Runaway Behavior Research Articles

Cell-level hazard evaluation of 18650 form-factor Lithium-ion battery with different cathode materials

The thermal runaway process was studied in a Fire Propagation Apparatus (FPA) for three types of Lithium-ion batteries (LIB) of 18650 form-factor. Cathode materials are lithium cobalt oxide (LiCoO2, or LCO), lithium nickel manganese cobalt oxide (LiNi1/3Mn1/3Co1/3O2, or NMC), and lithium iron phosphate (LiFePO4, or LFP). All batteries have a graphite anode and were at a 100% state-of-charge. Each LIB was externally heated to a thermal runaway event, with the heat input at constant values of 20.4 or 34.1 W, which yielded heating rates on the order of 1 K/s, representative of the thermal runaway propagation process. The mass loss fraction before the thermal runaway events and the maximum values are similar under different heat inputs for a given type of LIB. For different types of LIBs, the maximum mass loss fraction shows the trend of LCO>NMC>LFP. Under the same heating condition, NMC has the highest maximum surface temperature followed by LCO then LFP. A lumped heat transfer thermal runaway model is developed using two decomposition reactions and one internal short circuit reaction to model the internal heat generation. The effective model parameters are optimized using the measured surface temperature and mass loss fraction. The model is able to simulate the thermal runaway behavior of LIB under external heating conditions and reasonably matches the experimental data of LIBs with different cathodes. The model predicts that under the same heat input condition, the thermal runaway time of LCO is shorter than NMC and LFP; the effective average internal heat generations are 22.6, 20.2, and 11.5 kJ for LCO, NMC, and LFP, respectively. The thermal runaway model will be used to predict the thermal runaway propagation in a LIB module.

Thermal runaway of lithium battery based on Star CCM+

Based on the CFD software Star CCM+, the model of square lithium battery is built, and the transient simulation is completed by using the joint simulation and three-dimensional model. The gas venting at the valve is considered. this paper studies the temperature field and flow field distribution inside and outside the cell and battery, and observes physical characteristics such as temperature, volume fraction and flow rate during thermal runaway. It lays the foundation for the subsequent study of the thermal runaway behaviour of the gas injection process and the effective avoidance of thermal runaway.

Design of Remote Monitoring System for Lithium Battery Operating Statu

The safety of lithium batteries has always been an important problem that restricts the rapid development of lithium batteries. In view of the problems such as the untimely and difficult monitoring of the thermal runaway behavior of the lithium battery energy storage system, a remote monitoring system for the operating state of lithium batteries based on ZigBee and NB-IOT technology is designed. The real-time collection of the operating parameters of lithium batteries is realized through various sensors, the whole system is constructed by the Internet of things technology, and the uploading of operating parameters is realized through the network. It is verified that the system can operate stably, collect the operating parameters of lithium battery and upload relevant data in real time, facilitate the remote monitoring of staff, and provide a strong guarantee for the safety of lithium battery energy storage system.

Effect of low-pressure environment on thermal runaway behavior of NCM523/graphite pouch cells with different overcharge cycles

In the aviation field, the development and application of electric aircraft powered by lithium-ion batteries (LIBs) have received extensive attention. However, abuse due to overcharge poses a significant obstacle to its safe application. In this work, to investigate the thermal runaway (TR) behavior of overcharged LIBs in low-pressure flight environment, the TR characteristics of NCM523/graphite pouch cells with different overcharge cycles at 30 kPa are studied. The results suggest that the increase of overcharge cycles leads to a decrease of thermal stability, and an increase of TR intensity and heat release of the LIBs. In addition, the TR jet intensity at 30 kPa is significantly stronger than that of 95 kPa due to the larger differential pressure for the release of combustibles. The TR intensity and heat release at 30 kPa are significantly weaker than that of 95 kPa due to the lower oxygen content for burning. The electrochemical analysis and the disassembly photos confirm the destruction of electrode structure and the deposition of lithium. The X-ray computed tomography images and X-ray diffraction patterns suggest that the side reactions in the inner layer of the cell are more obvious than the outer layer, and the internal deformation expands from the inside out.

