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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]

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]

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]

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]

In order to ensure the safety and stability of the cooling system during the operation of the battery thermal management system combined with composite phase change material cooling and liquid cooling, it is usually necessary to continuously pump cooling water. It inevitably caused that the latent heat of composite phase change material could not be fully released and extra pump power was consumed. In the study, five different energy saving strategies were proposed and the energy efficiency ratio was defined to evaluate their cooling effects and energy saving. The effect of energy saving strategies on energy consumption of liquid cooling and latent heat utilization of composite phase change material was analyzed. The results show that III and V can meet their cooling requirements and have a high energy efficiency ratio. The screw pitch and cooling water flow rate in these two modes were investigated. The results show that the increase in screw pitch reduces the heat transfer efficiency, resulting in an increase in T max and Δ T max , and Δ T max exceeding the maximum range. Diminishing the cooling water flow will precipitate a rise in battery temperature, enabling the CPCM to operate at its maximum capacity and consequently decreasing Δ T max. As a cooling water flow of 20 ml/min in III and V all can satisfy the cooling requirements. Additionally, the III was also competent when the cooling water temperature was raised from 25 °C to 35 °C. [ABSTRACT FROM AUTHOR]

• Stimulus strategy with auxiliary heat load is valid for start-up promotion and heat transfer enhancement of PHP. • High interference temperature, weak auxiliary heat load and long period are optimal for stimulus strategy. • Phase-change mechanism and hysteresis of working medium in PHP is the main reason for validity of stimuls. Stimulus strategy is proposed to enhance the heat dissipation performance of Pulsating Heat Pipe (PHP) at low heat load for local hot spot regression in Battery Thermal Management (BTM). An auxiliary heat load is applied to stimulate the start-up of PHP. The performances of PHP with and without stimulus are compared and the properties of PHP after stimulus are discussed. It is concluded that the application of auxiliary heat load is able to stimulate the start-up of PHP in experiments. The strategy is mainly based on the phase-change mechanism as well as the hysteresis of working medium. Thermal resistance and the evaporator temperature are significantly reduced, if PHP starts operation after stimulus. Long period of stimulus and strong auxiliary heat load are favored for the reduction of thermal resistance and the shortening of period for start-up. The thermal resistance may be reduced by 29.1 ∼ 69.6 % and the temperature may be regressed by around 8 °C. However, PHP may suffer from temperature uplift and overshot to the maximum evaporator temperature. Therefore, high interference temperature coupled with weak auxiliary heat load and long period of stimulus are suggested as the optimal strategy. The verified strategy offers a new method for local hot spot regression and a possible way to mitigate the risk of thermal runaway, since the heat dissipation is enhanced at the initial stage of damage or destruction. [ABSTRACT FROM AUTHOR]

Summary: To balance the temperature uniformity and the compactness of the battery module, the heat transfer performance of spray cooling technology is theoretically analyzed in this article. The main factors affecting the heat transfer performance of spray cooling are discussed. Through the experiments, the influence of spray cooling on the thermal management of the battery thermal management system under high discharge rate is studied. The results show that, in spray‐cooling 4 + 2.5 m/s cooling mode, the total heat transfer coefficient K reaches 201.0 W/(m2 K), which is 409.3% higher than the heat transfer coefficient of the forced air cooling. In addition, the difference between the spray concentration of the heat source surface and the spray concentration of the mainstream area during steady‐state heat dissipation is an important factor affecting the heat transfer performance of spray cooling. Moreover, spray cooling can provide a lower temperature rise and a more uniform temperature distribution for the battery module. For the spray‐cooling 4 + 4 m/s case, the maximum temperature rise is only 10.3°C, and the temperature difference among the battery module is stably maintained within 5°C. Therefore, the proposed spray cooling battery thermal management system shows to be efficient approach in handling the heat accumulation of battery module. [ABSTRACT FROM AUTHOR]

