Thermal Runaway Reaction Research Articles

New insights on energetic properties of graphene oxide (GO) materials and their safety and environmental risks

Graphene oxide (GO) has been recognized as a thermally unstable and energetic material, but surprisingly its environmental and safety risks were not fully explored, defined, and regulated. In this study, systematic explosivity and flammability characterizations of commercial GO materials were conducted to evaluate the influence of key parameters such as physical forms (paste, powders, films, and aerogels), temperature, heating rate, mass, and heating environment, as well as their potential safety and environmental impacts. Results based on thermogravimetric analysis (TGA) showed that GO in paste and powder forms have lower temperature thresholds (>180–192 °C) to initiate micro-explosions compared to GO film and aerogels (> 205 °C and 213 °C) regardless of the environment (inert, air, or oxygen). The observed explosive behavior can be explained by thermal runaway reactions as a result of thermal deoxygenation and decomposition of oxygen functional groups. Flammability rating and limiting oxygen index (LOI) results confirmed that GO films are flammable materials that can spontaneously propagate flame in a low oxygen environment (~11 %). These results provided new insights about potential safety and environmental risks of GO materials, which somehow were not considered, suggesting urgent actions to improve current safety protocols for labeling, handling, transporting, and storage practices from manufacturers to the end-users.

Thermal behavior and failure mechanisms of 18650 lithium ion battery induced by overcharging cycling

Overcharging is one of the most serious safety problems in large-scale application of lithium ion battery (LIB). An in-depth understanding of the failure mechanism of battery overcharge is necessary to guide the safe design of battery system. In this paper, the electrochemical performance of commercial 18650-type cylindrical battery with Li(Ni0.5Co0.2Mn0.3)O2 cathode and graphite anode as the background is evaluated with different state of charge (SOC). The dynamic thermal behavior of overcharge in adiabatic conditions is studied, and the cathode materials, separator and anode materials after long-term overcharge cycle are characterized to identify the side reactions in battery. The results show that the battery impedance increases with the increase of SOC, and thereby greatly accelerating the attenuation of battery capacity. When LIB is charged and discharged in adiabatic conditions, the battery surface temperature of 116% SOC is about 10.03 °C higher than that of 100% SOC. Therefore, the battery with higher SOC has higher heating and is easy to induce the thermal runaway reactions. During the overcharge cycle, electrolyte decomposition, transition metal dissolution and phase transformation occur at the cathode, and serious lithium plating occur at the anode, as a result, increasing battery impedance, accelerating aging and increasing heat production. These results provide feasible support for understanding the overcharge mechanism and battery management system.

Modeling Thermal Behavior and Safety of Large Format All-Solid-State Lithium Metal Batteries under Thermal Ramp and Short Circuit Conditions

Solid-state batteries are often considered to have superior safety compared to their liquid electrolyte counterparts, but further analysis is needed, especially because the higher specific energy of a solid-state lithium metal battery results in a higher potential temperature rise from the electrical energy in the cell. We construct a model of the temperature rise during a thermal ramp test and short circuit in a large-format solid-state LCO∣LLZO∣Li battery based on measurements of thermal runaway reaction thermochemistry upon heating. O2 released from the metal oxide cathode starting at ∼250 °C reacts with molten Li metal to form Li2O in an exothermic reaction that may drive the cell temperature to ∼1000 °C in our model, comparable to temperature rise from high-energy Li-ion cells. Transport of O2 or Li through the solid-state separator (e.g., through cracks), and the passivation of Li metal by solid products such as Li2O, are key determinants of the peak temperature. Our work demonstrates the critical importance of the management of molten Li and O2 gas within the cell, and the importance of future modeling and experimental work to quantify the rate of the 2Li+1/2O2→Li2O reaction, and others, within a large format solid-state battery.

