperature sensors and pressure relief valves, but batteries that were previously safe can eventually become a fire risk.

Damage can arise from various factors, including manufacturing defects, collisions (particularly with e-bikes and e-scooters), or even dropping a device, which can cause internal damage not immediately visible. Exposure to heat, like direct sunlight during charging, can also contribute to battery degradation. Overcharging, often preventable through built-in safety mechanisms, is a common cause of failure, especially when using incorrect or modified chargers.

David Giles, CEO of Halifax-based TempAlert, emphasizes that using the wrong charger – one with an incompatible voltage – can severely damage a battery. He cautions that even if a charger fits, it may be designed for a different voltage, potentially causing significant harm. Repeated charging and discharging also contribute to battery wear.

The good news is that a battery rarely catches fire immediately upon failure. Instead, it undergoes a process called thermal runaway, a progressive self-heating that can lead to a fire. The earliest indication of a problem is a battery feeling unusually hot to the touch while charging, a sensation that usually subsides when unplugged. This may occur repeatedly before the battery remains hot even when disconnected.

The timeframe for a dangerous fire is unpredictable, ranging from days or weeks to just 20 minutes, depending on internal conditions. Regarding battery chemistry, while some believe LFP (lithium iron phosphate) batteries are safer, Vinny Gupta, an assistant professor at the University of Waterloo, notes that there are trade-offs between different types. LFP batteries have a higher thermal runaway temperature but release flammable gases when overheated.

To minimize risk, consumers should purchase batteries with recognized safety certifications (CSA, cUL, cETL) and use the correct charger. Charging devices should be placed on hard, non-flammable surfaces in visible locations, away from escape routes. Recognizing warning signs – excessive heat, swelling, unusual odors, gas, or smoke – is crucial. Devices like TempAlert stickers, heat detectors, and carbon monoxide detectors can aid in early detection.

If a battery overheats, it should be unplugged and moved to a safe location, and it should not be recharged. Damaged batteries should be taken to a technician or hazardous waste disposal site, not thrown in the trash. Call2Recycle provides additional guidance on proper disposal. In the event of unusual smells or smoke, immediate evacuation and a call to the fire department are essential.

“Lithium batteries are around us everywhere and that’s not going to change any time soon,” Gupta stated. “For the most part they’re safe, but ‘it’s important for people to be aware of the fact that they can fail and there are very simple things we can do that go a long way towards improving our personal safety.’”