Search

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]

Modern concepts in irreversible thermodynamics are applied to system transformation and degradation analyses. Phenomenological entropy generation (PEG) theorem is combined with the Degradation-Entropy Generation (DEG) theorem for instantaneous multi-disciplinary, multi-scale, multi-component system characterization. A transformation-PEG theorem and space materialize with system and process defining elements and dimensions. The near-100% accurate, consistent results and features in recent publications demonstrating and applying the new TPEG methods to frictional wear, grease aging, electrochemical power system cycling—including lithium-ion battery thermal runaway—metal fatigue loading and pump flow are collated herein, demonstrating the practicality of the new and universal PEG theorem and the predictive power of models that combine and utilize both theorems. The methodology is useful for design, analysis, prognostics, diagnostics, maintenance and optimization. [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]

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]

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]

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]

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 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]

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 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]

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]

Aged battery is prone to fire accidents. Thermal stability change of battery subjected to inhomogeneous aging is studied in this manuscript by accelerating rate calorimeter. The results indicate that thermal runaway time decreases for aged batteries. Solid electrolyte interphase and lithium plating suppress and accelerate onset exothermic side reactions. Transition metal dissolution accelerates positive electrode decomposition and oxygen release. T TR of aged batteries decreases compared to fresh battery. Microscopic changes of negative electrodes for batteries cycled at high and low temperature are inhomogeneous. T onset for batteries cycled at low temperature decreases as lithium plating covers all of the negative electrode surface. T onset for batteries cycled at high temperature and with 100% state of charge (SOC) increases. This is the same to battery stored at high temperature. Local lithium plating affects thermal stability of battery with 100% SOC less. However, T onset for batteries with SOC lower than 50% SOC and subjected to local lithium plating decreases compared to fresh battery. Local lithium plating accelerates onset exothermic side reactions for battery with SOC lower than 50% SOC. The results of this manuscript are important to thermal runaway prevention for batteries in their whole operation life. [Display omitted] [ABSTRACT FROM AUTHOR]

This study focused on the design of a battery pack cooling channel based on a Tesla Model S electric car. This study aimed to achieve a balance between cooling efficiency and pressure drop while maintaining safe and optimal operating temperatures for the batteries. A cooling channel design similar to the basic type employed in the Tesla Model S using 448 cylindrical Li-ion batteries was considered. Consequently, important parameters, such as the maximum temperature and temperature difference in the battery cells in a module, as well as the pressure drop of the coolant, were analyzed. In addition, the characteristics of the temperature changes in each cooling channel shape were investigated. The temperature limit for the battery in a module and the temperature limit difference were set to 40 °C and 5 °C, respectively, to evaluate the performance of the cooling system. Further, the effects of discharge rates (3C and 5C), cooling channel shapes (counter flow and parallel types), and coolant inlet velocities (0.1, 0.2, 0.3, and 0.4 m/s) on battery thermal management were analyzed. The results revealed that the parallel type channel yielded a lower pressure drop than the basic type channel; however, it was not as effective in removing heat from the battery. In contrast, the counter flow type channel effectively removed heat from the batteries with a higher coolant pressure drop in the channel. Therefore, a multi-counter flow type cooling channel combining the advantages of both these channels was proposed to decrease the pressure drop while maintaining appropriate operating temperatures for the battery module. The proposed cooling channel exhibited an excellent cooling performance with lower power consumption and better heat transfer characteristics. However, relatively minimal differences were confirmed for the maximum temperature and temperature difference in the battery module compared with the counter flow type. Therefore, the proposed cooling channel type can be implemented to ensure the optimal temperature operation of the battery module and to decrease system power consumption. [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]

The primary objective of this study was to explore the impact of integrating nano-additives on heat transfer enhancement within an LHTES (Latent Heat Thermal Energy Storage) system. Our findings revealed that introducing a minimal amount of nano-materials (less than 5.0 vol%) into the Phase Change Material (PCM) led to a remarkable alignment between experimental correlations and mixture models. Furthermore, employing the mixing model allowed for the accurate prediction of outcomes. In the current context of scientific research, there is a strong endorsement for the widespread adoption of Electric Vehicles (EVs) as a sustainable alternative to Internal Combustion Engines (ICEs), crucial for advancing decarbonization and mitigating climate-related crises. Lithium-ion batteries are the predominant choice for EVs and various electrical devices. However, the operational challenges posed by high temperatures, impacting their lifespan, charge/discharge cycles, and the risk of thermal runaway, necessitate effective thermal management systems. Given this background, our study focuses on simulating the heat dissipation of a single cylindrical Li-ion battery cell employing a Nano-enhanced Phase Change Material (NePCM)-based cooling system. We also introduce a novel fin design in this work. Through comprehensive analysis, we examine the performance of battery modules utilizing PCM and NePCM at different discharge rates, both with and without the newly proposed fin design. Our research demonstrates that the incorporation of fins and nanoparticles into PCM significantly enhances heat transfer and reduces the charging time compared to the base PCM. Notably, carbon-based nanoparticles outshine their metal-based counterparts in terms of melting rate and maintaining a uniform temperature profile within the battery. [ABSTRACT FROM AUTHOR]

