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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]

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]

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]

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]

The present study aims to evaluate the feasibility of a novel dual-evaporator loop heat pipe (DE-LHP) in battery thermal management systems (BTMS). A 3S4P (3-series and 4-parallel) Li-ion battery module with a 12.6 V and 10 Ah capacity is made and tested under various C rates for different environmental conditions. The battery generates an average heat of 11.28 W@1C and 24.44 W@1.5C with 100% discharge and 43.36 W@2C with 50% discharge at an ambient temperature of 30 °C. An increase in temperature from 30 to 40 °C results in a decline in the depth of discharge. The proposed DE-LHP is evaluated using deionized water with filling volumes of 12, 16, 20, and 24 mL. The DE-LHP started working above 5 W regardless of the filling volume, and before the evaporator reached dry-out, the DE-LHP transferred heat loads of 10, 30, 35, and 55 W with filling volumes of 12, 16, 20, and 24 mL, respectively. At a heat load of 30 W, the evaporator section of the 20-mL filled LHP demonstrated a minimum thermal resistance of 0.274 KW-1, while the condenser section exhibited a minimum thermal resistance of 0.372 KW-1 at a heat load of 35 W. The DE-LHP is found to be effective in transferring heat of 35 W to keep the module temperature below 60 °C. Based on these initial findings, it is suggested that incorporating the multi-evaporator LHP-based BTMS could be a feasible and efficient solution for the thermal management of battery modules/packs for electric vehicles. [ABSTRACT FROM AUTHOR]

This manuscript proposes a multi-stage constant current–constant voltage under constant temperature (MSCC-CV-CT) charging method by considering the cell temperature as the main metric for the dissipation of lithium-ion batteries. By combining the proposed method with a pulse current charging and series resonant converter, the rise in temperature is further slowed down. The proposed approach uses a closed-loop method to regulate the charging current rather than the thermal environment and battery heat. By simply raising the default temperature, it may simply handle applications that require faster charging. With the growth of improved lithium-ion batteries, the proposed method contains the potential to increase the initial charging current above 2 C, allowing for even quicker charging. This proposed smart charger with the new adaptive control algorithm considers the state of charge (SoC) and internal temperature of the battery as key components to adjust the current and voltage amplitude of battery input. The proposed MSCC-CV-CT charging mechanism uses a multi-stage current charging scheme with a simple, convenient-to-implement intelligent charge controller. In response to the battery temperature, state of charge (SOC), and internal resistance of the battery, the charging current is dynamically adapted using a controller that adversely reflects its aging and thermal condition. The experimental outcome proves that the proposed system reduces the charging time of the battery by 20 percent related to the conventional method. [ABSTRACT FROM AUTHOR]

False alarm resistant smoke detectors must pass the inflight smoke-detection certification test for implementation in aircraft. Inflight certification testing uses artificial smoke generators due to health and safety. Currently, there are no objective parameters to quantify an artificial smoke generator's aerosol production for certification testing. Therefore, this study's design was to create a framework for potential guidelines for standardizing an artificial smoke generator's aerosol production. Although the aerosols created by artificial smoke generators look like real smoke, there are inconsistencies between models that could create smoke detectors not activating during certification testing. Aerosols created by artificial smoke generators must be similar to smoke for many of the false alarm resistant smoke detectors to alarm. Therefore, verifying which artificial smoke generators produce an aerosol with similar particle characteristics to smoke is essential for the implementation of false alarm resistant detectors in aircraft. Furthermore, standardizing the artificial smoke generators for the total quantity of aerosol produced, rate of aerosol production, and repeatability of aerosol production and quantifying the effects of the ambient environment is necessary to ensure the reliability and integrity of the certification test. One possible result of a non-standard aerosol production during certification testing, specifically in regards to an unexpected overabundance of aerosol production, may cause the certification of smoke detection system that would not alarm the specified threat. Conversely, insufficient aerosol production during certification testing could create the requirement of a lower smoke detection threshold than intended, creating an unfair financial burden. This study found that artificial smoke generators produce an aerosol with similar particle size distributions and light scattering characteristics to smoke created by smoldering foam, smoldering wood, and lithium-ion battery thermal runaway vent-gas. Therefore, it is reasonable to conclude that aerosols from the tested artificial smoke generators are capable of alarming most false alarm resistant smoke detectors. Furthermore, there were measurable differences in the total quantity of aerosol produced and the rate of aerosol production between smoke generators used by four major airframe manufacturers for smoke-detection certification testing. In addition, changes in ambient temperature and pressure that may occur during a typical flight profile affected an individual smoke generator's production of aerosol. Sufficiently heating the smoke generator's mineral oil before aerosol production can mitigate the effects of varying ambient temperatures. [ABSTRACT FROM AUTHOR]

The thermal management of the batteries in electrical and hybrid vehicles is a major concern for operation safety, battery life, and performance. In the current research, the temperature of the battery is tracked for 10,000 s of operation while using a Ranque–Hilsch vortex tube (RHVT) for the thermal management of the battery. An analytical model is developed and validated to study the impact of the heat generated per unit volume from the battery, the mass ratio for the cold air at the outlet to the total air at the inlet (x), entered air pressure, temperature, and mass flow rate. The peak temperature of the battery can be reduced by increasing the pressure and mass flow rate of the air at the inlet, decreasing the temperature of the air at the inlet, and using four RHVTs instead of a single RHVT. The proposed system significantly decreased the maximum temperature of the battery to 48.12 °C, compared to the battery thermal management method of using direct air, which resulted in a temperature of 75.73 °C. Furthermore, employing four RHVTs to cool the battery further reduced the maximum temperature from 48.12 to 11.23 °C, demonstrating a substantial improvement compared to utilizing a single RHVT. Utilizing the RHVT provides a good solution for the battery thermal management problem because it is cheap, small, and reduces the temperature of the air rapidly. [ABSTRACT FROM AUTHOR]

