Abuse Conditions Research Articles

Sequential Multi-Scale Modeling Using an Artificial Neural Network-Based Surrogate Material Model for Predicting the Mechanical Behavior of a Li-Ion Pouch Cell Under Abuse Conditions

To analyze the safety behavior of electric vehicles, mechanical simulation models of their battery cells are essential. To ensure computational efficiency, the heterogeneous cell structure is represented by homogenized material models. The required parameters are calibrated against several characteristic cell experiments. As a result, it is hardly possible to describe the behavior of the individual battery components, which reduces the level of detail. In this work, a new data-driven material model is presented, which not only provides the homogenized behavior but also information about the components. For this purpose, a representative volume element (RVE) of the cell structure is created. To determine the constitutive material models of the individual components, different characterization tests are performed. A novel method for carrying out single-layer compression tests is presented for the characterization in the thickness direction. The parameterized RVE is subjected to a large number of load cases using first-order homogenization theory. This data basis is used to train an artificial neural network (ANN), which is then implemented in commercial FEA software LS-DYNA R9.3.1 and is thus available as a material model. This novel data-driven material model not only provides the stress–strain relationship, but also outputs information about the condition of the components, such as the thinning of the separator. The material model is validated against two characteristic cell experiments. A three-point-bending test and an indentation test of the cell is used for this purpose. Finally, the influence of the architecture of the neural network on the computational effort is discussed.

Analysis of the Thermal Runaway Mitigation Performances of Dielectric Fluids During Overcharge Abuse Tests of Lithium-Ion Cells with Lithium Titanate Oxide Anodes

Lithium titanate oxide cells are gaining attention in electric vehicle applications due to their ability to support high-current charging and their enhanced thermal stability. However, despite these advantages, safety concerns, particularly thermal runaway, pose significant challenges during abuse conditions such as overcharging. In this study, we investigated the effectiveness of various dielectric fluids in mitigating thermal runaway during overcharge abuse tests of cylindrical LTO cells with a capacity of 10 Ah. The experimental campaign focused on overcharging fully charged cells (starting at 100% State of Charge) at a current of 40A (4C). The tests were conducted under two conditions: the first benchmark test involved a cell exposed to air, while the subsequent tests involved cells submerged in different dielectric fluids. These fluids included two perfluoropolyether fluorinated fluids (PFPEs) with boiling points of 170 °C and 270 °C, respectively, a synthetic ester, and a silicone oil. The results were analyzed to determine the fluids’ ability to delay possible thermal runaway and prevent catastrophic failures. The findings demonstrate that some dielectric fluids can delay thermal runaway, with one fluid showing superior performance with respect to the others in preventing fire during thermal runaway. The top-performing fluid was further evaluated in a simulated battery pack environment, confirming its ability to mitigate thermal runaway risks. These results provide important insights for improving the safety of battery systems in electric vehicles.

Experimental measurement and modeling of the internal pressure in cylindrical lithium-ion battery cells under abuse conditions

The internal pressure evolution of cylindrical lithium-ion battery cells under abuse tests is evaluated in this work. The pressure evolution is recorded through a cavity at the center of the inner structure of the cylindrical cell. Understanding pressure buildup due to exothermic reactions aids in designing safety features, such as improved venting mechanisms. The pressure activation for the safety mechanism depends on both the venting cap design and the different abuse test conditions. This study focuses on two important parameters: the state of charge (SOC) and the overheating ramp. The SOC significantly influences the venting pressure activation at the overheating abuse tests. The 18650 cell exhibits a similar venting behavior as the 21700 cell, with pressure safety mechanisms activating sooner for the 18650 cell. The geometric structure of the battery and safety mechanisms significantly influence vent-activation thresholds. After the Current Interruptor Device (CID) breakdown, pressure rises exponentially until venting occurs, due to gas generation from the decomposition of internal components and electrolyte vaporization. With the experimental data for the overheating abuse test, a model that predicts the evolution of the pressure has been developed. For the overcharging abuse test, the pressure evolution has been measured with different current rates (C-rates) to simulate overcharge with standard charging current and fast charging current. However, the internal pressure inside the cell activates the current interrupt device, which avoids overcharging the cell, thus preventing the thermal runaway (TR) from occurring.

