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Electric mobility decarbonizes the transportation sector and effectively addresses sustainable development goals. A good battery thermal management system (BTMS) is essential for the safe working of electric vehicles with lithium‐ion batteries (LIBs) to address thermal runaway and associated catastrophic hazards effectively. However, PCMs suffer from low thermal conductivity issues, and hence, enhancement techniques include the use of fins, nano‐additives, extended graphite powder, and so forth. The use of composite phase change materials effectively addresses LIB thermal management widely used in electric vehicles while mitigating thermal runaway, besides providing flame retardancy, thermal/mechanical stability, and electrical insulation, and preventing leakage. It is noted that no single strategy of BTMS is brought down to a safe zone of temperature, and hybrid BTMSs are being employed, invariably involve phase change materials (PCMs) to a large extent. It is essential to utilize CPCMs to address the effects of low‐temperature environments and vibrations considering vehicle driving cycles and operating conditions. It is observed from the review that ultrasonic monitoring and early detection of internal short circuits are the steps towards mitigation of thermal runaway propagation. It is required to utilize optimization methods, machine learning and IoT tools for a feasible PCM based BTMS work. Present review briefly describes potential methods for effective utilization of PCMs, comparison among different methods, challenges associated and potential solutions. It is highly essential to develop compact and economical BTMS with effective CPCMs for better and safer LIB operation to attract large‐scale commercialization of electric vehicles. [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 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]

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

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

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

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]

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

The 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]

Energy storage like batteries is essential for stabilizing the erratic electricity supply. High temperatures when the power is charged and discharged will produce high temperatures during the charging and discharging of batteries. To maintain optimum battery life and performance, thermal management for battery energy storage must be strictly controlled. This study investigated the battery energy storage cabinet with four cases studies numerically. The results show that Case 1, as the initial design not performing optimally. Thermal buoyancy occurs, resulting in the temperature in the top area being warmer than the lower area. The battery surface temperature is steadily at 47 °C. Case 2 added fans on the center of the cabinet bottom surface to overcome the problem, while Case 3 added fans on the left side of the cabinet bottom surface. The battery surface temperatures in Cases 2 and 3 are steady at 39 °C and 37 °C. However, high temperatures still accumulated in the top area for both cases. Contrarily, Case 4 performs a better thermal distribution by adding exhaust air to the top side of the cabinet. The results revealed that the placement of exhaust air could enhance the removal of heat generated from the batteries accumulated in the top area. The battery surface temperature in Case 4 is relatively at 35 °C. Case 4 also performs the best thermal distribution, which desired temperature could be successfully achieved faster compared to other cases. [ABSTRACT FROM AUTHOR]

The design of lithium‐ion battery pack to meet the power requirements of two‐wheeled electric bikes for Indian conditions is studied here. Theoretical calculations are performed based on the technical data collected from various resources in India. In particular, the two‐wheeled "Activa 6G" vehicle is considered for the analysis. Based on the numerical analysis, a relation between cell parameters such as: C‐rate, voltage, capacity, pack configuration, and vehicle dynamics parameters like: weight of the vehicle, payload, travel range per charge, and energy consumption, has been established. Commercial cylindrical cells, namely: 18650, 21 700, and 26 650 are used in all the calculations. The corresponding battery packs are designed considering a range of 100 km. Furthermore, simulations are performed to understand the voltage‐discharge characteristics, state of charge and variation of cell concentration with respect to time as the battery discharges. The studies are extended to analyze the battery thermal management to estimate the degradation and heat generation rate, and hence, the optimum operating parameters, that is, optimal electrode thicknesses and particle size to enhance the endurance. Based on the degradation and heat generation profiles, the life of the battery pack made of 26 650 cells is found to be better as compared to the battery packs made of 18 650 and 21 700 cells. Furthermore, the analysis is extended for battery packs made of 26 650 cells in four different configurations, considering air and mineral oil as the cooling fluids to estimate the maximum temperature and hence degradation characteristics. Tapered configuration is found to be the best configuration among the four, yielding lowest maximum temperature and capacity fading. On the other hand, when mineral oil is used as the cooling fluid in rectangular configuration, the maximum operating temperature is found to be reduced by 4.49 K. However, usage of mineral oil adds to the periodic maintenance and replacement costs. [ABSTRACT FROM AUTHOR]