Evaluation and design of structures to contain lithium‐ion battery hazards

AbstractThis article is a continuation of BakerRisk's six‐part series on Battery Energy Storage System (BESS) hazards. Thus far, the series has introduced failure types, failure frequencies, fire mitigation methods, and quantifying explosion and fire hazard consequences related to BESS hazards. Lithium‐ion (Li‐ion) batteries have the potential for severe explosion and fire hazards due to the ability of Li‐ion batteries to experience thermal runaway reactions that can continue without supplemental oxygen. These hazards can have serious consequences on human life, equipment, and building integrity. Li‐ion batteries have many uses, from cell phones to electric vehicles, and are also located in various facilities such as BESS or battery test labs. This fifth article in the six‐part series provides a review of available analytical approaches to evaluate existing structures and design new structures for protection from Li‐ion battery hazards.

Resilience assessment framework for fast response process systems

Resilience is essential to ensure safe and sustainable process operations. It plays a critical role in enabling operations in the remote and extreme environments encountered during operations held offshore or in the Arctic. Resilience is a property of the process or system, and considers three distinct characteristics: absorption, adaptation, and recovery. This work proposes a resilience assessment framework of process systems with fast responses, such as reaction systems. The three characteristics are modelled using system design variables with covariate consideration. Subsequently, these three characteristics are integrated to assess resilience. To enhance the resilience, design changes and operational interventions are explored. The proposed framework is explained using the assessment of an autocatalytic reactor as a case study. A thermal runaway reaction is modelled for resilience, and operational intervention strategy such as adding inhibition is tested to enhance the resilience of the reactor. It was concluded that as the inhibitor injection time was decreased from 5.8 min to 1 min, the value of the proposed resilience metric increased from 0.7 to 0.9. This case study confirms the applicability and effectiveness of the proposed framework.

The effect of oxygen on the thermal stability and decomposition behaviours of 1,3-dimethylimidazolium nitrate for application using STA, ARC and FTIR

The thermal decomposition and runaway reaction of 1,3-dimethylimidazolium nitrate ([Mmim]NO3), a typical nitrate IL, were studied by a simultaneous thermogravimetric analyzer (STA) and accelerating rate calorimeter (ARC). The STA results show that the thermal decomposition of [Mmim]NO3 is divided into two stages, and the decomposition behaviour is similar in nitrogen or oxygen. The experimental results under adiabatic conditions indicate that [Mmim]NO3 has higher Tmax and Pmax than other imidazolium ILs, which reflects the greater explosion hazard of [Mmim]NO3. The apparent activation energies of [Mmim]NO3 were 86 kJ/mol and 83 kJ/mol, as calculated by the F-W-O and K-A-S methods. The complete thermal decomposition gas products of [Mmim]NO3 were analyzed by thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR), and the gas released by thermal decomposition of [Mmim]NO3 does not react with oxygen. Therefore, the decomposition reaction of [Mmim]NO3 was not positively related to the concentration of oxygen, which indicated that [Mmim]NO3 could play an active role in the reactions in the presence of oxygen. The results of this study may provide theoretical and experimental basis for [Mmim]NO3 safety precautions in storage and transportation.

Experimental study on thermal runaway of sodium nitrate-containing hazardous waste during thermal treatment

Sodium nitrate-containing organic solid waste (NaNO3-OSW) has been classified as hazardous waste because it engendered severe fire and explosion risk, while large amounts of NaNO3-OSWs were generated during the metal recovery process from e-waste recently. This study aims to characterize thermal runaway behavior and reaction mechanism of NaNO3-OSW via theoretical and experimental analysis. Component characterization results show that this waste contains 23.3% wt. NaNO3, mixed with 11.8% wt. ascorbic acid, 47.2% wt. dehydroascorbic acid, and 17.7% wt. polyvinylpyrrolidone. Thermal risk assessment could provide guidance on the kind of safety measurements. Results present that this waste is thermal sensitive with high deflagration potential while its minimum ignition temperature is 290 ℃, and the maximum explosion pressure is 0.51 MPa. The predicted self-accelerating decomposition temperature is 148.3 ℃ for a standard 50 kg package. Combustion behavior characterization could offer insights into the realization of essential safety during disposal. Results reveal that the self-redox reaction between organic compounds and NaNO3 has occurred in the temperature range of 276–405 ℃. The reaction mechanism suggests that the catalytic decomposition of ascorbic acid by melting NaNO3 is the crucial factor that results in intense combustion. The findings of this study provide practical insights into the in-situ disposal of this waste by removing organic compounds at low temperatures.