Investigation on electro-thermal behavior of liquid metal batteries under various abusive conditions

Liquid metal batteries (LMB) are one of the most promising solutions for grid-scale energy storage due to their characteristics of long life and low cost. On account of the all-liquid structure of LMB, the main challenge faced by many researchers is the impact of abusive conditions on the liquid-liquid interface stability and the intrinsic safety after an internal short circuit (ISC). This study set out to compare the influence of different abusive conditions on the electro-thermal characteristics of LMB through systemic experimental research, including mechanical (vibration, inclination), electrical (external short circuit) and thermal abuse (thermal shock). Results show that LMB has a strong self-healing ability under abuse conditions. It is worth mentioning that almost all the deformation of voltage and temperature caused by abusive conditions can be restored after the abuse is stopped, except for the ISC caused by the entire inclination. In comparison, mechanical abuse is more likely to induce ISC failure of LMB than electrical abuse and thermal abuse. In the vertical vibration of more than 10 Hz and inclination of more than 39.3°, the signs of transient ISC appear in the LMB voltage and temperature. Compared with mechanical abuse, there is only a temperature rise (550 °C to 564 °C) and coulombic efficiency reduction (98.3 % to 8 %) in the electrical and thermal abuse. This work is one of the first attempts to thoroughly examine the abuse performance of LMB and provides the first comprehensive assessment of LMB thermal safety.

Prevalence of anemia and related factors among Tabari cohort population: a cross-sectional study

BackgroundAnemia presents a considerable public health challenge, standing as a leading contributor to elevated rates of mortality and morbidity. Therefore, this study aimed to investigate the prevalence of anemia and related factors among Tabari cohort population.MethodsThis study involved a cross-sectional investigation carried out during the enrollment phase of the Tabari cohort. The Tabari cohort is a subset of the larger nationwide cohort study known as the “Prospective Epidemiological Research Studies in IrAN” (PERSIAN) cohort. The collected data included general information, anthropometric measurements, medical history and blood samples. Anemia was defined as a hemoglobin level less than 13 mg/dL for men and less than 12 mg/dL for women. Data were analyzed using SPSS V.16.ResultsOut of the 10,073 participants included in the analysis, 1,352 individuals (13.4%) were diagnosed with anemia. In the multiple regression analysis, the odds of anemia were significantly 2.31 times in females compared to males, 3.69 times in urban residents compared to rural residents, 1.41 times in social economic categories of IV and 1.35 in social economic categories of V compared to social economic categories of I, 1.70 times in drug abuse compared to non-drug abuse, 0.71 times in body mass index (BMI) categories of 25–29.9 kg/m² and 0.70 in BMI ≥ 30 kg/m² compared to BMI < 25, 0.77 times for triglycerides(TG) > 150 compared to below 150, 0.76 times for total cholesterol(TC) > 200 compared to below 200, 0.83 times for high waist-to-hip ratio (WHR) compared to low WHR, 1.33 times in low High-density Lipoprotein (HDL) compared to high HDL, 1.18 times in diabetics (DM) compared to non-DM, and 1.37 times in individuals with coronary heart diseases (CHD) compared to healthy individuals.ConclusionAnemia was a prevalent condition among Tabari cohort population. Several conditions including female gender, urban residence, Social economic level of IV and V, drug abuse, low HDL, high WHR, DM, and CHD conditions were significantly associated with increased odds of anemia. Furthermore, BMI categories of 25–29.9 kg/m² and ≥ 30 kg/m², high TC and high TG were significantly associated with decreased odds of anemia among this population.

Modeling state-of-charge dependent mechanical response of lithium-ion batteries with volume expansion

The behavior of lithium-ion batteries under mechanical abuse conditions has been studied extensively in recent years. Typically, characterization is performed by conducting experiments on discharged batteries to minimize the chances of thermal runaway and fire. However, studies have shown that material models calibrated at discharged state may not be as accurate at higher states of charge. In this study, a combined experimental-numerical method is proposed to simulate the stiffening of mechanical response in electrode stacks/jellyrolls of lithium-ion batteries at various states of charge and levels of confinement. Our study indicates that the mechanical properties of the jellyroll do not inherently change as a function of the state of charge, rather, the primary cause of the higher stiffness in charged batteries is the volume expansion of the jellyroll during charging. Therefore, mechanical characterization tests are conducted at the discharged state and the expansion of the jellyroll is induced in the finite element models to match the equivalent volume at the desired state of charge. In the second phase of the simulation, mechanical abuse loading is applied to validate the accuracy of simulations using the test data. This method was applied and validated for both pouch and cylindrical batteries with high accuracy.