The battery thermal management system (BTMS) with liquid cold plates has been proven to be effective in temperature control and heat transfer. In this work, a novel liquid cold plate featuring pin fins for the cooling of prismatic lithium-ion batteries is proposed. The performances of BTMS with liquid cold plates are numerically investigated by using a three-dimensional CFD model and compared under different coolant inlet velocities, pin fins' heights, and arrangements. The efficiency index (EI) is employed to evaluate the comprehensive performances of cold plates by considering heat transfer and liquid flow. The results indicate that the introduction of pin fins contributes to improving the heat transfer performance and thus reducing the maximum battery temperature rise (Δ T rise) and temperature difference (Δ T diff). Besides, both the Δ T rise and Δ T diff increase as the pin fins' height (PFH) decreases. However, the cooling micro-channel with pin fins featuring a dimensionless height (H d) of 1/4 provides the best thermo-hydraulic performance and the lowest power consumption under the same battery thermal performance. In addition, the cooling micro-channel with pin fins placed on two opposite heat transfer walls exhibits better heat transfer performance and thus better battery thermal performance, compared with the cooling micro-channel with pin fins placed on the single heat transfer wall. When the coolant inlet velocity of 0.4 m/s at a 3C discharge rate the Δ T rise and Δ T diff of the cold plates with pin fins staggered arrangement in stream-wise direction for the opposite walls on both top and bottom walls are reduced by 4.045K and 3.122K, respectively, compared with the cold plates without pin fins. • A novel LCP featuring pin fins for enhancing BTMS performance is proposed. • A transient thermo-fluid multi-physical field numerical model is developed. • Effects of pin fins' height and arrangement on the thermo-hydraulic performance are studied. • A novel LCP is used for enhancing temperature uniformity and reduce maximum temperature. [ABSTRACT FROM AUTHOR]

• Air-cooled thermal management of battery module has been explored numerically. • Thermal performance for inline and staggered cell arrangement was examined. • Negligible effect of cell arrangement occurs beyond a critical number of cells. • For small number of cells, the staggered arrangement slightly improves thermal uniformity. Global environmental concerns over increased emissions from the transportation vehicles have driven research instincts towards development of clean energy vehicles. Pure and hybrid electric vehicles coupled with lithium-ion batteries for energy storage are environmental friendly options to realize the future dream of low carbon emissions. However, an efficient battery thermal management system (BTMS) is a prerequisite for safe operation of such high voltage batteries to avoid thermal runaway and degradation, thereby maintaining the temperature uniformity in the battery pack. Thus, the present work numerically investigates the performance of an air cooled battery module for efficient removal of heat generated during the discharge process at different values of air-flow velocity, cell configuration and the number of cells in the battery module. A coupled electrochemical-thermal model is employed to model the discharge behaviour of the battery in conjunction with the two-dimensional flow and heat transfer model to monitor the temperature in and out of each battery cell. A correlation is developed for the maximum temperature in the module as a function of the number of cells in the system. The flow configuration (inline or staggered arrangement) of cells in the stack is observed to have no influence over the velocity and thermal field beyond a critical value of number of cells in the module. [Display omitted] [ABSTRACT FROM AUTHOR]

• An enhanced thermal network model with added thermal resistances and capacities. • Thermal resistances and heat capacities are determined via genetic algorithm. • The impact of added resistances and capacities on thermal response is discussed. • Temperature prediction error is reduced from 4.24 to 0.95 ℃. Battery thermal management is crucial for preventing the safety issues of lithium-ion batteries. Due to the simple modeling and fast calculation speed, the thermal resistance-capacity (RC) network model is broadly applied in the design of battery thermal management systems. However, the simplification of heat flow paths and the lumped definition of thermal capacity in traditional RC models result in large temperature prediction errors, which fail to reflect the thermal response in complex and diverse heat transfer situations. To improve the prediction accuracy, a decentralized centroid multi-path RC network model is constructed for a typical prismatic lithium-ion battery. This novel model incorporates multiple heat flow paths with additional thermal resistances and legitimately decentralizes the lumped heat capacity to other surface center points, resulting in a more realistic thermal response. A genetic algorithm is employed to determine the unknown thermal resistances and heat capacities at the attributed nodes. Results show that compared to the traditional RC network model, the multi-path decentralized RC network model can reduce the temperature prediction error from 4.24 to 0.95 ℃. This more refined modeling approach extends the application scope of thermal resistance network models to more complex scenarios while maintaining efficient simulation speed, which enables the attainment of more accurate and reliable onboard temperature predictions for lithium-ion power systems. [ABSTRACT FROM AUTHOR]