In this paper, a 60Ah lithium-ion battery thermal behavior is investigated by coupling experimental and dynamic modeling investigations to develop an accurate tridimensional predictions of battery operating temperature and heat management. The battery maximum temperature, heat generation and entropic heat coefficients were performed at different charge and discharge cycles with various state of charge (SOC) ranges and current. The results show that the developed model presents an accurate prediction in dynamic and quasi stationary regimes. Three SOC zones were identified during charge / discharge processes for which the entropic heat coefficient was endothermic or exothermic. The cycle initial state of charge impacts the battery operating temperature and heat dissipation which reduces by 13% for starting cycle with the battery discharge process. The highest battery temperature and energy amount were obtained for the battery SOC higher than 80%. Increasing the range of the battery SOC leads to increase the reversible and irreversible heat but the battery maximum temperature rise becomes stable for SOC ranging from 20 to 80%. Based on the experimental data, the new correlations were proposed for the battery maximum temperature, heat generation, entropic heat coefficients, and internal resistance for charge/discharge state. The proposed correlation estimates heat generation with high accuracy lower than 10% compared to the measurements. [ABSTRACT FROM AUTHOR]

This review of the literature explores the potentials of liquid micro-/mini-channels to reduce operating temperatures and make temperature distributions more uniform in batteries. First, a classification and an overview of the various methods of battery thermal management are presented. Then, different types of lithium-ion batteries and their advantages and disadvantages are introduced, and the components of batteries are described in detail. The studies conducted on the performance of micro-/mini-channels for cooling all types of rectangular and cylindrical batteries are reviewed, and the key finding of these studies is presented. It is shown that, in general, using counterflow configuration creates a rather uniform temperature distribution in the battery cell and keeps the maximum temperature difference below 5 ∘ C . The lowest battery maximum temperature is obtained for parallel and counterflow configurations in the straight and U-turn channels, respectively. In a parallel configuration, the peak point of the battery temperature is in the outlet area. However, in the counter-flow configuration, it occurs in the central region of the battery module. The survey of the literature further reveals that proper channel paths and flow configurations keep the battery maximum temperature within the safe range of 25 ∘ C < T max < 40 ∘ C . For such flow configurations, the pressure drop remains minimally affected. [ABSTRACT FROM AUTHOR]

Thermal runaway is a major concern for lithium-ion batteries in electric vehicles. A manufacturing fault or unusual operating conditions may lead to this event. Starting from a single battery cell, more cells may be triggered into thermal runaway, and the battery pack may be destroyed. To prevent this from happening, safety solutions need to be evaluated. Physical testing is an effective, yet costly, method to assessing battery safety performance. As such, the potential of a numerical tool, which can cut costs and reduce product development times, is investigated in terms of capturing a battery module's tolerance to a single cell failure. A 3D-FE model of a battery module was built, using a commercial software, to study thermal runaway propagation. The model assumes that when the cell jelly roll reaches a critical value, thermal runaway occurs. This approach was considered to study the module's tolerance to a single cell failure, which was in reasonable agreement with what had been observed in full-scale experiments. In addition, quantitative sensitivity study on the i) model input parameters, ii) model space, and iii) time resolutions on the computed start time instant and time duration of thermal runaway were performed. The critical temperature was found to have the greatest influence on thermal runaway propagation. The specific heat capacity of jelly roll was found to significantly impact the thermal runaway time duration. The multi-physics model for battery thermal propagation is promising and worth to be applied with care for designing safer batteries in combination with physical testing. [ABSTRACT FROM AUTHOR]

Reactive multilayer systems consisting of alternating nanoscale Al and Ni layers are applicable in joining, various pyrotechnic applications and thermal batteries. Since diffusion based high-temperature synthesis occurs without the presence of air, efforts have focused on investigating the understanding of the fundamental reaction processes and characteristics. The aim of this study is to expose the reactive multilayers to extrinsic induced tensile stress so that the self-propagating synthesis can proceed under these conditions. Further, the properties during and after the reaction will be investigated. Multilayers deposited by sputtering on Kapton® substrates with different bilayer– and total thicknesses as well as commercial Nanofoils® with thicknesses of 40 µm and 60 µm were used as samples. The investigations focused on the propagation velocity measured with a high-speed camera, the temperature regime determined with a high-speed pyrometer, and the formed phases after the synthesis examined via X-ray diffraction. The gained results of this study reveal important insights for the application of the reactive Al/Ni multilayer system in terms of stability or reliability related to propagation front velocity, maximum temperature and formed phases under induced external tensile stresses. [ABSTRACT FROM AUTHOR]

A large amount of storage may cause large-scale fire or explosion accidents due to the potential fire risk of lithium-ion batteries, which poses a great threat to the safety of personnel and property. In this study, the fire model of an individual cell is established according to the experimental data and the relevant parameters of thermal runaway simulation of large capacity battery are determined. The battery pack model is established according to the real setting of a warehouse. The fire characteristics of the battery pack spreading around in the warehouse environment are studied. The results show that the fire of lithium-ion batteries is preferentially diffused to the upper battery pack in the warehouse environment, and spread to the upper battery pack 19 s after the initial battery thermal runaway. The fire propagation of the horizontal battery pack is greatly affected by the distance. The farther the battery string is from the thermal runaway battery, the later the fire propagation battery string occurs. Furthermore, the role and effect of battery pack spacing, fire warning and automatic sprinkler system in fire are provided, so as to carry out better research on the storage safety of lithium-ion battery warehouses. [ABSTRACT FROM AUTHOR]