Effects of Li1.3Al0.3Ti1.7(PO4)3 solid-state electrolytes on the safety of hybrid solid–liquid batteries

Hybrid solid–liquid batteries (HSLBs) are emerging as promising solutions to address the safety issues of lithium-ion batteries. However, the effects of solid-state electrolytes (SSEs) on battery safety remain unclear, hindering the large-scale application of HSLBs. This paper presents a comprehensive investigation on the safety performance of HSLBs with different amounts of nano-sized Li1.3Al0.3Ti1.7(PO4)3 (LATP) SSEs in the LiNi0.9Co0.05Mn0.05O2 cathode under thermal, electrical, and mechanical abuse conditions. The HSLBs with LATP SSEs exhibit significantly enhanced tolerance to overcharge, as the battery with 5 wt% LATP does not go into thermal runaway throughout the whole overcharge process. In-depth characterizations reveal that the LATP additives experience electrochemical delithiation during overcharge and generate a protective coating layer on the cathode surface, thus effectively mitigating the cathode structural changes and cathode-electrolyte interfacial reactions. Benefiting from the coating layer, the HSLBs with LATP SSEs also exhibit reduced temperature rise rate and retarded thermal runaway during the accelerating rate calorimetry and oven tests, as well as enhanced rate performance and cycling stability. Finally, the safety, electrochemical performance, and cost of HSLBs and conventional LIBs are comprehensively compared through a radar graph, aiming to provide guidance for the rational design of high–energy density and high-safety batteries.

Research progress of aerogel used in lithium-ion power batteries

In recent years, with the rapid development of clean energy vehicles (i.e., electric vehicles and hybrid electric vehicles) and electrochemical energy storage stations, safety accidents have significantly increased. However, the abuse conditions such as overheating, overcharging, mechanical abuse, short circuits, etc., can result in thermal runaway of lithium-ion batteries (LIBs). Severe thermal runaway can lead to battery fire and even explosion, thereby threatening the safety of personnel. The application of a few aerogels to the thermal insulation layer between the cells of the lithium-ion battery modules can strengthen the safety of batteries. Among many aerogels, oxide aerogels show excellent insulation and high-temperature resistance. Therefore, aerogels, especially oxide aerogels, have aroused widespread research interest. This paper introduces the mechanism of thermal runaway of LIBs and systematically reviews several important oxide aerogels and the derived composites, especially those based on SiO2, Al2O3, and ZrO2 aerogels. The mechanical strength and high-temperature resistance of those aerogels are discussed. The application of aerogel in LIBs is also investigated in detail, and the all-around effect is caused by the introduction of aerogel materials. In addition, the thermal protection safety strategy of aerogel thermal insulation layers is proposed. It is supposed that this review could enable readers to deepen their understanding of this field.

Nanoporous Aramid Nanofiber Separators with High Modulus and Thermal Stability for Safe Lithium-Ion Batteries.

Developing high-safety separators is a promising strategy to prevent thermal runaway in lithium-ion batteries (LIBs), which stems from the low melting temperatures and inadequate modulus of commercial polyolefin separators. However, achieving high modulus and thermal stability, along with uniform nanopores in these separators, poses significant challenges. Herein, the study presents ultrathin nanoporous aramid nanofiber (ANF) separators with high modulus and excellent thermal stability, enhancing the safety of LIBs. These separators are produced using a microfluidic-based continuous printing strategy, where the flow thickness can be meticulously controlled at the micrometer scale. This method allows for the continuous fabrication of nanoporous ANF separators with thicknesses ranging from 1.6 ± 0.1µm to 2.7 ± 0.1µm. Thanks to the double-side solvent diffusion, the separators exhibit controllably uniform pore sizes with a narrow distribution, spanning from 40 ± 5nm to 105 ± 9nm, and a high modulus of 3.3 ± 0.5GPa. These nanoporous ANF separators effectively inhibit lithium dendrite formation, resulting in a high-capacity retention rate for the LIBs (80% after 240 cycles). Most notably, their robust structural and mechanical stability at elevated temperatures significantly enhances LIB safety under transient thermal abuse conditions, thus addressing critical safety concerns associated with LIBs.