Electric vehicles that utilize lithium-ion batteries (LIBs) as a power source provides viable solution to realize the decarbonization of transportation sector. However, their future application is severely hindered by the temperature sensitivity of LIBs. Thus, a well-designed battery thermal management system (BTMS) is recommended to ensure proper temperature environment for improving LIBs' performance. Here, the aim is to provide a clear and detailed understanding on the two-phase heat transfer technologies for BTMS, especially given the urgent demands for fast-charging and harsh operating conditions. The fundamentals of BTMS, including battery working principles, adverse temperature effects, and modelling approaches are first analyzed. What's more, typical battery cooling methods are briefly discussed and categorized in terms of working mediums. However, with the ever-growing trend towards high energy density and fast charging, these methods are insufficient to effectively regulate the temperature of batteries. To address the rigorous demands, two-phase heat transfer strategies, with heat transfer rate several orders of magnitude higher than typical BTMS, have gained great interests. The up-to-date progresses of such system based on refrigerant flow boiling, immersion boiling, spray cooling, and other strategies, are comprehensively reviewed. Besides, discussions on battery thermal management studies are presented from the perspectives of heat transfer mechanism, pros and cons, and future insights. This state-of-the-art review is expected to deliver guidance and draw more attention to the development of advanced thermal management approaches in EV applications. • A review of emerging two-phase battery thermal management strategies is presented. • Two-phase heat transfer-based BTMSs effectively control battery temperature. • The mechanism, limitations and future insights of emerging BTMS are discussed. [ABSTRACT FROM AUTHOR]

In this work, a novel battery thermal management system (BTMS) integrated with thermoelectric coolers (TECs) and phase change materials (PCMs) is developed to ensure the temperature working environment of batteries, where a fin framework is adopted to enhance the heat transfer. By establishing a transient thermal-electric-fluid multi-physics field numerical model, the thermal performance of the BTMS is thoroughly examined in two cases. The findings demonstrate that increasing the TEC input current, fin length, and thickness is beneficial for reducing the maximum temperature and PCM liquid fraction. Nevertheless, although the increase in fin length can lower the temperature difference, the influence of fin thickness and TEC input current on the temperature difference is tiny. Based on the numerical findings, the optimal fin length and thickness of 7 mm and 3 mm are obtained. In this situation, when the TEC input current is 3 A, the maximum temperature, temperature difference, and PCM liquid fraction in Case 1 are 315.10 K, 2.39 K, and 0.002, respectively, and those are respectively 318.24 K, 3.60 K, and 0.181 in Case 2. The configuration of Case 1 outperforms that of Case 2, due to the fewer TECs and greater distance from the battery pack to the TEC within Case 2. When experiencing a higher battery discharge rate, the TEC input current should also be correspondingly increased to ensure the temperature performance of the battery. The relative findings contribute to new insights into battery thermal management. • A novel BTMS combined with thermoelectric coolers and phase change materials is proposed. • A transient thermal-electric-fluid multi-physical field numerical model for the BTMS is developed. • The fin length, thickness, and TEC input current are suggested at 7 mm, 3 mm, and 3A. • The proposed BTMS can ensure battery temperature performance at high discharge rates. [ABSTRACT FROM AUTHOR]

• A novel hybrid battery thermal management is proposed. • The mathematical model is established and then validated by the experiments. • The effectiveness of the proposed management system is proved experimentally. • The space of the proposed system is optimized via the mathematical model. A novel hybrid battery thermal management system, combining air-forced convection with phase change material, is proposed. The effectiveness of the system is proved experimentally. The maximum temperature difference and the maximum temperature are controlled within the optimum range in the proposed thermal management system even though the dynamic charge/discharge current rate is 4 C rate. Meanwhile, the thermal performance is also compared under the passive and active strategy. The result shows that the thermal performance under the active mode is obviously superior to that under the passive mode. Comparing with the passive mode, the maximum temperature difference and the maximum temperature in the active mode are reduced 1.2 °C and 16 °C under 3 C rate, respectively. Moreover, the mathematical model, based on the three-dimension heat transfer model coupled with the electrochemical model, is carried out and then validated with experimental data. Taking advantage of the mathematical model, the space of designed structures is further optimized. [ABSTRACT FROM AUTHOR]

