I used to repair gas boilers, they are packed with safety features, its amazing they run at all.
They used to be semi mechanical, now its all cct board controlled.
If the fan doesnt start or if it draws too much current indicating a blockage it wont fire up, if the gas doesnt ignite the cct detects it by electrical failure of voltage passing through a flame, which is also acts as a diode so a short would fail as well preventing gas valve open.
The fan also detects too much flow indicating possible physical damage to boiler construction.
If the gas valve jams open they are designed to enable all the heat or unburnt gss to escape from the flue, if the fan isnt running the flame will be starved and be contained.
Quality Ebike batteries have voltage balancers, heat detection, solid construction and some have individual battery thermal lockouts.
But theres nothing to stop thermal runaway if it starts, there is no physical protection, no cutoff of power, no inherent construction to contain a runaway situation.
Gas cars dont either, but very few people park them in their homes.
We will look back in decades to come and there will be li- ion batteries in museums with people shaking their heads at them parked in hallways.
).
