It would be good to know why e-bike and e-scooter batteries are exploding and catching fire at what appears to be a disproportionately high rate.
After all, Li-ion isn't new tech. We've had laptops, mobile phones, portable power tools, portable vacuum cleaners and obviously electric vehicles for many years now, and yet it seems that e-bikes and e-scooters are far more dangerous than other Li-ion powered devices.
So far, a hightend fire risks were always linked to a specific product or batch (e.g. Galaxy Note, HP ProBook, etc), which is something that can obviously happen when manufacturing products. But the exploding e-bikes and e-scooters are made by a variety of manufacturers, and so it's not clear why they fail at such an alarming rate compared to other Li-ion based products.
The first thing is that size matters - a small mobile phone or vape battery catching fire is bad, but the volume of flame/gas/smoke isn't huge. Bike/scooter batteries are big enough to vent jets of flame out (like a smaller version of an EV battery), so the consequences of such are fire are more serious.
In terms of the fires themselves Li Ion batteries can ignite for various reasons including
- Internal manufacturing defects/flaws in cells
- Physical damage to cells (caused by dropping, crushing, piercing, vibration, etc.
- Internal pack issues (short circuit, inadequate or faulty voltage monitoring, water ingress, etc.)
- Inappropriate charging (too long, too fast), due to very basic or faulty charge boards/voltage monitoring
- Internal overheating or exposure to extreme external heat