Thermal Gases Research Articles

Explosion dynamics for thermal runaway gases of 314 Ah LiFePO4 lithium-ion batteries triggered by overheating and overcharging

Thermal runaway (TR) of LiFePO4 lithium-ion batteries (LFPs) can produce significant amounts of smoke, posing serious explosion hazards. This paper systematically investigated TR gas generation, explosion limits, explosion overpressure, and post-explosion gas compositions of 314 Ah LFPs under overcharging and overheating. Quantum chemical and explosion reaction kinetics calculations clarified the elementary reactions and compositional alterations occurring in gases and free radicals during the explosion process. The findings revealed that H2 constituted the primary component of TR gases, comprising 47.64 % and 53.12 % of the overcharging and overheating, respectively, followed by CO2 and CO. The ranges of explosion concentration for TR gases, when subjected to overheating and overcharging conditions, were 6.32–29.3 % and 6.83–26.91 %, respectively. At the point of maximum explosion overpressure (Pmax), the gas concentrations peaked at 15.86 % and 16.25 %. The elementary reaction R1 held a pivotal position in enhancing the explosion overpressure. As the TR gas concentration escalated, the Rate of Production (ROP) of R31 and R35 also surged, ultimately resulting in elevated concentrations of CO. The reactions R123, R250, and R279 facilitated the generation of H2 while simultaneously consuming hydrocarbon gases. This resulted in a risk of secondary explosion of the TR gas after the explosion. Post-explosion gas residual quantities followed the order: C2H6 < C2H4 < CH4 < H2 < CO. The results revealed crucial insights for developing explosion prevention and suppression in the process safety industry and Energy Storage Systems.

Transition metal enhanced black phosphorus for early thermal runaway gas detection of lithium-ion batteries: A theoretical study

Lithium-ion batteries have seen widespread use, bringing the issue of thermal runaway into sharp focus. Thermal runaway can be diagnosed by the characteristic gases produced (CO2, H2, CO, CH4, C2H4, C2H6). Black phosphorus (BP) with corrugated plane was utilized as the base material, enhancing its chemical activity with transition metals (Au, Ag, Pt, Pd). The four transition metal-enhanced BPs can selectively adsorb CO and C2H4 with different response characteristics, which can be used to identify CO and C2H4. This study provides theoretical guidance for the engineering application of transition metal-enhanced BP in monitoring thermal runaway gases in lithium-ion batteries.

Metal clusters modified hexagonal boron nitride for adsorption and sensing of lithium batteries thermal runaway gases

Developing efficient gas sensing materials for monitoring lithium batteries thermal runaway gases is essential for human safety. In this study, a detailed examination of the CH4, CO2, CO, and H2 adsorption property for the h-BN with metal clusters modification was conducted utilizing density functional theory. The incorporation of metal clusters (Pd4, Rh4, and Ru4) significantly improved the adsorption energy and charge transfer of h-BN towards gases compared to the unmodified h-BN. The Ru4/h-BN system demonstrated the highest adsorption capacity across all four gases, while the Pd4/h-BN system displayed remarkable recovery ability at room temperature (298 K). Furthermore, studying the adsorption mechanism via DOS revealed enhanced gas adsorption due to orbital hybridization. The work offers reliable theoretical foundation for the detection and prevention of thermal runaway gases in lithium batteries through the use of h-BN modified with metal clusters.

Enhancing detection of thermal runaway gases: Exploiting doping and vacancy effects in GeS quantum dots

This study investigates chemical modifications on Germanium Sulfide (GeS) quantum dots (QDs) for selective detection of thermal runaway gases (TRGs). We examine how doping with oxygen, phosphorus, silicon, and introducing sulfur vacancies at edge and surface regions affect the structural, electronic, and optical properties of GeS-QDs and their derivatives. Our findings reveal significant changes in bond parameters, formation energy, electronic band gap, and light absorption behavior. Oxygen doping enhances stability, while other dopants and sulfur vacancies increase reactivity towards TRGs (H2, CO, CH4, C2H4). All materials show favorable adsorption for these gases, with C2H4 displaying the strongest binding affinity. Adsorption minimally affects core electronic structure (HOMO) but shifts surface electronic states (LUMO). Sulfur vacancies reduce the energy gap, enhancing conductivity and facilitating TRGs detection. These results suggest that GeS-QDs can be effectively tuned for selective TRG detection by manipulating their chemical composition and surface characteristics.