In the present review, we have focused importance of phase change material (PCM) in the field of thermal energy storage (TES) applications. Phase change material that act as thermal energy storage is playing an important role in the sustainable development of the environment. Especially solid–liquid organic phase change materials (OPCMs) have gained the more importance due to their high heat of fusion. Various microencapsulation techniques of PCMs and eutectic PCMs have been discussed in detail along with their potential applications in the field of textile, building, solar and battery composites for thermal energy storage applications. Eutectic combinations of fatty acids and their eutectic mixtures are useful for obtaining the suitable temperature range. Thermal conductivity modifications with graphene oxide, carbon nanotubes, and expanded graphite have been reviewed in detail. The phase change material properties are tailored and enhanced using microencapsulation techniques and thermal conductive material to be use as effective thermal energy storage material. In this review, the graphene-based composites and their potential thermal energy storage applications have been focused. The Microencapsulation of phase change material provides several benefits by storing and protecting the PCM for longer duration of time. In present study, encapsulations techniques, different forms of encapsulation, eutectics and its theoretical method for calculation and its applications in battery, buildings and textiles are discussed. [ABSTRACT FROM AUTHOR]

The dynamic response characteristic is an important performance indicator of the proton exchange membrane fuel cell (PEMFC), which has a great influence on the durability and reliability. The cooling capacity is an important factor that affects the stability of the PEMFC output after the change. This research proposes to apply the micro-heat pipe array (MHPA) to the thermal management of PEMFC. A novel MHPA-PEMFC stack is designed, and four cases involving comparative dynamic response experiments are studied. The results show that compared with the traditional air-cooled PEMFC, the MHPA-PEMFC significantly reduces the maximum step voltage, dynamic internal resistance and step temperature, shortens the temperature response time and improves the internal temperature uniformity. In the case where the output current stepped up from 10 to 30 A, the maximum step voltage and the maximum dynamic impedance of MHPA-PEMFC are lower than those of PEMFC by 0.449 V and 0.037 Ω, respectively. The maximum step temperature has been reduced by 4.44 °C, and the temperature response time has been reduced by 180 s. The research results provide a basis for using MHPA in PEMFC thermal management applications. [ABSTRACT FROM AUTHOR]

The hybrid type electric multiple units (EMUs) are generally equipped with LiCoO2/Li4Ti5O12 lithium-titanate (LTO) batteries. LTO batteries are often in a state of high-rate charging and discharging since they are mainly used for emergency traction and braking recycling of EMUs. Under such operating conditions, LTO batteries have a higher risk of thermal runaway, which would induce battery fires in the operation and lead to grave consequences. In this paper, a fire suppression device containing a fire detection tube was proposed for the power battery system of hybrid EMUs. Meanwhile, experiments were conducted to detect thermal runaway of the single battery and thermal expansion of the battery module installed with the fire suppression device. The fire detection tube was filled with clean agent Dodecafluoro-2-methylpentan-3-one. During the experiment, when triggering the process of thermal runaway, the fire suppression device prevented the battery from catching on fire successfully. Moreover, the fire suppression device had good cooling performance. The thermal runaway temperature of the battery with the fire suppression device installed was lowered to 130°C or so, compared with 550°C of the single battery alone. The fire suppression device was then installed in the battery system of a hybrid EMU, which performed well in operation. [ABSTRACT FROM AUTHOR]

Currently, it is significant to study the fire suppression of battery modules in energy storage stations. In this work, the combustion tests of a single cell and battery module were conducted on the 243 Ah lithium iron phosphate battery. Meanwhile, the fire extinguishing effect of C6F12O on large-scale battery module fire was verified under a real-scale fire scenario. Results show that the thermal runaway process of a single cell can be divided into four stages. The thermal runaway process had an "incubation period" in stage II, which was suitable for early warning and fire extinguishing. Thermal runaway can propagate within the battery body and the thermal runaway propagation time was 121 s. Thermal runaway propagation can occur in the battery module, which is much more aggressive and risky than a single cell. It needed around 50 kJ to 60 kJ to support the thermal runaway propagation between an adjacent cell in the battery module. Furthermore, The C6F12O has good fire extinguishing and cooling effect, which can successfully inhibit the thermal runaway propagation in the battery module. Meanwhile, when the designed fire extinguishing concentration of C6F12O is reached in the battery pack, the subsequent battery will not be ignited even if the safety valve is opened. [ABSTRACT FROM AUTHOR]

Thermal runaway caused by external fire is one of the important safety issues of lithium-ion batteries. A fully coupled multi-region model is proposed to simulate the thermal response of lithium battery under fire conditions. The external fire is modelled by LES with an extended EDC combustion model. Heat conduction equations are solved for individual battery regions. The computational domain is subdivided into one fluid region and six solid regions, and a conjugate heat transfer boundary condition is applied to the interfaces. The proposed numerical model is then used to simulate the thermal response and thermal runaway behavior of a lithium battery pack under external fire conditions. The temperature distribution inside the battery pack is compared with the experimental results. The predictions are in good agreement with the experimental data. It is demonstrated that the proposed model has the capability to predict the thermal response of lithium battery subjected to external fire conditions. [ABSTRACT FROM AUTHOR]

Accidents involving fires and explosions caused by lithium-ion battery thermal runaway have severely hampered the development of electric vehicles. With the purpose of improving the safety of battery operation and avoiding thermal runaway of lithium-ion batteries. This work conducts a full-scale heat generation quantitative test of two types of LiNi1−x−yCoxMnyO2-based commercial batteries by measuring the voltage-temperature coefficient (dE/dT) and the overpotential using the galvanostatic intermittent titration technique (GITT). Results indicate that that the heat generation rates of the two types of batteries exhibit similar trends. Battery heat generation is a function of C-rate, temperature and state of charge. Among them, C-rate is the most important influencing factor. The reversible heat contribution is the most significant at higher temperatures and lower C-rates. In most cases, the irreversible heat accounts for the dominant contribution to the total heat generation. The contribution of heat generation due to mass transport limitation is dominant among irreversible heat, and it is more significantly affected by temperature and state of charge, whereas the ohmic contribution shows a minor impact. The detailed analysis of the reversible and irreversible heat generation can provide effective theoretical guidance for safety warning and fire protection of lithium-ion battery systems, minimize the probability of the risk of fire accidents of the lithium-ion battery. [ABSTRACT FROM AUTHOR]