Healthcare Use and Case Characteristics of Commercial Sexual Exploitation of Children: Teen Victims Versus High-Risk Teens.

The overall goal of this study was to provide further information about the characteristics of commercial sexual exploitation of children (CSEC) victims by comparing the characteristics of a known victim pool to high-risk patients identified. The specific objectives of this study were to describe patient demographic characteristics, pediatric healthcare use, familial psychosocial characteristics, and child sexual abuse case characteristics present in youth identified as high risk for CSEC victimization compared with a sample of known victims. A retrospective chart review was conducted on patients presenting to the emergency department or Child Advocacy Center for a concern of sexual abuse/assault at a midwestern U.S. academic pediatric medical center. Adolescents aged 12-21 years were included in the study. In the current study, multiple CSEC risk factors were noted to increase odds for CSEC victimization: homelessness or life on the streets, runaway behavior, living with mother only, placement in a juvenile detention center, placement in a residential treatment center or group home, and number of living arrangements (four or greater). Multiple elements of high-risk sexual behavior increased odds of CSEC victimization: legally age-inappropriate sex, gonorrhea diagnosis, trichomonas diagnosis, other sexually transmitted infection (STI) diagnoses, number of STIs, and chlamydia diagnosis. These findings suggest that age of sexual partners and number and types of STIs are associated with CSEC and should be validated in other groups. In addition, these data suggest that use of cocaine and opiates could serve as an important, yet underrecognized, risk factor.

Visual and thermal imaging of lithium-ion battery thermal runaway induced by mechanical impact

In this work, a rig was constructed to conduct destructive impact tests on cylindrical lithium-ion battery (LIB). The rig was intended to simulate the loss of mechanical integrity of the battery structure that might arise from heavy load and high impact. Thermal runaway behaviour of LIB from the tests was recorded by visual camera, thermal imaging and thermocouples. The findings revealed that there were two main hazards from mechanical impact on LIB. The first hazard originates from the reactive metallic electrodes that reached a very high temperature as a result of short-circuit and thermal runaway. Thermography of the aftermath showed that the battery content reached a temperature higher than 800 °C. The second hazard is the flame erupted due to the ignition of flammable electrolytes and combustible gases produced by battery components. As shown by thermography, the flame temperature can be higher than 500 °C. Even though violent failure behaviour was observed from the impact test, the large amount of heat was unable to induce thermal runaway reactions in the neighbouring cells. Thermography showed that all the surrounding cells remained at room temperature after the impact. Limited contact surface area retards the heat transfer process and deters the propagation of thermal runaway to the neighbouring cells.

Thermal Runaway and Fire Behaviors of Lithium Iron Phosphate Battery Induced by Overheating and Overcharging

Thermal Runaway and Fire Behaviors of Lithium Iron Phosphate Battery Induced by Overheating and Overcharging

Pressure Effect on the Thermal Runaway Behaviors of Lithium-Ion Battery in Confined Space

Pressure Effect on the Thermal Runaway Behaviors of Lithium-Ion Battery in Confined Space

Giving a voice to adolescents in residential care: Knowledge and perceptions of commercial sexual exploitation and runaway behavior

Commercial sexual exploitation of children (CSEC) is a multifaceted global phenomenon in which adolescents involved in the child welfare system form a high-risk population. However, studies conducted in European countries remain scarce. We recruited a sample of 67 adolescents (50.7% girls and 47.8% boys) aged between 13 and 18 years old (M = 15.8; SD = 2.2) in residential care in the child welfare system in the south-east of Spain, and surveyed them about their runaway behavior, knowledge and perception of CSEC, and possible related preventive measures. Using a mixed-methods approach, we found that 47.8% of the adolescents reported having run away from the residential center and 92.5% knew someone that had run away. A total of 71.6% of the adolescents were aware of the problem of CSEC, and demanded more education and protection. They highlighted various motivations for engaging in this type of behavior. The use of ICT emerged as an important risk factor to take into account in prevention programs.