Toxicity Assessment of Gas, Solid and Liquid Emissions from Li-Ion Cells of Different Chemistry Subjected to Thermal Abuse

Lithium-ion batteries (LIBs) are employed in a range of devices due to their high energy and power density. However, the increased power density of LIBs raises concerns regarding their safety when subjected to external abuse. The thermal behavior is influenced by a number of factors, i.e., the state of charge (SoC), the cell chemistry and the abuse conditions. In this study, three distinct cylindrical Li-ion cells, i.e., lithium nickel cobalt aluminum oxide (NCA), lithium titanate oxide (LTO), and lithium iron phosphate (LFP), were subjected to thermal abuse (heating rate of 5 °C/min) in an air flow reactor, with 100% SoC. Venting and thermal runaway (TR) were recorded in terms of temperature and pressure, while the emitted products (gas, solid, and liquid) were subjected to analysis by FT-IR and ICP-OES. The concentrations of the toxic gases (HF, CO) are significantly in excess of the Immediate Danger to Life or Health Limit (IDLH). Furthermore, it is observed that the solid particles are the result of electrode degradation (metallic nature), whereas the liquid aerosol is derived from the electrolyte solvent. It is therefore evident that in the event of a LIB fire, in order to enhance the safety of the emergency responders, it is necessary to use appropriate personal protective equipment (PPE) in order to minimize exposure to toxic substances, i.e., particles and aerosol.

Recent Development of Thermal Insulating Materials for Li-Ion Batteries

As one of the core components of electric vehicles, Li-ion batteries (LIBs) have attracted intensive attention due to their high energy density and good long-term cycling stability. However, some abuse conditions inevitably occur during battery operation, resulting in safety accidents such as the thermal runaway (TR) of LIBs. Therefore, the efficient and appropriate thermal insulation material design is crucial for LIB packs to effectively reduce or even inhibit the spread of TR. Based on it, in this review, we present the principle and influences of TR to provide the necessity of battery thermal management and thermal insulating materials. Then, we deeply discuss and compare the two kinds of representative thermal insulating materials: phase change thermal insulating materials and barrier-type thermal insulating materials. Their properties, synthesis methods, and modification means are investigated to provide some guidance for the future application of high-performance thermal insulating materials in the field of LIBs.

Analysis of the inhibition effects of C6F12O and low-pressure carbon dioxide on 72 Ah LiFePO4 module under the overcharging abuse condition

Fire disasters that happened in the energy storage station of LiFePO4 (LFP) cells have been growing rapidly in recent years. To meet the urgent need for fire and explosion prevention caused by the abused LFP cells, the application of C6F12O and low-pressure carbon dioxide (LCD) is proposed. The inhibition effects are investigated quasi-quantitatively. While the average mass flow rate of LCD is 4 times higher than that of C6F12O, the economy of LCD far exceeds C6F12O (the quality unit price of C6F12O is about 10 times to LCD). In particular, the suppression time of LCD is 9 times shorter than C6F12O when they were all released at the side of the module box alone. LCD shows extraordinary module cooling ability on the overcharged LFP module. The pure C6F12O application makes it hard to prevent thermal runaway over long durations. The releasing position of C6F12O (directly above the safety valve and on the side of the LFP module) is also tested. It is easier to suppress the flame when C6F12O is released directly above the safety valve. Additionally, the re-ignition is observed due to the electrostatic spark generated by the charging wire during the suppression process.

Experimental study on thermal runaway and flame eruption characteristics of NCM523 lithium-ion battery induced by the coupling stimulations of overcharge-penetration