Electric powered vehicle popularity gives us better option for reducing the hydrocarbon emissions for the clean environment and will help to minimizing the troposphere of ozone degradation. Evs that are powered by batteries are becoming more commonplace worldwide. A strong Battery Management System (BMS) is essential for the reliable and safe operation of batteries, which have been widely used in many large power applications, including EVs and hybrid EVs. Their optimal plan and the management are significant for safe and beneficial tasks. This review paper examined with about the oldest kind of battery-latest powered battery (Pb-acid battery) and the most recent innovation of battery, lithium-ion battery. The present paper deals about the recent improvement in three important areas like Battery pack shape, different battery material and thermal behaviour which covered main challenges for EVs operation. [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]

Conventional automobiles that operate on fossil fuels have recently been recognized as one of the significant contributors to environmental pollution, particularly given their increasing numbers in relation to the global population. Electric vehicle (EV) is considered as an excellent solution to this problem. The most difficult challenge is increasing the production of EVs using efficient and affordable batteries. All types of batteries used in EV have a power loss occurs in the form of temperature. The development of a battery thermal management system (BTMS) is a formidable obstacle. The new concept aims to improve the thermoelectric cooler (TEC) efficiency by integrating it with a thermoelectric generator (TEG), which is accomplished by fabricating a TEC‐TEG model. The goal of combining a TEG and a TEC is to utilize waste heat generated on the TEC hot side and convert it into a stream that can be used to feed the TEC and increase its efficiency. Finally, the objectives of this paper are:To investigate the working principle of TEC‐TEG model to regulate EV battery's temperature.To design a hybrid air‐forced TEC‐TEG model for EV batteries.To assess and verify the efficiency of a hybrid TEC‐TEG model in regulating an EV battery temperature. [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]

Electric vehicles are seen as the prevailing choice for eco-friendly transportation. In electric vehicles, the thermal management system of battery cells is of great significance, especially under high operating temperatures and continuous discharge conditions. To address this issue, a pack-level battery thermal management system with phase change materials and liquid cooling was discussed in this paper. A dynamic electro-thermal coupled model for cells, the enthalpy–porosity model for phase change materials, and the k-ε model for the coolant flow were used. Various parameters, such as ambient temperatures, discharge rates, components of phase change materials, inlet mass flow rates, and temperatures of the coolant were considered. The results indicated that a battery thermal management system with both phase change materials and liquid cooling is more effective than the one with only liquid cooling. The phase change material with a mass fraction of 10% expanded graphite in paraffin wax had a favorable performance for the battery thermal management system. Additionally, increasing the mass flow rate or decreasing the flow temperature of the coolant can reduce the maximum temperature of the battery pack. However, the former can limit the maximum temperature difference, while the latter will deteriorate the temperature uniformity. The present work may shed light on the design of battery thermal management systems in the electric vehicle industry. [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]

The aim of the present work is to develop and test an innovative cooling system for the thermal management of batteries for electric vehicles (EVs). At present, the technology most used for electric propulsion is based on lithium-ion cells. The power supply unit must often deliver a large amount of power in a short time, forcing the batteries to produce a considerable amount of heat. This leads to a high working temperature that can cause a sharp decrease in the battery performance or even a malfunction. Moreover, their working outside of the prescribed temperature range (20–40 °C) or with a significant temperature gradient across the battery meaningfully accelerates their aging or breakage. In this case, a battery thermal management system (BTMS) is necessary to allow the batteries to work as efficiently as possible. In the present work, a pulsating heat pipe with a three-dimensional structure is proposed as cooling technology for a battery pack. At first the performance of the proposed PHP is evaluated in a dedicated experimental setup under different boundary conditions and a wide spectrum of power input values. Then the PHP is tested by applying, as load at the evaporator section, heat power distribution corresponding to three different discharging processes of a battery. These tests, directly referring to an applicative case, show that the proposed 3D PHP has an optimal cooling ability and the possibility to offer a powerful solution for electrical battery thermal management. [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]

