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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]

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]

Composite phase change materials commonly exhibit drawbacks, such as low thermal conductivity, flammability, and potential leakage. This study focuses on the development of a novel flame-retardant phase change material (RPCM). The material's characteristics and its application in the thermal management of lithium-ion batteries are investigated. Polyethylene glycol (PEG) serves as the medium for phase change; expanded graphite (EG) and multi-walled carbon nanotubes (MWCNT) are incorporated. Moreover, an intumescent flame retardant (IFR) system based on ammonium polyphosphate (APP) is constructed, aided by the inclusion of bio-based flame-retardant chitosan (CS) and barium phytate (PA-Ba), which can improve the flame retardancy of the material. Experimental results demonstrate that the RPCM, containing 15% IFR content, exhibits outstanding flame retardancy, achieving a V-0 flame retardant rating in vertical combustion tests. Moreover, the material exhibits excellent thermomechanical properties and thermal stability. Notably, the material's thermal conductivity is 558% higher than that of pure PEG. After 2C and 3C high-rate discharge cycles, the highest temperature reached by the battery module cooled with RPCM is 18.71 °C lower than that of natural air-cooling; the material significantly reduces the temperature difference within the module by 62.7%, which achieves efficient and safe thermal management. [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]

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]

Nanoencapsulated phase change materials (NePCMs) are promising thermal energy storage (TES) and heat transfer materials that show great potential in battery thermal management systems (BTMSs). In this work, nanocapsules with a paraffin core and silica shell were prepared using an optimized sol-gel method. The samples were characterized by different methods regarding chemical composition, thermal properties, etc. Then, the nanocapsules were used as the coolant by mixing with insulation oil in the immersion cooling of a simulative battery. The sample doped with Ag on the shell with a core-to-shell ratio of 1:1 showed the best performance. Compared to the sample without doping material, the thermal conductivity increased by 49%, while the supercooling degree was reduced by 35.6%. The average temperature of the simulative battery cooled by nanocapsule slurries decreased by up to 3.95 °C compared to the test performed with pure insulation oil as the coolant. These novel nanocapsules show great potential in the immersion cooling of a battery. [ABSTRACT FROM AUTHOR]

This work investigates on the performance of a hybrid energy storage system made of a metal hydride tank for hydrogen storage and a lithium-ion battery pack, specifically conceived to replace the conventional battery pack in a plug-in fuel cell electric scooter. The concept behind this solution is to take advantage of the endothermic hydrogen desorption in metal hydrides to provide cooling to the battery pack during operation. The analysis is conducted numerically by means of a finite element model developed in order to assess the thermal management capabilities of the proposed solution under realistic operating conditions. The results show that the hybrid energy storage system is effectively capable of passively controlling the temperature of the battery pack, while enhancing at the same time the on-board storage energy density. The maximum temperature rise experienced by the battery pack is around 12 °C when the thermal management is provided by the hydrogen desorption in metal hydrides, against a value above 30 °C obtained for the same case without thermal management. Moreover, the hybrid energy storage system provides the 16% of the total mass of hydrogen requested by the fuel cell stack during operation, which corresponds to a significant enhancement of the hydrogen storage capability on-board of the vehicle. • Hybrid energy storage system for plug-in fuel cell electric scooter • Numerical modelling of metal hydride tank integrated with battery pack • Passive, self-sustained thermal management of metal hydride tank and battery pack • Enhanced on-board energy density and improved vehicle driving range [ABSTRACT FROM AUTHOR]

In a battery cooling system, by adopting a cooling optimization control strategy, the battery temperature under different external environments and load currents can be adjusted to ensure performance and safety. In this study, two modes of the thermal management system are established for the 6s4p (six serial and four parallel batteries in a stage) battery pack. A single particle model, considering battery aging, is adopted for the battery. Furthermore, a cooling optimization control strategy for the battery is proposed based on the triple-step nonlinear method, and then the optimization effect is validated under two C-rate charge–discharge cycles, NEDC cycles, and US06 cycles. Moreover, an extended PID control strategy is constructed and compared with the triple-step nonlinear method. A comparison of pump power, thermal behavior, and aging performance indicate parallel cooling is more advantageous. This verifies the validity of the triple-step nonlinear method and shows its advantages over the extended PID method. The present study provides a method to investigate the thermal behavior and aging performance of a battery pack in a BTM system, and fills in the research gaps in the cooling optimization control strategy for battery packs. [ABSTRACT FROM AUTHOR]

The thermal management system of batteries plays a significant role in the operation of electric vehicles (EVs). The purpose of this study is to survey various parameters enhancing the performance of a heat pipe-based battery thermal management system (HP-BTMS) for cooling the lithium-ion batteries (LIBs), including the ambient temperature, coolant temperature, coolant flow rate, heat generation rate, start-up time, inclination angle of the heat pipe, and length of the condenser/evaporator section. This review provides knowledge on the HP-BTMS that can guarantee achievement of the optimum performance of an EV LIB at a high charge/discharge rate. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are booming all over the world for a low carbon emission and greener environment. The fast charging is an urgent demand for consumers. However, the dramatic temperature rising during high-power charging has a high risk of trigging thermal runaway and other safety issues. This article proposes an external liquid cooling method for lithium-ion battery module with cooling plates and circulating cool equipment. A comprehensive experiment study is carried out on a battery module with up to 4C fast charging, the results show that the three-side cooling plates layout with low coolant temperature provides better temperature control effect, while the coolant velocity and type have very weak impact. Then the simulation model with high precision is built for ultra-fast charging, and a safe charging range under 5C charging is proposed. The safe charging range under 5C can be increased by 50.1%. The environment close to the room temperature demonstrates the best effects of external cooling. For actual applications in the EVs, the circulating cooling equipment outside EVs can be integrated with high-power charging infrastructure and provide a 117 km improvement in mileage under 5C safe charging which indicates a tremendous application prospect. [ABSTRACT FROM AUTHOR]

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

In this study, three-dimensional thermal simulations for a 54 V Lithium-ion battery pack composed of 18 LiFePO4 pouch battery cells connected in series were conducted using a multi-scale electrochemical-thermal-fluid model. An equivalent circuit model (ECM) is used as a subscale electrochemical model at each cell node of the battery, which is then combined with the macro-scale thermal and fluid equations to construct a model of the battery and battery pack. With the model, the cooling effects of indirect cooling and direct cooling battery thermal management systems (BTMS) on the battery pack under rapid discharging conditions are explored. It is found that when the battery pack is discharged at 2C, indirect cooling of the bottom plate can effectively dissipate heat and control the temperature of the battery pack. Under the 10C discharging condition, the maximum temperature of the battery pack will exceed 100 °C, and the temperature uniformity will be very poor when using indirect cooling of the bottom plate for the battery pack. Direct air cooling is also unable to meet the cooling requirements of the battery pack at a 10C discharging rate. The possible reason is that the convective heat transfer coefficient of direct air cooling is small, which makes it difficult to meet the heat dissipation requirements at the 10C condition. When single-phase direct cooling with fluorinated liquid is used, the maximum temperature of the battery pack under the 10C discharging condition can be controlled at about 65 °C. Compared with air direct cooling, the pressure drop of fluorinated liquid single-phase direct cooling is smaller, and the obtained battery pack temperature uniformity is better. From the detailed study of fluorinated liquid single-phase direct cooling, it is concluded that increasing the coolant flow rate and reducing the cell spacing in the battery pack can achieve a better cooling effect. Finally, a new cooling method, two-phase immersion cooling, is investigated for cooling the battery pack. The maximum temperature of the battery pack discharged at a 10C rate can be controlled below 35 °C, and good temperature uniformity of the battery pack is also achieved at the same time. This study focuses on fluorinated liquid immersion cooling using numerical simulations, showing that it is a promising cooling method for lithium-ion battery packs and deserves further study. This paper will provide a reference for the design and selection of BTMS for electric vehicles. [ABSTRACT FROM AUTHOR]