In recent years, electric vehicles powered by lithium-ion batteries have developed rapidly, and the safety and reliability of lithium-ion batteries have been a paramount issue. Battery management systems are highly dependent on sensor measurements to ensure the proper functioning of lithium-ion batteries. Therefore, it is imperative to develop a suitable fault diagnosis scheme for battery sensors, to realize a diagnosis at an early stage. The main objective of this paper is to establish validated electrical and thermal models for batteries, and address a model-based fault diagnosis scheme for battery sensors. Descriptor proportional and derivate observer systems are applied for sensor diagnosis, based on electrical and thermal models of lithium-ion batteries, which can realize the real-time estimation of voltage sensor fault, current sensor fault, and temperature sensor fault. To verify the estimation effect of the proposed scheme, various types of faults are utilized for simulation experiments. Battery experimental data are used for battery modeling and observer-based fault diagnosis in battery sensors. [ABSTRACT FROM AUTHOR]

In order to improve the performance of a battery thermal management system (BTMS) based on phase change material (PCM), expanded graphite (EG) is added to paraffin to form composite PCM (CPCM), and embedded aluminum fins are coupled with liquid cooling to enhance heat transfer. A heat generation model for lithium‐ion batteries (LIBs) is established and verified by experiments. The cooling performances of four BTMS designs were simulated. The effects of the thermal characteristics of LIBs were investigated at various velocities and directions of coolant flow as well as EG fractions in CPCMs. The simulation results indicate that Design IV shows a good cooling effect at a coolant flow rate of 0.06 m s−1 and an EG fraction of 12 wt%. Under ambient temperatures of 26°C, 35°C and 40°C, the maximum battery temperatures are 28.14°C, 37.15°C and 42.09°C, respectively, and the maximum temperature difference over the battery module is 1.88°C, 1.89°C and 1.92°C, respectively. The charge‐discharge cycle performances of the four BTMS designs were further investigated. In Design IV, the maximum temperature and the maximum temperature difference in the battery module remain unchanged during five cycles under 1, 2 and 3 C discharge rates. The new BTMS has significantly improved the secondary heat storage problem of PCMs and the temperature uniformity of LIBs. The fin structure combined with liquid cooling is efficient in enhancing the heat transfer of CPCM for battery thermal management. [ABSTRACT FROM AUTHOR]

Recently, there has been growing recognition of the significance of energy and environmental challenges. Utilization of lithium-ion batteries in electric vehicles has shown considerable potential and benefits for tackling these issues. The effective management of battery temperature has become a crucial factor in the advancement and widespread adoption of lithium-ion batteries in electric vehicles. In this study, a thermo-coupled pseudo-two-dimensional (P2D) electrochemical model is employed to simulate the heat generation of the NCM811-21700 cylindrical battery cell at various discharge rates at an ambient temperature of 25 °C, and is validated by experimental data. The validation results demonstrate that the thermo-coupled P2D model can effectively predict the battery voltage curve during the discharge process with less than 4% errors. Although there is a slightly larger error in the temperature prediction during the battery 2C and 3C discharge processes, the maximum error approaches 10%, which is still generally within an acceptable range. In addition, the battery's electrochemical and thermal characteristics during discharge are presented. The suggested thermo-coupled electrochemical model can be used for applications in the thermal management system of the NCM811-21700 battery. [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]