Adhering to the thermal management requirements of prismatic battery modules, an improved lightweight parallel liquid cooling structure with slender tubes and a thin heat-conducting plate is proposed. The multiobjective optimization of the structure, operating parameters of the thermal management system, and thermal characteristics of a battery module are carried out. The effects of the equivalent diameter of the square tubes and the inner diameter of the circular tubes on the maximum temperature, maximum temperature difference of the batteries, and coolant pressure drop of liquid cooling battery thermal management system (BTMS) are investigated. The more significant factors, selected as the design variables, are the equivalent diameter of the square tubes, the inner diameter of the circular tube, and the coolant inlet velocity. Combining the computational fluid dynamics (CFD) method with multiobjective optimization, the different conditions of heat management parameters obtained by Latin hypercube sampling are numerically calculated, and the optimization of these parameters is carried out by the second-generation Elitist Nondominated Sorting Genetic Algorithm (NSGA-II). Compared with the thermal characteristics of the battery module before optimization, the maximum temperature of the module after optimization is reduced by 9.3%, the maximum temperature difference is reduced by 20.7%, and the coolant pressure drop from inlet to outlet is reduced by 49.1%. [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]

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]

Refrigerant indirect contact phase-change cooling system flows refrigerant into a cold plate and utilizes the phase-change to exchange heat with the battery. However, R134a, commonly used, is being gradually restricted due to its environmental impact. A new kind of near azeotrope mixed refrigerant R1234yf/R152a (mass ratio 60.5:39.5) is proposed under environmental protection and safety. Based on the fluid-structure interaction model, the evaluation of different indirect contact phase-change cooling systems for battery thermal management (BTM) using R1234yf/R152a is investigated. After obtaining battery (150 Ah, 3.2 V LiFePO4) parameters, heat generation power, and main test conditions through experiments, the thermal properties are numerically studied by computational fluid dynamics (CFD). At 1 C discharge rate, the temperature gradient (TG) of single battery and the maximum temperature difference (TD) among batteries are analyzed for two cases: The maximum TD among batteries of Case_b is 6.5°C lower than that of Case_a. In addition, the effect of the mixed refrigerant and traditional liquid cooling on the battery temperature is studied at different evaporation temperatures (ETs) (20°C, 25°C) and different mass flow rates (MFRs) (0.02, 0.10, and 0.18 kg/s). The results show that both the increase of inlet MFR and the reduction of inlet ET may significantly improve the battery module cooling rate. Compared with 0.02 kg/s, as the MFR increases, the temperature drop slopes to 9.56 and 11.2 at 20°C. The battery module temperature uniformity is improved with the increase of ET. Overall, the mixed refrigerant has advantages in temperature uniformity and consistency. The new mixed refrigerant plays a positive role in controlling battery temperature. [ABSTRACT FROM AUTHOR]

In this study, the thermal behavior and performance of pouch type Lithium-ion batteries cell used in Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV) at different discharge rates were investigated based on numerical simulations. Numerical simulation was performed through a traditional software package using the dual potential Multi-Scale Multi-Dimensional (MSMD) battery model to analyze the cell discharge behavior and investigate its thermal performance. When the battery load is increased, non-uniform thermal distribution and temperature rise has been observed. It has been seen that applied model is accurate to be used in battery thermal management systems to ensure uniform thermal distribution of battery cell. Air, liquid and phase change materials (FDM), which are one of the three methods of cooling systems, were applied to the battery cell in cooling discharge state and their performance was compared. Comparing the performances of the cooling systems, the simulation results reflected the fact that the liquid cooling system, which is also quite common in commercial, cools the battery better than the others, as it cools the battery by 1.11% with air, 3% with liquid, 1.33% with FDM. [ABSTRACT FROM AUTHOR]