Study of thermal runaway and the combustion behavior of lithium-ion batteries overcharged with high current rates

Overcharged lithium-ion batteries can experience thermal runaway that can cause spontaneous combustion or an explosion. By measuring the heat release rate, surface temperature, flame temperature, positive and negative electrode temperature and mass loss of 18650 NCM lithium-ion battery, the combustion and explosion characteristics of lithium-ion battery under different current rates were analyzed. The results show that the 18650 lithium-ion battery undergoes two thermal runaway behaviors when overcharge at a high current rate. The first thermal runaway leads to a continuous explosion reaction, while the second thermal runaway has a combustion and explosion reaction that is more violent than the first thermal runaway. As the current rate increases from 1 C to 3 C, the time for the first thermal runaway to occur decreases from 1554 to 360 s, the time for the second thermal runaway to occur decreases from 2515 to 522 s, and the explosive response becomes more violent.

Aging effect delays overcharge-induced thermal runaway of lithium-ion batteries

This research focuses on the effect of overcharging on aged batteries, and the experiments aim to show the thermal runaway (TR) behavior of batteries with different degrees of aging. In order to clarify the typical behavioral characteristics of overcharge-induced battery thermal runaway, commercial 18,650 type LiMn2O4 (LMO)/graphite batteries with different capacity retention rates (CRRs) were applied for overcharge testing operation. The changes of external characteristics, such as surface temperature, voltage and fire explosion phenomena of aged batteries during the whole process of thermal runaway under overcharge conditions were investigated. The results showed that the battery TR trigger time was negatively correlated with the CRR. The batteries having CRR of 86.7%, 80.8%, and 75.2% took 28.2%, 32.5%, and 52.0% longer than fresh battery to reach the TR triggering temperature. Besides, they took 54.1%, 91.8% and 115.1% longer than fresh battery to reach the lithium plating time point. The deposition of manganese oxide on the cathode surface and the phenomenon of lithium plating on the anode surface together lead to the reduction of reversible lithium. With the deepening of aging, the amount of reversible lithium inside the battery decreases, which is the main reason why the TR trigger time is delayed.

(Digital Presentation) Modeling Thermal Behavior and Safety of Large Format All-Solid-State Lithium Metal Cells Under Thermal Ramp and Short Circuit Conditions

We are submitting this abstract in the understanding that a virtual option is likely to be offered for the Spring, 2022 ECS meeting. We are only interested in the virtual option for this presentation. It has often been posited that solid-state batteries are inherently safer than liquid electrolyte Li-ion batteries because there is no flammable organic solvent present in the battery. However, thermal safety is a multi-faceted issue with other considerations such as onset temperature, maximum temperature, total heat generation, maximum heating rate, etc. These considerations need to be looked at in greater detail, including their dependence on the volumetric and gravimetric energy densities. Safety concerns become even more important as stable graphite anodes are replaced with potentially highly reactive and energetic lithium metal anode. In this presentation, we will report on our work using differential scanning calorimetry (DSC) heat flow data to construct a transient, 2D model of heat generation and temperature distribution in a large format cell with a LixCoO2 cathode, Li7La3Zr2O12 solid electrolyte, and lithium metal anode. We will present on the thermal runaway behavior of this cell chemistry during a thermal ramp test in an oven and due to the formation of an internal short circuit. Our analysis will focus on the total amount of heat generated, onset temperature for self heating, maximum temperature, and maximum heating rate. We also analyze how the battery state of charge affects these properties. Related work in our group focuses on collecting DSC data for Li metal solid state cells and may also be highlighted.

(Digital Presentation) An Electrochemical-Thermal Coupled Thermal Runaway Multiphysics Model for Lithium Polymer Battery

