Development and performance optimization of a portable Gas Chromatography - Photoionization Detection system for trace electrolyte leakage detection in lithium batteries

With the widespread application of lithium batteries in energy storage systems, their safety concerns have attracted increasing attention. Electrolyte leakage, as one of the primary safety hazards, necessitates highly sensitive and rapid detection technologies for early warning. Addressing the limitations of conventional methods (e.g. mass spectrometry and spectroscopic analysis) including high equipment costs, complex operational procedures and limited sensitivity, this study developed a portable detection system integrating gas chromatography-photoionization detection (GC-PID) for trace electrolyte leakage detection of volatile organic compounds (VOCs) in lithium batteries. The GC-PID system comprises a thermal desorption module, a resistively heated low-thermal-mass(LTM) chromatographic column and a photoionization detector, integrated with vacuum-assisted sampling to enable rapid separation and sensitive detection of volatile electrolytes. By setting the adsorption tube temperature (with a thermal desorption heating rate of 25 °C/s) and the chromatographic column heating program (with a resistively heated module at a heating rate of 35 °C/min), along with optimizing the makeup gas flow rate to 13 mL/min, high-efficiency separation of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) was achieved. The system completed detection within 10 min, demonstrating detection limits of 112.32 and 94.82 μg/m³ for EMC and DEC respectively, significantly outperforming conventional sensors. Experimental results revealed wide linear ranges (DEC: 201–5270 μg/m³, R²≥0.999; 4020–79,050 μg/m³, R²≥0.999) and excellent repeatability (RSD<5 % for high-concentration samples). When coupled with vacuum-assisted volatilization technology, the system achieved precise detection of leakage in lithium batteries. This methodology combines high sensitivity, rapid response and portability, providing a reliable solution for real-time monitoring and safety prevention of electrolyte leakage in lithium batteries.