The thermal runaway of lithium-ion batteries under extreme coupled abuse conditions has seriously hindered the sustainable development of lithium-ion new energy vehicles. To reveal the complex thermal runaway behavior mechanism of overcharged lithium-ion batteries induced and by nail penetration, In this paper, a coupled stimulated thermal runaway experimental platform was built, and experimental studies of overcharge-penetration coupled stimulated thermal runaway and flame eruption dynamics were carried out on 18650-type NCM523 lithium-ion batteries from macro and minutiae viewpoints, in which the states of charge (SOC) of the overcharged batteries were 100 %, 105 %, 110 %, 115 %, 120 %, 125 %, 130 %, 135 %, 140 %, 145 % and 150 %. The results showed that the maximum battery surface temperature during overcharging increased from 32.7°C at 100 % SOC to 66.1°C at 150 % SOC, an improvement of 102 %. The thermal runaway battery temperature increased from 529.0°C at 100 % SOC to 657.1°C at 150 % SOC, an increase of 24.2 %. The thermal runaway maximum flame temperature increases from 485.5°C at 100 % SOC to 983.9°C at 150 % SOC, an improvement of 102.6 %. The flame area of medium overcharged> high-level overcharged> low-level overcharged batteries and the flame area of thermal runaway increased by 22213.95 cm2 compared to the maximum of 100 % SOC, and the flame propagation speed of the batteries after thermal runaway showed that the greater the SOC, the stronger the intensity of the flame. The higher the degree of overcharging, the higher the danger of thermal runaway on the side of the battery and near the positive electrode, and the danger of thermal runaway in overcharged lithium-ion batteries increases with the increase of SOC.

Association between childhood abuse and risk of post-COVID-19 conditions: Results from three large prospective cohort studies

BackgroundSignificant early life adversities, such as childhood sexual and physical/emotional abuse, are associated with risk of poor health outcomes but are understudied risk factors for post-COVID-19 conditions. In this prospective study, we examined the associations between combined exposure to sexual and physical/emotional abuse during childhood with risk of post-COVID-19 conditions in adulthood. Additionally, we explored the extent to which lifestyle, health-related and psychological factors explain this association. MethodsWe used data from three large, ongoing cohorts: Nurses’ Health Study (NHS)-II, NHS3, and the Growing Up Today Study. Between April 2020 and November 2021, participants responded to periodic COVID-19 surveys. Participants were included if they responded to a questionnaire about childhood abuse, subsequently tested positive for SARS-CoV-2 infection and responded to questions about post-COVID-19 conditions. Childhood sexual abuse was measured before the COVID-19 pandemic with the Sexual Maltreatment Scale of the Parent-Child Conflict Tactics Scale, and physical/emotional abuse was measured with the Physical and Emotional Abuse Subscale of the Childhood Trauma Questionnaire. Post-COVID-19 conditions, defined as COVID–19–related symptoms lasting 4 weeks or longer (e.g., fatigue, dyspnea), were self-reported in the final COVID-19 questionnaire in November 2021. Sexual abuse and physical/emotional abuse were examined separately and jointly in relation to post-COVID-19 conditions. Data on key lifestyle (e.g., cigarette smoking), health-related (e.g., asthma, diabetes), and psychological factors (e.g., depression and anxiety) were obtained. ResultsOf 2851 participants, the mean age (range) was 55.8 (22.0–75.0) years; 2789 (97.8 %) were females, and 2750 (96.5 %) were whites. We observed a dose-dependent relationship between severity of childhood abuse and post-COVID conditions (p-trend:<0.0001); participants with severe versus no childhood abuse had a 42 % higher subsequent risk of post-COVID conditions [relative risk (95 % confidence interval): 1.42 (1.25 to 1.61)]. Key lifestyle, health-related, and psychological factors mediated 25.5 % of this association. Both sexual and physical/emotional abuse, were independently associated with post-COVID conditions. ConclusionsIn this prospective study of 2851 participants, childhood abuse was significantly associated with increased risk of post-COVID conditions. Biological pathways connecting childhood abuse with subsequent risk of post-COVID conditions should be investigated.

Identification of novel TTN gene variant in a patient exhibiting severe dilated cardiomyopathy co-occurring with acute fibrinoid organizing pneumonia.

Dilated cardiomyopathy (DCM) is often hereditary, with 20% to 40% of nonischemic cases showing familial linkage, yet genetic testing is underused. This report describes an unreported pathogenic nonsense variant in the Titin (TTN) gene (NM_001267550.2:c.92603G>A) in a 24-year-old man with severe DCM and acute fibrinoid organizing pneumonia, highlighting a unique cardiopulmonary pathology. We conducted detailed gross, histopathologic, immunophenotypic, and exome-based DNA sequencing analysis in the workup of this case. We also included the patient's clinical and radiologic findings in our study. With rapid clinical deterioration and complex comorbidities, including substance abuse and psychiatric conditions, which precluded transplantation, the patient's cardiac function progressively worsened. Autopsy findings included extreme cardiomegaly, biventricular hypertrophy, and acute and chronic pericarditis. Significant pulmonary pathology consistent with acute fibrinoid organizing pneumonia was also noted. Molecular testing confirmed a deleterious maternally inherited TTN variant that was absent in the sibling of the proband and the extant medical literature, highlighting its rarity and significance. This case contributes to the ongoing body of work on the impact of TTN variants on DCM. It suggests a potential link between genetic variants and complex cardiac injury patterns, emphasizing the need for further investigation into the interplay between cardiomyopathy and pulmonary pathology.