With the rising energy demand, safe and efficient energy storage technologies have been increasing in importance. Lithium-ion batteries (LIBs) have been dynamically prevalent as energy storage and power sources for various electrical systems, from communication purposes to transportation applications. Lithium Polymer (LiPo) batteries are a subcategory of LIBs that use a solid or semisolid (gel) polymer to act as both a separator and electrolyte for the system. Compared to a conventional liquid electrolyte, gel polymer electrolyte is more thermally and electrochemically stable and relatively safer. Various companies produce a vast number of different LiPo batteries; however, a limited number of studies have been conducted concerning modeling and simulation. Besides exploring new materials for performance enhancement, engineering a reliable model is equally vital to exploit and optimize existing LiPo batteries' potential.In this study, a multiphysics model for a mobile Lithium Cobalt Oxide (LCO)-graphite- Poly(vinylidene fluoride - hexafluoropropylene) (PVdF-HFP) pouch LiPo battery was established to characterize the battery's behavior. The pseudo-2-dimensional electrochemical model and 3D thermal-thermal runaway model were coupled with temperature and heat generation variables. Working voltage and temperature during galvanostatic discharge were examined for the electrochemical-thermal model. In contrast, temperature as a function of time during an oven test was analyzed for thermal runaway models. The electrochemical-thermal and thermal runaway behavior was investigated using the simulation model, and validations were compared with experimental data. Overall, the models can be employed as a design tool to evaluate the component design and estimate the system performance of LiPo batteries for commercial applications.KEYWORDS: Multiphysics model, Lithium-polymer battery, Thermal runaway

Dendrite‐accelerated thermal runaway mechanisms of lithium metal pouch batteries

AbstractHigh‐energy‐density lithium metal batteries (LMBs) are widely accepted as promising next‐generation energy storage systems. However, the safety features of practical LMBs are rarely explored quantitatively. Herein, the thermal runaway behaviors of a 3.26 Ah (343 Wh kg−1) Li | LiNi0.5Co0.2Mn0.3O2 pouch cell in the whole life cycle are quantitatively investigated by extended volume‐accelerating rate calorimetry and differential scanning calorimetry. By thermal failure analyses on pristine cell with fresh Li metal, activated cell with once plated dendrites, and 20‐cycled cell with large quantities of dendrites and dead Li, dendrite‐accelerated thermal runaway mechanisms including reaction sequence and heat release contribution are reached. Suppressing dendrite growth and reducing the reactivity between Li metal anode and electrolyte at high temperature are effective strategies to enhance the safety performance of LMBs. These findings can largely enhance the understanding on the thermal runaway behaviors of Li metal pouch cells in practical working conditions.

Experimental study on the runaway behaviors of Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 battery used in electric vehicle under thermal failure

Experimental study on the runaway behaviors of Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 battery used in electric vehicle under thermal failure

Evaluation of Large-Format Lithium-Ion Cell Thermal Runaway Response Triggered by Nail Penetration using Novel Fractional Thermal Runaway Calorimetry and Gas Collection Methodology

To simultaneously optimize the battery design, reduce risk, and maintain safety margin, it is important to design from the ground up based on test determined cell-specific thermal runaway behavior as a function of heat output and analysis of the expelled gases. These data will inform the analytical models used for design optimization. Here we analyze the thermal runaway behavior of the 134 A-h GS Yuasa Li-ion cell (LSE134) using a novel large format fractional thermal runaway calorimeter and gas collection methodology. Results indicate an average total thermal runaway energy yield of 2.86 MJ, or 1.6 times the stored electrochemical energy; this follows an assertion commonly found in literature that energy yield scales linearly with capacity. The average fractional energy distribution was 2% through the cell body, 53% through the electrode winding, and 45% through the ejecta material and gases. Lot-to-lot variability in heat output was also identified. Additionally, it was found that an average of 416.6 SL of gas was generated which is approximately 3.1 l A-h−1. The exhaust gas was determined to be a mixture of carbon dioxide, methane, ethane, oxygen, hydrogen, and other short chain hydrocarbons. Carbon dioxide was the largest component by volume with a range of 41% to 52% followed by hydrogen which ranged from 28% to 41%. Larger cells appear to result in strong ejecta flow driven events with higher fractions of the total energy delivered via the flow as compared to smaller format Li-ion cells (e.g. 18650 and 21700).

