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The frequent occurrence of thermal runaway accidents of lithium-ion batteries has seriously hindered their large-scale application in new energy vehicles and energy storage power plants. Careful analysis of lithium-ion batteries can essentially determine the cause of the accident and then reduce the likelihood of lithium-ion battery thermal runaway accidents. However, there are few current studies on lithium-ion battery accident investigation, and the destruction of traces due to the violent reaction of the battery's thermal runaway increases the difficulty of battery accident investigation. The thermal runaway accident scenarios of lithium-ion batteries with different states of charge will show different regular characteristics of the thermal runaway properties and trace characteristics of lithium-ion batteries. Establishing the relationship between the thermal runaway characteristics of lithium-ion batteries, the trace law and the state of charge can effectively improve the technology of in-depth battery accident investigation. This study investigated the thermal runaway and trace characteristics of lithium-ion batteries triggered by nail penetrating at different states of charge using 8 Ah soft pack lithium iron phosphate batteries as the research object. The results show that lithium iron phosphate Li-ion batteries do not trigger thermal runaway under nail penetrating conditions when the state of charge is less than 20%, with no obvious phenomena and slight changes in the voltage and surface temperature of the battery, with the temperature only rising by 5 ℃. Both the 60% and 100% SOC LiFePO4 batteries underwent thermal runaway within a few seconds after the needle puncture and produced a large amount of white smoke, with the voltage rapidly dropping to 0 V and the maximum temperature on the front of the battery reached 93 ℃ and 125 ℃, respectively, and the rate of temperature rise was significantly higher in the latter than in the former, with both reaching temperatures above 200 ℃ at the penetration point and higher than at the entry point, while the 100% SOC battery showed electrical sparks and more smoke after the puncture due to a more violent internal short-circuit. The state of charge affects the cracks and particle spacing on the surface of the anode electrode and the smoothness of the surface. The results of this paper provide ideas for qualitative and quantitative analysis of lithium-ion battery accident causation, which can provide guidance for effectively improving the ability to investigate lithium-ion battery accidents. [ABSTRACT FROM AUTHOR]

NiS/Ni@HCNF electrode enable the cell with excellent storage capacity and superior thermal safety performance. [Display omitted] • Catalytic chemistry inspired hollow carbon nanofibers loaded with NiS/Ni is designed. • Such delicate structure shows superior cycling and rate property than many TMSs. • The favorable Li+ storage actions and related reaction kinetics are discovered. • Using the designed structure markedly promotes the thermal safety of LIBs. Transition metal sulfides (TMSs) based anodes hold a very broad application prospect in lithium ion batteries (LIBs). In this work, the catalytic effect of metallic nickel at high temperature was used to generate hollow carbon nanofibers loaded with NiS and Ni (denoted as NiS/Ni@HCNF). The heteroatoms doped carbon fibers buffer the huge volumetric change of NiS during the discharge/charge process, and enhance the ion transport efficiency and electrical conductivity. In addition, the high specific surface area brought by the hollow carbon nanofibers can accelerate the electrolyte penetration and speed up the transport of ions as well as electrons. When used as anode of half cell, this electrode gives 958.5 and 612.9 mAh/g after running 1000 cycles under 1 and 2 A/g, showing the extremely-low attenuation rates of 0.0483 % per cycle and 0.0643 % per cycle, respectively. Impressively, NCM//NiS/Ni@HCNF battery shows the discharge capacity of 187.6 mAh/g at 1st cycle. Regarding the next 100 cycles, the relatively-high discharge capacities (>110 mAh/g) and coulombic efficiency (CE) values (>96 %) are discerned. It is noted that the usage of NiS/Ni@HCNF electrode improves the activation energy for thermal runaway, corroborating the elevated thermal safety of battery. [ABSTRACT FROM AUTHOR]

The activation of thermal batteries requires plentiful heat to melt the ambient solid electrolyte into an ionic conductor with high ionic conductivity for large current discharge. The process necessitates massive heating powder to provide heat, severely reducing the effective specific energy of the thermal battery. To decrease energy consumption, we developed the LiCl–LiBr–KBr–CsBr molten salt with low melting point of 239 °C, fusion enthalpy at 59.08 J/g, specific heat capacity of 0.38 J/K·g and 0.88 J/K·g in the solid and liquid states, correspondingly, which takes 44% less heat to reach the operating temperature (generally 500 °C) compared to the commonly used LiF–LiCl–LiBr electrolyte. These reductions not only enable the battery to discharge across a broad temperature range, but also lessens the quantity of pyrotechnic heating pellets and enhances the thermal battery's overall specific energy and safety. [ABSTRACT FROM AUTHOR]

The concept of e-mobility is gaining the utmost importance owing to stringent emission norms. However, the safety issues associated with propulsion batteries are posing a major threat to their success. The occurrences of accidents caused due to thermal runaway in electric two-wheelers grabbed global attention. In this research work, an effort is being taken to address this concern, by arranging the battery cells in a pentagonal arrangement and employing forced air convection. The influence of air velocity (0.15, 0.30, and 0.45 m/s) and air inlet position (60, 75, and 90 mm) and intermediate cell distance (4, 6, and 8 mm) on the thermal performance of the battery is investigated using a numerical approach. Maximum cell temperature, pressure drop across the channel, maximum air velocity, maximum turbulent kinetic energy, and maximum turbulence intensity are considered output responses. A grey relational analysis (GRA) is used to identify the optimum level for all input parameters considering all output responses. The optimal forced convection parameters for the proposed pentagonal cell arrangement are the intermediate cell distance of 6 mm, air velocity of 0.45 m/s, and air inlet position of 90 mm from the center of the cell arrangement. With this arrangement, the peak cell temperature is reduced from 48.32 to 36.83 °C (8%). The study is extended with an airflow improviser to examine the influence of its geometrical parameters (improviser angle, fillet angle, and its distance from the center of the battery module) on the battery cell temperature. At the optimal conditions, the presence of an airflow improviser increases the air velocity from 1.76 to 2.302 m/s (19%) and turbulence intensity from 196 to 0.350 m2/s2 (33%). Thus, the cell temperature could be reduced to the extent of 8.6% by adopting the pentagonal cell arrangement with airflow improviser and optimal operating parameters. [ABSTRACT FROM AUTHOR]