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

The discharge performance of lithium-ion batteries (LIBs) is severely degraded at low temperatures. The existing LIBs preheating systems face challenges including high costs and consumption of battery capacity. Therefore, this paper developed an innovative electrically-controlled crystallization electrode based on calcium chloride hexahydrate (CCH) (ECE-CCH) by melting-solidification method and devised an electrically-controlled phase change material (PCM) preheating system based on CCH (EPS-CCH) for LIBs. The stable supercooling and great heat storage/release properties of the CCH, as well as the excellent low-voltage electrically-controlled crystallization performance of ECE-CCH, enable EPS-CCH to achieve safe and controllable thermal management of LIBs at the optimal operating temperature. Under the premise of maintaining the stable supercooling and heat storage properties of CCH (50.67 wt% CaCl 2 solution), 48 wt% CaCl 2 solution was selected as the heat storage material (melting point: 31.5 °C, latent heat: 153.0 J /g). The ECE-CCH could release the latent heat of the supercooled CCH solution in <5 s at low DC voltages (1.0–2.0 V). 100-cycle experiments illustrated that ECE-CCH had good cycle stability and an optimal operating voltage range of 1.0–1.5 V. Finally, EPS-CCH was designed to achieve on-demand control of thermal management of LIBs at low temperatures. Compared to LIBs without EPS-CCH at 5 °C, LIBs with EPS-CCH exhibited a significantly increased discharge capacity of 14.27%, 11.35%, and 7.04% at discharge rates of 0.5C, 1.0C, and 1.5C, respectively. The research findings of the ECE-CCH and the EPS-CCH would promote the development of LIBs preheating technologies. • A novel electrically-controlled electrode based on calcium chloride hexahydrate (CCH) was developed. • The crystallization of supercooled CCH was electrically triggered by 1.5 V DC voltage. • The crystallization behavior of supercooled CCH was investigated in-depth. • The EPS-CCH achieved a smart thermal management of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Efforts to mitigate environmental pollution from the use of petroleum-based energy sources have promoted research on rechargeable secondary batteries for applications such as electric vehicles and energy storage systems. In this context, Li-ion batteries have attracted significant interest. Notably, the thermal management of such batteries is crucial for achieving a stable output and long lifespan and reducing the risk of thermal runaway. Despite extensive exploration of various cooling schemes, thermal management techniques for Li-ion batteries continue to face challenges due to the high thermal resistance resulting from low thermal conductivity of thermal interfacial materials and inadequate convective heat transfer. Therefore, this study is aimed at using laser-induced graphene (LIG) to enhance the heat transfer characteristics and battery thermal management. LIG is applied through direct laser irradiation on the polyimide substrate of a LiFePO 4 battery. Thermal tests conducted under a discharge rate of 5C demonstrate that immersion cooling using HFE-7000 on the LIG surface substantially reduces the temperature increase by up to 84.3% compared with conventional air cooling. In addition, immersion cooling with LIG surfaces results in outstanding cooling performance through nucleate boiling, attaining a maximum temperature of 37.5 °C, which is lower than that (43.5 °C) on a pristine polyimide surface. Overall, this research provides valuable insights into the thermal management of high-performance batteries operating under extreme conditions, such as high-speed charging, high-power discharging, and high-temperature conditions, with significant implications for future applications. • Introducing laser-induced graphene (LIG) for novel immersion, boiling cooling. • Various aspects of battery behavior were investigated, including discharge rates, working fluids, and temperatures. • LIG-coated battery enhances thermal performance, especially in high-temperature and high C-rate conditions. • LIG-coated battery exhibited a remarkable temperature reduction of up to 84.3%. [ABSTRACT FROM AUTHOR]

The demand for high energy density in lithium-ion battery packs for electric vehicles poses a challenge to maintaining its optimum operating temperature while reducing the risk of thermal runaway (TR) propagation. This study proposes a novel hybrid TR propagation mitigation system that balances heat transfer and thermal insulation requirements using low and high thermal conductivity phase change materials (PCM), heat pipes (HP), and air-cooling. The design and optimization of such a mitigation system are complex due to the many design parameters involved. The Adaptive-Kriging-High dimensional model representation (Adaptive-Kriging-HDMR) is used to establish a surrogate model of the system, and the sensitivity of the system's design parameters is evaluated with the maximum battery temperature and the system weight as the targets, thereby improving the efficiency of model calculation and reducing the dimension of optimization parameters. Then, the design of the sensitive parameters is optimized using an extended elitist non‐dominated sorting genetic algorithm (E-NSGA-II) multi-objective optimization algorithm. The results show that the modeling difficulty and optimization calculation time are significantly reduced by using a surrogate model. The calculation time for a single surrogate model only takes a few seconds instead of several hours for the original three-dimensional heat transfer and flow calculation. The thermal conductivity of high thermal conductivity-PCM, the distance between battery and low thermal conductivity-PCM, the battery spacing, and the HP length significantly affect the system. The optimized system substantially reduces the overall weight of the battery system while ensuring its good heat dissipation capability. In the case of TR in a single battery, the system succeeds in limiting the TR propagation to the same row, with the maximum battery temperature in the second row being only 64.3 °C, well below the battery TR trigger point. Under more severe conditions, such as TR occurring in two batteries simultaneously, the maximum battery temperature in the second row is 155.5 °C, and no TR spreads to the adjacent row. This study provides a rapid and effective method for designing a TR propagation mitigation system. It can serve as a reference for the engineering design and optimization of battery thermal management systems. [ABSTRACT FROM AUTHOR]

This study introduces a streamlined modeling framework that integrates a volume-averaged thermal (VAT) model with the Tank-in-Series battery model, a recently developed volume-averaged electrochemical model. The framework enables efficient simulations of electrochemical-thermal interactions in large-scale battery packs. This framework is used to investigate the effects of coolant flow rates and inlet temperature, initial and ambient temperatures, battery pack configurations, and cell-to-cell manufacturing related variations. Results showed a notable current distribution variation among modules connected in parallel at the end of discharge and beginning of charge. This is found to be directly related to the temperature variation in the battery pack governed by the coolant mass flow rate. Additionally, with the introduction of a 0.5% cell-to-cell to variation in the cell design parameters for the purpose of simulating manufacturing variation, a significant voltage variation of over 0.2 V across cells is found to be possible. Furthermore, rapidly changing the inlet temperatures to simulate a potential battery management system failure indicated the risk of some cells in the pack exceeding the desired cut-off voltage. The present framework can be used to design battery packs with effective thermal management strategies, enhancing the overall reliability and performance of battery systems. • Developed a multiphysics modeling framework to simulate electrochemical-thermal characteristics of Li-ion battery packs • Flexible, scalable, and efficient physics-based simulation of Li-ion battery packs • In-depth analysis of Li-ion battery pack at various operating conditions, including extreme thermal conditions • Effect of cell-to-cell manufacturing variation on cell-level and pack-level electrochemical and thermal characteristics [ABSTRACT FROM AUTHOR]