To enhance our understanding of the thermal characteristics of lithium-ion batteries and gain valuable insights into the thermal impacts of battery thermal management systems (BTMSs), it is crucial to develop precise thermal models for lithium-ion batteries that enable numerical simulations. The primary objective of creating a battery thermal model is to define equations related to heat generation, energy conservation, and boundary conditions. However, a standalone thermal model often lacks the necessary accuracy to effectively anticipate thermal behavior. Consequently, the thermal model is commonly integrated with an electrochemical model or an equivalent circuit model. This article provides a comprehensive review of the thermal behavior and modeling of lithium-ion batteries. It highlights the critical role of temperature in affecting battery performance, safety, and lifespan. The study explores the challenges posed by temperature variations, both too low and too high, and their impact on the battery's electrical and thermal balance. Various thermal analysis approaches, including experimental measurements and simulation-based modeling, are described to comprehend the thermal characteristics of lithium-ion batteries under different operating conditions. The accurate modeling of batteries involves explaining the electrochemical model and the thermal model as well as methods for coupling electrochemical, electrical, and thermal aspects, along with an equivalent circuit model. Additionally, this review comprehensively outlines the advancements made in understanding the thermal behavior of lithium-ion batteries. In summary, there is a strong desire for a battery model that is efficient, highly accurate, and accompanied by an effective thermal management system. Furthermore, it is crucial to prioritize the enhancement of current thermal models to improve the overall performance and safety of lithium-ion batteries. [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]

Electrification on transportation and electricity generation via renewable sources play a vital role to diminish the effects of energy usage on the environment. Transition from the conventional fuels to renewables for transportation and electricity generation demands the storage of electricity in great capacities with desired power densities and relatively high C-rate values. Yet, thermal and electrical characteristics vary greatly depending on the chemistry and structure of battery cells. At this point, lithium-ion (Li-ion) batteries are more suitable in most applications due to their superiorities such as long lifetime, high recyclability, and capacities. However, exothermic electrochemical reactions yield temperature to increase suddenly which affects the degradation in cells, ageing, and electrochemical reaction kinetics. Therefore, strict temperature control increases battery lifetime and eliminates undesired situations such as layer degradation and thermal runaway. In the literature, there are many distinct battery thermal management strategies to effectively control battery cell temperatures. These strategies vary based on the geometrical form, size, capacity, and chemistry of the battery cells. Here, we focus on proposed battery thermal management strategies and current applications in the electric vehicle (EV) industry. In this review, various battery thermal management strategies are documented and compared in detail with respect to geometry, thermal uniformity, coolant type and heat transfer methodology for Li-ion and post-lithium batteries. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) offer a potential solution to face the global energy crisis and climate change issues in the transportation sector. Currently, lithium-ion (Li-ion) batteries have gained popularity as a source of energy in EVs, owing to several benefits including higher power density. To compete with internal combustion (IC) engine vehicles, the capacity of Li-ion batteries is continuously increasing to improve the efficiency and reliability of EVs. The performance characteristics and safe operations of Li-ion batteries depend on their operating temperature which demands the effective thermal management of Li-ion batteries. The commercially employed cooling strategies have several obstructions to enable the desired thermal management of high-power density batteries with allowable maximum temperature and symmetrical temperature distribution. The efforts are striving in the direction of searching for advanced cooling strategies which could eliminate the limitations of current cooling strategies and be employed in next-generation battery thermal management systems. The present review summarizes numerous research studies that explore advanced cooling strategies for battery thermal management in EVs. Research studies on phase change material cooling and direct liquid cooling for battery thermal management are comprehensively reviewed over the time period of 2018–2023. This review discusses the various experimental and numerical works executed to date on battery thermal management based on the aforementioned cooling strategies. Considering the practical feasibility and drawbacks of phase change material cooling, the focus of the present review is tilted toward the explanation of current research works on direct liquid cooling as an emerging battery thermal management technique. Direct liquid cooling has the potential to achieve the desired battery performance under normal as well as extreme operating conditions. However, extensive research still needs to be executed to commercialize direct liquid cooling as an advanced battery thermal management technique in EVs. The present review would be referred to as one that gives concrete direction in the search for a suitable advanced cooling strategy for battery thermal management in the next generation of EVs. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) with relatively high energy density and power density are considered an important energy source for new energy vehicles (NEVs). However, LIBs are highly sensitive to temperature, which makes their thermal management challenging. Developing a high-performance battery thermal management system (BTMS) is crucial for the battery to retain high efficiency and security. Generally, the BTMS is divided into three categories based on the physical properties of the cooling medium, including phase change materials (PCMs), liquid, and air. This paper discusses the effect of temperature on the performance of individual batteries and battery systems, at first. Then, a systematic survey of the state-of-the-art BTMS is presented in terms of liquid-based, PCM-based, and air-based BTMS. To further utilize the heat source of the vehicle, the BTMS integrated with the vehicle thermal management system (VTMS) is discussed. Finally, the challenges and future prospects for BTMS with the ability to cut off the thermal runaway are discussed. The primary aim of this review is to offer some guidelines for the design of safe and effective BTMS for the battery pack of NEVs. [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]