Theoretical designing of Ni-doped PtSTe monolayer as a promising gas sensor upon thermal runaway gases in the Li-ion battery

This study proposes Ni-doped Janus PtSTe (Ni-PtSTe) as a novel sensing material for detecting three critical gases (CO, CO2, and C2H4), with potential applications in gas sensors and Li-ion battery monitoring. The Ni-doping favors the Te surface of the PtSTe monolayer, with a formation energy of -1.19 eV. The adsorption capacity follows the order: CO > C2H4 > CO2, with chemisorption in CO and C2H4 systems and physisorption in CO2 system. The analysis of electronic properties in gas adsorbed Ni-PtSTe systems indicate a reduced bandgap in CO and C2H4 systems, resulting in the sensing response of 99.25% and 97.71%, respectively. The work function increases significantly in the presence of CO and C2H4, suggesting its suitability as a work function-based sensor. These results highlight the promising sensing capabilities of Ni-PtSTe monolayer, expanding the horizon for PtSTe-based materials and inspiring cutting-edge research.

Adsorption and sensing properties of Pd-doped Janus HfSSe monolayer for thermal runaway gases in lithium-ion batteries: A DFT study

Detecting thermal runaway gases in lithium-ion batteries (LIBs) is an effective means of identifying early battery failures and is significant in ensuring the safe operation of LIBs. This work investigated the adsorption characteristics of CO2, CO, H2, CH4, C2H2, C2H4, and H2O on intrinsic and Pd-doped HfSSe monolayers using density functional theory (DFT). Our calculations showed that all gases were physically adsorbed on the intrinsic HfSSe monolayer, but the Pd-doped HfSSe monolayer had an enhanced adsorption effect for gas molecules. Additional computations of the band structure, deformation charge density, density of states, and frontier molecular orbitals revealed that the Pd-HfSSe monolayer demonstrated superior CO and C2H4 adsorption and sensing capabilities. The analysis of recovery time revealed that Pd-HfSSe may be used as a gas sensor for identifying C2H4. This study provides a theoretical basis for applying Pd-HfSSe as a gas sensor to detect thermal runaway gases in LIBs.

Experimental investigation of explosion hazard from lithium-ion battery thermal runaway effluent gas

Fire and explosion hazards present a serious concern to the widespread adoption of battery technology. This work experimentally investigates the explosion hazards associated with synthesized lithium-ion battery thermal runaway effluent gases (TREG) in an enclosed garage space typical of modern construction in North America. Pressure rise inside the compartment is examined using high-frequency piezoelectric pressure transducers. Data on overpressure and impulse is compared with known ranges for structural damage and bodily injury thresholds and calculation methods for maximum overpressure. Data on time-resolved overpressure are compared with a vented explosion model from literature. These comparisons support that existing models for maximum overpressure and time-resolved pressure rise remain valid for the examined synthesized TREG. Correlations are developed between gas volume and measured impulse and overpressure. An extension of this analysis with values of TREG production from literature supports that pressures measured in these experiments can be generated from ignition of gases released from batteries sized in the range of 3300W⋅h to 80 500W⋅h.

First-principles design of PtPd bimetal dispersed WTe2 monolayer for sensing thermal runaway gases: Enhanced performance against single Pt or Pd dispersion

To conduct the early-monitoring of thermal runaway for the Li-ion battery (LIBs), this work purposes PtPd bimetal dispersed WTe2 (PtPd-WTe2) monolayer as a promising sensing material to realize the high-sensitive detection of thermal runaway gases (H2, CO, CO2, C2H2 and C2H4). The adsorption behavior of PtPd-WTe2 monolayer upon such five gas molecules are compared with single Pt- and Pd-dispersed WTe2 monolayer from the first-principles insight to highlight the combined catalytic property of two noble metal atoms. Results reveal that Pt-, Pd- and PtPd-WTe2 monolayer all behave good chemical and thermal stability at 498 K with good binding force between the noble metal atom(s) and the pristine WTe2 surface. Besides, PtPd-WTe2 monolayer behaves much enhanced adsorption performance with more negative adsorption energy and much higher sensing response with larger bandgap changing rate than Pt- and Pd-WTe2 monolayer upon five typical gas molecules. Moreover, the desorption property analysis manifests the necessity conducting the heating process to realize the reusability of PtPd-WTe2 monolayer for gas sensing. These findings manifest the strong potential of PtPd-WTe2 monolayer as a resistive gas sensor for detections of the thermal runaway gas species thus evaluating the operation status of the LIBs, which may stimulate the further deeper investigations about WTe2-based materials for gas sensing applications across multiple fields.

Fundamental Limits of Feedback Cooling Ultracold Atomic Gases.