• Developed and analyzed a novel hybrid battery pack thermal management system. • Incorporated a novel three-stage cooling strategy into the thermal management system. • Latent heat of PCM effectively extracts heat from the cylindrical Li-ion cells. • Secondary coolants increase the overall heat transfer coefficient of PCM. This paper introduces a novel hybrid thermal management concept, which use secondary coolants (air and water) to extract heat from a phase change material (paraffin), resulting in increased heat extraction capability of the paraffin and improvement the overall thermal performance of the battery module. This concept was analyzed using experimental and numerical studies. The experimental studies were conducted to obtain the temperature and heat flux profiles of the battery module. The numerical model is developed and validated using the experimental data obtained. The outcome of the study showed that the battery module temperature reached the phase change temperature threshold of the PCM in the fifth discharge cycle, and the through the use of latent heat the battery module temperature was maintained between 42 and 44 °C. Additionally, the thermal uniformity started to increase once the PCM started to change and the PCM utilization was ∼2.3 % after seven discharge cycles. Therefore, the proposed thermal management concept for the battery module can sustain the thermal environment needed for effective operation of the Lithium-ion batteries. [ABSTRACT FROM AUTHOR]

This article surveys the mathematical principles essential for understanding the thermal management of Li-ion batteries, the current technological state of the art, and the solution. Since the thermal management of electric drive vehicles has environmental, economic, and safety impacts, this review focuses on the efficient methods of battery thermal management (BTM) that were proposed to overcome the major challenges in the electric vehicle industry. The first section examines the perspective of battery-driven vehicles, the principles of Li-ion batteries with a thermal runaway, and their implication for battery safety. The second section discusses mathematical approaches for effective BTM modeling, including the thermal-fluidic network model, lumped capacitance model, spatial resolution lumped capacitance model, equivalent circuit model, impedance-based model, and data-driven model. The third section presents the current state-of-the-art technologies, including air-based, liquid-based, PCM-based, in situ BTM methods, and heat pipe and thermoelectric module-based methods. The conclusion section summarizes the findings from existing research and the possible future directions to achieve and employ better thermal management techniques. [ABSTRACT FROM AUTHOR]

In the work, a composite cooling system coupled with PCM (phase change material) and liquid cooling was designed. The influence of parameters such as spacing, EG (expanded graphite) content, battery direction, coolant flow rate and pipe diameter on the cooling performance was analyzed. The results revealed that: (1) The increase of spacing makes the temperature of the pack decrease, but the effect degree of increasing the spacing on temperature performance decreases when the spacing exceeds 14 mm. At the same time, CPCM formed by the added high thermal conductivity material expanded graphite and paraffin can effectively improve the temperature control performance of the pack, which can control the temperature at 313.15K under the condition of an ambient temperature of 308.15K (2) By comparing the maximum temperature and the temperature difference of the pack under different discharge methods, it is concluded that the poles facing inward can reduce the accumulation of the interior heat. (3) The convective heat transfer coefficient and Nu number of the pack are increasing as the flow rate increases, but the slope of the temperature versus flow rate decreasing slowly. After increasing the inlet size, the inner wall surface area of the pipe increases and the average convective heat transfer coefficient of the pack reduces. However, the Nu number increases with the increase of the pipe diameter, indicating that the growth of the pipe diameter can enhance the heat transfer rate. (4) Orthogonal experiment and fuzzy correlation analysis were combined to analyze the parameters that affect the thermal performance of the BTMS. It was determined that using a proper coolant flow rate can maximize the thermal performance of the pack. • A composite cooling system coupled with PCM and liquid cooling is designed. • Influences of the key parameters on the cooling performance are analyzed. • Orthogonal experiment and fuzzy correlation analysis are used to analyze affecting parameters. • Some results for enhancing cooling performance are obtained. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are the most commonly used battery type in commercial electric vehicles due to their high energy densities and ability to be repeatedly charged and discharged over many cycles. In order to maximize the efficiency of a li-ion battery pack, a stable temperature range between 15 °C to 35 °C must be maintained. As such, a reliable and robust battery thermal management system is needed to dissipate heat and regulate the li-ion battery pack's temperature. This paper reviews how heat is generated across a li-ion cell as well as the current research work being done on the four main battery thermal management types which include air-cooled, liquid-cooled, phase change material based and thermo-electric based systems. Additionally, the strengths and weaknesses of each battery thermal management type is reviewed in this study. It was determined that air cooled systems are suited for short-distance travel electric vehicles, liquid cooled are for electric vehicles that require long-distance travel, larger battery packs and for high thermal loads, phase change material based are for electric vehicles with constant thermal loads and stable ambient temperatures and thermo-electric battery thermal management systems are best best suited in conjunction with the other types for better control. • Present simplified heat generation model for li-Ion batteries. • Review of upcoming PCM Cooling BMS models. • Analysis of strengths and weaknesses of air, liquid, PCM, and thermoelectric BMS. • Recommendation on appropriate BTMS type for different EV models. • Identified main attributes required for an effective BMS for EV systems. [ABSTRACT FROM AUTHOR]

For cylindrical Li-ion battery packs, the battery thermal management system can be properly designed and analyzed from an energy-exergy viewpoint during charging and discharging to ensure the proper functionality of batteries; however, not been explored yet. Hence, cylindrical Li-ion battery pack with novel-designed serpentine microchannel-cooled thermal management system are analyzed. Applying the Multi-Scale Multi-Domain Newman, Tiedemann, Gu, and Kim model, an electrochemical model is used for the 3D battery thermal modeling. Effects of circular and rectangular cross-sectional shaped microchannels and using ternary hybrid nanofluids [THNF1 (Al 2 O 3 (0.5%) + Cu (0.5%) + MWCNT (1%)/water) and THNF2 (Al 2 O 3 (0.5%) + Cu (0.5%) + Graphene (1%)/water] are investigated at a 3C-discharge rate. Results indicate that the use of ternary hybrid nanofluid and microchannel cross-sectional shape has a strong influence. Maximum temperature, temperature uniformity, pumping power, heat transfer coefficient to pressure drop ratio, and entropy generation are the key factors. The present simulation can predict individual battery thermal behavior during charging and discharging. The suggested design successfully lowers the cell temperature to 305.24 K by using THNF2 and the temperature difference to 5.23 K of the 26,650-type cylindrical cell. Rectangular cross-sectioned microchannel is found to be more effective. The thermal control of batteries is greatly enhanced by using ternary hybrid nanofluid. The suggested technique will improve the battery life. • Novel serpentine microchannel-cooled system is proposed for cylindrical battery pack. • Multi-Scale Multi-Domain Newman, Tiedemann, Gu and Kim model is used for battery. • Different microchannel cross-sections and ternary hybrid nanofluids are investigated. • Thermal performance parameters, pressure drop and entropy generation are evaluated. • Suggested design and fluid successfully keep cell temperature within desired range. [ABSTRACT FROM AUTHOR]

