Sitting outside a bar at the weekend, Zoe Williams noticed something coming out of her bag that looked and smelled like a naked flame. Ordinarily, she would have thought it was her vape, but that was in her mouth. She put it down to a mirage until someone said: “Your bag’s on fire.”
It was her good fortune to be sitting opposite a chemistry teacher friend, who explained what had happened through a series of rhetorical questions: What is a spare vape battery made of? What are keys made of? What happens to a lithium battery when you connect metal to both ends? The result: a closed circuit inside the handbag. Not only had the bag caught fire, but her keyring — holding a plastic portrait of her nieces circa 2017 — had melted. She was also sitting opposite her sister, who reacted surprisingly well to the sight of her molten children.
The Science Behind the Fire
Lithium batteries are highly reactive when their terminals are bridged by a conductor, such as metal keys. This creates a short circuit, generating intense heat and potentially igniting surrounding materials. In this case, the vape battery and keys in the bag completed the circuit, leading to flames and melted plastic.
Conflicting Advice on Battery Disposal
Opinion was divided on what to do with the lithium battery after the fire was extinguished. One person said put it in water; another warned against it. The first person was joking, but the chemistry teacher ensured proper handling.
A Surprising Upside
Williams' younger niece, an engineering student, took a long view: while the fire was bad in a bar and would have been worse on a plane, in a survival scenario where one needs to keep warm overnight, a person carrying a powerful battery and keys would be a massive hit. Anyone with a magnifying glass or two dry sticks would look amateurish. “Yet another win for STEM expertise, and also my vaping hobby,” Williams wrote.
The incident highlights the dangers of carrying loose lithium batteries with metal objects, but also the potential resourcefulness in unexpected situations.
