Burning lithium-ion batteries release toxic gases like hydrogen fluoride and carbon monoxide, complicating firefighting. Even after appearing extinguished, residual energy can cause the battery to reignite. What is the biggest cause of a lithium-ion battery exploding?
At a certain level, the chemical reaction creates thermal runaway, causing rapid overheating and quickly affecting adjacent cells. Batteries will spontaneously ignite, burning at extremely high temperatures of between 700◦c and 1000◦c, and releasing dangerous off gases that in enclosed spaces can become a flammable vapour cloud explosion (VCE).
Mechanical injury is another leading cause of lithium battery fires and explosions. Physical damage to a battery, whether from crushing, puncturing, or bending, can compromise its structural integrity.
To understand why lithium-ion batteries sometimes fail, you need to know what’s going on under the hood. Inside every lithium-ion battery, there are two electrodes—the positively charged cathode and the negatively charged anode—separated by a thin sheet of “microperferated” plastic that keeps the two electrodes from touching.
Puncturing a swollen lithium-ion battery may lead to fire and explosion. Even if your device still works, if the battery is swollen, the battery must be replaced immediately, using the device or leaving it connected to power can be dangerous.
Due to the self-sustaining process of thermal runaway, Lithium-ion battery fires are also difficult to quell. Bigger batteries such as those used in electric vehicles may reignite hours or even days after the event, even after being cooled. Source: Firechief® Global