plus there are usually 2 (or even 3 or 4) of them close together in a battery section of the mod and when even 1 starts to spray out and burn, other batteries will also be damaged and may explode.
Due to the recent public death, I feel compelled to be unusually persnickety about terminology. So to get annoyingly nit picky:
This is one of those situations where there is no perfect exact single term.
“explode” is a technical term which is different from “flash burn” or “detonate”. They describe the speed of gas release as well as the effects thereof such as a shockwave or flying debris.
When a battery fails it’s case generally ruptures and releases the now gasified electrolyte. That rupture is generally at specially weakened area in the case. The material ejected is usually hot gasses and happens very quickly. This can be pretty dangerous.
“Flash burn” doesn’t work because most of the time there is no actually burning or flashing though the gas is hot enough to burn a person.
A few Vapes have literally “exploded”. This can happen when the vape itself is also a strong airtight container. Generally vapes are specifically designed not to be such, but in the past some have been made. Generally long ago when batteries weren’t powerful enough to rupture the case. The gas is not released until the vape case ruptures, and this can not only produce flying debris from the case but also the anode and cathode of the battery. This makes things exponentially worse as that can include lithium which is highly flammable. Again, this is extremely rare and requires the vape to be of an antique type no longer generally sold.
“Detonate” is of course right out. That happens when the gas release is so fast it’s supersonic and a shockwave is produced.
“Burst” would be most accurate except it does not viscerally impart the level of potential injury possible due to the heat of the materials involved. “Vent” is also used but has similar problems as burst.