Predictors of runaway behavior in adolescent Saudi girls

The phenomenon of girls running away from home is an increasingly widespread social challenge confronted by families, welfare agencies, and governmental organizations in Jeddah, Saudia Arabia. This study compared runaway girls and a control group on various measures and investigated the predictors of runaway behavior among Saudi adolescent girls. A sample of young adolescent girls (N = 77, aged between 14 and 21 years) included a purposive sample of runaways (N = 33), comprised of all the girls living in a social care home in Jeddah who had left their homes at least once, and a control group (N = 44) selected via cluster sampling. The participants were assessed using a demographic questionnaire, the Family Cohesion Scale, and the Basic Psychological Need Satisfaction Scale. Inter-group differences were apparent and differences were also found based on the circumplex model. The results of the stepwise discriminant analysis showed six variables (family cohesion, age, education, number of sisters, number of brothers, and birth order) that remained and explained 80.82% of group membership variation. Lack of family cohesion, along with several demographic variables, can lead to complicated emotional attitudes among adolescent girls which trigger runaway behavior. Although runaway youth services must continue to stay focused on safety and short-term residential care, the underlying causal factors must be identified as well.

A coupled conjugate heat transfer and CFD model for the thermal runaway evolution and jet fire of 18650 lithium-ion battery under thermal abuse

Thermal runaway (TR) is a major safety concern for lithium-ion batteries. A TR model incorporating the resulting jet fire can aid the design optimization of battery modules. A numerical model has been developed by coupling conjugate heat transfer with computational fluid dynamics (CFD) to capture the cell temperature and internal pressure evolution under thermal abuse, venting and subsequent combustion of 18650 lithium-ion batteries. The lumped model was employed to predict the thermal abuse reactions and jet dynamics, while the vented gas flow and combustion were solved numerically. Model validation has been conducted with newly conducted experimental measurements for the transient flame height of jet fire and temperatures at selected monitoring points on the cell surface and above the cell. The validated model was then used to investigate the effect of the SOCs on the evolution of TR and subsequent jet fires. Increasing SOCs shortens the onset time of TR and enlarges the peak jet velocity. The peak heat release rates and flame height of the jet fire increase with the increase of SOC. The developed modeling approach extends the TR model to jet fire and it can potentially be applied to assist the design of battery modules. • A coupled conjugate heat transfer and computational fluid dynamics model. • Dynamic boundary conditions to couple internal and external parameters. • Capturing thermal runaway and jet fire behavior of lithium-ion battery.

Sexual abuse, psychological symptoms and hopelessness among runaway female adolescents in Turkey

ABSTRACT This seminal study from Turkey investigates sexual abuse (SA) victimization, psychological symptoms, and hopelessness in female adolescents with runaway behavior. A total of 76 female adolescent participants aged 15–18 completed the Brief Symptom Inventory (BSI) and Beck Hopelessness Scale (BHS). Among these adolescents, 63.1% (n = 48) were victims of SA, 61.8% (n = 47) had a Global Severity Index (GSI) T-score of 63 or above, and 68.4% (n = 52) had moderate–severe hopelessness. Although there was no significant difference, the SA rate was higher in those who had experienced SA before running away. ‘Intrafamilial relationship problems’ and ‘SA-related factors’ were the most frequently reported reasons for runaway behavior. Victims of SA had significantly higher scores in all BSI subdimensions and global symptom severity than those previously not SA victims. The results suggest that high levels of psychological symptoms, hopelessness, history of SA, and poor parent–child relationships are possible factors that can describe female adolescents who have run away from home. Psychosocial prevention programs involving adolescents and parents are needed to prevent at-risk female adolescents from running away from home.

Towards A Theory of Why Kids Run Away: Evaluating Strain and Control Mechanisms to Account for First-time Running Behavior Among Males vs. Females

ABSTRACT Between 5–9% of American adolescents experience 1+ episode of independent homelessness. Although multiple stressors have consistently been shown to precede runaway behavior, sampling homeless populations fails to capture variation between juveniles who run/do not run. This research uses Waves I and II of the Add Health public use data to examine conditions likely to result in a first-time run among males vs. females. Specifically, we argue that strains/negative emotion derived from Agnew’s general strain theory and social controls derived from Hirschi’s social bond theory will act as positive and negative motivations, respectively, to predict first-time runs. We find significant, main effects on running for multiple strain and control measures. However, results of our integrated models suggest that, while composite strain and depression increase the odds of running across gender, composite social control is associated with lower odds of running for females only. This finding underscores prior research suggesting that social bonds may have a stronger protective impact on females considering a first-time run.