Thermal management is of great significance to ensure that a battery pack works at a reasonable temperature and avoids thermal runaway. In this study, three different designs of liquid cooling-based lithium-ion battery modules with wavy tubes are proposed. A three-dimensional transient simulation of the designed structure is carried out. The effects of the coolant mass flow rate, separated dual tube structure, connection mode of adjacent tube lines (series mode and parallel mode), and coolant flow direction are discussed. The results show that increasing the mass flow rate of coolant in the range of 0–0.01 kg·s−1 can significantly reduce the maximum temperature of the battery module. On the contrary, the temperature difference increases markedly with the rise of the mass flow rate. Until the mass flow rate is greater than 0.006 kg·s−1 , the temperature difference of the battery module changes less and stabilizes at 4.2°C–4.4°C. In addition, compared with the series mode, the parallel mode can improve the thermal performance of the battery module, especially in reducing the maximum temperature. The reverse flow of coolant on both sides of the battery with a separated dual tube structure can obtain the optimal cooling effect. This study provides a new way to optimize the cooling capacity of the thermal management system for a cylindrical lithium-ion battery module. [ABSTRACT FROM AUTHOR]

Summary: As lithium‐ion batteries (LIBs) are used in autonomous underwater vehicles (AUVs) power systems, their thermal safety and reliability have seriously inhibited the development of AUVs toward high speed and long voyage. However, the related research on AUVs' battery thermal management is very limited. In this article, a novel and efficient liquid cooling scheme is proposed, for battery thermal management of AUV, which adopts bionic wave cooling channels. A three‐dimensional heat dissipation model of the battery was developed, which considered the influence of battery internal resistance and state of charge on battery heat generation. The effects of discharge rate, channel shape, coolant mass flow rate, coolant inlet direction, and dynamic operation strategy on the battery maximum temperature and temperature variation were investigated during discharging process. It was found that the battery with bionic wave channels was superior to the battery with straight channels, regarding cooling efficiency. The maximum temperature and temperature difference of the former decreased by 12.8 and 5.3 K compared with the latter at 5C current discharging rate. Based on the bionic wave channels, increasing the mass flow rate of coolant was the most efficient route to reducing the maximum temperature and improving the uniformity of the battery temperature. A mass flow rate equal to 2.5 × 10−4 kg s−1 is reasonably recommended by considering the cooling efficiency comprehensively. The direction of the coolant inlet had little effect on the maximum temperature of the battery, but it significantly improved the uniformity of the battery temperature. Under the premise of meeting the cruising requirements of AUVs, alternating low‐rate and high‐rate discharge was more conducive to improving the temperature behavior of the battery. The conclusions of this article can provide reference for the battery thermal management system of AUVs. [ABSTRACT FROM AUTHOR]

The temperature of battery modules in electric vehicles must be controlled adequately to remain within a specified range for optimum performance. In this research work, thermal management of battery modules with PCM was investigated experimentally and computationally. The Li-Ion battery pack cooled with a PCM for removing heat generated during the battery charging and discharging cycles. Computations and experiments were carried out to estimate the heat transfer, solidification and melting characteristics of the PCM used in the thermal management of a Li-Ion cell module. Four PCM (GR44, RT50, OM35, and paraffin wax) with different melting temperature were used for the study. Battery operating temperature and melting point are the key parameters for selection of PCM. Experiments have been carried out only for OM35 and paraffin wax, because OM35 melting point is within the battery operating temperature and paraffin wax for considering harshest condition. The OM35 melting temperature range is below 35 °C which is accordance with a desire to keep battery temperature below that temperature. Based on experimental and simulation results, it was found that OM35 is keeping battery temperature range minimal, which was the ideal for Li-Ion battery thermal management. [ABSTRACT FROM AUTHOR]

The electrical and thermal characteristics of Li-ion batteries (LIBs) are closely related and need to be further investigated. Especially for the promising immersion cooling LIBs, the interaction between battery performance and immersion thermal management system still needs to be clearly illustrated. This research aims to reveal the electro-thermal equalization behaviors of LIB modules with immersion cooling. An electro-thermal test platform was established for a series-connected LIB module. Besides the experimental research on the thermal control capability, the electro-thermal equalization behaviors of the LIB module with different cooling methods are also investigated at steady and dynamic operations. Results show that the electrical inconsistency between the LIBs with different cooling schemes intensifies at the end of discharge, and the voltage deviation (δ U,t) increases quickly at high rates. However, immersion cooling can mitigate this behavior effectively. As the immersion height ratio varies from 0 to 1, the δ U,t at the end of the 2C discharge declines from 17.1% to 4.3%, then rises to 7.9%. From a general viewpoint, the indicators, including the equalization rates of the voltage, average temperature, and temperature difference, are defined further to assess the electro-thermal equalization behaviors of the module. According to the estimation, the equalization capacities are static flow > forced flow > air cooling for all indicators. Static flow immersion cooling demonstrates superiority in thermal and electrical equalization, while forced flow immersion cooling is still necessary at high discharge rates for reducing thermal recovery time and temperature rise. [Display omitted] • Battery immersion cooling test was developed for electro-thermal performance. • Immersion cooling mitigates the aggravation of voltage deviation of batteries. • Effect of immersion heights on electro-thermal equalization behavior was discussed. • The equalization rates are proposed to assess equilibrium ability. • The equalization behavior of module shows static flow > forced flow > air cooling. [ABSTRACT FROM AUTHOR]

In order to improve the heat dissipation performance of lithium-ion batteries in hot climate, a coupled heat dissipation model including different air inlet and air outlet arrangements and PCM thicknesses was established by extracting cooling air from a vehicle air-conditioner. At the condition of the fixed PCM thickness, the effects of air inlet and air outlet arrangement on heat dissipation performance (HDP) of battery pack were researched, and the results indicate that case 5 is the optimal choice because of the low energy consumption and good HDP. The results of PCM thickness on HDP of battery pack be investigated through catastrophe theory analysis method. Thus, the results reveal that case 8 has highest evaluation value 0.97536 of the heat dissipation level of the battery pack among them. Based on the above results, four cases had been investigated to pursue the lower temperature difference of battery pack, and the results indicate that case 10 is the optimal choice, because of the lower energy consumption and temperature difference. • A coupled heat dissipation model including different air inlet and air outlet arrangements and PCM thicknesses was established. • Effects of different conditions on the heat dissipation of the battery pack is studied. • Catastrophe model was used to evaluate the heat dissipation level of the battery pack. [ABSTRACT FROM AUTHOR]