We investigate the fundamental viability of cooling ultracold atomic gases with quantum feedback control. Our Letter shows that the trade-off between the resolution and destructiveness of optical imaging techniques imposes constraints on the efficacy of feedback cooling, and that rapid rethermalization is necessary for cooling thermal gases. We construct a simple model to determine the limits to feedback cooling set by the visibility of density fluctuations, measurement-induced heating, and three-body atomic recombination. We demonstrate that feedback control can rapidly cool high-temperature thermal clouds in quasi-2D geometries to degenerate temperatures with minimal atom loss compared to traditional evaporation. Our analysis confirms the feasibility of feedback cooling ultracold atomic gases, providing a pathway to new regimes of cooling not achievable with current approaches.

Adsorption of LIBs Thermal Runaway Gases on TM-Decorated HfS2 Surface: A DFT Study.

With the wide application of lithium-ion batteries (LIBs) in different fields, safety accidents occur frequently. Therefore, it is necessary to monitor the thermal runaway gas for an early warning. In this article, the adsorption properties of the characteristic gases of LIBs thermal runaway gases are studied by density functional theory (DFT). The adsorption structure of TM (Co/Rh/Ir)-decorated HfS2 (TM@HfS2) is established, and its adsorption properties for C2H4, CH4, and CO are studied. The adsorption energy, charge transfer, band, DOS, charge difference density, work function, and recovery time are discussed in detail. The results show that Ir@HfS2 has the strongest adsorption performance for C2H4 and CO, so C2H4 and CO can be stably adsorbed on the surface of the Ir@HfS2 monolayer. The adsorption energy of CH4 on Co@HfS2 is stronger than those of Rh@HfS2 and Ir@HfS2, but the adsorption energy is still very small. By applying biaxial strain to Co@HfS2, we found that the adsorption energy increases with the increase in negative strain. This study provides a theoretical basis for the regulation of the adsorption properties of HfS2 by different transition metals.

Adsorption performance and fitting of thermal runaway gases in power batteries on CuO-doped SnS monolayer: A DFT study

Thermal runaway failure of power batteries will release a large amount of thermal runaway gas (TRG), causing serious environmental pollution and safety accidents. Therefore, monitoring TRG is crucial to battery safety. In this paper, the adsorption capacity of TRG on SnS monolayer and SnS-CuO monolayer are compared based on DFT. SnS-CuO monolayer exhibits strong adsorption for C2H4 and CO. Compared with the SnS monolayer, the Eads are improved by 285.10 % and 527.24 %, respectively. Meanwhile, the electron affinity of TRG strongly correlates with adsorption properties (SSE < 0.06, R-square > 0.9, and RMSE < 0.2), indicating that it plays a significant role in explaining the adsorption characteristics of different TRG. Furthermore, the dielectric constant of the solvent exhibits a stronger correlation with the adsorptive properties of TRG (R-square > 0.96 and RMSE < 0.004), indicating the environmental tunability of TRG adsorption. In general, this research reveals the potential of SnS-CuO monolayer as a gas sensor for C2H4 and CO and provides theoretical guidance for exploring the impact of various TRG and solvent environments on the adsorption performance of SnS-CuO monolayer. It is expected to be widely used in TRG monitoring of power batteries in the future.

Computational investigation of pure antimonene and antimonene/bismuthene heterostructure for detecting thermal runaway gases

The widespread use of lithium-ion batteries in everyday life has emphasized the critical need for safety precautions, particularly in monitoring the release of thermal runaway gases to ensure human well-being. This study employs density functional theory (DFT) to construct adsorption models of pure antimonene, bismuthene, below and above of the heterostructure of Sb/Bi. Pure Sb and Bi exhibited semiconducting behavior, whereas the heterostructure of antimonene with bismuthene transformed the semiconducting behavior to metallic. Target gases, including C2H4, CH4, H2, CO, and CO2, were adsorbed onto these models. All gases displayed physiosorption with the studied materials. By analyzing adsorption energy, charge transfer, energy band structure, density of states, work function, sensing response, electron localization function (ELF), and recovery time, the research reveals that the heterostructure displays strong adsorption properties, a robust sensing response, and quicker desorption times, suggesting its potential as a resistive gas sensor. This theoretical exploration offers valuable insights for experimentalists aiming to design and synthesize novel, sensitive materials for detecting thermal runaway gases.

