Lithium batteries are all prone to thermal runaway. When it happens it is not the fire as such but where the device happens to be. If it is while in an aircraft it is more serious than in an automobile.
With electronic circuit boards the more individual chips on a board the greater the probability of one failing. With cars like the Tesla that have a great many individual cells the odd of a fire increases dramatically and the manufacturer adds circuitry to remove individual failed cells and this works most of the time.
Fire codes mandate smoke and fire detectors in houses and they should be added to garages where an e-bike or electric car is kept.