This study proposes a probabilistic quantification technique that applies an expert inference method to warn of the risk of a fire developing into a thermal runaway when a lithium-ion battery fire occurs. Existing methods have the shortcomings of low prediction accuracy and delayed responses because they determine a fire only by detecting the temperature rise and smoke in a lithium-ion battery to initiate extinguishing activities. To overcome such shortcomings, this study proposes a method to probabilistically calculate the risk of thermal runaway in advance by detecting the amount of off-gases generated in the venting stage before thermal runaway begins. This method has the advantage of quantifying the probability of a fire in advance by applying an expert inference method based on a combination of off-gas amounts, while maintaining high reliability even when the sensor fails. To verify the validity of the risk probability design, problems with the temperature and off-gas increase/decrease data were derived under four SOC conditions in actual lithium-ion batteries. Through the foregoing, it was confirmed that the risk probability can be accurately presented even in situations where the detection sensor malfunctions by applying an expert inference method to calculate the risk probability complexly. Additionally, it was confirmed that the proposed method is a method that can lead to quicker responses to thermal runaway fires. [ABSTRACT FROM AUTHOR]

Efficient heat transfer control is highly demanded for dynamic thermal management of equipment and buildings especially when the environmental temperature dramatically changes. Thermal switches, the current approach of heat transfer control, suffer from the issues of low switching ratios below eight and sharp state transition between "on" and "off". Herein, a continuously‐tuned thermal regulator with an ultrahigh thermal‐conductivity change ratio of 43 based on superaligned carbon nanotube aerogel is reported, which works on the regulation of both thermal interfacial resistance and conduction pathways by compressive deformation‐induced microstructure evolution. This thermal regulator can stabilize the device temperature at 25 °C when the environmental temperature varies by 7 and 11 °C under the natural convection and forced convection conditions, respectively. Toward practical application, the thermal regulator with flexibility is wrapped around a cylindrical lithium‐ion battery to control the operation temperature within the optimal range of 20–40 °C for enhanced discharging performance even at an environmental temperature of −20 °C. Besides, by combining the thermal regulator with radiative cooling film, the house model temperature can be lowered by 2.7 °C during daytime and raised by 1.1 °C during nighttime compared with the bare one. This efficient thermal regulation approach offers an effective solution for practical thermal management. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new application scenario of carbon quantum dots for precise tumor ablation was estabished. • The carbon quantum dots act as a photothermal medium as well as a fluorescence probe in this two-photon fluorescence-guided precise photothermal therapy. • A single human malignant melanoma (A375) cancer cell can be precisely located and swiftly destroyed in five seconds. • A balanced two-photon fluorescence and photothermal performance of the carbon quantum dots enabled the precise and swift ablation. The utilization of carbon quantum dots (CQDs) for photothermal therapy has emerged as a hot research topic. However, there has been limited research on killing one single cancer cell which is critical in reducing unnecessary damage to the surrounding healthy tissues. In this work, we developed a two-photon fluorescence-guided precise photothermal therapy in a single human malignant melanoma (A375) cancer cell utilizing bifunctional N -doped CQDs. Resulting from the two-photon fluorescence of the CQDs, one single cancer cell can be located and simultaneously destroyed by the photothermal effect of the same CQDs. Specifically, the balanced two-photon absorption cross-section (7000 GM) and photoluminescence quantum yield (8.4%) of the CQDs enable the fluorescence-guided photothermal treatment to be achieved in only 5 s under the irradiation of 800 nm laser of 27.5 mW, much faster than the control experiment without the guidance of fluorescence. The heat generated by the aggregated CQDs is in sufficient amounts while being confined in a small area, as evidenced by the numerical simulations and photothermal experiments, to limit the range of thermal treatment in the cells. This work provides a new approach for realizing photothermal therapy with minimal damage and establishes a new application scenario of CQDs for precise tumor ablation. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) have emerged as the most commercialized rechargeable battery technology. However, their inherent property, called thermal runaway, poses a high risk of fire. This article introduces the "Battery Immersed in Fire Prevention Material (BIF)", the immersion-type battery in which all of the LIB cells are surrounded by a liquid agent. This structure and the agent enable active battery fire suppression under abusive conditions while facilitating improved thermal management during normal operation. Abuse tests involving a battery revealed that the LIB module experienced fire, explosions, and burnouts with the target cell reaching temperatures of 1405 °C and the side reaching 796 °C. Conversely, the BIF module exhibited a complete lack of fire propagation, with temperatures lower than those of LIBs, particularly 285 and 17 °C, respectively. Under normal operating conditions, the BIF module exhibited an average temperature rise ~8.6 times lower than that of a normal LIB. Furthermore, it reduced the uneven thermal deviation between the cells by ~5.3 times more than LIB. This study provides a detailed exploration of the BIF and covers everything from components to practical applications. With further improvements, this technology can significantly enhance fire safety and prevent the thermal degradation of batteries in the real world. [ABSTRACT FROM AUTHOR]

This paper provides insights into the four key behaviors and mechanisms of the aging to failure of batteries in micro-overcharge cycles at different temperatures, as well as the changes in thermal stability. The test results from a scanning electron microscope (SEM) and an energy-dispersive spectrometer (EDS) indicate that battery failure is primarily associated with the rupture of cathode materials, the fracturing and pulverization of electrode materials on the anode current collector, and the formation of lithium dendrites. Additionally, battery safety is influenced by environmental temperatures and the battery's state of health (SOH), with failed batteries exhibiting the poorest stability and the highest mass loss rates. Under isothermal conditions, micro-overcharge leads to battery failure without thermal runaway. Thus, temperature stands out as the most influential factor in battery safety. These insights hold significant theoretical and practical value for the development of more precise and secure battery management systems. [ABSTRACT FROM AUTHOR]