As a common safety issue, thermal runaway (TR) of lithium-ion batteries (LIBs) may propagate to adjacent batteries and grow into a large-scale fire, in a multi-cell array or pack. A dynamic pressure chamber was developed to investigate the effect of airflow rates on TR propagation among pouch LIBs under the ambient pressures of 95 kPa and 20 kPa. The results indicate that the ununiform heating and asynchronous trigger of TR between two side of battery are occurred when the TR propagated from TR battery with high temperature over 800°C. The TR propagation can be slowed down under low ambient pressure, e.g., propagation time under 20 kPa is 83 s slightly slower than 73 s under 95 kPa with same airflow rate of 60 L/s. As the increase of airflow rate under 20 kPa from 60 L/s to 150 L/s, peak heat release rate and total heat release increase from 6.1 kW to 29 kW, and from 287 kJ to 872 kJ, and TR fire behaviours also are intensified, which can further shorten the TR propagation time from 83 s to 71 s, through heat feedback from TR combustion fire. The release of toxic/flammable or potentially explosive gases, such as 3620 ppm for total hydrocarbons, 0.97% for CO under 20 kPa during TR propagation needs to be paid attentions especially with low airflow rate. Airflow rate under low pressure condition of 20 kPa has a great impact on the TR propagation, and some mitigation measures and protection design about the LIB module used under low pressure environments should be taken. [ABSTRACT FROM AUTHOR]

The conductivity of the electrolyte and the kinetics of Li+ inside lithium-ion batteries (LIBs) will decrease at low temperatures, which may promote the formation of lithium dendrite. The growing of lithium dendrites will penetrate the separator, and cause the internal short circuits and thermal runaway of cells. Thus, battery preheating is essential to improve the safety of LIBs. To investigate the temperature changes of battery during discharging and preheating at low temperatures, the electro-thermal model and the preheating model of LIBs at low temperature are established and verified based on the second-order equivalent circuit model. The internal resistance of battery decreases with the increase of temperature. Moreover, a battery module with polyimide flexible heating film is proposed, and the heating films are arranged on both sides of the battery symmetrically. When the power of heating films is 1 W, 3 W, and 5 W, it takes 395 s, 190 s and 126 s to preheat the battery temperature from − 10°C to 25°C, respectively. Additionally, different heating powers can be arranged in the heating process to reduce the heating time and temperature difference of battery. The research in this study contributes to the preheating of LIBs in cold regions, and has certain reference value. [ABSTRACT FROM AUTHOR]

Modern commercial electric vehicles often have a liquid-based BTMS with excellent heat transfer efficiency and cooling or heating ability. Use of cooling plate has proved to be an effective approach. In the present study, we propose a novel liquid-cold plate employing a topological optimization design based on the globally convergent version of the method of moving asymptotes (GCMMA) method. Comparison with a traditional liquid-cold plate with straight cooling channels revealed that the topology-optimized configuration provides more uniform temperature distribution on the cold plate surface by reducing 48 % of the maximum temperature difference and 57 % of the temperature standard deviation for Q0 = 1255 W/m2. This shows that the topology optimization method is a useful and high-efficiency approach for the innovative design of liquid-cooling plates used for battery thermal management. [ABSTRACT FROM AUTHOR]

Electronic applications using lithium-ion batteries are increasingly operated under adverse conditions such as high operating currents and elevated environmental temperatures. Prolonged operation in these adverse conditions induces thermal stresses which can initiate thermal runaway (battery fires). Understanding thermal and performance envelopes for cells is crucial for battery systems' safe operation. To explore the performance and thermal envelope for safe operation, there is a need for computational tools to predict a cell's thermal and electrical behavior in any given environment. This paper introduces a model which predicts temperature and voltage profiles of a cell based on operating conditions (current, environmental temperature, etc.). The technique is developed by (1) establishing a 2-resistor-capacitor (2-RC) equivalent circuit model (ECM), (2) parameterizing the ECM in terms of circuit, degradation, and Arrhenius parameters, (3) calibrating parameters through high-pulse-power-characterization (HPPC) and time-constraint insulated-high-pulse-power (TC-IHPP) tests, (4) validating the ECM through discharging tests, and (5) exploring simulated scenarios and examining the ECM's predictions. Validation results show that with calibrated parameters, the ECM predicts a cell's electrical and temperature behavior reasonably accurately in a thermal environment and thermal runaway under extreme operating conditions. A degradation model predicts that a cell undergoing thermal runaway loses full capacity before failure initiation. Results show that irreversible and reactive heat are driving factors for a cell's heating during cycling at low and high temperatures, respectively. Thus, the ECM was simplified by removing additional parameters, which minimized the computational and experimental work required to set up the model. The simplified ECM (SECM) is suitable for scenarios where only average temperature is desired and can predict average temperature and voltage profiles as the original ECM. Finally, a theoretical model is provided to organize effects of electrical activity, thermal runaway kinetics, and environmental temperature on the likelihood for a cell to fail in thermal runaway. [ABSTRACT FROM AUTHOR]

A one-dimensional model of an electrochemical battery does not adequately simulate thermal runaway in a large battery; a three-dimensional model is required. Here, we combine a one-dimensional electrochemical cell with a two-dimensional resistor network to simulate thermal distribution in a lithium-ion battery. Based on electrode current density and the potential distribution, the temperature distribution, as a function of discharge time is predicted using two principal source equations for heat generation: one for the electrochemical reaction and the other for the current collector resistance. The model outputs were in good agreement with the experimental data of Kim et al. [1]. Our results provide an overview of temperature distribution, and also the discharge curves at varying discharge rates. Our findings can be used to optimize the design of large batteries and control their thermal characteristics. [ABSTRACT FROM AUTHOR]