Temperature Control of Exothermic Reactions Using n-Octadecane@MF Resin microPCMs Based on Esterification Reactions

Reaction thermal runaway, caused by excessive temperatures of the reaction system, threatens the safety of operators. Latent heat storage by phase change materials (PCMs) has the advantages of high energy storage density and stable temperature during the energy storage process, which was widely applied in many fields and provides a new idea for the temperature control of thermal runaway reactions. In this study, microencapsulated phase change materials (microPCMs) with a melamine-formaldehybe (MF) resin shell was fabricated by in situ polymerization. The characterization of the micro morphology, chemical bonds, crystal structure, thermal properties, and thermal stability of microPCMs showed that the prepared microPCMs had integrated spherical morphologies and smooth surfaces, with an encapsulation ratio of approximately 70% and good thermal stability. Furthermore, taking the esterification of propionic anhydride (PA) and 2-butanol (2B) as examples, n-octadecane@MF resin microPCMs was used to control the reaction temperature under various operation conditions in semi-batch reactors. The experimental results showed that the mechanism of the n-octadecane@MF resin microPCMs on the control of reaction temperature in semi-batch reactors was the combination of both physical and chemical interactions. The applications of microPCMs for the control of reaction temperature hold great potential for use in industrial processes.

Temperature distribution and pressure oscillation characteristics of di-tert-butyl peroxide overpressure relief in a confined space

Pressure relief can effectively reduce the damage caused by the thermal runaway reaction of organic peroxides in the chemical process. To further understand the overpressure relief mechanism of di- tert -butyl peroxide (DTBP), pressure vessel test system and numerical simulation method were combined to systematically analyze the dynamic relief characteristics of DTBP in a confined space. The three-dimensional spatial distribution and variation law of temperature, pressure, and airflow velocity during the relief process were also revealed. The results show that a high-speed under-expanded jet is generated when DTBP overpressure relief occurs, and low temperature and negative pressure are produced inside the vessel and near the vent. The airflow velocity first increases and then decreases during the relief process, with a maximum value of 487 m/s. Both the internal temperature and pressure show prominent damping oscillation characteristics, and the oscillation period is between 2.1 ms and 2.3 ms. The pressure oscillation curves at different positions present different peak shapes, and the closer to the vent, the smaller the pressure amplitude. The consistency between the experimental results and simulation data also verifies the reliability of the numerical model.

Experimental study on thermal runaway characteristic parameters of parallel battery modules

This work introduces a method for measuring the main physical quantities, such as short-circuit current and capacity loss, in the thermal runaway process of the parallel battery module and presents detailed analysis and discussion on a 25 Ah commercial prismatic lithium-ion ferrous phosphate (LFP) battery. By establishing a basic circuit model of the thermal runaway process of the parallel battery module, experiments were conducted to observe the thermal runaway process of the parallel battery module. The parameters related to the electrothermal effect in the thermal runaway process were obtained by either direct measurement or calculation. The results showed that the short-circuit resistance of the cell, which was triggered to thermal runaway changed dramatically. The minimum resistance was about 0.5 mΩ, and the peak current of discharge was more than 1100 A. During the stable discharge process of the other parallel cells to the thermal runaway cell, the short-circuit resistance was about 10 mΩ. In the stable discharge stage, the electric heating power was about 600 to 900 W. However, the power of thermal runaway reaction from the cell itself was still more than 30 times the heating power of the electrothermal effect, exceeding 21 kW. The accuracy of the measurement method and analysis method was also verified by comparing the same parametric data obtained using different methods. The results showed that the method is feasible for studies on the mechanism and simulation of thermal runaway of parallel battery modules.