Rapid safety assessment of reconstituted infant formula using electrical impedance analysis

A rapid method to assess freshness is crucial for the safe handling of reconstituted infant formula (RIF) and prevention of food-borne illnesses in infants. This study explored the use of electrical impedance measurement (EIM) at a constant frequency for real-time freshness evaluation of RIF. Initial electrical impedance of 89.16 ± 0.47 Ω decreased to 74.29 ± 0.23 Ω within 48 h at room temperature (20 °C) storage. Under temperature abuse conditions (30 °C), the electrical impedance rapidly dropped from 75.48 ± 0.52 Ω to 60.15 ± 4.76 Ω within 18 h, indicating more rapid spoilage. Notable changes in the electrical impedance were observed during temperature abuse. Empirical model analysis revealed a strong positive correlation between electrical impedance and conventional freshness parameters such as pH, protein, and microbial growth. This study demonstrates the potential of EIM for the rapid detection of freshness changes in RIF, offering valuable insights into the prevention of food-borne illnesses in infants.

Microstructural and rheological influence of different strategies to mitigate oil migration in chocolate pralines during storage in limiting conditions

Chocolate pralines are metastable systems in which oil migration, particularly at high storage temperatures, represents the main contributor to quality loss. In this study, two strategies were compared to retard this migration respect to a control sample (C); the use of a barrier consisting of cocoa butter high-melting (CB) and the use of an oleogel realized with beeswax and sunflower oil (CA). Samples were stored in thermal abuse conditions (28 °C) and subjected to: microstructural, rheological and ability to retain oil in the filling analysis and colorimetric evaluation. Microstructure highlighted the highest percentages of oil in CA samples filling during storage, respect to C and CB, as confirmed by oil release. According to fundamental rheological analysis, C and CB showed the highest filling yield stress values respect to CA, which showed a linear and homogenous trend. Dynamic rheological analysis underlined the presence of an increase in the elastic modulus during storage, suggesting matrix aggregation and gummy filling cream, which was lowest for CA, supporting the positive effect exhibited by this barrier. For empirical-imitative analysis, CA showed a more spreadable and creamy filling. Results revealed the ability of beeswax oleogels to improve quality attributes of pralines during storage, also at higher temperatures.

Investigating the safety of solid/liquid hybrid electrolyte lithium-ion battery: A comparative study with traditional LIBs under abuse condition

Lithium-ion battery (LIB) with solid‒liquid hybrid electrolyte is an important milestone in the development of all-solid-state battery (ASSB) to achieve higher energy density. In-depth understanding of the safety of solid‒liquid hybrid electrolyte battery (HS-LIB) is investigated for the first time: a detailed analysis and comparison of the possibility and severity of thermal runaway (TR) of HS-LIB and LIB are performed under typical abuse conditions to further explain the practical safety of HS-LIB in multiple dimensions. Poor thermal safety is identified by the lower self-heating onset temperature Tonset (78 °C) and thermal runaway triggering temperature Ttr (138 °C) of HS-LIB with 100 % state of charge (SOC), as well as higher maximum temperature Tmax (>1200 °C) and 2–3 times maximum temperature rise rate dT/dtmax (349.3 °C/s) higher than LIBs. The significant volume changes of SiOx as an anode material contribute to uneven SEI formation, while the resultant cracks and voids accelerate SEI decomposition prematurely. The lower thermodynamic parameter-apparent activation energy Ea also indicates that the test battery has lower thermal stability, and the comparative results of the TNT-equivalent corroborated the greater thermal hazards. External overheating conditions also results in a lower Ttr (168 °C) and shorter time to thermal runaway ttr (177 s) due to faster heat absorption with dT/dtmax (933.8 °C/s). Self-generation of heat by SE in the temperature range that triggers the main response to TR and the high energy release in a short period of time exacerbate the TR hazard. Worse electrical behavior is proven through lower state of charge (114 %) and higher dT/dtmax (>420 °C/s). Encouragingly, HS-LIB exhibits excellent mechanical safety, due to the double roles of solid-state electrolytes: as an electrolyte and a separator, which avoids internal short-circuits caused by melting of the separator at hot spots. Lower thermal stability with greater hazards is explained by a correlation mechanism analysis and these experimental results can provide some reference for the safe design of ASSB.