The ordered aggregation of polymer donor and acceptor greatly affects the charge transport and charge recombination in polymer solar cells (PSCs). The post-production treatment of the active layer is the most widely applied strategy to improve the micro-distribution of polymer. Here, we demonstrated a simple method for high performance solar cell with thermal annealing (TA) and solvent vapor annealing (SVA). For the PSCs based on PTB7:PC71BM, the champion power conversion efficiencies (PCEs) were improved from 7.96 to 8.68% by employing TA + SVA and further to 8.86% with SVA + TA treatment. The enhanced PCEs of PSCs undergoing SVA + TA process are mainly attributed to the formation of a network phase separation structure with donor and acceptor phases penetrating each other and the improvement of the crystallinity of PTB7, while the improved photovoltaic performance with TA + SVA treatment is owing to the improved carrier mobility of blend films. Our work provides a useful strategy toward highly efficient PSCs without time-consuming and laborious fabrication procedures. [ABSTRACT FROM AUTHOR]

Low-temperature polymer electrolyte fuel cell systems (FCSs) need to reject large amounts of low temperature heat. Often a mobile FCS's cooling capacity limits the FCS power output. Cryogenic hydrogen is typically utilized as a direct heat sink using heat exchangers (HXs), even though HXs destroy most hydrogen exergy. This paper investigates synergies between FCS thermal management and cryogenic hydrogen exergy utilization in terms of their benchmark performance: the FCS coolant circuit supplies heat at coolant temperature level to a so named reversible cryogenic exergy utilization system (rCEUS) comprised of thermodynamically ideal heat engine processes. The rCEUS converts this heat partly to electrical energy (the value of which equals the hydrogen exergy) and rejects remaining heat to hydrogen to heat it to coolant temperature. The rCEUS output power is used to support the FCS, so the FCS rejects less heat and a significant fraction of this heat is utilized by the rCEUS. As a result, significantly less heat has to be transferred to ambient and the fuel demand decreases. In this paper, three hydrogen storage options are compared: liquid hydrogen, subcooled liquid hydrogen and cryo-compressed hydrogen. Different para- and orthohydrogen compositions are evaluated. For typical FCS operating points, rejected FCS heat to ambient is reducible by 40–67%. FCS power demand is reducible by 14–31%. FCS rejected heat to ambient reduction is 4.5–8 times larger than that of conventional HXs. Calculations are based on hydrogen's lower heating value. [ABSTRACT FROM AUTHOR]

This article presents the relevance of precise thermal conductivity measurements of solid materials used in heat exchange and heat insulating devices at low temperatures. The dependence of thermal conductivity of solids on the chemical composition and methods of mechanical and thermal processing of the material are considered at low temperatures. The device, principle of operation, and results of metrological studies of the State primary special standard of the unit of thermal conductivity of solids in the temperature range from 2 K to 300 K GET 141-2020 are presented. Compared to GET 141-84, in effect until 2020, GET 141-2020 includes the fabricated cryostat and a cell for measuring thermal conductivity. The range of reproduction of the unit of thermal conductivity of solids in GET 141-2020 is expanded compared to that of GET 141-84 from 0.1–10 W/(m·K) to 0.05–15 W/(m·K), and the range of temperature change is increased from 4.2–90 K to 2–300 K. A method of thermal conductivity measurements using the developed cryostat is described. Methods for ensuring a reliable thermal contact between the test sample and the heat-measuring plates of the heater and of the cell body are elaborated. The metrological characteristics of GET 141-2020 are analyzed; the measurement uncertainty budget is calculated when reproducing the unit of thermal conductivity of solids. GET 141-2020 is used to calibrate thermal conductivity measurements during the verification and calibration of equipment for measuring thermal conductivity. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries should continuously be operated at the optimum temperature range 15 ∼ 40 ∘ C for the best performance. Surface temperature monitoring is critical for the safe and efficient operation of the battery. In this study, initially, the electrical parameters of the battery are determined by applying a second-order equivalent circuit model. This model then is integrated with a thermal model based on the temperature dependent behavior of the electrical parameters and the heat generated. The input parameters to the electro-thermal model include the current, the ambient fluid temperature and the output parameters include the terminal voltage, state of charge, cell core temperature and cell surface temperature. In this research, the entropic coefficient and battery thermal parameters have been taken into consideration concurrently, which will lead to both saving plenty of time and cost compared to other methods. The accuracy of the suggested analytical approach for estimating the surface temperature and the amount of heat generation is validated with the pulse-rest tests of an 18,650 cylindrical lithium-ion battery with a nominal capacity of 2600 mAh at three different ambient temperatures and three charge/discharge current rates. The comparison of results indicate that the maximum error of the proposed algorithm is about 0.6 K under a wide range of test conditions. [ABSTRACT FROM AUTHOR]

The effects of airflow rate on the thermal runaway (TR) propagation characteristics of lithium-ion batteries (LIBs) with different arrangements in 30 kPa low-pressure environment are studied. The results show that the increase of airflow rate leads to a more vigorous TR reaction, a higher TR peak temperature. The TR onset time shows a trend of shortening at first and then delaying with the increase of airflow rate. In addition, the increase in the number of batteries leads to an increase in the TR time of a single battery. The main reason for the above phenomena is that the high oxygen content caused by high airflow rate promotes the combustion of LIBs. Meanwhile, the higher airflow rates also lead to an increase in convective heat transfer, and the increase in the number of batteries changes the thermal conductivity, which aggravates the heat loss and delays the TR time of LIBs. [ABSTRACT FROM AUTHOR]

Studying biomolecules in their native environment represents the ideal sample condition for structural biology investigations. Here we present a novel protocol which allows to delivery proteins into eukaryotic cells through a mild thermal stimulation. The data presented herein show the efficacy of this approach for delivering proteins in the intracellular environment of mammalian cells reaching a concentration range suitable for successfully applying biophysical methods, such as double electron electron resonance (DEER) measurements for characterising protein conformations. [ABSTRACT FROM AUTHOR]