Lithium battery temperatures will increase if the heat produced during the charging and discharging procedures is not promptly vented externally. Fewer investigations have been conducted on materials that can retain good flexibility at room temperature and shape stability at high temperatures under the existing thermal management system for phase change materials (PCM). In this study, a particular kind of flexible composite PCM (CPCM) at room temperature is created to address the issue of heat transfer between the PCM and the power battery. The characteristics of hardness, room-temperature flexibility, form stability at high temperature, and thermal conductivity are compared with those of three other thermally induced flexible CPCMs. The flexibility at room temperature of the new CPCM is demonstrated by the results, which makes assembly easier and helps further lower the contact thermal resistance. Charge–discharge test comparisons of the battery modules employing the chosen CPCM and thermally induced CPCM are performed to further evaluate their thermal management capabilities. The thermally induced CPCM exhibits larger maximum temperature profiles at the discharge rates of 1C, 2C, and 3C than the room-temperature flexible CPCM. The variations in maximum temperatures are 0.96, 1.48, and 2.08 °C. [ABSTRACT FROM AUTHOR]

We explore anisotropic properties in the thermal expansivities of hydrogen-ordered ice IX and its hydrogen-disordered counterpart, ice III. The free energies of these ice forms are calculated to obtain the lattice constants for the tetragonal unit cell and the thermal expansivities at various thermodynamic conditions in the framework of quasi-harmonic approximation, taking account of their anisotropic nature. The thermal expansivities are also examined by applying a thermodynamic relation that connects them with the Grüneisen parameters and the elastic compliances. Both calculations suggest that ice III and IX exhibit a negative thermal expansion along the a-axis but have a positive one along the c-axis at low temperatures. It is found that nonaffine deformation in the variation of the lattice constant beyond affine transformation (the Born approximation) is essential in the theoretical calculation of the thermal properties of ice III and IX. We also find that the nonaffine deformation is described by the shift of the minimum energy positions in the potential manifold of hydrogen-ordered ice along a limited number of the normal mode coordinates, which is irrelevant to the system size. These modes become unstable against an applied strain, so that the potential minimum moves along those normal coordinates away from that of the affine-transformed structure. The unstable modes are all symmetry-preserving modes, and the space-group symmetry is an invariant under displacement along either of those normal coordinates. The number of the unstable modes in ice IX is 8 while it is 1 in another hydrogen-ordered ice VIII. [ABSTRACT FROM AUTHOR]

The operation of solid-state Li batteries, which are promising power supplies for portable electronic devices and electric vehicles, is accompanied by heating. Therefore, investigating the thermal stability of battery systems is essential. In this study, we report the impact of annealing on the interface of a Li3PO4 electrolyte and LiNi0.5Mn1.5O4 electrode in thin-film batteries. The batteries with the interface annealed at 200 °C show low Li3PO4–LiNi0.5Mn1.5O4 interface resistance of 7.2 Ω cm2. Furthermore, the batteries exhibit stable charge–discharge characteristics with high current density up to 1170 μA cm−2, similar to those of batteries with the non-annealing interface. The batteries with the interface annealed at 450 °C show high Li3PO4–LiNi0.5Mn1.5O4 interface resistance of 490 Ω cm2, resulting in low battery performance. X-ray photoemission spectroscopy indicates that the P in Li3PO4 is reduced by high-temperature annealing, possibly causing the performance degradation of batteries. This study provides an in-depth understanding of the interfaces of solid-state batteries and is expected to facilitate the development of thermally stable batteries. [ABSTRACT FROM AUTHOR]

Transfected stem cells and T cells are promising in personalized cell therapy and immunotherapy against various diseases. However, existing transfection techniques face a fundamental trade-off between transfection efficiency and cell viability; achieving both simultaneously remains a substantial challenge. This study presents an acoustothermal transfection method that leverages acoustic and thermal effects on cells to enhance the permeability of both the cell membrane and nuclear envelope to achieve safe, efficient, and high-throughput transfection of primary T cells and stem cells. With this method, two types of plasmids were simultaneously delivered into the nuclei of mesenchymal stem cells (MSCs) with efficiencies of 89.6 ± 1.2%. CXCR4-transfected MSCs could efficiently target cerebral ischemia sites in vivo and reduce the infarct volume in mice. Our acoustothermal transfection method addresses a key bottleneck in balancing the transfection efficiency and cell viability, which can become a powerful tool in the future for cellular and gene therapies. [ABSTRACT FROM AUTHOR]

The temperature and temperature differences in the battery module rise as a result of the high heat output produced by lithium-ion batteries during operation. This can reduce the operating safety of the battery and reduce the battery life. As a result, the temperature of the batteries must be controlled well by thermal management. Thermal control of batteries employs both active and passive techniques. In this study, PCM, which is a passive cooling system, was used. It has been observed that by placing PCM around the battery, it effectively reduces the peak temperature during the end of discharge in the battery cell. The RT-27 and nano-doped RT-27 with suitable melting range were used as PCM. Four different situations were investigated at 0.3C and 0.5C discharge conditions. These are battery models coated with only the battery, RT-27, coated with nano-RT-27, and coated with RT-27 and nano-RT-27, respectively. The peak temperature was found to be higher when the battery module without PCM was compared to the others. The battery module coated on both surfaces with RT-27 and nano-RT-27 performed better than the other modules. At 0.3 C-Rate, the peak temperature reduces by 1.8 K while it is 4.4 K at 0.5C-Rate. [ABSTRACT FROM AUTHOR]