Optical control and coherent coupling of spin diffusive modes in thermal gases

Quantum science and technology devices exploiting collective spins in thermal gases are extremely appealing due to their simplicity and robustness. This comes at the cost of dealing with the random thermal motion of the atoms which is usually an uncontrolled source of decoherence and noise. There are however conditions, for example, when diffusing in a buffer gas, where thermal atoms can occupy a discrete set of stable spatial modes. Diffusive modes can be extended or localized, have different magnetic properties depending on boundary conditions, and can react differently to external perturbations. Here, we selectively excite, manipulate, and interrogate the longest-lived of these modes by using laser light. In particular, we identify the conditions for the generation of modes that are exceptionally resilient to detrimental effects such as light induced frequency shifts and power-broadening, which are often the dominant sources of systematic errors in atomic magnetometers and comagnetometers. Moreover, we show that the presence of spatial inhomogeneities in the pump introduces a coupling that leads to a coherent exchange of excitation between the two longest-lived modes. Our results demonstrate that systematic engineering of the multi-mode nature of diffusive gases has great potential for improving the performance of quantum sensors based on alkali-metal thermal vapors, and opens new perspectives for quantum information applications. Published by the American Physical Society 2024

Constructing Single-Atom Active Sites Embedded in Hexagonal Boron Nitride for Adsorption and Sensing of Lithium Battery Thermal Runaway Gases.

The utilization and selectivity of single atoms have garnered significant attention among researchers. However, they are easy to agglomerate because of their high surface energy. To overcome this challenge, it is crucial to seek suitable carriers to anchor single metal atoms to achieve optimal performance. In this work, the structures of transition metal single atoms embedded in hexagonal boron nitride (MB2N2, M = Fe, Co, Ni, Cu, Zn) are constructed and used for the adsorption and sensing of lithium battery thermal runaway gases (H2, CO, CO2, CH4) through the DFT method. The adsorption behavior of MB2N2 was evaluated through the adsorption energy, sensitivity, and recovery time. The calculation results indicate that CoB2N2 exhibits strong adsorption capacity for both H2 and CO. The sensitivity of FeB2N2 toward CO is as high as 3.232 × 1016. Subsequently, the adsorption mechanism was studied through TDOS and PDOS, and the results showed that hybridization between orbitals enhanced the gas adsorption performance. This study presents novel approaches for designing single-atom carriers and developing MB2N2 sensors for detecting lithium battery thermal runaway gases.

Explosion characteristics of lithium-ion batteries vent gases containing dimethyl carbonate at elevated temperatures

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.

A comparative DFT study on the adsorption properties of lithium batteries thermal runaway gases CO, CO2, CH4 and C2H4 on pristine and Au doped CdS monolayer

The thermal runaway gases, such as CO, CO2, CH4, and C2H4, will leak from the battery electrolyte when lithium batteries in extreme discharge or thermal runaway conditions. The structural properties, differential charge density (DCD), density of state (DOS), gas adsorption properties, desorption time, work function and front-orbit theory calculation of pristine and Au doped CdS monolayer are explored and compared by first-principle calculation. The adsorption energy of CO, CO2, CH4 and C2H4 on the surface of Au–CdS are –0.89 eV, –0.40 eV, –0.14 eV and –0.77 eV, respectively. After doping, the adsorption type of CO and C2H4 are chemical type. Partial density of states shows that the gas molecules react with doped precious metal atoms. The adsorption ability of Au–CdS can be ranged as CO>C2H4>CO2>CH4. C2H4 on the surface of Au–CdS can desorb within 10 s at room temperature. As a result, Au–CdS exhibits tremendous prospective application as CO or C2H4 gas sensor. This study demonstrates that the adsorption and sensing properties of CdS monolayer can be improved effectively by the introduction of precious metal.

Geochemical Characteristics of Thermal Springs and Insights Into the Intersection Between the Xiaojiang Fault and the Red River Fault, Southeastern Tibet Plateau

AbstractDuring the ongoing uplift and expansion of the southeastern margin of the Tibetan Plateau, the front edge of the Sichuan‐Yunnan rhombic block (SYB) has experienced intense tectonic activity and frequent seismicity. In this study, the fluid geochemistry in the primary active faults at the front edge of the SYB was investigated, with the aim of understanding the tectonic activity and intersection relationship between the Xiaojiang fault (XJF) and the Red River fault (RRF). Thermal spring water and gases exhibit a coupled spatial distribution relationship; relatively high ion concentrations and 3He/4He ratios (Rc/Ra ratios of 0.21 to 0.62Ra) are observed along the RRF, Qujiang fault (QJF), and Shiping‐Jianshui fault (SJF). Multidisciplinary research results have indicated that mantle‐derived intrusion has been detected in the crust beneath the QJF and SJF. The current tectonic activity in the front edge of the SYB remains intense, with compressive stresses shifting toward the western side of the XJF and accumulating on the QJF and SJF. This has led to the development of fractures, enhancing the water–rock interaction and deep‐derived gas degassing along the faults. The unmixing characteristics of fluids at the intersection area of these two faults suggest the absence of conduits for fluid migration between the faults. Owing to the lower gas 3He/4He ratios, lower shear strain rates, stable reservoir temperature field, and extremely low historical seismicity in the Indo‐Chinese block, it is speculated that the current movement of the XJF may not cut through the RRF and continue southward.

