With the advantages of high energy and power densities, Li-ion batteries (LiBs) are widely used to power an increasingly diverse range of applications, including portable electrochemical energy-storage devices, electric vehicles, and large energy-storage power plants. In addition, they are considered the most competitive power sources for future green smart grids. With the increasing demand for energy sources and storage devices, LiBs with high energy density are continuously being pursued. However, high energy densities could result in high safety risks. The conventional organic liquid electrolyte components and olefin-based separators used in existing LiBs are flammable. In addition, nonuniform distribution of components, inhomogeneous interfacial contacts, and electrical, thermal, or mechanical abuses in the battery operating process can cause internal short circuit, thus releasing large amounts of Joules heat, resulting in a rapid temperature rise and thermal runaway propagation, thus triggering toxic gas release, smoke, fire, combustion or even explosion. To improve the safety and cycling lifetime of LiBs, the mechanism and process of thermal runaway must be understood. In addition, detection and warning technologies must be developed for the early-stages warning of the battery thermal runaway. Compared with technologies on monitoring the terminal voltage, current, and surface temperature, the gas-sensing approach can effectively detect the thermal runaway at a very early stage. During the thermal runaway process, LiBs produce characteristic gases, such as O2, H2, carbon oxides (CO, CO2), hydrocarbons (C2H4, CH4, etc.), and fluorine gases (HF, POF3, etc.), through chemical or electrochemical reactions. As such, the thermal runaway behavior of LiBs could be monitored and early warnings can be issued by detecting the composition and concentration of the released characteristic gases. This review comprehensively presents the research progress and prospects of gas-sensing techniques for the thermal runaway of LiBs. First, the paper summarizes the main causes and processes of the thermal runaway of LiBs. Next, the characteristic gas generation and corresponding detecting techniques are described. Then, this paper elaborates on the research progress on the gas detecting and sensing technologies for the early warning of the thermal runaway. Furthermore, gas-sensing technologies for the early warning in the thermal runaway in LiBs are proposed. This review provides guidance for the gas sensing technologies to achieve an early warning system of the thermal runaway in LiBs. Moreover, the findings of this study show the development of LiBs with high safety and high energy density.
Keywords:lithium-ion batteries
;
thermal runaway
;
early warning
;
gas releasing
TAN Zejie. Research progress of gas-sensing technologies for the monitoring and early warning of thermal runaway in lithium-ion batteries[J]. Energy Storage Science and Technology, 2023, 12(11): 3456-3470
(4)正极材料的热分解反应:当电池温度达到170 ℃时,正极活性材料[如LiFePO4(LFP)、过渡金属氧化物(LiCoO2(LCO)、LiMn2O4(LMO)、Li(Ni x Co y Mn z )O2(NCM)等)]与电解液发生歧化和分解反应,释放O2和大量热。这个过程被认为对热失控过程中的产热有最大贡献[53-54]。
Fig. 3
Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]
在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89]。如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析。他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重。原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变。Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差。不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测。但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号。张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)]。他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%。
Fig. 4
(a) Schematic of the gas analysis system with GC; (b) Comparison of the gas volume and gas-releasing rate in different LIBs; (c) Gas components of the LIB with LFP cathode during thermal runaway[87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率。Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O。Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物。Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加。
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... [30](a) Schematic of the thermal runaway detection setup; (b) Readings of the various sensors in the thermal runaway process[30]Fig. 12 热失控气体探测技术2.1 热失控气体及其产生机理
... (4)正极材料的热分解反应:当电池温度达到170 ℃时,正极活性材料[如LiFePO4(LFP)、过渡金属氧化物(LiCoO2(LCO)、LiMn2O4(LMO)、Li(Ni x Co y Mn z )O2(NCM)等)]与电解液发生歧化和分解反应,释放O2和大量热.这个过程被认为对热失控过程中的产热有最大贡献[53-54]. ...
1
... (4)正极材料的热分解反应:当电池温度达到170 ℃时,正极活性材料[如LiFePO4(LFP)、过渡金属氧化物(LiCoO2(LCO)、LiMn2O4(LMO)、Li(Ni x Co y Mn z )O2(NCM)等)]与电解液发生歧化和分解反应,释放O2和大量热.这个过程被认为对热失控过程中的产热有最大贡献[53-54]. ...
... [63];(b) 不同SOC产气对比 [74];(c) 不同加热方式(加热棒、弹簧加热)产气对比(数据来源于ref.[78]);不同 (d) 加热温度和 (e) 加热功率下CO产气对比[79]Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... [63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... 在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89].如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%.
(a) Schematic of the gas analysis system with GC; (b) Comparison of the gas volume and gas-releasing rate in different LIBs; (c) Gas components of the LIB with LFP cathode during thermal runaway[87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
... [68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... ; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... ; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
Comparison of the gas releasing in LIBs with respect to (a) cathodes[63]; (b) SOC [74]; and (c) different heating modes (heating by cylindrical heating rod and spring heating ring), data are from ref. [78]; comparison of CO releasing during the LIB thermal runaway (a) at different temperatures, and (e) with different heating powers[79]Fig. 3
... 在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89].如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%. ...
... [87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%. ...