The existing conventional vehicle transportation landscape in India is grappling with challenges stemming from extensive air pollution, health risks, surging oil prices, limited fossil fuel resources, substantial oil import expenses and energy volatility. To counter these issues, Electric Vehicles (EVs) are progressively replacing internal combustion engines, offering a promising route toward decarbonization and mitigating climate concerns. EVs rely on electric motors powered by batteries, predominantly Lithium-ion batteries (LIBs), known for their superior attributes such as low self-discharge, high energy density and extended life cycle. Nevertheless, LIB performance is significantly influenced by operating temperatures, with suboptimal conditions leading to decreased efficiency, power loss and faster aging. Addressing this, an effective Battery Thermal Management System (BTMS) becomes crucial to maintain batteries at optimal temperatures, enhancing their efficiency and safety. This study focuses on a computational analysis of passive heating systems employing Fins and Phase Change Materials (PCM) for 18650 Li-ion battery thermal management at low temperatures, with specific attention to battery module analysis. Numerical analysis using ANSYS FLUENT investigates the influence of varying PCM thickness on heat transfer, predicting temperature distribution and discussing its impact on battery output performance. [ABSTRACT FROM AUTHOR]

This study investigates the airflow and thermal management of a compact electric energy storage system by using computational fluid dynamic (CFD) simulation. A porous medium model for predicting the flow resistance performance of the battery modules in a battery cabinet is developed. By studying the influence of rack shapes, the effects of heat exchanger arrangements and other parameters on the airflow and battery thermal distribution are analyzed. When applying a larger bottom air channel, the inlet flow uniformity of each battery cabin in the cabinet increases by 5%. Meanwhile, temperature standard deviation decreases by 0.18 while raising the flow rate from 3 m/s to 8 m/s, indicating better temperature uniformity in the battery cabin. When the charge–discharge ratio reaches 0.5 C, the temperature deviation of the entire cabinet significantly increases, reaching 8 K. Furthermore, a rack-level thermal management scheme is proposed to effectively reduce the thermal deviation of the container electric energy storage system and improve the overall temperature uniformity. Results reveal that the rack-level thermal management of the wavy cabinet in the electric storage container can effectively improve the thermal uniformity of the distributed battery cabin, and the overall thermal deviation is controlled within 1.0 K. [ABSTRACT FROM AUTHOR]

In order to improve the energy efficiency of pure electric vehicles, the author proposes a thermal energy recovery and automation monitoring system for motor equipment based on new energy vehicles. Based on the analysis of the battery thermal management model, a series heat exchange model between the motor and the battery was established. An integrated thermal management system control strategy based on motor waste heat recovery was proposed for electric vehicles in low temperature environments, and simulation and validation were conducted at different environmental temperatures (-10~0 °C). The simulation results show that this configuration can shorten the heating time by 111-343 seconds compared to traditional battery thermal management systems during the heating stage. During the insulation stage, frequent activation of positive temperature coefficient thermistor can be avoided and the battery temperature can be maintained around 20 °C, which is not only conducive to extending the battery life but also reduces the comprehensive energy consumption by 4.39-7.70%. On the other hand, this configuration can reduce the impact of low temperature on comprehensive energy consumption from 9.77-2.07%. It is proved that heat recovery can effectively alleviate the range anxiety caused by ambient temperature. [ABSTRACT FROM AUTHOR]

Holographic lenses (HLs) are part of holographic optical elements (HOE), and are being applied to concentrate solar energy on a focal point or focal line. In this way, the concentrated energy can be converted into electrical or thermal energy by means of a photovoltaic cell or a thermal absorber tube. HLs are able to passively track the apparent motion of the sun with a high acceptance angle, allowing tracking motors to be replaced, thus reducing the cost of support structures. This article focuses on a review of the materials used in the recording of a holographic lens (HL) or multiple HLs in photovoltaic and/or concentrating solar collectors. This review shows that the use of photopolymers for the recording of HLs enables high-performance efficiency in physical systems designed for energy transformation, and presents some important elements to be taken into account for future designs, especially those related to the characteristics of the HL recording materials. Finally, the article outlines future recommendations, emphasizing potential research opportunities and challenges for researchers entering the field of HL-based concentrating solar photovoltaic and/or concentrating solar thermal collectors. [ABSTRACT FROM AUTHOR]

The performance of lithium-ion battery (LiB) is influenced by the operational temperature. The thermal management of the battery module depends upon the interaction between coolant and battery surface. The study focuses on analysis of vortex interactions as a commercial dielectric coolant (FC 3283) circulates within battery module. The analysis indicates that the arrangement reduces the maximum average temperature by 26 °C in comparison with the conventional methods. However, a maximum temperature difference of 4 °C persists at final row of battery cells. Therefore, the vortex generators (V.G.) are deployed to alter the flow behavior to achieve uniform cooling of LiB. Rectangular V.G. alleviates the temperature difference by stretching primary vortices. The V.G.s promote smaller induced vortices, enabling a multiscale distribution of turbulent kinetic energy, reducing the concentration of turbulence near central region of the cell. The induced vortices ensure uniform heat transfer along the cell length. Furthermore, a 15% increase in vorticity magnitude and a 33% rise in an average Nusselt number in the region near the last-row cells is achieved. Overall, employment of V.G.s results in a 2.5 °C reduction in maximum cell temperature difference. A novel metric, the operational effectiveness factor (OEF), is coined to assess the combined effect of heat transfer enhancement and additional pumping requirements resulting from the different positions of the V.G. A high OEF value implies the ability of the configuration to maintain a more uniform cell temperature while ensuring lower parasitic power. Middle V.G. configuration achieved highest OEF of 1.35, while bottom V.G. configuration exhibited lowest OEF of 1.11. [ABSTRACT FROM AUTHOR]

