If the cell temperature rises above a critical point, internal materials decompose exothermically — generating more heat than can be dissipated. The result is gas formation, pressure build-up, the release of flammable and sometimes toxic vapours, and eventually open flames. Neighbouring cells can also be triggered by the heat, allowing the process to spread across an entire battery pack.
Particularly insidious: thermal runaway doesn't always give sufficient warning and can occur hours or even days after seemingly minor damage — for example after a device or vehicle is dropped.
An active battery fire protection box such as the Li-Ion Safety Box M from RUK-Technologies provides exactly that controlled charging and storage place: temperature monitoring, automatic shutdown and suppression in a closed system — before thermal runaway spreads into the operation.
See the Li-Ion Safety Box M fire protection box