Internal Pressure-Temperature Coupling Analysis Method for Thermal Decomposition of GFRP Composites Based on the Overlapping Elements Method.

A method of internal pressure-temperature coupling analysis for the thermal decomposition of GFRP composites under high-temperature conditions was established, which incorporates coupled calculations of heat transfer equations, the Arrhenius equation, Darcy's law, and the ideal gas state equation. Using the overlapping mesh method, the coupling calculation of temperature and internal pressure is realized based on the UMATHT and USDFLD user subroutines developed. Specifically, two user subroutines, UMATHT-1 and UMATHT-2, are used to define the heat transfer equation and gas diffusion equation separately. Numerical simulations are conducted to simulate the polymers' thermal decomposition in high-temperature environments. For glass fiber/vinyl ester composites and glass fiber/phenolic composites, the predicted temperature and pressure values are in good agreement with experimental measurements, and porosity and permeability are then analyzed. Due to the accumulation of thermal decomposition gases, inter-pressure within the material surged and reached a peak value. After that, it began to decrease, but the factors affecting the pressure decrease vary at different positions. Specifically, the pressure closest to the heating surface is influenced by the combined effects of decomposition rate, permeability, and porosity, while the pressure far away from the heating surface is only affected by the initial permeability. The pressure in the intermediate region may be influenced by both increased porosity and initial permeability.

Cu-decorated HfS2 and Cu-embedded HfS2 for adsorption and gas sensing of lithium-ion thermal runaway gases: A DFT study

Lithium-ion batteries are found in every corner of our lives, and safety concerns have received significant attention. Therefore, monitoring thermal runaway gases from lithium-ion batteries is crucial for human safety. In this paper, density functional theory (DFT) is used to establish the adsorption models of Cu-decorated HfS2 (Cu@HfS2) and Cu-embedded HfS2 (Cu-HfS2), taking C2H4, CH4, H2, CO and CO2 as target gases. By calculating the adsorption energy, charge transfer, charge differential density, energy band, density of states, work function, sensing response, and recovery time, it is found that Cu@HfS2 has a strong adsorption effect on C2H4, CO and H2, and Cu-HfS2 has a better adsorption effect on CH4 and CO2. At room temperature, the chemisorption of CO by Cu-HfS2 is stable, the sensing response is better, and the desorption time is shorter, so it has the potential to be used as a resistive gas sensor. This study provides theoretical guidance for exploring the influence of different metal doping methods on the adsorption characteristics and gas sensing properties of HfS2.

Влияние заполнения прослоек малотеплопроводными газами на тепловую защиту оконных блоков с экранами

ISPU scientists have developed energy-saving constructions of window units with heat-reflecting screens, have tested them in a climate chamber, and have carried out simulation modeling of the heat transfer process through these constructions. Despite a large number of scientific papers that consider experimental laboratory studies and numerical simulation of heat transfer processes through translucent constructions, there is no data on the effect of the application of low thermal conductivity gases in the gaps formed by glass and metal elements on increasing the thermal protection of window units with screens. The correct calculation of the reduced heat transfer resistance of window units with screens and low-thermal conductivity gases affects the correctness of the heat balance for premises and, consequently, the quality of the design of energy systems to ensure the indoor microclimate. Thus, the development of models of heat transfer process through a window unit with screens is an urgent task to ensure the indoor microclimate. Simulation numerical modeling is carried out using the finite element method based on the fundamental laws of heat transfer. The authors have developed a two-dimensional simulation model of heat transfer through a window unit with heat-reflecting screens, in which the gaps between the glass and aluminum foil are filled with argon and krypton. The distribution of resistance to heat transfer along the height of a translucent enclosing structure has been studied. The adequacy of the proposed simulation model is confirmed by comparison with data of other scientists and regulatory documentation. Filling the gaps between glass and metal foil with argon makes it possible to increase the zonal heat transfer resistance of a window unit with screens in relation to the base-case scenario (air) by 6–23 %, krypton by 8–58 % (depending on the measurement location and the number of screens). The application of the developed simulation model will make it possible to more accurately determine the potential to use heat-reflecting screens in windows for intermittent heating systems of buildings.