Nickel chloride (NiCl2) is a typical hexagonal layered semiconductor material with wide application. However, it is mainly restricted by complicated technological process within ultrahigh dehydration temperature. Utilizing copper doping, a sort of high purity and remarkable crystallinity NiCl2 is fabricated using a simple low‐temperature calcination technique. The dehydration temperature is decreased from 600 to 400 °C because the adsorbed copper ions on NiCl2 dihydrate surface can weaken NiO bond strength. Serving for thermal battery cathode, copper‐doped NiCl2 exhibits remarkable discharge ability at 500 mA cm−2, equipped with supernormal power density of 16.27 kW kg−1 and energy density of 717 Wh kg−1 simultaneously. Its energy density is increased by 28% compared to NiCl2. Copper doping optimizes thermodynamics process of discharge reaction and modifies local electronic structure of NiCl2. For copper‐doped NiCl2, the shift of Ni 3d and Cl 3p to lower energy level results in elevated redox potential, and the reduction of bandgap accelerates the carrier mobility, further promoting discharge degree. Utilizing metal ions dopant, this research surmounts the low‐temperature synthesis of NiCl2 and addresses its inferior electrochemical performance, ensuring high energy‐power output. This will expand the application scenarios of NiCl2‐based cathode materials. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have received extensive attention due to their numerous advantages, including a high theoretical specific capacity, high energy density, abundant reserves of sulfur in cathode materials, and low cost. Li–S batteries also face several challenges, such as the insulating properties of sulfur, volume expansion during charging and discharging processes, polysulfide shuttling, and lithium dendritic crystal growth. In this study, a composite of a porous multi-site diatomite-loaded graphene oxide material and a PAN fiber membrane is developed to obtain a porous and high-temperature-resistant GO/diatomite/polyacrylonitrile functional separator (GO/DE/PAN) to improve the electrochemical performance of Li–S batteries. The results show that the use of GO/DE/PAN helps to inhibit lithium phosphorus sulfide (LPS) shuttling and improve the electrolyte wetting of the separator as well as the thermal stability of the battery. The initial discharge capacity of the battery using GO/DE/PAN is up to 964.7 mAh g−1 at 0.2 C, and after 100 cycles, the reversible capacity is 683 mAh g−1 with a coulombic efficiency of 98.8%. The improved electrochemical performance may be attributed to the porous structure of diatomite and the layered composite of graphene oxide, which can combine physical adsorption and spatial site resistance as well as chemical repulsion to inhibit the shuttle effect of LPS. The results show that GO/DE/PAN has great potential for application in Li–S batteries to improve their electrochemical performance. [ABSTRACT FROM AUTHOR]

Generalist microbes have adapted to a multitude of environmental stresses through their integrated stress response system. Individual stress responses have been quantified by E. coli metabolism and expression (ME) models under thermal, oxidative and acid stress, respectively. However, the systematic quantification of cross-stress & cross-talk among these stress responses remains lacking. Here, we present StressME: the unified stress response model of E. coli combining thermal (FoldME), oxidative (OxidizeME) and acid (AcidifyME) stress responses. StressME is the most up to date ME model for E. coli and it reproduces all published single-stress ME models. Additionally, it includes refined rate constants to improve prediction accuracy for wild-type and stress-evolved strains. StressME revealed certain optimal proteome allocation strategies associated with cross-stress and cross-talk responses. These stress-optimal proteomes were shaped by trade-offs between protective vs. metabolic enzymes; cytoplasmic vs. periplasmic chaperones; and expression of stress-specific proteins. As StressME is tuned to compute metabolic and gene expression responses under mild acid, oxidative, and thermal stresses, it is useful for engineering and health applications. The modular design of our open-source package also facilitates model expansion (e.g., to new stress mechanisms) by the computational biology community. Author summary: A fundamental understanding of multi-stress adaptation in E.coli has potential industrial relevance. While individual stress responses have been quantified through the protein regulatory network in E.coli, the systematic quantification of the cross-stress & cross-talk among stress responses remains lacking. Here, we develop a new modeling pipeline by which thermal, oxidative and acid stress response can be coupled to each other, and the metabolic activities, protein and metabolic flux redistribution due to cross-stress & cross-talk can be quantified. We optimize the effective rate constants in the integrated model. We then confirm the model robustness by validating against the published data under single stress. Finally, we use the model to characterize the cross-adaptation between protective and catalytic proteins as well as between chaperones present in different cellular compartments. We find effective cross-protection against cross stress by adapting the E.coli cells to the thermal stress first. We also indicate the presence of cross-talk through trade-offs by which the cell may refuse to give up more protein allocation away from one stress response to the other, because doing so would decrease stress tolerance further. The single stress plug-in design makes the model build-up pipeline flexible and expandable, allowing incorporation of more stressors into the model architecture for industrial applications. [ABSTRACT FROM AUTHOR]

To tackle the issue of inferior rate capability and cycle stability for MnO-based materials as a lithium-ion battery (LIB) anode, robust reduced graphene oxide (rGO) protected porous MnO nanoplates were constructed to relieve the pulverization and gradual aggregation during the conversion process. Such rGO protection and porous characteristics endowed MnO–rGO with excellent cycle stability and enhanced charge transfer kinetics. At 100 mA g−1, it exhibited superior rate capability as high as 1398.5 mA h g−1 and delivered a specific capacity of 726 mA h g−1 even at a current density of 1000 mA g−1. The porous MnO–rGO based cell exhibited thermal runaway at 204 °C, while the commercial graphite-based cell experienced thermal runaway at 197 °C, which demonstrated better safety performance. This facile method provides an efficient and low-cost approach to synthesizing rGO wrapped porous transition metal oxides electrodes for LIB applications. [ABSTRACT FROM AUTHOR]