A solid, amorphous, lithiated carbon phosphonitride displaying lithium ion conductivity

Thermal runaway reactions resulting in catastrophic battery failure and combustion have invigorated a search for non-flammable electrolytes. We report the synthesis of non-flammable inorganic lithiated carbon phosphonitride (Li–C–P–N) amorphous solids in various solvents, their spectroscopic and other characterization aimed at greater molecular structure understanding, and their ionic conductivities. The resin precursor to this polymeric material is the product of reacting solvated P(CN)3 and LiN(CN)2 ​at room temperature. The resulting resin can be cast from various polar aprotic solvents and produces Li–C–P–N films upon drying. The reaction mechanism was studied by time-resolved 31P solution NMR. A fully cured sample was studied by 31P, 13C and 7Li MAS NMR, including variable temperature 7Li MAS NMR observations of changes in satellite transitions arising from Li ​+ ​ion motions. Films dried at room temperature under inert atmosphere were temperature cycled as high as 250 ​°C to measure conductivity as a function of temperature and thermal curing. Thermally treated, partially solvated Li–C–P–N films cast from pyridine and dimethoxyethane/acetonitrile exhibit ionic conductivities as high as 10−5 ​S ​cm−1 above 100 ​°C, depending on temperature and cure procedure, although conductivity drops dramatically in films held above 150 ​°C. We propose that the conductivity of Li+ ions through the films is highly dependent on the presence and identity of tightly-bound solvent, the presence of excess LiN(CN)2 retained in the Li–C–P–N matrix, as well as the structure of the cross-linked Li–C–P–N network.

Thermal runaway front in failure propagation of long-shape lithium-ion battery

Long, large-format lithium-ion batteries have become prominent in recent years in high-power application scenarios, such as in electrochemical energy storage stations, electric vehicles, and electric ships. In these batteries, failure is always initiated from a local point and then propagates to the full cell, requiring countermeasures to quench the in-cell thermal runaway propagation. This study investigates the thermal runaway propagation behaviors of long, large-format lithium-ion batteries. A thermal runaway front exists during the propagation of thermal runaway; it separates the failure zone and normal zone and carries significant information regarding the thermal runaway reactions. The characteristics of the thermal runaway front are investigated through experiments and simulations. The thermal runaway front moves forward with an average velocity of approximately 24.14 mm·s−1, driven by the large temperature gradient between the failure and intact zones. The velocity of the thermal runaway front is correlated with the thermophysical properties of the battery. A modeling analysis indicates that the velocity of the thermal runaway front in propagation has a square root correlation with the thermal conductivity and heat generation rate. This square root correlation links the failure process and the thermophysical properties of the battery and can contribute to the future safety design of large-format batteries.

Model Discrimination for Hydrogen Peroxide Consumption towards γ-Alumina in Homogeneous Liquid and Heterogeneous Liquid-Liquid Systems

The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

Thermal Runaway and Fire Suppression Applications for Different Types of Lithium Ion Batteries

With the improvement of lithium-ion battery (LIB) technology, safety is becoming increasingly urgent topic for battery electric vehicles (BEVs). Short circuits, overcharging, high temperatures and overheating can cause thermal runaway reactions and the release of the flammable electrolyte which makes fire suppression very difficult. This study focuses on the mechanism of thermal runaway and fire suppression applications of LIBs. In order to understand this, 10 experiments were carried out. The experiments were divided into as Exp. A and Exp. B. A manual water suppression system was used in Exp. A and an automatic boron-based suppression system (AUT-BOR) was used in Exp. B. LIBs were heated in a controlled manner with a heat source and the effects of thermal runaway and fire suppression were observed. In Exp. A, a large amount of water was required to extinguish the LIB fires. The holes and slits which formed in the LIB after a fire were useful for injecting water. A projectile effect of cylindrical cells was observed in Exp. A. The Exp. B results showed that AUT-BOR mitigates risks effectively and safely. Also, AUT-BOR provides an early fire warning system and spot cooling to prevent thermal runaway reactions while localizing and suppressing the fire. In Exp. B, fire detection and suppression occurred without any explosion.