Electric vehicles with a pack of lithium-ion batteries (LIBs) are taking a significant place in the field of transportation. Since lithium-ion battery efficiency relies on battery pack temperature, the temperature of the battery pack must be maintained within the safe limits for proper working of the system. This paper proposes a novel experimental method to dissipate and maintain the thermal energy emitted by LIBs based on a nickel foam/paraffin composite and a composite of copper foam/paraffin for thermal management of Panasonic NCR 18650B cylindrical lithium-ion battery cells. The results indicate that the surface temperature of the battery is reduced by 30.95% by comparing with ambient air convection and 24% temperature reduction by comparing with PCM by the application of nickel foam at a 2C discharge rate. By using copper foam/paraffin composite 34% and 25% temperature reduction by comparing with ambient air convection and PCM (paraffin) accordingly was achieved at a 2C discharge rate. Additionally, the result of temperature uniformity on the thermal management of the battery pack was also studied. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are incorporated with higher energy density batteries to improve the driving range and performance. The lithium-ion batteries with higher energy density generate a larger amount of heat which deteriorates their efficiency and operating life. The currently commercially employed cooling techniques are not able to achieve the effective thermal management of batteries with increasing energy density. Direct liquid cooling offers enhanced thermal management of battery packs at high discharging rates compared to all other cooling techniques. However, the flow distribution of coolant around the battery module needs to be maintained to achieve the superior performance of direct liquid cooling. The objective of the present work is to investigate the heat transfer characteristics of the lithium-ion battery pack with dielectric fluid immersion cooling for different fin structures. The base structure without fins, circular, rectangular and triangular fin structures are compared for heat transfer characteristics of maximum temperature, temperature difference, average temperature, Nusselt number, pressure drop and performance evaluation criteria (PEC). Furthermore, the heat transfer characteristics are evaluated for various fin dimensions of the best fin structure. The heat transfer characteristics of the battery pack with dielectric fluid immersion cooling according to considered fin structures and dimensions are simulated using ANSYS Fluent commercial code. The results reveal that the symmetrical temperature distribution and temperature uniformity of the battery pack are achieved in the case of all fin structures. The maximum temperature of the battery pack is lower by 2.41%, 2.57% and 4.45% for circular, rectangular, and triangular fin structures, respectively, compared to the base structure. The triangular fin structure shows higher values of Nusselt number and pressure drop with a maximum value of PEC compared to other fin structures. The triangular fin structure is the best fin structure with optimum heat transfer characteristics of the battery pack with dielectric fluid immersion cooling. The heat transfer characteristics of a battery pack with dielectric fluid immersion cooling are further improved for triangular fin structures with a base length -to -height ratio (A/B) of 4.304. The research outputs from the present work could be referred to as a database to commercialize the dielectric fluid immersion cooling for the efficient battery thermal management system at fast and higher charging/discharging rates. [ABSTRACT FROM AUTHOR]

Batteries have wide applications in engineering. They are extensively used in hybrid electric vehicles (HEVs) and electric vehicles (EVs), where a suitable battery thermal management system (BTMS) is vital in ensuring the safety and reliability operations of batteries. The purpose of this study is to offer an air-cooling system that utilizes a novel V-type staggered arrangement of plate-fin heat sink for forced air cooling. To keep the temperature of a lithium-ion battery pack within the optimal temperature range for the safety of the battery and the consumer to prevent the battery from catching fire. The paper also presents a comparison between straight rectangular fins and V-type staggered arrangement heat sinks. The thermal management of batteries equipped with a heat sink is numerically controlled, to ensure the battery's overall performance and longevity modules/packs for electric cars. A three-dimensional heat sink model was constructed and a numerical approach was used to explore the impacts of the number of fins on the heat sink, fin spacing and angle of inclination of the fins at different inlet air mass flow rates and varied heat input. The analysis presents a computational approach and traditional heat transfer theory. [ABSTRACT FROM AUTHOR]