Highlights: The phase change materials possess conformable configuration to the structure of Li-ion batteries in macro-scale and multidirectional thermal pathways for rapid and uniform heat transfer in micro-scale. Hierarchically structured phase change materials achieve dual-mode thermal management ability for heating and cooling Li-ion batteries. Excellent practical battery thermal management performance was verified by 18,650 Li-ion batteries in both cold and hot environments. Phase change materials (PCMs) are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries (LIBs) according to real-time thermal conditions, guaranteeing the reliable operation of LIBs in both cold and hot environments. Herein, we report a liquid metal (LM) modified polyethylene glycol/LM/boron nitride PCM, capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction. Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB's structure and heat-conduction characteristic. Typically, soft and deformable LMs are modified on the boron nitride surface, serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m−1 K−1 in the vertical and in-plane directions, respectively. In addition, LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system. As a proof-of-concept, this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10 °C at high charging/discharging rate, opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway. [ABSTRACT FROM AUTHOR]

Understanding the effect of heat on skin cells is important for the prevention of burn injury. Knowledge of the heat dose required to kill cells can be used to study the cellular mechanisms involved in thermal injury cell death, to assist with the development of novel burn treatments. In this study, primary human skin dermal fibroblasts were exposed to temperatures from 37 to 54 °C for 1 h and the relative cell viability of heat-treated and control cells was assessed. Cell damage and viability were assessed by light microscopy, MTT assay and live/dead staining. The LD50 for 1 h of heat exposure was 48 °C for primary fibroblasts; and there was evidence that thermal damage to cells begins to occur at 43 °C. This study presents a reproducible method for examining the effect of heat on primary human cells grown in culture on a cellular level and can be used in the future to study the mechanisms behind heat-induced cell death, to inform burn injury prevention efforts and effective post-burn treatment. [ABSTRACT FROM AUTHOR]

A computational analysis of the thermal management system of a battery-pack, whereby the cells are actively cooled at their surfaces by being immersed in a nanofluid medium. Nanofluids used in the automotive and energy management systems are selected and modelled within this work. The present study is conducted by carefully observing the flow structures, thermal energy distribution, entropy generation and pumping power requirements within the battery-pack, to be able to present a resource helpful for designers in the preliminary stages of their thermal management system. This study throws light beyond the case of the battery-pack thermal management, to other applications that require to be maintained at a given temperature or require a certain quantity of heat to be removed from it. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries have high energy density, excellent life cycle, and low self-discharge characteristics, but their performance is sensitive to temperature. In particular, the performance of lithium-ion batteries is degraded, and the internal resistance increased may prevent the battery from operating such as charged or discharged at subzero temperatures. Therefore, the study of thermal stability of lithium-ion batteries at low temperatures is as important as the battery thermal safety problem at high temperatures. In this paper, an analysis of preheating methods for battery packs designed for aircraft engine startup in low-temperature environments is conducted. The battery pack was designed by the design constraints that assumed ambient of −32 °C. The preheating is carried out using external heating for operation of the battery pack in low-temperature environments. Sixteen resistance heaters are installed inside the battery pack, which consists of 112 cylindrical lithium-ion cells. In addition, for effective heating of cylindrical battery cells, the battery cells are inserted inside the aluminum square battery tray, and the resistance heaters are attached sides of the battery tray for heating it. The thermal analysis when the designed preheating method was applied was carried out to review thermal distributions such as temperature uniformity of batteries according to heating. The heating volume of the resistance heater and the modification of the aluminum tray was considered, and the modified design method provided additional cell temperature homogeneity within the battery pack, resulting in thermal management strategy to use the battery pack in low temperatures. [ABSTRACT FROM AUTHOR]

Non-uniform heating of RF energy is the main obstacle for its large-scale application in blanching. In this study, we proposed a new blanching method: steam (ST)-assisted radio frequency (RF) blanching of fresh-cut stem lettuce cuboids. The relative peroxidase (POD) activity, heating uniformity, and physicochemical properties of samples treated by steam-assisted RF blanching at different conditions (RF-50 °C + ST-2.5 min, RF-65 °C + ST-2 min, and RF-80 °C + ST-1 min) were evaluated in comparison with single RF heating and steam blanching. Both the temperature distribution images and the heating uniformity index indicated that steam-assisted RF blanching overcame the defect of local overheating of single blanching mode and achieved more uniform temperature distribution. Besides steam-assisted RF, blanched reduced the thermal damage to cells, which can be demonstrated by lower relative electrolyte leakage rate, thereby maintained better texture, color, and higher vitamin C retention at the same relative POD activity of 5%. Among the three steam-assisted RF blanching treatments, RF-80 °C + ST-1 min achieved optimum heating uniformity and quality of samples. This study suggested that steam-assisted RF blanching can be used as a potential blanching method to improve inactivation efficiency of enzyme and quality of fruits and vegetables. [ABSTRACT FROM AUTHOR]

In this paper, low-temperature thermal batteries (LTBs) pertain to thermal batteries that have a lower operating temperature (less than 300 °C) than conventional thermal batteries. Nitrate eutectic salt is the most potential electrolyte for LTBs due to its lower melting point, qualified electrochemical performance, and thermal stability. Several nitrate-based systems offer the potential for use in LTBs. The conventional sulfide cathode materials are not compatible with molten nitrates, so transition metal oxides with higher potential such as Ag2CrO4, MnO2, and LiMn2O4 must be used instead. This article gives an overview of the discharge performance of LTBs using molten nitrate electrolytes. [ABSTRACT FROM AUTHOR]

Different battery thermal management (BTM) for a 18650 cylindrical Li-ion battery pack were simulated based on the lumped model. Phase change material (PCM) was introduced for its benefits: high latent heat and uniform melting temperature. However, the heat absorbed into the PCM was not dissipated to the environment. Thus, an additional cooling mechanism was required to reach satisfying temperature limits (45 °C for lifespan and 50 °C for safety). These include natural convection cooling, forced convection cooling, finned-natural convection cooling, PCM cooling, and PCM cooling coupled with liquid cooling channels. The temperature of the battery pack using natural convection, finned-natural convection, and PCM cooling reached 62.1 °C, 55 °C, and 50 °C, which were equal or over (50 °C), while it decreased to 49 °C using forced convection, which was over (45 °C). However, PCM coupled with liquid cooling channels satisfied the requirements, and the temperature was reduced to 42 °C using this system. [ABSTRACT FROM AUTHOR]