Experimental Study on Fire Characteristics of Lithium-ion Battery using Cone Calorimeter

The lithium-ion battery is the most popular type of secondary battery because of its high energy density. It has been widely used in mobile power and energy storage systems. However, several accidents can occur in systems using lithium-ion batteries, and most of the reported losses have resulted from battery fires and explosions. In this study, a cone calorimeter experiment was performed to investigate the fire characteristics of lithium-ion batteries and assess their heat release rate (HRR), which is the most representative property for fire events. Fires involving cylindrical standard batteries consist of two combustion stages. The first burning stage is due to the package material and intercalated lithium of the battery, and the second stage is attributed to the thermal runaway reactions of the electrolyte. The second combustion stage has a greater peak HRR than the first stage and is accompanied by a violent explosion. In a comparison of the HRRs with the oxygen consumption rate, the HRRs measured on the basis of the mass loss rate show higher maximum values and extremely narrow heat release times.

Thermal runaway in a prismatic lithium ion cell triggered by a short circuit

Thermal runaway response due to a short circuit in a prismatic lithium iron phosphate battery (LiFePO4) is investigated. The decomposition of both positive and negative electrodes is simulated, representing all the reported exothermic reactions during thermal runaway using lumped and segregated models. It is shown that the reaction kinetics for similar chemistries reported in literature exhibit vastly different decomposition behavior, and that experimental rate kinetics reported in literature do not match decomposition behavior. A short circuit produces thermal runaway reactions that expand initially lengthways along the electrodes and then radially until reaching the wall of the cell; once thermal runaway has reached the cell edges, it rapidly propagates along the length of the cell. Using a reduced accuracy lumped model under predicts the time to reach thermal runaway as well as the average and maximum temperatures reached inside the battery. The magnitude of the short circuit plays a critical role in determining whether thermal runaway will occur throughout a battery. Inaccurate battery material properties are shown to play only a small part in the predicted thermal runaway behavior while initial temperature of simulation, applied heat transfer coefficient and electrode void fraction have a large effect on the thermal runaway response.

The fire risk of portable batteries in their end-of-life: Investigation of the state of charge of waste lithium-ion batteries in Austria.

The increased utilisation of lithium-ion batteries in the last years does not come without cost. Due to thermal runaway and exothermic degradation reactions, portable batteries pose enormous risks to waste management systems and infrastructure in their end-of-life phase. All over Europe, the number of waste fires caused by lithium-ion batteries are rising. The risk of a battery fire is mainly influenced by the probability and severity of a thermal runaway or exothermic degradation, which depends on the current state of charge (SOC) of the respective battery. In order to determine the distribution of the SOC which is one of the main influence factors to waste fires caused by lithium-ion batteries, 980 waste battery cells were representatively sampled, manually dismantled and analysed using a prototypic laboratory test stand. Approximately 24% of the analysed cells and batteries had a residual SOC of at least 25%, and approximately 12% had a residual SOC of at least 50%. Hence, approximately every fourth to eighth portable battery threatens to cause a waste fire when critically damaged. Furthermore, a distinct relationship between the actual cell voltage and the residual SOC was found for end-of-life portable batteries.

PH-Based Control of the Kinetics and Process Safety of the Highly Exothermic Reaction Between Ammonium Chloride and Sodium Nitrite for Flow-Assurance Applications