The temperature has a significant effect on the lifespan and the safety of the batteries which are one of the core components of electric vehicles. A well-designed battery thermal management system is required to adjust the temperature of the batteries within an appropriate range for thermal safety, and further minimize the energy consumption for energy savings. However, these two goals form a tradeoff. Typically, increased energy consumption for cooling results in safer batteries thermally. To examine this tradeoff, firstly, a linear electro-thermal model is built to evaluate the thermal dynamics of the operating battery-cooling module. The linear model accounts for the heat generation based on internal resistance, and the heat transfer based on a resistance–capacitance model. Such linear model reduces the computation of the model simulation to dynamically catch up with the change of temperatures and to implement control strategies on the cooling system in a short time. Based on this model, a model predictive control (MPC) framework is proposed to design thermal control methods, which considers both thermal safety and energy saving. The weight of these two goals can be adjusted to explore the tradeoff between them. Finally, we investigate the performance of the MPC framework by applying the Urban Dynamometer Driving Schedule (UDDS) to the battery module. The simulation results show that the electro-thermal model is effective for battery thermal dynamics evaluation. Additionally, the tradeoff between the two goals is demonstrated by the simulation. • A fast temperature prediction and closed-loop thermal control framework is proposed. • An electro-thermal model of an active-liquid-cooling battery module is developed. • A thermal prevention control strategy is proposed. [ABSTRACT FROM AUTHOR]

Preventing thermal runaway propagation is critical to improve the fire safety of electric vehicles. Experiments are conducted on the designed battery modules to study the effects of aerogel, liquid cooling plate, and their combination on the prevention mechanism of thermal runaway propagation. The characteristics of temperature, voltage, mass loss, and venting during the thermal runaway propagation process are compared and analyzed. The results indicate that: (1) adding the insulation material of aerogel can postpone the thermal runaway propagation, but may not completely cut-off the propagation process; (2) there is no obvious delay of thermal runaway propagation by adding the liquid cooling plate only, the propagation speed may be accelerated instead; (3) the thermal runaway propagation can be prevented by using aerogel and liquid cooling plate together. The study reminds us that safety design of battery thermal management system should consider the comprehensive heat transfer pathways in order to effectively prevent thermal runaway propagation. [ABSTRACT FROM AUTHOR]

Summary: Thermal management of large‐scale Li‐ion battery packs is of great significance to their safety and life cycle, which would impact their applicability in electric vehicles. Of the many strategies developed for this purpose, indirect liquid cooling has already demonstrated quite high potentials in thermal regulation of such battery systems. In this study, a compact lightweight serpentine wavy channel configuration was chosen to construct an indirect liquid cooling system for a battery module of cylindrical Li‐ion cells. The serpentine channel has a number of six internal minichannels. Experimental test data were used to conduct a comprehensive thermal analysis to examine the highest temperature, the maximum temperature difference, and the heat accumulation percentages, and so forth within the battery pack. Results have revealed the ability of the cooling system to maintain the module temperature within appropriate working conditions for electric vehicle applications for most cycling tests including two driving cycles. Furthermore, the analysis insights raised by this study could be useful in understanding the cooling performance of the liquid‐based thermal management systems for electric vehicles. [ABSTRACT FROM AUTHOR]

Summary: Lithium‐ion batteries, as the only source of driving force for electric vehicles (EV), directly determine the vehicle's power performance, driving mileage, and working stability. The performance, safety, and longevity of lithium‐ion batteries are related to battery temperature. In this article, surface topography has been added in mini‐channel liquid cooling plate, the influence of different shapes, different heights, different diameters, and different numbers of surface topography on the cooling effect of mini‐channel liquid cooling plate were researched by using CFD method. This article revealed that the addition of surface topography in mini‐channel can affect the flow trajectory of coolant and improve the cooling capacity of the cold plate. When five cylindrical surface topography with a diameter of 10 mm and a height of 1.5 mm were added in each channel, the highest temperature of the battery can be suppressed to 42.01°C and the maximum temperature difference can reach 15.78°C under 3C discharge rate, compared with the smooth mini‐channel, decreased by 1.02°C and 0.85°C, respectively. [ABSTRACT FROM AUTHOR]

It is seen from this figure that the maximum temperature rise of the cell module decreases as the increasing rate of fluid flow. The maximum temperature rise of the cell module is under 40 °C and 36 °C respectively since the flow rate is 0.40 × 10−3 L·s−1 and 1.20 × 10−3 L·s−1, indicating that increasing flow rate increases the cooling capability of the LCP. • A new cooling plate is developed for controlling undesirable cell temperature field. • Inlet and outlet of cooling plate have big impact on cell temperature distribution. • Increasing flow rate decreases cell temperature rise markedly. • Cooling plate channel width has weak impact on cell temperature distribution. • Channel width has great effect on ratio of power consumption of cooling plate. The thermal management for a lithium ion battery cell plays a pivotal role in enhancing the cell performance and reliability for electric vehicles. In this work, a novel serpentine-channel liquid cooling plate with double inlets and outlets is developed for better managing an undesirable temperature distribution of a cell module. With a simplified model for the cell module, numerical analyses are implemented using the software of FloEFD to study effects of flow directions, flow rates and channel widths of the cooling plate on cell temperature distribution under different operating conditions; Likewise, a ratio of power consumption as a non-dimensional number is defined to analyze the hydraulic performance of the developed cooling plate. Results show that locations of the inlet and the outlet as well as flow directions have great impacts on the cell temperature distribution and the ratio of power consumption of the cooling plate. Increasing fluid flow rate substantially decreases the maximum temperature rise of the cell module while it has little effect on the temperature distribution. Moreover, the channel width of the cooling plate has a strong influence on its ratio of power consumption as well as the cell temperature distribution but it has a weak influence on the cell maximum temperature rise. Interestingly, the developed serpentine-channel cooling plate offers one a new method to design a lithium ion battery thermal management system for controlling temperature distribution of a cell module. [ABSTRACT FROM AUTHOR]

This paper describes a set of experimental tests carried out to better understand the thermal behavior of Lithium-ion batteries under load and the capability of various cooling fluids in maintaining the working conditions within a safe range for the cells. Despite several theoretical models are available in the literature, very few experimental data are reported. Different types of cells have been analyzed. The generation of hot spots has sometimes been registered, their occurrence being independent of cell geometry and size; instead, the battery's history and age, appeared the main factors in determining the onset of hot spots on the surface of the cell. Two experimental rigs have been set up to test the capability of different cooling fluids in removing the surplus heat generated in a Li-ion battery module, where the cells of interest have been replaced with electrically heated elements with the same thermal characteristics of the cells. It was thus possible to safely investigate "extreme" operating conditions, where the occurrence of a thermal runaway is possible. Among the tested fluids, air was unable to adequately limit the surface temperature increase, while a perfluorinated polyether, allowed to work within the optimal temperature range, even under severe operating conditions. • The thermal behavior of different types of Li-ion batteries has been experimentally investigated. • The cells have been tested under both ordinary and severe operating conditions. • Dangerous operating conditions of the batteries have been identified. • A reliable and dedicated experimental facility has been set up. • The cooling efficiency of a range of thermal fluids has been evaluated. [ABSTRACT FROM AUTHOR]