This study contains experimental and numerical investigation of the shape effect of the pack on the performances of PCM (or GNP/PCM) based passive thermally protected battery packs. Also, the performances of the PCM and thermally enhanced GNP/PCM composite for battery thermal protection are compared from low to high discharge rates. The thermal response results show that the cylindrical pack performs worse than the rectangular pack in terms of the maximum temperature and maximum temperature difference performance criteria. For the maximum temperature restriction criteria, 7% GNP/RT44 composite, that has enhanced thermal conductivity, performs better at first, but then its performance deteriorates compared to RT44 depending on the increase of its viscosity. It was determined that 7% GNP/RT-44 extend the effective protection times by 95.8%, 73.3% and 28.0% at the discharge rates of 4.4 W, 6.6 W and 8.8 W, respectively. [ABSTRACT FROM AUTHOR]

Elastic and plastic properties of materials and phase transitions at extreme conditions vary with both hydrostatic pressure and deviatoric stress. To generate and measure controlled deviatoric stress at pressures beyond those accessible with large volume differential and rotational presses and optical access for spectroscopy, experiments tested the combination of diamond anvil cell and thin film technology. Thin films of polycrystalline Cr-doped Al2O3 ruby were prepared using pulsed laser deposition on single-crystal substrates of either Al2O3 sapphire or yttria-stabilized cubic zirconia for contrasting initial film stress, and loaded in diamond anvil cells for confining stress. The piezospectroscopic response of the ruby films demonstrates consistently higher deviatoric stress in the film on zirconia relative to the film on the control sapphire, and an increase in deviatoric stress with applied load. Complementary synchrotron X-ray diffraction of the zirconia substrate confirmed that no pressure-induced phase transitions impacted the stress state of the ruby film, but differences in compressibility of film and substrate result in changes in film stress analogous to thermal expansion mismatch. This technique may be applied to evaluate elastic and plastic response of thin films of a variety of materials under extreme stress. [ABSTRACT FROM AUTHOR]

spt23 plays multiple roles in the thermal tolerance of budding yeast. spt23 regulates unsaturated lipid acid (ULA) content in the cell, which can then significantly affect cellular thermal tolerance. Being a Ty suppressor, spt23 can also interact with transposons (Tys) that are contributors to yeast's adaptive evolution. Nevertheless, few studies have investigated whether and how much spt23 can exert its regulatory functions through transposons. In this study, expression quantitative trait loci (eQTL) analysis was conducted with thermal-tolerant Saccharomyces cerevisiae strains, and spt23 was identified as one of the most important genes in mutants. spt23-overexpression (OE), deletion (Del), and integrative-expressed (IE) strains were constructed. Their heat tolerance, ethanol production, the expression level of key genes, and lipid acid contents in the cell membranes were measured. Furthermore, LTR (long terminal repeat)-amplicon sequencing was used to profile yeast transposon activities in the treatments. The results showed the Del type had a higher survival rate, biomass, and ethanol production, revealing negative correlations between spt23 expression levels and thermal tolerance. Total unsaturated lipid acid (TULA) contents in cell membranes were lower in the Del type, indicating its negative association with spt23 expression levels. The Del type resulted in the lower richness and higher evenness in LTR distributions, as well as higher transposon activities. The intersection of 3 gene sets and regression analysis revealed the relative weight of spt23's direct and TY-induced influence is about 4:3. These results suggested a heat tolerance model in which spt23 increases cell thermal tolerance through transcriptional regulation in addition to spt23-transposon triggered unknown responses. Key points: • spt23 is a key gene for heat tolerance, important for LA contents but not vital. • Deletion of spt23 decreases in yeast's LTR richness but not in evenness. • The relative weight of spt23's direct and TY-induced influence is about 4:3. [ABSTRACT FROM AUTHOR]

Overcharge is a common case of battery thermal abuse, which can accelerate the aging of battery and cause the attenuation of battery capacity. In extreme conditions, overcharge can generate a large amount of heat, leading to battery failure and thermal runaway. Therefore, it is necessary to take measures to improve the safety during the overcharge process. In this paper, phase change materials (PCMs) are used to mitigate the temperature of overcharged lithium-ion batteries (LIBs), which proves that PCMs can effectively reduce the battery surface temperature as well as the probability of thermal runaway. In order to identify the appropriate PCM on the thermal management of overcharged LIBs, PCMs with phase change temperatures (PCTs) of 37°C, 43°C, 58°C are used in the tests. The results show that the PCM-37 exhibits the best performance. In addition, different degrees of overcharge also bring different effects to the battery, while the applications of PCMs can well mitigate the sharp increase in temperature. The findings demonstrate the feasibility of PCMs on improving the thermal safety of overcharging LIBs and further provide guidance on the development of more efficient battery thermal management systems (BTMSs) where the overcharge usually occurs. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) exhibiting high capacity and energy density are in high demand in emerging markets such as electric vehicles and energy storage systems. However, these LIBs often show intrinsic shorter cycle life and higher risk of short circuit, which may result in thermal runaway and explosion. This work reviewed those polymers employed to improve cycling performance and safety of LIBs. First, some novel separator membranes, which prevent the direct contact of cathode with anode to induce disastrous short circuit, were developed with an aim at imparting safety to LIBs. For example, composite separators comprising ceramic and polymer show higher abuse tolerance for LIBs. Surface modification of the cathode active materials by polymers (e.g., polyimide (PI)) results in greatly enhanced electrochemical performance of LIBs, especially for layered LiNixCoyMnzO2. Another unique technology was developed, which involves coating reactive oligomer/polymer on the particle surface of cathode active materials to effectively limit the probability of short circuit and, eventually, thermal runaway of cells in an abusive environment. The fundamental mechanisms of the secondary oligomer/polymer reaction to form a dense highly cross-linked film on the pellet surface to inhibit thermal runaway were then discussed. This was followed by the last topic on polymer coated anodes used to suppress Li dendrite formation at the anode surface. Li dendrites may cause short circuit and capacity fading during cycling in LIBs. Some representative polymers including PI, polyurea and polycyanoacrylate that can greatly inhibit dendrite formation at anode surface were discussed. [ABSTRACT FROM AUTHOR]