Summary The highly exothermic reaction between ammonium chloride (NH4Cl) and sodium nitrite (NaNO2) has an important application in the area of flow assurance. Because of the high heat generation, this reaction has been used as a heat source for the fluidization of low-melting-point deposits formed during oil and gas production. Because this reaction is strongly pH dependent, the incorrect choice of pH can result in an uncontrollable temperature increase caused by the system’s inability to dissipate the large amount of heat generated in a short time, causing accidents such as structural damage and explosions. Thus, the aim of this work was to study a method that involved adjusting the pH over time to ensure controlled heat generation, with high calorimetric conversion, and avoid the development of a thermal-runaway reaction (pH-based control of the kinetics and process safety). The kinetics and thermodynamics of this reaction were studied using heat-flow reaction calorimetry and attenuated total reflection (ATR)-Fourier-transform infrared (FTIR) (ATR-FTIR) spectroscopy. Following a semiempirical approach, calorimetric and spectroscopic data were fitted to a kinetic equation using nitrite, ammonium (NH4+), and hydronium concentrations. The molar enthalpy calculated was –322.92 kJ/mol, and the Arrhenius parameters were determined as the frequency factor [ln(A)] = 22.21 and the apparent activation energy (Ea) = 63.40 kJ/mol. The kinetic model constructed made it possible to properly evaluate the pH profile that should be maintained to control the kinetics (heat-generation rate) and process safety [time to maximum rate under adiabatic conditions (TMRAD)] of the reaction. The strategy of adjusting the pH over time ensured controlled heat generation and high calorimetric conversion, which cannot be achieved by simply adding catalyst at the beginning of the reaction, and minimized the risk of developing a runaway reaction. However, in real applications, the pH control must be made using the balance between the thermal risk (TMRAD) and the performance of the method (qr), because although it is possible to decrease the thermal risk (increase the value of TMRAD) by increasing the pH, this increase is accompanied by a decrease in the heat-generation rate. Thus, from the proper balance of these factors (qr and TMRAD), pH control can ensure adequate levels of heat production within an acceptable thermal risk.

Lithium-Ion Battery Thermal Runaway Electro-Thermal Triggering Method and Toxicity Analysis

In high temperature condition, lithium-ion batteries have a greater risk of thermal runaway. Lithium-ion batteries may be exposed to smoke, combustion, or even explosion, which poses a greater threat to humans and the environment. In this paper, the electro-thermal triggering method is used to induce thermal runaway of the lithium-ion batteries. The most representative ternary polymer lithium-ion battery (NMC), lithium cobalt oxide battery (LCO), lithium iron phosphate battery (LFP) in the market were selected as experimental samples, all using 18650 batteries, and then the state of charge of battery samples were adjusted to 0%, 30%, 50%, 100%. The thermal runaway reaction phenomenon of lithium-ion batteries and the surface temperature of the batteries were recorded. The positive electrode samples of the batteries were characterized by X-ray diffraction and electron microscopy, and the thermal runaway reaction products were analyzed. The results show that with the increase of the state of charge, the thermal runaway reactions of the batteries are more severe. Thermal runaway reaction products contain a large amount of toxic substances, and prevention and protection are necessary.

Thermal Hazard Characteristics of Unsaturated Polyester Resin Mixed with Hardeners.

Unsaturated polyester resin (UP) is a critical polymer material in applications of many fields, such as the chemical industry, military, and architecture. For improving the mechanical properties, some hardeners, such as methyl ethyl ketone peroxide (MEKPO) or tert-butyl peroxy-2-ethylhexanoate (TBPO), can trigger the curing reaction in UP polymerization, which causes that UP changes the structure from monomer to polymer. However, polymerization is a strong exothermic reaction, which can increase the risk of thermal runaway reaction in UP. Therefore, the mechanisms and characteristics in the thermal runaway reaction of UP mixed with hardeners should be studied for preventing and controlling UP explosion. The thermal hazards of UP mixed with hardeners were determined by thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC) analysis. According to the results, UP mixed with MEKPO exhibited a more violent mass loss and exothermic reaction than UP mixed with TBPO. Furthermore, the thermal runaway reactions of UP mixed with MEKPO or TBPO with different mixing proportions of 1:1, 3:1, and 5:1 were determined. Irrespective of MEKPO or TBPO, the mixing proportions of 3:1 exhibited a high onset temperature and low enthalpy of curing reaction (ΔHexo). This demonstrated that this proportion was safer during UP polymerization. The results of this study can provide useful information for preventing UP explosion and developing polymerization technology.