Summary: The cooling and thermal management of battery packs, which are the most important components used in electric vehicles (EV), are of critical importance for the efficiency and performance of EV. This study aims to analyze the usability of machine learning algorithms in determining the thermal parameters of the battery thermal management system (BTMS) used in EV and to determine the machine learning algorithm with the highest prediction performance. The prediction performance of three different artificial neural networks developed by using Levenberg‐Marquardt, Bayesian Regularization (BR), and Scaled Conjugate Gradient (SCG) machine learning algorithms have been extensively and comparatively investigated. As input parameters of the models, discharge rate, flow rate, and inlet temperature values were defined and the average temperature of the battery surface and maximum temperature difference on the surface values were estimated. The coefficient of determination values for the Levenberg‐Marquardt, BR, and SCG algorithms was calculated as 0.99848, 0.98751, and 0.97592, respectively. The results showed that the machine learning algorithms can determine the thermal parameters of the BTMS of EV with high accuracy. However, it has been observed that the highest prediction accuracy belongs to the Levenberg‐Marquardt algorithm. [ABSTRACT FROM AUTHOR]

To improve the thermal performance of electric vehicle batteries, a novel cooling system of liquid cold plates coupled with air flow channels (LCP‐AFC) for battery thermal management was proposed. Three‐dimensional models were established for simulation. The effects of five factors on the heat dissipation of the electric vehicle battery module were studied, which included the battery discharge rate, inlet temperature of cooling liquid, nanofluids, airflow velocity, liquid, and air flow directions. The results showed that the maximum temperature Tmax and temperature difference ΔT of the battery module under 1 C discharge rate could be reduced by 1.1°C and 0.92°C compared to the single liquid cooling. Comparing the LCP‐AFC with single air cooling, the Tmax and ΔT of the battery module under 4 C discharge rate could be reduced by 18.74°C and 2.71°C. The temperature uniformity of the battery module was not satisfied with the inlet temperature of the cooling liquid, which was lower than 15°C. The heat transfer performance was improved by adding Al, Cu, or Ag nanoparticles into the deionized water. Among them, Ag–water nanofluid had the most significant cooling effect. Parallel flow indicated better thermal performance than cross flow and counter flow. The developed cooling system of LCP‐AFC offers a new method to design lithium‐ion battery thermal management system for controlling temperature distribution of a battery module. [ABSTRACT FROM AUTHOR]

The development of electric vehicles plays an important role in the field of energy conservation and emission reduction. It is necessary to improve the thermal performance of battery modules in electric vehicles and reduce the power consumption of the battery thermal management system (BTMS). In this study, the heat transfer and flow resistance performance of liquid cold plates with serpentine channels were numerically investigated and optimized. Flow rate (m ˙), inlet temperature (Tin), and average heat generation (Q) were selected as key operating parameters, while average temperature (Tave), maximum temperature difference (ΔTmax), and pressure drop (ΔP) were chosen as objective functions. The Response Surface Methodology (RSM) with a face-centered central composite design (CCD) was used to construct regression models. Combined with the multi-objective non-dominated sorting genetic algorithm (NSGA-II), the Pareto-optimal solution was obtained to optimize the operation parameters. The results show that the maximum temperature differences of the cold plate can be controlled within 0.29~3.90 °C, 1.11~15.66 °C, 2.17~31.39 °C, and 3.43~50.92 °C for the discharging rates at 1.0 C, 2.0 C, 3.0 C, and 4.0 C, respectively. The average temperature and maximum temperature difference can be simultaneously optimized by maintaining the pressure drop below 1000 Pa. It is expected that the proposed methods and results can provide theoretical guidance for developing an operational strategy for the BTMS. [ABSTRACT FROM AUTHOR]

