Ultrafast DMC sensor based on mixed phase bismuth oxide for early warning thermal runaway of lithium-ion batteries

Early fault detection of lithium-ion batteries (LIB) is crucial for the safe operation of electrical measurement systems. Detecting the dimethyl carbonate (DMC) vapor in the LIB electrolyte can effectively improve the early warning time. However, the response speed of the existing semiconductor resistive gas sensors is significantly slower compared with the commonly used temperature and pressure sensors. To address the issue within gas sensors, a DMC gas sensor with an extremely fast response speed was developed based on mixed-phase bismuth oxide, which can effectively respond to 20 ppm DMC within 6 s. Moreover, the sensor successfully triggered the alarm approximately 15 min before the start of thermal runaway and within 22 s after the mechanical rupture of the battery in the simulated abuse test, demonstrating the application potential of gas sensor in the early fault warning of LIB.