A comparative study on mechanical-electrical-thermal characteristics and failure mechanism of LFP/NMC/LTO batteries under mechanical abuse

Understanding the failure behaviors and failure mechanisms of lithium-ion batteries under mechanical abuse is essential for numerical reconstruction of abuse scenarios for different types of cells. This study investigates the mechanical-electrical-thermal characteristics, components tensile properties and failure mechanisms of LiFePO4 (LFP), Li(Ni0.5Mn0.3Co0.2)O2 (NMC), and Li2TiO3 (LTO) cells through indentation experiments, including ball intrusion, cylindrical intrusion, and out-of-plane compression modes at quasi-static loading rates. Additional ball intrusion experiments were conducted at varying loading rates. This study compares the effects of different material systems on battery performance under standardized mechanical abuse conditions. Post-test examinations analyze surface damage and internal component fracture morphology. Two distinct fracture modes were observed: ductile fracture and brittle fracture. The findings suggest that, under the same loading mode, LTO cells exhibit distinct failure behavior compared to NMC and LFP cells, attributed to differing material properties and resulting fracture modes during intrusion. Based on the analysis of the tensile results of the battery components, the cell fracture mode may be related to the tensile strength of the separator. The loading rate significantly impacts the mechanical-electrical-thermal performance of pouch cells, resulting in increased cell stiffness and shorter internal short circuit duration at higher loading speeds. However, the effect of loading rate is consistent across cells with different material systems.

(Invited) Lyten’s High Energy Li-S Batteries for a Sustainable and Circular EV Economy

Li-ion batteries (LIB), though widely used in EV batteries will be unable to meet the demands of the rapidly expanding vehicular market, mainly due to the challenges of cost and availability of key materials globally with limited resources, complicated by geopolitical factors. Li-S batteries promise significant advantages over Li-ion batteries with potentially higher specific energy, lower cost, and enhanced safety. However, their implementation has been hampered by poor cycle life due mainly to polysulfide shuttle caused by the soluble polysulfide intermediates. Lyten, an advanced materials company, has developed a family of new 3D Graphene™ materials for various applications including lithium-sulfur batteries. The mechanically flexible and electrically conductive framework of 3D graphene and its hierarchical porous structure make it an ideal host for potentially confining sulfur intermediates and mitigate the polysulfide shuttle. Lyten 3D Graphene™ materials have already shown enhanced sulfur utilization in Li-S cells far superior to the commercial nanocarbons (Fig. 1), even while their further fine-tuning is on-going. Lyten has established environmentally friendly 3D graphene-sulfur cathode fabrication methodology with high sulfur loadings using an aqueous binder.In parallel, Lyten has been developing new protected Li anodes, advanced stable electrolytes that can function at low quantities (electrolyte/sulfur ratio), and multi-functional separators with an ability to block polysulfide crossover. Integration of these cell components resulted in Li-S cells with specific energy comparable to current Li-ion cells (250-275 Wh/kg). The cycle life is, however, relatively modest with 300 cycles @ 100% DOD, C/3 in coin cells, and ~150 cycles@100% DOD and over one thousand cycles @ 50% DOD in multi-layer pouch cells and 18650 cylindrical cells. There is a steady growth in both these categories enabled by further tuning of 3D graphene and advances in other materials.Recently, Lyten has set up semi-automatic assembly lines for both multi-layer pouch and 18650 cylindrical cells, targeting an annual capacity of 2.4 MWh. These cells have started showing excellent consistency in specific energy in both cell formats. Fig.2 shows the narrow variability in the performance of 35 pouch and 18650 cells made recently for a customer.Finally, preliminary safety tests performed on the recent prototype cells have yielded surprisingly good results for the Li-S cells containing Li metal anode. Tolerance to usual abuse conditions, e.g., internal and external shorts, overcharge and overdischarge, as demonstrated in our ARC tests will be an additive advantage of Lyten Li-S cells. Figure 1