"Aviva reports that 71% of adults surveyed in the UK didn't know the signs that a lithium-ion battery, the type found in e-bikes and e-scooters, is on the verge of failure. These warning signs include heating, leaking, swelling, and unusual smells and noises."
Before covid, my sense of smell was very good - my battery has always stunk a little bit, but I've been using it for three years without flames.
Perhaps battery manufacturers should build in smelloalarms™ , as well as temperature activated and cell cracking noise detection alarms? Other enterprising companies could make retrofit kits of the same? Perhaps small animals or AIs could be trained to recognise these warning signs? "What's that, Ratty? My battery is about to explode?!?!? Thanks, have a peanut."