With the development of computer technologies and battery systems, mobile robot systems have gained an important place in our lives. The Li-ion batteries, which attract attention for portable applications due to their high power output, light weight, and no memory effect, must operate in a limited temperature range in order to operate safely and for a long application life. This case makes it necessary to use battery thermal control systems that will provide temperature control for Li-ion battery applications. Within the scope of our study, Li-ion battery thermal management systems were investigated in detail. A detailed literature review was carried out on air thermal management systems, with their application and systemic convenience. Due to restricted packaging space for battery in mobile robots, cooling will be more challenging in the future. The air thermal management system, which has limited thermal management capability due to the low thermal properties of the air, is a thermal management method that will be sufficient especially for low scale applications. [ABSTRACT FROM AUTHOR]

Sorts of Li-ion batteries (LIB) have been becoming important energy supply and storage devices. As a long-standing obstacle, safety issues are limiting the large-scale adoption of high-energy–density batteries. Strategies covering materials, cell, and package processing have been paid much attention to. Here, we report a flexible sensor array with fast and reversible temperature switching that can be incorporated inside batteries to prevent thermal runaway. This flexible sensor array consists of PTCR ceramic sensors combined with printed PI sheets for electrodes and circuits. Compared to room temperature, the resistance of the sensors soars nonlinearly by more than three orders of magnitude at around 67 °C with a 1 °C/s rate. This temperature aligns with the decomposition temperature of SEI. Subsequently, the resistance returns to normal at room temperature, demonstrating a negative thermal hysteresis effect. This characteristic proves advantageous for the battery, as it enables a lower-temperature restart after an initial warming phase. The batteries with an embedded sensor array could resume their normal function without performance compromise or detrimental thermal runaway. [ABSTRACT FROM AUTHOR]

This electrode has excellent storage capacity and superior thermal safety performance. [Display omitted] • A coral reef inspired trimetallic-phase ternary metal sulfides with N/S doped carbon protector was designed. • This ternary metal sulfides shows superior cycling and rate property than many TMSs. • The favorable Li+/Na+ storage actions and related reaction kinetics are discovered. • Using the designed structure markedly promotes the thermal safety of cells. Traditional transition metal sulfides (TMSs) have shown favorable potentials in energy storage. Nevertheless, its further usage is plagued by the issues of particle breakage and large volume change. In this work, the nanostructured ternary TMSs coupled with N/S doped carbon protector (NiCoFe-S@NSC) is delicately designed via compositional regulation and spatial structure protection strategies. As lithium ion batteries anode, this electrode gives an impressive capacity of 995.7 mAh/g after running 1000 cycles at 1 A/g. More importantly, NiCoFe-S@NSC electrode still shows a discharge capacity of 221.94 mAh/g after running 20,000 cycles at 10 A/g, reflecting an extremely-low capacity decay rate of 0.0377 ‰ per cycle. As sodium ion batteries anode, a high initial discharge capacity of 896.4 mA h g−1 can be found. Even after running 400 cycles at 5 A/g, the electrode still displays a reversible capacity of 334.5 mAh/g with outstanding coulombic efficiency above 98.0 %. Impressively, LiNi x Co y Mn 1-x-y O 2 //NiCoFe-S@NSC full cell gives incipient discharge/charge capacities of 186.89/240.18 mAh/g. Moreover, the discharge capacities for the following 100 cycles remain above 150 mAh/g. Thermal runaway tests also demonstrate the higher thermal safety of cells with NiCoFe-S@NSC electrode, accompanying with the promoted activation energy. [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]

To reduce the thermal runaway risk of lithium-ion batteries, a good thermal management system is critically required. As phase change materials can absorb a lot of heat without the need for extra equipment, they are employed in the thermal management of batteries. The thermal management of a Sanyo 26,650 battery was studied in this work by using different composite phase change materials (CPCMs) at different charge–discharge rates. The thorough analysis on the thermal conductivity of CPCMs and the effect of CPCMs was conducted on the maximum surface temperature while charging and discharging. The findings demonstrate the ability of the composite thermal conductivity filler to increase thermal conductivity. It is increased to 1.307 W/(m K) as the ratio of silica and graphene is 1:1 (CPCM-3). The CPCMs can reduce the surface temperature of the cell, and the cooling effect of CPCM-3 is the most obvious, which can reduce the maximum temperature of the cell surface by 13.7 °C and 19 °C under 2 C and 3 C conditions. It is also found that the risk of thermal runaway of batteries under CPCMs thermal management is effectively reduced, ensuring the safe operation of the battery. This research can assist in the safe application of batteries and the development of new energy sources. [ABSTRACT FROM AUTHOR]