Real-time monitoring of the battery thermal status is important to ensure the effectiveness of battery thermal management system (BTMS), which can effectively avoid thermal runaway. In the study of BTMS, driver behavior is one of the factors affecting the performance of the battery thermal status, and it is often neglected in battery temperature studies. Therefore, it is necessary to predict the dynamic heat generation of the battery in actual driving cycles. In this work, a thermal equivalent circuit model (TECM) and an artificial neural network (ANN) thermal model based on the driving data, which can predict the thermal behavior of the battery in real-world driving cycles, are proposed and established by MATLAB/Simulink tool. Driving behaviors analysis of different drivers are simulated by PI control as input, and battery temperature is used as output response. The results show that aggressive driving behavior leads to an increase in battery temperature of nearly 1.2 K per second, and the average prediction error of TECM model and ANN model is 0.13 K and 0.11 K, respectively. This indicates that both models can accurately estimate the real-time battery temperature. However, the computational speed of the ANN thermal model is only 0.2 s, which is more efficient for battery thermal management. [ABSTRACT FROM AUTHOR]

Thermal runaway propagation of the power battery pack is an essential factor affecting the safety of electric vehicles. The commonly adopted propagation inhibition methods mainly include adding heat insulation materials and enlarging battery spacing, which could cause problematic heat dissipation and lower the system energy density. Herein, an innovative battery thermal management system composed of non-uniform thermal conductivity phase change materials and assisted liquid cooling is proposed. Combining the phase change materials with high and low thermal conductivity balances heat transfer and heat insulation requirements. The cooling performance and the ability of thermal runaway propagation mitigation of the proposed schemes are numerically studied. The results show that the proposed strategy can meet the heat dissipation requirements under normal operation and control the thermal runaway in a safe range by transferring the heat generated from the battery thermal runaway in the set direction. The maximum battery temperature and the temperature difference are 38.1 °C and 2.1 °C, respectively, under 3C discharge. Under thermal runaway conditions, the strategy successful confines the thermal runaway propagation within the middle row. The maximum battery temperature in other rows can be controlled under the irreversible thermal runaway reaction temperature of 200 °C. Further study found that increased thermal conductivity benefits the battery heat dissipation and reduces the risk of thermal runaway. However, it propagates faster and broader once the thermal runaway is triggered. In comparison, the decrease of thermal conductivity is beneficial to the mitigation of propagation but may reduce the overall heat dissipation of the battery module. This study can provide a new way to solve the contradiction between battery temperature control and thermal runaway spread suppression. • An innovative strategy is proposed to mitigate thermal runaway propagation. • Non-uniform phase change materials with different thermal conductivity are adopted. • The thermal runaway generated heat can be limited to transfer in a specific direction. • A suitable combination of high and low thermal conductivity for PCM is necessary. • Temperature control and thermal runaway suppression can be achieved simultaneously. [ABSTRACT FROM AUTHOR]

The battery thermal management system with phase change material coupled cold plates was investigated with the numerical simulation method. The results show that, the temperature and temperature difference of the battery pack decreases with the increase of the flow rates of the cold plate in the system, while the power consumption of the cold plate significantly increases, which leads to poor efficiency of the system. To improve the efficiency of the coupled thermal management system, an adjusting strategy was introduced to optimize the thickness distribution of phase change materials with the system volume fixed. The optimized results of typical cases show that, the optimal phase change material thickness distribution can be obtained by only 5 adjusting steps. Compared with the original system, the maximum temperature of the battery pack drops by 1.1 K and the temperature difference narrows down by 29% after the optimization. To achieve the same temperature difference in the battery pack, the power consumption of the optimized system lowers down by 64% compared with that of the original system. [ABSTRACT FROM AUTHOR]