... [87];(d) Raman谱气体检测系统示意图;(e) 不同体积分数CO2 的Raman峰变化[89];(f) 气体传感器热失控气体监测系统示意图;(g) 热失控过程中不同气体的浓度变化[68](a) Schematic of the gas analysis system with GC; (b) Comparison of the gas volume and gas-releasing rate in different LIBs; (c) Gas components of the LIB with LFP cathode during thermal runaway[87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
... [87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
1
... 在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89].如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%. ...
4
... 在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89].如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%. ...
... [89];(f) 气体传感器热失控气体监测系统示意图;(g) 热失控过程中不同气体的浓度变化[68](a) Schematic of the gas analysis system with GC; (b) Comparison of the gas volume and gas-releasing rate in different LIBs; (c) Gas components of the LIB with LFP cathode during thermal runaway[87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
... [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
4
... 在密闭空间中引发LIBs热失控,并将产生的气体通过注射器或者载气(Ar、N2等)导出至GC、MS、FTIR、Raman等中可以进行电池热失控气体成分和浓度检测[9,60,87-89].如图4(a)所示,Wang等人[87]在固定体积的容器内加热引发电池热失控,通过容器压力变化结合理想气体状态方程计算产气体积;并用取样袋收集气体,通过GC对热失控过程释放的气体进行定性和定量分析.他们指出不同电极的电池热失控产气量和产气速率的顺序为NCM811>NCM622>NCM523>NCM111>LFP[图4(b)];而且依据GC数据分析可知,尽管LFP和NCM电池热失控产气成分相似(均为CO2、H2、CO、C2H4、CH4、C2H6、C3H8和C3H6,其含量超过总量的95%),但是LFP电池产生的H2含量[36%,图4(c)]高于NCM(15%~20%),表明LFP电池在热失控后排放气体的爆炸危险将比NCM电池的严重.原位差分电化学质谱法(differential electrochemical mass spectrometry,DEMS)可用于研究LIBs电化学过程中的气体演变.Xiao团队[88]使用DEMS定量研究单晶和多晶LiNi0.76Mn0.14Co0.10O2正极材料在工作过程中产生的气体(如CO2、CO、O2和H2)的来源和演变,发现相较于单晶LiNi0.76Mn0.14Co0.10O2,多晶LiNi0.76Mn0.14Co0.10O2由于比表面积大,在长期循环过程中由于表面碳酸锂盐和电解液氧化分解,导致热失控释放O2和H2产速快、产量高,因此以多晶LiNi0.76Mn0.14Co0.10O2为正极活性材料的LIBs安全性较差.不同于GC技术,Raman光谱技术具有高时间分辨率、高通量且无需气体组分分离和预处理过程的优点,能够对热失控气体进行实时分析,得出气体在热失控阶段中的变化规律,对LIBs热失控危险进行预测.但是Raman光谱中除含有目标信号外,还含有各种噪声信号,需要在测试过程中扣除光谱基线背景并对光谱进行降噪处理,才能得出准确的气体信号.张伟团队[89]对18650型三元LIBs进行热滥用实验,采用离散小波变换和自适应迭代重加权最小二乘法对Raman数据进行预处理,再结合偏最小二乘定量模型和Kennard-Stone算法构建了包括空气成分(N2、O2)在内的特征气体的拉曼光谱定量回归模型,从而原位分析了锂离子热失控实际场景中特征烃类和非烃类气体的信息变化[图4(d)和4(e)].他们确定了电池热解气体的主要成分为CO2、CO、H2、CH4、C2H4以及C3H6,总体积超过电池热解气体总体积的98.6%. ...
... [89];(f) 气体传感器热失控气体监测系统示意图;(g) 热失控过程中不同气体的浓度变化[68](a) Schematic of the gas analysis system with GC; (b) Comparison of the gas volume and gas-releasing rate in different LIBs; (c) Gas components of the LIB with LFP cathode during thermal runaway[87]; (d) Schematic of the gas diagnosis system by using Raman spectroscopy; (e) Raman peaks as a function of CO2 volume ratios [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
... [89]; (f) Schematic of the gas diagnosis system with gas sensors; (g) Concentration changes of different gases collected during thermal runaway process[68]Fig. 4
此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
1
... 此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...
1
... 此外,将以上气体分析技术联用也是近年来LIBs热失控气体检测的重要发展趋势,可以提升对气体种类和浓度的分辨率.Srinivasan等人[90]采用FTIR和GC-MS联用,对LTO||LMO软包LIBs产气行为进行离线化学分析,指出电池热失控前会有大量有机碳酸酯(如DMC、EC、PC等)排出;而热失控发生后最终气体产物主要是碳酸酯氧化分解所产生的CO2、CO和H2O.Gachot等人[91]将GC-MS与电喷雾电离高分辨质谱法(electrospray ionization mass spectrometry,ESI-HRMS)相结合,利用GC-MS可分析具有高挥发性产物和ESI-HRMS识别中等挥发性成分(如环氧乙烷低聚物)的优点,研究电池中电解质的热/电化学降解产物.Zhang等人[60]结合Raman光谱和GC-MS检测对18650型LIBs热失控过程所释放的气体进行解析,发现热失控气体成分主要以CO2、CO和一些碳氢化合物气体为主,且其浓度呈现先迅速增加后缓慢上升的趋势;并且随SOC增加,内部材料中发生的副反应越多,LIBs热失控后产生的气体量、热失控严重程度和热失控后的质量损失均增加. ...