• Structural theory is adopted to design the bifurcating channels of the cold plate. • Effects of structural parameters and flow rate on cooling performance are studied. • Optimization of main channel width has the greatest effect on reducing pressure drop. For rectangular Li-ion batteries, this paper optimized the heat dissipation of the cold plate embedded with leaf-like network according to the structural theory. Not only the distributed network layer was established, but also the collection network layer was designed to mitigate the inherent temperature gradient problem of the conventional single channel. The effects on the split point of symmetrical/asymmetrical bifurcation, the width ratio of symmetrical bifurcation, the inlet mass flow rate, the number of feed-out channels and the width of main channel on the thermal performance of cooling plate were numerically simulated. The results demonstrated that the heat dissipation was better when the split point is near the limit position of the outer channel. Compared with the offset bifurcation network, the symmetric bifurcation network can achieve better heat transfer characteristics, but its pressure drop was slightly higher than that of offset bifurcation network. The increase of width ratio and inlet mass flow can meet both maximum temperature and temperature uniformity objectives, but at the expense of pressure drop. Compared with the single feed-out channel, the double feed-out channels can meet both the thermal performance and the pressure drop requirements. As the width of the main channel (D 1) was elevated, pressure drop greatly declined on the basis of heat transfer. The simulation results can provide a reference for the design of cold plate embedded fractal-like network based on battery thermal management systems. [ABSTRACT FROM AUTHOR]

• A novel design of an efficient air-cooling system for improving the performance of lithium-ion batteries. • It is revealed that the average Nusselt numbers (Nu) are an increasing function of Reynolds numbers (Re). • The cells, which receive fresh cold external flow cause a substantial reduction in the cell surface temperature. • Increasing Re also reduces the cooling pack outlet temperature, which leads to the improved life of the batteries. Modern society depends on energy storage systems like Lithium-ion (Li-ion) batteries. Li-ion battery cells are delicate to changes in temperature. Extreme environmental conditions affect their life cycle and performance. Therefore, effective cell temperature management is a must for secure and dependable battery operation. Additionally, the high production costs of electric cars must be countered by the adaptability of the battery pack design for modern electric vehicles. As the chemical reactions generate more heat and raise the battery's temperature, it may cause the battery to explode and cause fires in the workplace. To address this issue, the present work attempts to numerically study a novel design of an efficient air-cooling system for improving the performance of lithium-ion batteries by reducing the operational temperatures under a different coolant flow rate. The main output of the presented study is the analysis of a novel design of an efficient air-cooling system for lithium-ion batteries. The study aims to reduce the operational temperatures of the batteries under different coolant flow rates to improve their performance and service life. The numerical simulations are carried out using a finite volume-based computing tool with the K-epsilon (k-ε) turbulence model. The analysis is performed for various pertinent parametric ranges, including the spacing between the batteries, Reynolds numbers, and average Nusselt numbers. The results indicate that increasing air inlet velocity (Re) substantially reduces the average air temperature of the cooling pack and temperature difference (ΔT) of the battery cells, and the cooling pack's average heat transfer rate (Nu) increases monotonically as the Re increases. [ABSTRACT FROM AUTHOR]

• The quantity of heat generation that induce TR in lithium-ion batteries is lower than in other overheating strategies. • The trigger time of thermal runaway decreases with the increasing current density. • The series tab connection will accelerate the thermal runaway of the adjacent battery. • The parallel tab connection will induce thermal runaway propagation to all parallel-connected batteries. Thermal runaway (TR) of lithium-ion batteries is the main safety obstacle to the further development of electric vehicles (EVs) and electric energy storage systems (EESSs). Understanding the mechanism of TR propagation is one of the primary ways to improve the thermal safety of the lithium-ion battery. In this paper, an electro-thermal model coupled with the lumped thermal runaway model is applied to investigate the TR behaviors induced by tab overheating and the TR propagation in a battery module with different tab connection methods. The electro-thermal model is used to calculate the heat generation at tabs and the cell body during the normal charge/discharge process, and the lumped thermal runaway model is applied to calculate the TR behavior and TR propagation in the battery module. The results exhibit that the TR behavior and TR propagation are influenced by different aspects (C-rates, insulator, and tab connection modes) in the battery module. The largest quantity of heat generation is at 3C-rate, about 0.98 kJ, because of the heat accumulation in the battery. Besides, the quantity of heat generation that induce TR in lithium-ion batteries in this paper is lower than that from the reference, which means that tab overheating is more dangerous than other heating strategies for triggering the thermal runaway of batteries. The trigger time of TR decreases with the increasing C-rate and the tab connection modes mitigate the TR propagation in the battery module at a low C-rate because of the increasing heat dissipation rate, while the TR propagation is accelerated in the battery module at a high C-rate. At low C-rate conditions, the parallel tab connection exhibits a more significant effect on mitigating the TR behavior, and the effect of mitigation decreases with the increasing C-rate. At high C-rate conditions, the series tab connection accelerates the TR propagation to the adjacent battery, while the parallel tab connection speeds up the TR propagation of all the connected batteries. This work is important for understanding the TR propagation mechanism and improving the thermal safety of pouch-type lithium-ion batteries in EVs. [ABSTRACT FROM AUTHOR]

Highlights • A novel cooling strategy based on the air distribution pipe is proposed for the cylindrical Lithium-ion battery module. • The 3D CFD model of the battery module based on the air distribution pipe is constructed. • The temperature of battery near the positive pole is higher than that near the negative pole during discharging. • The maximum temperature of battery module can be effectively reduced via increasing inlet pressure. • The maximum temperature of battery module declines when the diameter and number of rows for orifice become large. Abstract For a typical air cooling thermal management system, the inlet and outlet of air flow on both sides of the battery module would increase the temperature difference. In here, a novel cooling strategy based on air distribution pipes is proposed for the cylindrical Lithium-ion battery module. The three-dimensional computational fluid dynamics model of battery module is constructed and validated by the experimental tests. The thermal behavior of battery module and the flow field of air have been explored using numerical simulations at different discharge rates, and then the effects of orifice parameters, inlet pressure and discharge rate on the performance of air cooling strategy have been analyzed. The results show that the maximum temperature of the battery module can be effectively reduced by the increase of inlet pressure resulting in a significant rise of power consumption. Meanwhile, it declines when the diameter and number of rows of the orifice increase, following a minor rise in power consumption. When the inlet pressure is 100 Pa, the diameter of the orifice is 1.5 mm, the number of rows of the orifice is 5 and the discharge rate is 3C, the maximum temperature of battery module decreases from 325.9 K to 305.7 K in comparison to that under none air cooling condition. In addition, the maximum temperature difference of battery module is within 3 K. When the battery module discharge at the current rate of 4C and 5C, the maximum temperature of battery module maintains within 313.15 K, but the temperature difference slightly exceeds the optimal range at 5C discharge when the inlet pressure is 200 Pa, the diameter of the orifice is 1.5 mm and the number of rows of the orifice is 5. Moreover, it is an efficient and a practical cooling strategy with no need to modify the arrangement of the battery module. [ABSTRACT FROM AUTHOR]

