Thermal runaway

Thermal runaway is an uncontrolled self-heating failure state in a battery cell where heat builds faster than it can escape. In lithium-ion battery systems it can lead to very high temperatures, venting, smoke, fire or explosion, especially when a cell is damaged, misused, charged incorrectly, stored incorrectly, exposed to extreme temperatures or affected by a product defect. In a home battery context the term may appear in battery safety guidance, installation information, emergency response material or risk assessments rather than in everyday app controls. The term describes a failure condition rather than a normal charge stage, a user setting, a routine ageing symptom or evidence that a particular home battery is unsafe.