Highlights • A plug-in OHP with flat-plate evaporator and tube condenser was developed. • Excellent heat transfer performance of plug-in OHP was achieved using ethanol-water mixtures. • EV battery temperature could be well-controlled below 46.5 °C based on the plug-in OHP. Abstract The development of highly-efficient, cost-effective, and reliable cooling schemes of electric vehicle (EV) battery is still a big challenge for massive commercialization of EVs. In this work, a proof-of-concept plug-in oscillating heat pipe (OHP) with flat-plate evaporator and tube condenser has been developed and experimentally tested for the potential applications in EV battery thermal management. Pure water, ethanol, and binary-fluid mixtures of them at different mixing ratios (MRs) ranging from 1:1 to 4:1 were used at volumetric filling ratios (FRs) of 30%, 40% and 50%. Owing to the zeotropic properties in phase transition and the complex molecular interactions between the ethanol component and water component, the OHP charged with ethanol-water mixtures exhibited better start-up and heat transfer performance. The average battery pack temperature could be controlled below 46.5 °C under the power input of 56 W. Besides, well-satisfied temperature uniformity was achieved on the battery module and the maximum temperature differences were mostly in the range of 1–2 °C. The complementary features for ethanol-water mixture thermo-physical properties and temperature/concentration gradients induced mass transport account for the OHP performance improvement. The novel plug-in OHP associated with desirable heat transfer performance provides a promising candidate for battery thermal management system. [ABSTRACT FROM AUTHOR]

• Thermal performance of refrigerant-based battery thermal management system for a real HEV battery pack is analyzed. • Effect of battery discharging C-rate, refrigerant mass flow rate, inlet temperature, vapor quality, and heating power on thermal performance of battery pack is studied. • Thermal performance of battery pack at real driving cycle operational conditions for refrigerant cooling is discussed. • Heat flow distribution on the battery pack at different discharging C-rates is analyzed. The thermal performance of refrigerant-based battery thermal management system (BTMS) for a real HEV battery pack in both the cooling and heating conditions is numerically and experimentally investigated in this paper. The heat generation model of battery cells and the numerical methodology for predicting the cooling performance of refrigerant-based cooling system are validated by experiments and the predicted results are consistent with experimental data. The effects of discharging C-rate, mass flow rate, initial temperature and vapor quality of refrigerant on thermal performance of battery pack are analyzed in detail. The thermal performance of refrigerant-based BTMS at a real driving cycle is also examined. The results indicate that the discharging C-rate has a significant impact on thermal performance of battery pack due to the distinctive heat transfer behaviors of battery pack at different discharging C-rates. Increasing mass flow rate of refrigerant is contributed to descend the maximum temperature and improve temperature uniformity of battery pack. Decreasing initial temperature of refrigerant is beneficial to reducing the maximum temperature of battery pack but is disadvantageous to temperature uniformity. The effect of vapor quality on thermal performance of battery pack is limited. The cooling performance of refrigerant satisfies the requirement of BTMS at the real driving cycle. The optimum heating power of the battery pack at heating condition ranges from 400 W to 460 W. [ABSTRACT FROM AUTHOR]

Battery aging in electric vehicles affects both thermal characteristics and electrochemical performance of batteries. In this paper, a more realistic and generic model combining electrochemical reactions, capacity decay and heat transfer is developed for the design of battery thermal management system (BTMS) to ensure efficient and durable operation of batteries. Multiphysics behaviors of the battery pack with heat pipe-BTMS (HP-BTMS) and micro heat pipe-BTMS (MHP-BTMS) under different working cycles are analyzed and compared. It is found that HP-BTMS and MHP-BTMS can provide good thermal management for batteries for several working cycles only. Both HP-BTMS and MHP-BTMS fail to provide effective cooling to the batteries after 1250 cycles, due to the higher heat generation of the aged battery due to solid electrolyte interphase (SEI) formation. As MHP-BTMS always shows a better cooling performance than that of HP-BTMS, optimizations are made for MHP-BTMS in terms of the heat transfer performance. The results show that MHP-BTMS with X direction MHP, non-equidistant arrangements and cold plates can effectively control the battery temperature even after 1250 cycles and prevent the SEI formation and capacity decay. • A new model couples electrochemistry, capacity fade and heat transfer. • The comparison between HP-BTMS and MHP-BTMS is performed. • The electrochemical and thermal characteristics in different cycles are analyzed. • BTMS shows poor cooling capacity after long term operation due to SEI formation. • The optimization schemes of BTMS are proposed for the aged battery. [ABSTRACT FROM AUTHOR]