New energy automobiles possess broad application prospects, and the charging technology of vehicle power batteries is one of the key technologies in the development of new energy automobiles. Traditional lithium battery charging mostly adopts the constant current-constant voltage method, but continuous and frequent charging application conditions will cause temperature rise and accelerated capacity decay, which easily bring about safety problems. Aiming at the above-mentioned problems related to the charging process of lithium-ion batteries, this paper proposes an optimization strategy and charging method for lithium-ion batteries based on an improved electric-thermal coupling model. Through the HPPC experiment, the parameter identification of the second-order RC equivalent circuit model was completed, and the electric-thermal coupling model of the lithium battery was established. Taking into account the two factors of charging time and charging temperature rise, the multi-stage charging strategy of the lithium-ion battery is optimized by the particle swarm optimization algorithm. The experimental results show that the multi-stage constant current charging method proposed in this paper not only reduces the maximum temperature during the charging process by an average of 0.83% compared with the maximum temperature of the battery samples charged with the traditional constant current-constant voltage (CC-CV) charging method but also reduces the charging time by an average of 13.87%. Therefore, the proposed optimized charging strategy limits the charging temperature rise to a certain extent on the basis of ensuring fast charging and provides a certain theoretical basis for the thermal management of the battery system and the design and safe charging method of the battery charging system. [ABSTRACT FROM AUTHOR]

In order to ensure the safety and extend the lifecycle of lithium-ion power batteries in electric vehicles, a battery thermal management system based on minichannel liquid cooling is proposed to cool rectangular lithium-ion batteries, and a three-dimensional cooling system model is established. The effects of the number of channels, the thickness of heat conducting silicone grease and the thermal conductivity of the battery itself on the temperature rise and voltage drop changes during the discharge process of the battery are studied. The results show that the maximum temperature of the battery decreases with the increase of the number of channels, and the voltage drop inside the channel increases with the increase of the number of channels. The maximum temperature of the battery increases with the increase of the thickness of the thermal grease, but the increase is only 1.26 K. The maximum temperature and local temperature difference of the battery change significantly with the change of the thickness of the battery and its own thermal conductivity. The simulation results will be beneficial to the design of a battery thermal management system based on minichannel liquid cooling. [ABSTRACT FROM AUTHOR]

Summary: Flying car is an effective transport to solve current traffic congestion. The power batteries in flying cars discharge at a high current rate in the takeoff and landing phase, evoking a severe thermal issue. Flat heat pipe (FHP) is a relatively new type of battery thermal management technology, which can effectively maintain the temperature uniformity of the battery pack. We have constructed a resistance‐based thermal model of the batteries considering the impact of the state of charge (SOC), battery temperature, and current on the battery heat generation. The FHP model is developed based on segmental heat conduction model, and integrated into the battery model to form the battery‐FHP‐coupled model for a battery module. Experiments are carried out to verify its accuracy. Then, the battery thermal performance is analyzed under the different discharging conditions including constant discharge rates and dynamic discharge rates for flying cars. Under the condition of the flying cars, the battery maximum temperature appears at the end of takeoff stage, while the maximum temperature difference appears during the forward flight segment. Moreover, different FHP heat dissipation structures are studied to further improve the battery thermal performance. The configuration with the best performance is adopted for the battery pack, and it can meet the heat dissipation requirements of the pack at a discharge rate of 3C or that of flying cars. Finally, the influence of inlet cooling air velocity and temperature on battery thermal performance is investigated. According to the research results, air velocity has little effect on the battery maximum temperature at the discharge rate of flying cars, but it can obviously affect the temperature decrease rate. Besides, the battery maximum temperature and its temperature difference develop linearly with the air temperature. [ABSTRACT FROM AUTHOR]

