Thermal Runaway
SafetyAlso known as: TR, Battery Thermal Runaway
Thermal runaway is a failure mode where a battery cell enters a self-sustaining exothermic (heat-generating) reaction that rapidly increases temperature beyond safe limits. It can be triggered by internal short circuits, overcharging, physical damage, or manufacturing defects.
Once thermal runaway begins in one cell, it can propagate to adjacent cells (thermal propagation), potentially engulfing an entire battery container. Modern BESS designs incorporate multiple layers of protection: cell-level fuses, BMS monitoring, liquid cooling, gas detection, fire suppression systems, and container-level thermal barriers. Fire safety design and testing are critical for insurance and regulatory compliance.