• Diverging channel design cooling plate with oblique fins is newly proposed. • Thermal unbalance of the battery module is improved using the proposed design. • Cell-to-cell temperature difference in the pack cooling is decreased by 19.07%. • The pumping power to satisfy the temperature conditions is decreased by 67.8%. In this study, the thermal and hydraulic performances of a battery thermal management system are investigated in terms of the design of the cooling plate. A diverging channel with oblique fins (DCOF) cooling plate is newly proposed to overcome the limitations of the conventional straight channel cooling plate. The diverging design is applied to control the coolant velocity and heat transfer area, with oblique fins inserted to enhance the heat transfer efficiency. A simulation model of the battery and cooling system is developed and experimentally validated. When the DCOF design is applied to the battery module, the temperature uniformity is improved in terms of the temperature difference and standard deviation. As the investigation is extended from the module to the battery pack, the temperature difference and temperature standard deviation in the battery module are improved by 19.07% and 27.14%, respectively. Considering the power consumption of the cooling system, as the thermal performance of the DCOF design and baseline design is maintained, the power consumption of the coolant pump of the DCOF design is significantly reduced by 67.8%. [ABSTRACT FROM AUTHOR]

• A battery thermal management system that uses fins to enhance the combination of thermoelectric cooler and phase change material was established. • Compared the effects of four thicknesses of fins on the thermal management performance. • It was proved that adding fins is beneficial to improve the thermal management performance under three working conditions. • The influence of the input current on the cooling power and COP of TEC was analyzed. In this study, a hybrid active & passive BTMS(Battery Thermal Management System) that uses fins to enhance the combination of TEC(Thermoelectric Cooler) and PCM(Phase Change Material) is shown. The cold side of the TECs produces a cooling effect, which is used to cool the PCM and prevent it from melting completely in a short time, thereby extending the temperature control time. Fins are used to transfer the heat of the PCM to the cold side of the TECs, and effectively cool the batteries at high temperatures. The effects of different fin thicknesses (2 mm-8 mm) and different TEC input currents (1A-6A) on thermal management performance were analyzed by numerical simulation. The results show that the temperature control time was prolonged by 12% when the fins were increased from 2 mm to 8 mm, but the temperature difference increased by 13.7%. When the current changed from 1A to 6A, the temperature control time increased by 87.42%, but the temperature difference and COP became worse. Comprehensive analysis of temperature control time, temperature difference, COP, 4 mm fin thickness, and TEC input current of 3A were optimal for the model in this paper. [ABSTRACT FROM AUTHOR]

Thermal management of Lithium-ion batteries is a key element to the widespread of electric vehicles. In this study, we illustrate the validation of a data-driven numerical method permitting to evaluate fast the behavior of the Immersion Cooling of a Lithium-ion Battery Pack. First, we illustrate an experiment using a set up of immersion cooling battery pack, where the temperatures, voltage and electrical current evolution of the Li-ion batteries are monitored. The impact of different charging/discharging cycles on the thermal behavior of the battery pack is investigated. Secondly, we introduce a numerical model, that simulates the heat transfer and electrical behavior of an immersion cooling Battery Thermal Management System. The deterministic numerical model is compared against the experimental measurements of temperatures. Then, we perform a Bayesian calibration of the multi-physics input parameters using the experimental measurements directly. The informative distributions outcoming of this process are used to validate the model in different experimental conditions and reduce the uncertainty in the model's temperatures predictions. Finally, the learned distributions of inputs and the numerical model are used to design the system under realistic conditions representing a realistic racing car operation. A Sobol indices based sensitivity analysis is performed to get further analysis elements on the behavior of the BTMS. • We develop a data-driven fast numerical model to predict the behavior of the battery pack. • We provide data of an experimental test case of Li-ion cells immersion cooling. • We apply Bayesian calibration method to get posterior distributions of input parameters using experimental data. • Our approach allows reducing the numerical error bar of the model temperature response dramatically. [ABSTRACT FROM AUTHOR]

• Lithium-ion battery module and thermal management interactions were simulated. • The system was thermally managed using fuel. • A comparative analysis was performed for verification and assessment. • N-heptane fuel was found as a feasible coolant in hybrid electric vehicle batteries. Battery thermal management system (BTMS) design is crucial for its performance, which can be associated with extra costs and system complexity. Most of the current studies are focused on the BTMS design but with a little focus on the improvement of coolants. In this work, the feasibility of using combustion engine fuel for the LIB thermal management of hybrid electric vehicles is investigated. N-heptane is used as a dielectric hydrocarbon coolant in the introduced system. The thermal performance of the proposed system is investigated numerically using the CFD software ANSYS-Fluent. To benchmark and validate the system performance, a comparative study is made among other common approaches, including the use of air and 3M-Novec 7200. A variety of input parameters are accounted for, including inlet velocities and discharge rates. The results show that air cooling is the least effective method to control the battery module temperature uniformity and the Li-ion battery safety limit. At the same time, n-heptane and 3M-Novec 7200 have shown good control of the module temperature range (20 °C–40 °C) at various discharge rates and different inlet velocities. However, using n-heptane is a considerable improvement to the cost of the system and reduction in its weight and maximum temperature, compared to that using 3M-Novec 7200 coolant. For instance, at 0.1 m · s - 1 , n-heptane has reduced the Li-ion battery maximum temperature at 1 C and 2 C discharge rates by more than 7.9 °C (2.6%) and 17.9 °C (5.65%), respectively, compared to those predicted using the same battery module without cooling. [ABSTRACT FROM AUTHOR]