Poor thermal transport within lithium-ion batteries fundamentally limits their performance, safety, and lifetime, in spite of external thermal management systems. All prior efforts to understand the origin of batteries' mysteriously high thermal resistance have been confined to ex situ measurements without understanding the impact of battery operation. Here, we develop a frequency-domain technique that employs sensors capable of measuring spatially resolved intrinsic thermal transport properties within a live battery while it is undergoing cycling. Our results reveal that the poor battery thermal transport is due to high thermal contact resistance between the separator and both electrode layers and worsens as a result of formation cycling, degrading total battery thermal transport by up to 70%. We develop a thermal model of these contact resistances to explain their origin. These contacts account for up to 65% of the total thermal resistance inside the battery, leading to far-reaching consequences for the thermal design of batteries. Our technique unlocks new thermal measurement capabilities for future battery research. [ABSTRACT FROM AUTHOR]

Li‐ion batteries (LIBs) that promise both safety and high energy density are critical for a new‐energy future. However, recent studies on battery thermal runaway (TR) suggest that the higher the energy is compressed in a battery, the thermal accidents with fires and explosions can occur in a more catastrophic way. This "trade‐off" between energy density and safety poses challenging obstacles toward the future applications of the developing high‐energy chemistries. Herein, the thermal studies on the most appealing high‐energy (HE)‐LIB chemistries are carefully reviewed. The TR characters of the HE‐LIBs, the material thermal failure behaviors as well as the underneath reaction mechanisms, and the most advanced TR mitigation technologies are comprehensively summarized. Moreover, the effectiveness of different TR mitigation routes is analyzed. Based on the analysis, the main challenges for TR mitigation in HE chemistries are further explained. Finally, opinions on the future TR mechanism studies and the promising safety design routes to overcome this intrinsic "trade‐off" between high energy and safety are presented. [ABSTRACT FROM AUTHOR]

Li‐ion batteries (LIBs) that promise both safety and high energy density are critical for a new‐energy future. However, recent studies on battery thermal runaway (TR) suggest that the higher the energy is compressed in a battery, the thermal accidents with fires and explosions can occur in a more catastrophic way. This "trade‐off" between energy density and safety poses challenging obstacles toward the future applications of the developing high‐energy chemistries. Herein, the thermal studies on the most appealing high‐energy (HE)‐LIB chemistries are carefully reviewed. The TR characters of the HE‐LIBs, the material thermal failure behaviors as well as the underneath reaction mechanisms, and the most advanced TR mitigation technologies are comprehensively summarized. Moreover, the effectiveness of different TR mitigation routes is analyzed. Based on the analysis, the main challenges for TR mitigation in HE chemistries are further explained. Finally, opinions on the future TR mechanism studies and the promising safety design routes to overcome this intrinsic "trade‐off" between high energy and safety are presented. [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]

Lithium-ion batteries (LIBs) are widely used in electrochemical energy storage and in other fields. However, LIBs are prone to thermal runaway (TR) under abusive conditions, which may lead to fires and even explosion accidents. Given the severity of TR hazards for LIBs, early warning and fire extinguishing technologies for battery TR are comprehensively reviewed in this paper. First, the TR reaction mechanism and hazards of LIBs are discussed. Second, the TR early warning and monitoring methods of LIBs are summarized in five aspects consisting of acoustic, heat, force, electricity, and gas. In addition, to reduce the fire and explosion hazards caused by the TR of LIBs, the highly efficient extinguishing agents for LIBs are summarized. Finally, the early warning technology and fire extinguishing agent are proposed, which provides a reference for the hazard prevention and control of energy storage systems. [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 lithium-ion battery (LIB) thermal runaway (TR) has been a major safety problem, and effective countermeasure to suppress the TR becomes indispensable. Owing to the outstanding cooling capacity, the water mist presents efficient suppression effect on TR, but the comprehensive understanding on the cooling mechanisms remains unclear. In this work, the fine water mist (FWM) that is driven by the air flow has been applied to suppress the TR, and the cooling control processes under various thermal hazard conditions have been comprehensively analyzed. Results show that TR can be efficiently suppressed with the FWM applied before the critical temperature, which is identified as 252.5 ± 2.5°C. The average surface cooling rate increases from 1.04 to 1.22°Cs−1 with the increasing flow rate, and the total heat dissipation maintains approximately at 2.10 kJ, once the flow rate exceeds 0.2 mLs−1. It is identified that the most efficient cooling process can be obtained under the duration of 80 s. The influence of the flow rate and duration of the FWM on the cooling effect has been discussed to comprehensive reveal the control mechanism, and the excellent cooling control effect of the FWM flow has been verified. [ABSTRACT FROM AUTHOR]