High-Sensitivity Lithium-Ion Battery Thermal Runaway Gas Detection Based on Fiber-Enhanced Raman Spectroscopy

Thermal runaway gas analysis is a powerful technique for lithium-ion battery (LIB) safety management and risk assessment. Here, we propose a novel hollowcore antiresonant fiber (HC-ARF)-based Raman gas sensing device for simultaneously sensitive detection of thermal runaway gas products (CH4, C2H6, C2H4, C2H2, CO, CO2, and H-2). A micromirror is attached to the rear of fiber, which provides 3.1 times Raman signal enhancement compared to bare fiber, and two filtering methods are adopted to effectively filter out the background noise signal of fiber. With 200-mW excitation power and 60-s integration time, a low limit of detection (LOD) is achieved: 0.8, 3.0, 1.4, 1.5, 9.2, 4.2, and 4.1 ppm center dot bar for CH4, C2H6, C2H4, C2H2, CO, CO2, and H-2, respectively, which is verified through the detection of low-concentration gases. The proposed device has a short response time and does not require gas separation from the battery, and we believe that this provides a new idea for nondestructive detection of battery status and in situ assessment of battery health.