In this study, a comprehensive simulation study was carried out to obtain detailed battery temperature behaviors. The influences of air inlet temperature, air flow rate, C‐rate, and free stream temperature were investigated on the temperature uniformity and maximal battery temperature. Taguchi design is implemented to investigate the main effects of four control parameters in the battery thermal management process. Results indicated that as the free stream temperature (delta = 7.3366) was the most influential factor for the temperature uniformity, the air inlet temperature (delta = 0.2679) was the most efficient factor for the maximal battery temperature. The contribution of the air inlet temperature was 28% and 38% for temperature uniformity and maximal battery temperature, respectively. Additionally, the free stream temperature contributed 32% to temperature uniformity and 25% to the maximum battery temperature. The airflow rate was found to be the least effective factor for temperature uniformity (delta = 2.8672) and maximal battery temperature (delta = 0.0506). The results could be helpful in the design of a lithium‐ion battery thermal management process to improve temperature uniformity and maximal battery temperature. [ABSTRACT FROM AUTHOR]

Battery thermal management system (BTMS) may seem a very standard term, but it is the lifeline of an efficient battery pack module in various vehicles and standalone stationary energy storage systems. The majority of the available literature is aimed toward temperature optimization of batteries in hotter climatic conditions. The cold temperature‐related effects on battery packs have amplifying implications on the battery cycle life and operational capacity. The electric vehicles operating in cold temperature environment face sudden fluctuations in temperatures across the battery pack module due to large temperature gradient between battery surface and internals, and ambient conditions. This work focuses on addressing the problem related to sudden drop in cell temperatures when battery operations are switched off (cold stop conditions). The phase change materials (PCMs) based passive BTMS system is evaluated in this study. The BTMS with different designs and PCMs are modeled in Multiphysics environment and simulated close to extreme cold temperature environments. The formulated models are then used for comparing commercially available PCMs material for their efficiency and viability. The main parameter evaluated was rate of temperature decrease, it was observed that organic mixture‐type PCMs are best suited for cold temperature application. [ABSTRACT FROM AUTHOR]

Because of their high energy capacity and power density, lithium‐ion batteries are an essential component of electric and hybrid vehicles; however, they frequently experience excessive temperature rise because of heat creation inside the batteries. The charge state and charge/discharge rate play a major role in this heat generation. Due to its high latent heat, compact design and lightweight nature without requiring any external power, passive techniques like phase change material (PCM) and heat pipe (HP) cooling have gained widespread popularity. Therefore, this work focussed on hybrid BTMS integrating Heat Pipe with PCM for better thermal management of battery pack supported by a heat pipe that is used to analyse the thermal performance of a battery module having three and four lithium‐ion batteries placed in series and parallel. The objective of maintaining temperature gradient of less than 5°C between the adjacent cells and maintaining the overall battery temperature in the range of 25°C–45°C has been successfully achieved. The results of experiments at various discharge rates showed that a heat pipe was crucial to quickly transferring heat and maintaining temperature homogeneity for PCM‐based battery modules. It can be concluded that the data presented above can offer views for creating and improving battery heat management systems. [ABSTRACT FROM AUTHOR]

A distributed circuit approach is used to simulate the development of electric potentials across a cell membrane and the resulting poration dynamics for ∼700 ns duration voltage pulses. Besides electric field effects, temperature increases from a pulse train are included on an equal footing to probe heating effects. The results show (i) strong heating and power dissipation at the membrane in keeping with previous simpler models, (ii) an initial spike in the membrane temperature within 100 ns timescales, (iii) a monotonic increase in membrane temperature with successive pulses to about 8 K over twelve pulses within roughly 10 μs, and (iv) large temperature gradients in excess of 2 × 107 K/m at the polar membrane region indicative of a strong source for thermo-diffusive transport. Our results suggest that inherent heating during repeated pulse application may be used to tailor excitation sequences for maximal cellular transport, broaden the permeabilization beyond the polar regions for greater transmembrane conduction, and lower the electric field thresholds for greater efficiency in longer duration irreversible electroporation protocols. More generally, the present analysis represents an initial step toward a comprehensive analysis-based optimization for tumor treatment that could select waveforms for tissues, factor in heating effects (whether for synergistic action or to ascertain safe operating limits), and engineer temporal manipulation of wavetrains to synchronize with timescales of selective bio-processes of interest for desired transient responses. [ABSTRACT FROM AUTHOR]

Most battery cells are developed according to a standard design and optimized regarding their electrical properties. However, firstly, there is a demand for an individual cell design adapted to the application. Secondly, additional properties, for example, thermal and mechanical, are decisive for the cell behavior and should be considered in the overall design. Therefore, the present work introduces a model-based development tool for the holistic design of format-flexible battery cells, which are optimized for their future application, allowing for different cell geometries within one battery system. The different approaches and simulation models for the single design steps are presented, and the prediction of the electrochemical, electrical, and thermal behaviors of the cell and whole battery system is described. A key aspect here is the appropriate interconnection of the single models in a way that helps to narrow down the multitude of interacting parameters in a systematic manner and, thus, makes a holistic design possible. In a last step, the functionality of the tool is shown in a case study by means of an e-bike battery pack. [ABSTRACT FROM AUTHOR]

This study proposes a simulation technique for investigating a battery thermal management system based on direct refrigerant cooling (BTMS-DRC). The main focus is to investigate the temperature uniformity and working temperature of the module housing. The simulation technique employs a finite element method for a combined conduction–convection heat transfer to predict the module housing temperature. The refrigerant side is based on two-phase flow evaporation, which is represented by the convection heat transfer under a certain refrigerant saturation temperature. The real BTMS-DRC, which is based on the dual-evaporator vapor compression refrigeration system, is constructed for experimentation with the test bench. The simulated result is validated with the experimental results to ensure correction of the modelling. Error rates of approximately 2.9–7.2% are noted throughout the specified working conditions. The BTMS can produce temperatures of less than 35 °C under conditions where 80–320 W heat is generated. The difference in the temperature of the module is around 1.7–4.2 °C. This study also investigates the impact of heat generation, the convection heat transfer coefficient (href), the refrigerant saturation temperature, and thermal conductivity on the module's temperature. The thermal conductivity ranges from 25 to 430 W/m·K, while the href ranges from 80 to 400 W/m2·K. [ABSTRACT FROM AUTHOR]

