Early detection and warning system for lithium battery thermal runaway

Thermal runaway occurs when the electrolyte within a battery cell becomes overheated and initiates a hard-to-stop and dramatic exothermic reaction. In a battery pack, this can easily spread from cell to cell, resulting in a large and near-inextinguishable fire. An early warning system that can detect the conditions leading to thermal runaway is a useful tool in building safe battery system suitable for use in safety-critical applications such as aviation. Flux Aviation Limited and Cranfield University are working together to test novel sensing methods for early detection of thermal runaway conditions. Cranfield is supporting this project through use its expertise in practical battery testing, its facilities, its skills in data analysis and algorithm development, and its knowledge of electric aviation and flight certification.

Impact and findings

As of April 2024, Cranfield has worked to upgrade its existing Phoenix Lab (designed for aggressive testing of battery modules or small packs) to accommodate a deliberate combustion event. The lab has been upgraded for the safe management of lithium battery combustion products and instrumented for Flux Aviation’s battery packs. An initial test has been carried out with success, and further testing will follow over the next few months. Cranfield will also be supporting algorithm design.