Heat generation and accumulation during working schemes of the lithium-ion battery (LIB) are the critical safety issues in hybrid electric vehicles or electric vehicles. Appropriate battery thermal management is necessary for ensuring the safety and continuous power supply of rechargeable LIB modules. In this study, thirty cylinder 18650-type cells were fabricated a 6S5P battery module with a 2-mm spacing between cells to evaluate exothermic trajectories. The modules, equipped with a forced-air cooling system, were charged at 1 C-rate and discharged at 1, 1.5, and 2 C-rates for three cycles in each test; thermocouples were connected to the cells to track the variances in temperature and voltage. The efficiency of the developed forced-air cooling system was estimated to be 73.0% in case 1 with the 1 C discharge rate, and the temperature difference (TD) was less than 5.0 °C. The maximum temperature (Tmax) of this case was maintained below 45.0 °C showing uniform heat distribution. Moreover, extreme heat accumulation developed inside the module and damaged the adjacent LIBs during fast 2 C discharge test. Our TD testing showed that a forced-air cooling system in the LIB module provides effective heat dispersion under normal discharge conditions. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the thermal management based on phase change slurry (PCS) and mini channel cooling plate for the lithium-ion pouch battery module was proposed. The three-dimensional thermal model was established and the optimum structure of the cooling plate with mini channel was designed with the orthogonal matrix experimental method to balance the cooling performance and energy consumption. The simulation results showed that the cooling performance of PCS consisting of 20% n-octadecane microcapsules and 80% water was better than that of pure water, glycol solution and mineral oil, when the mass flow rate was less than 3 × 10−4 kg s−1. For different concentrations of PCS, if the mass flow rate exceeded the critical value, its cooling performance was worse than that of pure water. When the cooling target for battery maximum temperature was higher than 309 K, the PCS cooling with appropriate microcapsule concentration had the edge over in energy consumption compared with water cooling. At last, the dimensionless empirical formula was obtained to predict the effect of the PCS's physical parameters and flow characteristics on the heat transfer and cooling performance. The simulation results will be useful for the design of PCS based battery thermal management systems. Highlights • Battery thermal management based on the PCS and mini channel was proposed. • The cooling plate was designed to balance the cooling effect and energy consumption. • The management cooled battery effectively and performed better than water cooling. • The optimal mass flow rate for different concentrations of PCS was determined. • The dimensionless empirical formulas were obtained. [ABSTRACT FROM AUTHOR]

In order to investigate a simple and efficient liquid cooling method for the rectangular Li-ion power batteries used in electric vehicles, the cold plate with serpentine-channel configuration shaped like U-tube is established. Subsequently, the effect of cooling channel number, the layout of channels and inlet temperature of coolant on cooling performance of battery thermal management system are analyzed. The numerical simulation results demonstrate that the layout of channels in length flowing-direction with 5-channels has the most efficient cooling performance. This design can reduce the maximum temperature by 26 °C compared with the 2-channels along width flowing direction. And the maximum temperature of cooling system rises with the increase of inlet temperature of the coolant. However, there exists an upper limit on the number of channels and the inlet temperature with the consideration of efficiency and safety of cooling system. The above results will be helpful to design cold plate for thermal management system of Li-ion power batteries. [ABSTRACT FROM AUTHOR]

Summary: With the depletion of fossil fuels and the aggravation of environmental pollution, the research and development speed of electric vehicles has been accelerating, and the thermal management of battery pack has become increasingly important. This paper selects the electric vehicle battery pack with natural air cooling as the study subject, conducts simulation analysis of the heat dissipation performance of battery packs with and without vents. Then this paper researches on the influence of internal flow field and external flow field. Field synergy principle is used to analyze the effect of velocity field and temperature field amplitude. The results show the following: it is found that the maximum temperature rise and the internal maximum temperature difference of the battery pack with vents are reduced by about 23.1% and 19.9%, raising speed value can improve the heat dissipation performance, and raising temperature value can decrease the heat dissipation performance. Reasonable design of the vents can make the inner and outer flow field work synergistically to achieve the best cooling effect. Then the reference basis for the air cooling heat dissipation performance analysis of electric vehicle, battery pack structure arrangement, and air‐inlet and air‐outlet pattern choosing are offered. [ABSTRACT FROM AUTHOR]

Summary: Some potential safety risks for lithium ion battery such as overheating, combustion, and explosion occurred in practical application may cause accidents of electric vehicles. Phase change material (PCM)‐based thermal management system was demonstrated as a feasible approach. However, the batteries have to endure various environment and climate, which would not work normally under cold area. Especially when the surrounding temperature falls to below 10°C, which can bring about the energy and power of Li‐ion batteries rapidly reducing. In this study, a coupling heating strategy of the PCM‐based batteries module with 2 heat sheets at low temperature was proposed for batteries module and cannot only balance the temperature among different batteries in the module but also ensure to pre‐heat the batteries module at low temperature. The experiment displayed that 7% of EG in paraffin‐based composite PCMs was the best proportion for batteries module, considering both fluidity and thermal conductivity factors. In addition, the temperature difference of PCM‐based batteries module was 2.82°C, while that of the air‐based one was 14.49°C, which was 5 times more than former, exhibiting an excellent performance in balancing temperature uniformly, and was beneficial for prolonging the lifespan of batteries. The coupling heating strategy‐based PCM with heat sheets provided as an extremely promising technology for lithium batteries module at low temperature. [ABSTRACT FROM AUTHOR]

• A novel encapsulated inorganic phase change material (EIPCM) is synthesized. • EIPCM shows good phase change properties and thermal stability. • EIPCM exhibits good battery thermal management effect on the battery module. • EIPCM delays the battery thermal runaway and inhibits the heat propagation. • The nonflammable EIPCM protects batteries from heavy fire risks and hazards. Although widely used in the thermal management of lithium-ion batteries, organic phase change material (PCM) with flammability has been reported to aggravate the fire risk and heat hazards of battery thermal runaway (TR). To reduce the fire risk of PCM during battery TR, an encapsulated inorganic PCM (EIPCM) was synthesized by a nano-encapsulation method of interfacial polymerization in this study. Na 2 HPO 4 ·12H 2 O was used as the inorganic core material and silica was adopted as the encapsulated matrix to reduce the inherent defects. The synthesized EIPCM was characterized by a series of tests, demonstrating good phase change properties and thermal stability. The melting temperature of the EIPCM was measured as 51 °C associated with the latent heat of 111.69 kJ/kg. The thermal management effects of EIPCM were further investigated on battery modules at various discharge rates. The results show that EIPCM exhibited good cooling performance, leading to a 23.7% reduction of the peak battery temperature from 86.6 °C to 66.1 °C at a high discharge rate of 3C, and the temperature difference was kept within 3 °C. The TR behavior of batteries with IPCM was further explored, and the results indicate that EIPCM could delay the occurrence of TR by 495 s and decrease the peak surface temperature of the battery by 194 °C. With the nonflammable EIPCM, the fire of TR showed rapid extinction, protecting the batteries from heavier fire hazards. It is also found that EIPCM could inhibit the heat propagation of TR. The prepared EIPCM in this work with good thermal management effects and TR suppression performance has great prospects in practical battery applications, energy storage and other fields. [ABSTRACT FROM AUTHOR]