Electrical power networks consist of numerous energy control zones connected by tie-lines, with the addition of nonconventional sources resulting in considerable variations in tie-line power and frequency. Under these circumstances, a load frequency control (LFC) loop gives constancy and security to interconnected power systems (IPSs) by supplying all consumers with high-quality power at a nominal frequency and tie-line power change. This article proposes employing a proportional–integral–derivative (PID) controller to effectively control the frequency in a one-area multi-source power network comprising thermal, solar, wind, and fuel cells and in a thermal two-area tie-line IPS. The particle swarm optimization (PSO) technique was utilized to tune the PID controller parameters, with the integral time absolute error being utilized as an objective function. The efficacy and stability of the PSO-PID controller methodology were further tested in various scenarios for proposed networks. The frequency fluctuations associated with the one-area multi-source power source and with the two-area tie-line IPS's area 1 and area 2 frequency variations were 59.98 Hz, 59.81 Hz, and 60 Hz, respectively, and, in all other investigated scenarios, they were less than that of the traditional PID controller. The results clearly show that, in terms of frequency responses, the PSO-PID controller performs better than the conventional PID controller. [ABSTRACT FROM AUTHOR]

A microchannel heat sink (MCHS) is a potential solution for chip and battery thermal management. The new microchannel structure is beneficial for further improving the thermal-hydraulic performance of MCHSs. Inspired by leaf veins, six new channel structures were designed, and the effects of the channel structures (three parallel structures named PAR I, II, and III and three pinnate structures named PIN I, II, and III), channel depths (0.4, 0.8, and 1.6 mm), and heat fluxes (20, 50, and 80 kW/m2) were investigated via numerical simulation. The cooling medium was water, and the heating area was 40 × 40 mm2. Both PAR II and PIN III exhibit superior overall performance, characterized by the highest Nusselt number and the lowest heating wall temperature. Moreover, PIN III demonstrates the lowest standard deviation in heating wall temperature, while PAR II exhibits the lowest friction factor. The greater the channel depth is, the larger the solid–liquid contact area is, leading to a reduced wall temperature at the interface under identical conditions of inlet Reynolds number and heating wall heat flux. Consequently, an increase in the Nusselt number corresponds to an increase in the friction factor. The maximum value and standard deviation of the heating wall temperature increase with increasing heat flux, while the Nusselt number and friction factor remain unaffected. The overheating near the two right angles of the outlet should be carefully considered for an MCHS with a single inlet–outlet configuration. [ABSTRACT FROM AUTHOR]

To increase the oxygen mass transport, water removal, and cell performance of proton exchange membrane fuel cells, tapered flow field configurations (FFCs) considering porous medium thickness (PMT) and thermal contact resistance (TCR) are proposed. In this work, the impact of the tapered FFC on the internal electrochemical process and overall cell performance is quantitatively explored using a three-dimensional multiphase fuel cell model. The tapered FFC is compared without and with account for both the PMT and the TCR between bipolar plates and gas diffusion layers. Compared to the conventional FFC, an increased ratio of the side length for the inlet to that for the outlet (L I/O) for the tapered FFC, addressing both the PMT and the TCR improves hydrogen, and oxygen delivery, water removal, and cell performance. The tapered FFC design with a L I/O of 1.2 is superior to all other tapered FFC designs in terms of uniformity of reactants, with an improvement in pressure drop by 68.74%, current density by 7.57%, and power density by 12.63%. These improvements result in an overall enhancement of cell performance. • A tapered FFC is proposed for fuel cells considering thermal contact resistance and porous medium thickness. • Thermal contact resistance reduced heat dissipation and water retention capability. • TCR and PMT between GDL and BP enhance PEM fuel cell performance. • The pressure drop improved for case 6 (L i/o 1.2) by approximately 68.74% from case 1 (L i/o 0.7). • The power density in case 6 (L i/o 1.2) is improved by 12.63% from case 1 (L i/o 0.7). [ABSTRACT FROM AUTHOR]

A technology for early warning (of over 25 minutes) of thermal runaway in lithium-ion batteries based on common characteristic resistances supported by thermodynamic calculations was derived. With great potential in practical application for avoiding property losses and human casualties, this technology was proven to be efficient and accurate. [ABSTRACT FROM AUTHOR]

Features of the dynamics of topological defects in an electroconvective structure formed in a π/2-twisted nematic liquid crystal have been studied. The electroconvective structure (Williams domains) is a system of rolls similar to the system of convective cells in thermal convection. Hydrodynamic flows in rolls of the twisted nematic liquid crystal are helicoidal because the axial velocity component existing in addition to the tangential component has opposite directions in the neighboring rolls. This feature is responsible for the formation of stable localized extended objects—linear defects—oriented normally to Williams domains. The continuity condition for a helicoidal flow of an anisotropic liquid in twisted nematic liquid crystals prevents the decay of a linear defect into single dislocations. The length of the linear defect and the number of dislocations in it are controlled by an ac voltage applied to a liquid crystal cell. In contrast to the case of planar orientation, where linear defects decay into single dislocations with increasing applied voltage, zigzag oscillations appear in this case, but the structure of domains remains stationary. The boundaries between zig and zag regions in the core of the linear defect are dislocations with the topological charges S = +1 and –1. An "elementary" decay of a dislocation with the topological charge S = +1 (kink) into the dislocation with S = –1 (antikink) and two dislocations the topological charges S = +1 has been found for the first time in the linear defect of a certain length. The decay of the topological defect is possibly due to the appearance of the local instability of the orientational twist mode of the director n in the defect core caused by the critical growth of hydrodynamic fluctuations with increasing applied voltage. It has been shown that the detected decay of the topological soliton is qualitatively well described by the perturbed sine-Gordon eq-uation. [ABSTRACT FROM AUTHOR]

