Abstract: In order to solve the problems such as long detection period and easy cross interference in traditional detection methods of thermal runaway gas of lithium ion batteries, the potential risk of pyrolysis gas of lithium batteries were systematically and quantitatively studied. In this paper, gas Raman spectroscopy combined with a variety of gas safety quantitative analysis methods was proposed to comprehensively study the toxicity and potential explosion risk of ternary lithium-ion battery pyrolysis gas. Based on the established thermal runaway characteristic gas prediction model, the variation law of thermal runaway gas concentration, gas generation, explosion limit, pressure characteristics and explosion severity of lithium-ion battery under different SOC (25%, 50%, 75%, 100%) was emphatically analyzed, and the battery fire toxicity was evaluated in combination with the actual scenario. The research shows that: The Raman spectral gas concentration quantitative model can accurately predict the thermal runaway gas concentration information of lithium-ion batteries. H2, CO2 and CO concentrations account for 80.31%~94.56% of the total thermal runaway gas released. The maximum pressure, maximum pressure boost rate, explosion index and gas explosion limit range show a trend of decreasing first and then increasing with the increase of SOC. Lithium-ion batteries with 50%SOC show the best gas safety, with the narrowest explosion limit range of 9.66% to 25.27%, and battery fires are disastrously toxic.

Key words: Raman spectrum, lithium-ion batteries, thermal runaway, multi-component characteristic gas analysis, quantitative analysis of gas risk