In advanced battery thermal management systems for electric vehicles, liquid cooling (LC) is typically coupled with a phase-change material (PCM) cooling for secondary heat dissipation. However, a continuous LC consumes a considerable amount of energy without considering the operating conditions. In this study, the thermal behaviors of tubular PCMs were examined under different liquid temperatures (25, 45, and 65 °C) to simulate the complex operating conditions of battery modules. In addition, a thermal management module coupling the PCM and copper pipe (CP) with LC was assembled to enhance the secondary heat dissipation of PCM cooling, particularly in a high-temperature environment. The experimental results confirmed the superior cooling effect of the PCM–CP module, even at high temperatures. Moreover, a dynamic LC (DLC) mode was proposed to reduce the energy consumption caused by LC, where LC operates intermittently. The effects of the LC activation time on the cooling behavior were explored. A coefficient illustrating the energy efficiency ratio (EER) was defined to evaluate the cooling performance and energy consumption of the two DLC modes with varying working times. The results proved that DLC-2 performed better than DLC-1 with E E R ¯ j values of 0.35 and 0.24, respectively. These results are expected to provide insights into the development of advanced energy-saving thermal management systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Summary: The performance, lifetime, and safety of electric vehicles (EVs) are highly reliant on the battery's capacity and temperature. Battery thermal management system (BTMS) involves techniques to control the battery's thermal behavior by maintaining temperature and temperature uniformity within an optimal range. Air cooling BTMS is frequently used in EVs due to its design simplicity and cost‐effectiveness. Only limited works have utilized passive convective heat transfer enhancement strategies for air‐cooled BTMS, especially fin‐based structures for cylindrical lithium‐ion battery packs. Present work introduces a novel design by incorporating the interrupted fins into a conventionally air‐cooled BTMS. The proposed design offers superior heat transfer efficiency as well as ease of manufacturing when compared to the existent herringbone fin design used in prior air‐cooled BTMS literature. Results indicate that the average temperature of the cells and maximum temperature difference were reduced by 5.646 and 7.958 K, respectively, by incorporating an optimal uniform interrupted fin arrangement. The average temperature of the cells was reduced by 0.479 K when the interrupted fins were added to increase the area, compared to 0.088 K for an equivalent area enhancement in a conventional fin. The uniform interrupted fin improved the temperature uniformity by 5.05%, but the area enhanced conventional fin deteriorated it by 1.59%. The non‐uniform interrupted fin arrangement, resulted in an improvement of 4.47%, over uniform interrupted fins, in the battery pack's temperature uniformity. [ABSTRACT FROM AUTHOR]

Summary: Battery thermal management technology is critical to the lifespan and performance of the lithium‐ion battery packs. In this work, a reverse layered series cooling scheme with a U/Z type flow pattern is introduced to enhance the temperature uniformity of the forced‐air cooling BTMS. The cooling performance of the current design is investigated and compared with that of the parallel cooling for the dynamic unsteady heat generation process. It is demonstrated that the proposed cooling scheme provides good cooling performance and uniform temperature distribution. Then, the geometric structure of the proposed cooling scheme with a U‐type inlet/outlet manifold is optimized by the response surface methodology and the Cuckoo search algorithm. In comparison with the initial design, the maximum temperature of the optimized design is reduced by 0.97°C and the temperature difference is reduced by up to 36.4% (1.23°C) with the pressure drop increased merely by 1.28 Pa. [ABSTRACT FROM AUTHOR]

• Three layout schemes of liquid cooling plate were discussed. • The heat dissipation in a liquid cooling system was considered under various factors. • The heat dissipation scheme for imported coolant cooling of variable temperature was proposed. • The solution reduces the temperature difference of the battery pack by 36.09 %. To promote energy conservation and emission reduction, the electric vehicles (EVs) are developing rapidly. An effective battery thermal management system (BTMS) can extend the service life of batteries and avoid thermal runaway. In this study, a liquid-cooling management system of a Li-ion battery (LIB) pack (Ni-Co-Mn, NCM) is established by CFD simulation. The effects of liquid-cooling plate connections, coolant inlet temperature, and ambient temperature on thermal performance of battery pack are studied under different layouts of the liquid-cooling plate. Then, A new heat dissipation scheme, variable temperature cooling of the inlet coolant, is proposed. Results indicate that connecting two sets of liquid coolant plates in a 3-series, 1-parallel configuration can effectively reduce the maximum temperature of the battery pack from 48.73 ℃ to 30.75 ℃, while controlling the maximum temperature difference to 3.98 ℃ at the end of discharge. Simultaneously, the proposed cooling scheme reduces the maximum temperature difference within the battery pack by 36.09 % at the beginning of the discharge period. This study provides a valuable reference into advancing BTMSs of battery pack-level for EVs. [ABSTRACT FROM AUTHOR]