Battery thermal management system (BTMS) is essential for maintaining batteries in electric vehicles at a uniform temperature. The aim of the present work is to propose most suitable cooling for BTMS. The most significant factors in battery thermal management are operating temperature, reliability, safety, and battery life cycle. The experimental setup is designed and fabricated for that purpose. In experimental work, thermal performance parameter, i.e. variation of maximum cell temperature in battery pack with natural and forced convection, is studied and compared at three different charging rates low (1 C), moderate (2 C), and high (3 C). The numerical model for natural and forced convection battery thermal management is developed using Ansys 22.1. For the present work, the cylindrical cell Li-ion battery pack is considered and simulates the cooling effect due to natural convection and forced convection. For the various flow rate of air, the cooling effect is investigated and efficient flow velocity is obtained by a numerical model for two climatic conditions. Further, the cooling performance of the battery pack with and without fin for optimum velocity is simulated. Based on experimentation, it is seen that forced convection gives better results as compared to natural convection. The temperature drops from 60.46 °C to 43.03 °C (28.82%) at 1 C, 65.81 °C to 48.01 °C at 2 C (27.06%), and 67.05 °C to 50.4 °C (24.77%) at 3 C heat generation rate when forced convection is used for cooling purpose. In the numerical studies, charging of Li-ion cell at 1.5 C rate is studied. Using forced convection maximum temperature is reduced by 27.26% when the inlet velocity is kept 2 m s−1 when ambient is 27 °C. Using fin, battery cell maximum temperature is reduced by 39.23%, as compared with natural convection. Using fin at 27 °C atmospheric temperature, battery cell maximum temperature is reduced by 39.23%, as compared with natural convection, and when the atmospheric temperature reaches to 41 °C, the maximum temperature is reduced to 51.26 °C (12.75%). [ABSTRACT FROM AUTHOR]

The thermal behavior of flooded lead–acid batteries with different distances between their electrodes, in which there takes place a temperature rise, was investigated at different rates of charging and discharging of these batteries with the use of the PIV method. It was established that, in the case of small rates of charging and discharging of such a battery, a decrease in the distance between its electrodes leads to a decrease in the temperature rise and in the heat generation in it, while, in the case where these rates are large, the opposite effects take place. [ABSTRACT FROM AUTHOR]

This study aims to improve the performance of automotive battery thermal management systems (BTMS) to achieve more efficient heat dissipation and thus reduce hazards during driving. Firstly, the research parameters and properties of composite thermally conductive silicone materials are introduced. Secondly, the heating principle of the power battery, the structure and working principle of the new energy vehicle battery, and the related thermal management scheme are discussed. Finally, the research results are presented from the experimental test and controller design. In addition, to achieve the research goal, the composite thermally conductive silica gel plate (CSGP) material is studied in detail and parametrically analyzed, and the heating mechanism of the power battery is discussed in depth. The temperature characteristics after adding CSGP are experimentally tested, and the controller of the BTMS of the new energy vehicle is designed, including hardware circuits and software modules. The findings show that the temperature characteristics of the battery module have obvious limitations without CSGP. When the battery module operates at a 4C magnification, the temperature exceeds the safety threshold by 38.4%, with particular potential safety risks. Then, the maximum temperature of the battery module with CSGP can be controlled within 50 °C, and the temperature characteristics are prominently improved. Lastly, the controller of the BTMS is tested, and the results reveal that it has remarkable voltage recovery ability. According to the research results, the performance of automotive BTMS can be significantly improved, and better heat dissipation can be effectively achieved by adding CSGP. This helps reduce the hazards of driving. Moreover, the designed controller performs well in voltage recovery, providing solid theoretical support for further developing the CSGP battery management system. [ABSTRACT FROM AUTHOR]

The specificities of temperature-dependent electrochemical modelling strategies of 18650 Li-ion batteries were investigated in pseudo-2D, 2D and 3D domains using finite element analysis. Emphasis was placed on exploring the challenges associated with the geometric representation of the batteries in each domain, as well as analysing the performance of coupled thermal-electrochemical models. The results of the simulations were compared with real reference measurements, where temperature data were collected using temperature sensors and a thermal camera. It was highlighted that the spiral geometry provides the most realistic results in terms of the temperature distribution, as its layered structure allows for a detailed realisation of the radial heat transfer within the cell. On the other hand, the 3D-lumped thermal model is able to recover the temperature distribution in the axial direction of the cell and to reveal the influence of the cell cap and the cell wall on the thermal behaviour of the cell. The effect of cooling is an important factor that can be introduced in the models as a boundary condition by heat convection or heat flux. It has been shown that both regulated and unregulated (i.e., natural) cooling conditions can be achieved using an appropriate choice of the rate and type of cooling applied. [ABSTRACT FROM AUTHOR]

Vanadium redox flow batteries are recognized as well-developed flow batteries. The flow rate and current density of the electrolyte are important control mechanisms in the operation of this type of battery, which affect its energy power. The thermal behavior and performance of this battery during charging and discharging modes are also important. As a consequence, the aim of this investigation is to deeply study the impact of different working parameters on the temperature distribution and state of charge of these batteries. To achieve these goals, a single battery thermal model is established. The effects of various operating parameters, including working temperature, molar concentration, flow rate, and current density of the electrolyte, on the thermal behavior, state of charge, and performance of this type of battery are investigated. It is observed that the temperature distribution of high flow rate (90 mL min−1) is more uniform than that of other flow rates (30 and 60 mL min−1). In the end of the discharging mode, the battery voltage performance increases with the increase in the electrolyte flow rate. The temperature distribution of high current density (80 mA cm−2) is relatively uneven, and the local heating is produced at the battery outlet. The end time in the charging and discharging modes for the case of the high current density (80 mA cm−2) is faster than other current densities (20 and 40 mA cm−2). [ABSTRACT FROM AUTHOR]