Lithium-ion (Li-ion) battery charging is a crucial issue in energy management of electric vehicles. Developing suitable charging patterns, while taking into account of various contradictory objectives and constraints is a key but challenging topic in battery management. This paper develops a model based strategy that optimizes the charging patterns while considers various key parameters such as the charging speed, energy conversion efficiency as well as temperature variations. To achieve this, a battery model coupling both the electric and thermal characteristics is first introduced. Three key but conflicting objectives, including the charging time, energy loss and temperature rise especially for internal temperature, are formulated. Then, multi-objective biogeography-based optimization (M-BBO) approaches are employed to search the optimal charging patterns and to balance various objectives with different combinations. Optimization results of four M-BBO approaches are compared, and the Pareto fronts for battery charging with various dual-objectives and triple-objectives are analysed in detail. Experimental results confirm that the developed strategy can offer feasible charging patterns and achieve a desirable trade-off among charging speed, energy conversion efficiency and temperature variations. The Pareto fronts obtained by this strategy can be adopted as references to adjust charging pattern to further satisfy various requirements in different charging applications. [ABSTRACT FROM AUTHOR]

Thermal management is a crucial strategy that needs to be carefully considered for lithium-ion batteries under extreme operating conditions. One promising approach is the use of phase change material (PCM), which can bring benefits such as passively thermal buffering and extending lifespan. In this paper, a paraffin/expanded graphite (EG) composites based battery module (PCM module), as well as the two dimensional thermal model is proposed. The effects of different EG mass fractions associated with different phase change enthalpy and thermal conductivity are investigated firstly under high-rate discharge condition. The results show that an optimal mass fraction of EG is needed to achieve the best thermal performance and the EG mass fraction of 15–20% is recommended to be used for battery thermal management. In order to further improve the overall performance, we also design a novel pyrolytic graphite sheets (PGS)-enhanced paraffin/EG composites based battery module (PCM/PGS module). EG with porous structure can create the primary thermal conductive network for PCM to increase the heat absorption rate. PGS forms the secondary thermal conductive network for the module to improve the whole thermal homogeneity. As a result, the as-designed PCM/PGS module presents much better heat dissipation performance and temperature uniformity compared with the PCM module during discharge–charge cycles. Also, the introduction of PGS is beneficial for thermal fluctuations and energy saving, for instance, the thermal performance of PCM/PGS module with a convective heat transfer coefficient of 50 W m −2 K −1 is comparable to PCM module with 200 W m −2 K −1 . In the case of failure mode, to achieve the prevention of thermal runaway propagation, the spacing between cells for PCM module is up to 14 mm. However, the use of PGS lowers the spacing (i.e. less composite PCM consumption) by a decreasing rate of ∼71.4% in comparison with PCM module. [ABSTRACT FROM AUTHOR]

To achieve safe, long lifetime, and high-performance lithium-ion batteries, a battery thermal management system (BTMS) is indispensable. This is especially required for enabling fast charging-discharging and in aggressive operating conditions. In this research, a new type of battery cooling system based on thermal silica plates has been designed for prismatic lithium-ion batteries. Experimental and simulations are combined to investigate the cooling capability of the BTMS associated to different number of cooling channels, flow rates, and flow directions while at different discharge C-rates. Results show that the maximum temperature reached within the battery decreases as the amount of thermal silica plates and liquid channels increases. The flow direction had no significant influence on the cooling capability. While the performance obviously improves with the increase in inlet flow rate, after a certain threshold, the gain reduces strongly so that it does not anymore justify the higher energy cost. Discharged at 3 C-rate, an inlet flow rate of 0.1 m/s was sufficient to efficiently cool down the system; discharged at 5 C-rate, the optimum inlet flow rate was 0.25 m/s. Simulations could accurately reproduce experimental results, allowing for an efficient design of the liquid-cooled BTMS. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are commonly used in hybrid electric and full electric vehicles (HEV and EV). In HEV, thermal management is a strict requirement to control the batteries temperature within an optimal range in order to enhance performance, safety, reduce cost, and prolong the batteries lifetime. The optimum design of a thermal management system depends on the thermo-electrochemical behavior of the batteries, operating conditions, and weight and volume constraints. The aim of this study is to investigate the effects of various operating and design parameters on the thermal performance of a battery module consisted of six building block cells. An electrochemical-thermal model coupled to conjugate heat transfer and fluid dynamics simulations is used to assess the effectiveness of two indirect liquid thermal management approaches under the FUDC driving cycle. In this study, a novel pseudo 3D electrochemical-thermal model of the battery is used. It is found that the cooling plate thickness has a significant effect on the maximum and gradient of temperature in the module. Increasing the Reynolds number decreases the average temperature but at the expense of temperature uniformity. The results show that double channel cooling system has a lower maximum temperature and more uniform temperature distribution compared to a single channel cooling system. [ABSTRACT FROM AUTHOR]

In this paper, techniques to improve cooling and temperature uniformity in a simple battery pack are examined. Four battery pack configurations are developed. In the first configuration, an inlet plenum is added to a simple battery pack. In the second configuration, jet inlets are incorporated along with the inlet plenum, and in the third configuration, multiple vortex generators are added in addition to the inlet plenum. Finally, in the fourth configuration, an inlet plenum, jet inlets, and multiple vortex generators are incorporated into the battery pack. The results conclude that by adding inlet plenum, multiple vortex generators, and jet inlets in the same configuration, significant improvements are observed. The results also show that the maximum temperature of the battery pack is reduced by ∼5%, and the temperature difference between the maximum temperature and the minimum temperature exhibited by the battery pack is reduced by 21.5%. Moreover, there is a ∼16% improvement in the temperature uniformity of a single cell. [ABSTRACT FROM AUTHOR]

To curb the greenhouse gas (GHG) and carbon emission in line with the Paris climate agreement, the road transportation needs to be electrified. The predicted electrification of the road transport can substantially reduce the GHG emission. The fundamental component in electric vehicles (EVs) is the power battery, in which its performance is affected by temperature. To improve the cooling performance and enhance temperature uniformity in the battery stack, a battery thermal management system (BTMS) comprising heatsinks with fluid channels and multi-phase change materials (PCMs) was investigated in this paper. The module consists of eight prismatic cells with nine fluid passages and PCMs attached at each side of the cell. The heatsink containing PCMs is separated into three equal portions, each is filled with different PCMs. The cooling effectiveness and temperature uniformity of the BTMS were carefully explored based on compactness of the battery stack and cooling fluids. The results indicate that increasing the PCMs thickness supressed the temperature rise by more than 2.85 K and provide better temperature uniformity compared to increasing the fluid channel width for the same volume of heatsink to volume of the battery unit ratio. Liquid cooling is more effective than air cooling in mitigating temperature especially at high ambient temperature. Choosing an appropriate ratio of volume of cooling channel to battery unit is particularly essential and can minimize operation cost. [ABSTRACT FROM AUTHOR]