Thermal runaway is a phenomenon in which the temperature of a system or material increases uncontrollably, leading to a self-sustained and accelerating increase in temperature. This can occur in various contexts, such as in chemical reactions, electrical systems, and energy storage devices.

In chemical reactions, thermal runaway can happen when the heat generated by a reaction exceeds the heat dissipation capacity of the system, causing a chain reaction that produces even more heat. This can result in a rapid increase in temperature, potentially leading to explosions or fires. Examples of chemical reactions that can undergo thermal runaway include reactions involving highly reactive substances, exothermic reactions, or reactions that produce flammable gases.

In electrical systems, thermal runaway can occur when the heat generated by electrical components, such as resistors or transistors, exceeds their ability to dissipate heat. This can lead to a rise in temperature, which can further increase the resistance of the component, causing it to generate even more heat. This positive feedback loop can result in the component overheating and potentially failing, leading to system malfunctions or even fires.

In energy storage devices, such as batteries, thermal runaway can occur when the internal heat generated during charging or discharging exceeds the device's ability to dissipate heat. This can cause a rapid increase in temperature, leading to a breakdown of the internal components, release of flammable gases, or even explosion and fire.

Thermal runaway is a critical safety concern in many industrial processes, electrical systems, and energy storage applications. Proper design, monitoring, and safety measures, such as temperature sensors, thermal management systems, and protective devices, are important to mitigate the risk of thermal runaway and ensure safe operation of systems and processes.