• PCM-cooled and PCM-heated BTMS are reviewed. • Phase change fluid (PCF), flexible phase change material (FPCM) and Hybrid cooling are analyzed. • The flammability of organic PCM needs to be solved for BTMS. • The stability of inorganic PCM needs to be solved for BTMS. • Various issues and challenges of BTMS based on PCM are identified. It is known that the performance of a power battery is greatly affected by temperature. The battery pack needs an efficient thermal management system to make the power battery work in a reasonable temperature range. Battery thermal management system (BTMs) based on phase change materials (PCM), as a passive thermal management method, has the advantages of low operating cost and good temperature uniformity. This paper mainly introduces the BTMs based on PCM, including the cooling and heating system based on PCM. For the cooling system of PCM, the performance of composite phase change materials (CPCM) and its heat transfer enhancement, phase change fluid (PCF), flexible phase change materials (FPCM), and hybrid cooling systems are analyzed. For the PCM heating system, the PCM latent heat for preheating of the power battery in a cold environment has also been discussed. Finally, this paper concluded that the next research directions should focus on the improvement of thermal conductivity of PCM, flame retardancy of organic PCM, thermal stability of inorganic PCM, PCF and FPCM, and PCM-based coupled battery thermal management. [ABSTRACT FROM AUTHOR]

l The critical thermal issues of lithium-ion batteries are introduced. l The design principles for batteries thermal management are presented. l The latest advances on battery thermal management systems are summarized. l Emerging technologies for next-generation power batteries are discussed. Replacing conventional gasoline-powered cars with electric vehicles (EVs) can reduce not only pollution emissions but also the dependence on fossil fuels. As the most widely used power source to propel EVs, lithium-ion batteries are highly sensitive to the operating temperatures, rendering battery thermal management indispensable to ensure their high performance, long cycle life and safe operation. In this review, we summarize the recent advances in thermal management for lithium-ion batteries. The critical thermal issues caused by high temperature, low temperature and temperature non-uniformity are firstly discussed. The design principles and the existing thermal management systems are then presented and elaborated extensively. Emerging technologies such as thermoelectric devices and internal heating methods for future battery thermal management are analyzed. We highlight that the combination of passive and active cooling/heating methods is promising to meet the stringent thermal requirements, particularly under dynamic conditions with drastic power fluctuations. Finally, the remaining challenges and perspectives of thermal management systems with high efficiency and durability are provided. This review offers comprehensive guidance on the design of advanced thermal management system for next-generation power batteries. [ABSTRACT FROM AUTHOR]

• 3D-printed polymer-based battery thermal management system is proposed • Coolant flow architecture reduces the effect of polymer low thermal conductivity • Low coolant temperature raise leads to lower BTMS energy consumption The thermal performance of a novel battery thermal management system produced by additive manufacturing is investigated through simulations. The performance of 3D-printed polymer-based battery thermal management systems is investigated for heat-managing high power density Li-ion batteries for electric vehicles and stationary applications. The manufacturing of the battery packs through 3D-printing allows for greater complexity and novelty in the design of the coolant flow domains, in order to achieve a high heat transfer coefficient by the coolant. Having a high heat transfer coefficient at the coolant side allows the use of lower conductive materials in the body of the battery pack. The proposed system takes advantage of 3D-printing technology to embedded heat fins in the cooling channel. The simulations consider various discharging rates from 2C to a high of 3C to take the battery from a 100% to 20% state of charge in the discharging process. For the charging rates 2C and 3C, the maximum battery temperature within the pack reached 22.8°C and 24.5°C, respectively. However, the maximum temperature difference across a six-battery pack reached no more than 1.5°C and 4.5°C, respectively. A maximum temperature difference achieved by the proposed system shows the ability of the 3D-printed polymer-based system to achieve the required performance and demonstrates the potential of such systems that are equipped with the advantage of additive manufacturing. [ABSTRACT FROM AUTHOR]