Although numerous cathode materials with excellent properties have been developed for use in molten salt thermal batteries, similar progress is yet to be made with anode materials. Herein, a high-performance lithium-impregnated metal foam anode (LIMFA) is fabricated by impregnating molten lithium into a gold-coated iron–chrome–aluminium (FeCrAl) foam at 400 °C. A test cell employing the LIMFA FeCrAl anode exhibited a specific capacity of 2627 As g−1. For comparison, a cell with a conventional Li(Si) anode was also discharged, demonstrating a specific capacity of 982 As g−1. This significant improvement in performance can be attributed to the large amount (18 wt%) of lithium incorporated into the FeCrAl foam and the ability of the FeCrAl foam to absorb and immobilize molten lithium without adopting a cup system. For thermal batteries without a cup, the LIMFA FeCrAl provides the highest-reported specific capacity and a flat discharge voltage curve of molten lithium. After cell discharge, the FeCrAl foam exhibited no lithium leakage, surface damage, or structural collapse. Given these advantageous properties, in addition to its high specific capacity, LIMFA FeCrAl is expected to aid the development of thermal batteries with enhanced performance. [ABSTRACT FROM AUTHOR]

Rock salt is found in nature either in a single crystal or polycrystalline form, where crystal structure, grain, and grain boundary properties have major effects on its strength. The compressive strength of single-crystal rock salt is highly dependent on the loading direction with respect to rock salt's crystal orientation. Most salt formations are either located in a hot environment or exposed to elevated temperatures. Therefore, the influence of temperature should be considered when evaluating the constitutive behavior of rock salt. In this paper, the details of the design of a new high-pressure thermal cell that can withstand a confining pressure up to 15 MPa and a maximum temperature of 150 °C are presented. Three types of polycrystalline rock salt specimens with different grain and grain boundary properties were synthesized to study the effects of grain and grain boundary properties on the strength properties of polycrystalline rock salt. The results of the experiments were then used to examine the influences of grain size, grain boundary properties, annealing process, and temperature on the unconfined compressive strength of polycrystalline rock salt. In addition, 18 natural single-crystal rock salt specimens were prepared and tested at three different crystal orientations relative to loading direction at different temperatures. Specimens tested parallel to [1 0 0] and 19° to (1 0 0) in (0 1 0) showed quite a similar behavior. However, specimens tested on 30° to (1 0 0) in (0 1 0) exhibited a much higher unconfined compressive strength at 20 °C, while their unconfined compressive strength was significantly reduced when the temperature was increased. [ABSTRACT FROM AUTHOR]

The seminal work by Sadi Carnot in the early nineteenth century provided the blueprint of a reversible heat engine and the celebrated second law of thermodynamics eventually followed. Almost two centuries later, the quest to formulate a quantum theory of the thermodynamic laws has thus unsurprisingly motivated physicists to visualize what are known as 'quantum thermal machines' (QTMs). In this article, we review the prominent developments achieved in the theoretical construction as well as understanding of QTMs, beginning from the formulation of their earliest prototypes to recent models. We also present a detailed introduction and highlight recent progress in the rapidly developing field of 'quantum batteries'. [ABSTRACT FROM AUTHOR]

Hyperthermia has been studied as a noninvasive cancer treatment. Cancer cells show stronger thermal cytotoxicity than normal cells, which is exploited in hyperthermia. However, the absence of methods evaluating the thermal cytotoxicity in cells prevents the development of hyperthermia. To investigate the thermal cytotoxicity, culture temperature should be regulated. We, thus, developed a culture system regulating culture temperature immediately and accurately by employing metallic culture vessels. Michigan Cancer Foundation-7 cells and normal human dermal fibroblasts were used for models of cancer and normal cells. The findings showed cancer cells showed stronger thermal cytotoxicity than normal cells, which is quantitatively different from previous reports. This difference might be due to regulated culture temperature. The thermal stimulus condition (43 °C/30 min) was, further, focused for assays. The mRNA expression involving apoptosis changed dramatically in cancer cells, indicating the strong apoptotic trend. In contrast, the mRNA expression of heat shock protein (HSP) of normal cells upon the thermal stimulus was stronger than cancer cells. Furthermore, exclusively in normal cells, HSP localization to nucleus was confirmed. These movement of HSP confer thermotolerance to cells, which is consistent with the different thermal cytotoxicity between cancer and normal cells. In summary, our developed system can be used to develop hyperthermia treatment. [ABSTRACT FROM AUTHOR]

With the extensive application of lithium batteries and the continuous improvements in battery management systems and other related technologies, the requirements for fast and accurate modeling of lithium batteries are gradually increasing. Temperature plays a vital role in the dynamics and transmission of electrochemical systems. The thermal effect must be considered in battery models. In this paper, a simulation model of a lithium battery with thermal characteristics is established. This thermal model is coupled with a temperature-dependent 2-RC equivalent circuit model to form an electro-thermal model for lithium-ion batteries. The hybrid pulse power characterization test is used to estimate the equivalent circuit parameters. Finally, under NEDC and DST conditions, battery voltage and temperature estimation results of the electro-thermal model are analyzed to verify the correctness and accuracy of the model. The voltage error is within − 0.16 ~ 0.20 V under the NEDC condition. Moreover, under the DST condition, the maximum relative error in the electro-thermal model is within 5%. [ABSTRACT FROM AUTHOR]