The electrolyte is a critical component of lithium-ion batteries (LIBs). The electrolyte commonly consists of carbonate mixture and lithium salt. During thermal runaway, the carbonate mixture is vented into the environment along with LIBs venting gases, potentially leading to fire or explosion incidents. In this study, in an 8 - L stainless steel cylindrical explosion vessel, the explosion characteristics of carbonates (dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC)), and LIBs venting gases were identified, and the mutual influences between different carbonates were also clarified, and the effects of carbonate mixture on explosion characteristics of LIBs venting gases were investigated, such as the overpressure, the rate of pressure rise, lower flammability limits (LFL) and limiting oxygen concentrations (LOC). The results indicated that the explosion severity of carbonate mixture (DMC and EMC) increased with the increasing EMC content. As the carbonate mixture content increased in mixtures of carbonates and LIBs venting gases, the maximum overpressure, the maximum rate of pressure rise and LOC increased, while LFL showed a decrease trend. Furthermore, the LOC prediction method of NFPA 69 (A standard offers a method for estimating the LOC for fuels) can predict LOC well on LIBs venting mixtures. The LFL of the mixture of carbonates and gases vented from LIBs was calculated by using CHEMKIN. The results showed that the calculated values were good agreement with the experimental data. Moreover, the changes in the concentration of intermediate products during the combustion of the mixture were analyzed. It was found that introducing EMC and DMC mixtures into the gases vented by LIBs caused an increase in the concentrations of H2, CO and C2H4 in the reactants. The underlying causes of this phenomenon were sufficiently analyzed and discussed. The findings of this research contribute to a deeper understanding of the risks associated with mixtures vented from LIBs and offer valuable insights for designing explosion-proof transport containers and LIBs energy storage stations.

Dimethyl carbonate (DMC) is a common component of lithium-ion batteries (LIBs) electrolyte, which is vented into the environment along with LIBs thermal runaway vent gases (BVG). This study used different ratios of DMC/BVG mixtures to simulate the combustible components vented from LIBs thermal runaway process. The explosion characteristic parameters of the DMC/BVG mixtures, such as the peak overpressure (Pex), the peak rate of pressure rise ((dp/dt)ex), lower flammability limits (LFL) and limiting oxygen concentrations (LOC), were investigated in an 8-L stainless steel cylindrical explosion vessel. The results indicated that as the percentage of DMC increased, maximum Pex, maximum (dp/dt)ex and LOC of the mixtures increased, while LFL showed a decrease trend. In addition, LFL decreased approximately linearly as increasing the initial temperature. The Britton correlation method can estimate LFL at varying initial temperatures. The research results are helpful to better understand the risk of the mixtures vent from LIBs and provide a reference for the explosion-proof design of LIBs’ transport containers and LIB energy storage stations.

To explore the inhibitory effect of argon gas and explosion-eliminating chamber on methane-air deflagration flame propagation in the tube, based on the Φ = 120 mm, L = 5.5 m stainless steel pipeline test system to measure methane-air deflagration flame structure, flame propagation speed, and deflagration pressure. The results show that: 10–30% argon is mixed into the methane-air premixed gas with different equivalent ratios. With the increase in the mixed argon content, the tensile distortion and instability of the flame front increase, and the average value of flame propagation speed decreases by 2.52–60.0%. The first and second deflagration pressure peaks are reduced by about 13.1–62% and 17.7–86.5% respectively. The average value of the methane-air deflagration flame propagation velocity was reduced by 5.7–37.0% with the explosion-eliminating chamber laid at the nozzle. The second and third deflagration pressure peaks are reduced by about 10–30% and 50–90% respectively. The inhibitory effect of argon on the propagation of methane-air flame is considered better than the laying of the explosion-eliminating chamber under the experimental conditions.

为了探究弱封闭管道向抑爆装置内泄爆对火焰传播特性的影响,在内径120mm、长5.5m不锈钢管道受薄膜约束的开口端放置消爆仓,采集甲烷-空气预混气体的火焰结构、火焰传播速度和爆燃压力等参数.实验结果表明:甲烷-空气预混火焰出现了Tulip火焰结构;消爆仓内放置的抑爆环可以减弱管道内火焰传播时的湍流程度,有效降低了火焰传播速度;实验工况下气体爆燃压力时程曲线均有相似变化趋势,且相同条件下布设消爆仓可以明显衰减"外部爆炸"和"火焰振荡加剧湍流"产生的压力峰值.

To study the influence of an acoustic absorbing material (AAM) on the noise and vibration of a methane-air deflagration flame in a square plexiglass tube, a high-speed video camera, pressure sensors, and a noise and vibration tester were used to test the deflagration flame propagation velocity, deflagration pressure, noise and wall vibration characteristics in the tube. The tube length is 540 mm with a cross section of 80 × 80 mm2, and its wall thickness is 12 mm. The experimental results indicate that under the conditions of 8.96% CH4 by volume and fixed repeating obstacles, the built-in AAM of polyester fiber cotton can reduce the peak velocity of the deflagration flame propagation by 11.3%. In addition, the average maximum sound pressure level of the deflagration flame noise is decreased by 17.6%, and the peak vertical vibration velocity of the tube outer wall is decreased by 85.6%. Therefore, using AAM can effectively attenuate the flame propagation and its harmful effects. For the case with an AAM, the flame propagation velocity and deflagration pressure reached the maximum values at 33 ms after ignition, and the values were 62.50 m s-1 and 27.74 kPa, respectively. Similarly, the time history curves of the noise and the tube wall vibration caused by deflagration presented certain correlations. The experimental results and analysis in this paper provide reference values for controlling the hazards of gas explosions in underground mines and other combustible gases in industrial pipelines.

为了研究混入煤粉的铵油炸药的相容性以及煤粉与铵油炸药之间的相互作用,采用差示扫描量热仪(DSC)研究了铵油炸药、混入煤粉的铵油炸药、硝酸铵和混入煤粉的硝酸铵的热分解特性.用Kissinger方程求解了铵油炸药和混入煤粉的铵油炸药的表观活化能(Ea),考察了煤粉与铵油炸药的化学相容性.研究结果表明:在常压氮气氛围的环境中,铵油炸药和硝酸铵的DSC曲线中的热分解均为吸热峰;当煤粉和硝酸铵混合后,煤粉与硝酸铵会在硝酸铵的热分解温度之前发生化学反应,随着煤粉含量的提高,硝酸铵的热分解逐渐转变为放热峰,说明煤粉能极大地降低硝酸铵的热稳定性;使用DSC法研究混入煤粉的铵油炸药相容性等级为4级,煤粉与铵油炸药的相容性差.