Search

Electric autonomous underwater vehicles (AUVs) are facing more urgent battery thermal management (BTM) demands than electric cars, as their battery compartment design is constrained by limited volume, airtightness and impact loads. In this paper, a novel hybrid battery thermal management strategy of metal foam/paraffin composite combined with thermal bridges is proposed for the AUVs' BTM. A three-dimensional model considering the non-thermal equilibrium effect for AUVs' battery module was developed. Gradient PCMs and gradient foam porosity were introduced to improve the temperature and melting behaviors in various regions of AUVs' battery pack. The trade-off between performance and weight of metal foam/PCM composite on AUVs' battery thermal management was also quantitatively analyzed. The results showed that the temperature in the top region of the battery pack was higher than that in the bottom region due to the natural convection of the liquid PCM. The positive gradient porosity of metal foam has the advantages of large porosity increasing the heat storage and small porosity improving the thermal conductivity, both benefit to reduce the maximum temperature of the battery module. The positive gradient latent heat and melting point hybrid strategy of PCM demonstrates the best thermal management performance when compared with constant parameter cases, and the maximum temperature of battery modules is more sensitive to the melting point of PCM. When the metal foam/PCM composite was introduced, the weight of the battery module increased by 27.1%, while the maximum temperature and temperature difference of the battery module decreased by 44.27 K and 11.1 K, respectively. The safe working time of the battery module was extended by 105.7%, and the mass-energy density that can be utilized was increased by 61.9%. The findings can help AUVs to achieve the goals of high speed and long range. • The metal foam/paraffin composite was innovatively used for AUVs' BTM. • A 3D model was established considering non-thermal-equilibrium effect. • The thermal and melting behaviors of battery module were discussed in depth. • The performance of metal foam/paraffin with gradient parameters was compared. • The trade-off between performance and weight of metal foam/paraffin was evaluated. [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]

To maintain the optimal battery performance, it is essential to develop an efficient battery thermal management system for keeping the battery operation temperature within the appropriate range. In this work, a novel design of cold plate featuring airfoil fin channel is developed as a highly effective cooling module of a prismatic LiFePO 4 battery pack. The thermal performance of battery and the thermo-hydraulic performance of the cooling module for the cold plate featuring airfoil fin channel, U-type channel and serpentine channel are numerically investigated and compared to reveal the superiority of the novel cold plate. The results indicate that compared with the U-type channel and the serpentine channel, the airfoil fin channel can enhance the total heat dissipation amount by 3.47% and 4.64%, respectively. Besides, the airfoil fin channel can provide the smallest battery maximum temperature and temperature difference under the same coolant flow rate. The airfoil fin channel provides the smallest pressure loss and heat transfer coefficient but the largest overall thermo-hydraulic performance indictor in terms of j / f factor. Under the same requirement of battery cooling performance, the remarkably smaller power consumption is required for the airfoil fin channel compared with the U-type channel and serpentine channel. • A novel cold plate with airfoil fins is designed for cooling battery. • Performance of airfoil fin cold plate and two conventional cold plates is compared. • Airfoil fin cold plate is of the largest heat dissipation capacity. • Airfoil fin cold plate is of the best overall performance. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing demand for electrical vehicles, which are more energy efficient and environmentally friendly than their traditional counterpart. One of the crucial aspects of electrical systems is energy storage. A promising option for energy storage is Lithium-ion batteries (LIBs) due to their high energy density, longer life cycles, and faster charging when compared to other batteries. The disadvantage of employing LIBs is that they are more difficult to maintain because they are more prone to failure, and they are greatly dependent on the system's thermal behavior, which has led to an emphasis in research on battery thermal management systems (BTMSs). The BTMS aims to address this issue by limiting the temperature fluctuation of the battery cells to maintain the average temperature within recommended limits throughout the charging and discharging processes. There has been a continuous interest in nanofluids and phase change materials (PCMs) because of their unique properties and their potential thermal application as a cooling medium for high-density batteries. Recent studies have aimed to use different active and passive methods with varying materials and cooling system geometries to achieve the highest possible thermal performance. The current review aims to outline the recent studies on thermal management systems for LIBs. Three main sections have been presented in this paper. The first section reviewed studies on nanofluids in different BTMSs, the other one highlighted techniques adopted to overcome the low thermal conductivity drawback in PCMs for BTMs, and the last one focuses on the effects of combining both cooling approaches. We believe that the present review paper provides useful information that could be a significant step toward developing high-performance BTMS. • A summary of the most recent research on BTMS of LIBs. • Nanofluids and PCM-based BTMS attract significant interest in LIBs. • PCM with carbon additives enhance LIB pack temperature uniformity. • Incorporation of fins has demonstrated effectiveness in improving BTMS performance. • Metal foams with PCMs enhance BTMS performance via improved thermal conductivity. [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]

Phase change material (PCM) is widely adopted to construct integrated battery thermal management systems (BTMSs) for all climates. However, integrated BTMSs in cylindrical battery modules remain arduous challenges due to the compact/massive cuboid-shaped PCM module and the curved surface of the cells. Herein, we propose a novel all-climate BTMS integrating units-assembled composite PCM (CPCM) module with force air convection. The CPCM module assembled by sleeve-like CPCM units provides developed airflow channels and enlarged heat transfer surface from 1.17 × 10−3 to 3.63 × 10−3 m2 for enhancing convective heat transfer. Consequently, compared to conventional cuboid-shaped module, the thermal resistance of the units-assembled module is remarkably reduced by 52.0% and 60.1%, and the heat flux is enhanced by 7 times under both cooling and preheating modes. In cooling tests, this BTMS demonstrates superior performance by controlling the temperature and temperature difference below 40.30 and 2.80 °C at 3-C discharge, respectively. In preheating tests, it effectively preheats the battery module from 0 to 10 °C in 302 s with a low temperature difference of 3.82 °C. Furthermore, this units-assembled CPCM module saves 53.8 wt% of the CPCM dosage, and thus the energy density of the battery module is increased from 75.6 to 94.4 Wh·kg−1. • All-climate BTMS integrates units-assembled CPCM module with force air convection. • Units-assembled CPCM module provides developed internal structure for heat transfer. • Thermal resistance of CPCM module is reduced, and heat flux is enhanced by 7 times. • BTMS shows superior cooling, preheating and heat-preservation performances. • BTMS reduces CPCM module weight, increasing the energy density of battery module. [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]

To ensure the optimal operating temperature of lithium-ion batteries, a novel thermoelectric-based battery thermal management system coupled with water cooling and air cooling is proposed in this work. Also, a hydraulic-thermal-electric multiphysics model is established to assess the system's thermal behavior. Through numerical simulations, the effect of different cooling parameters, including TEC (thermoelectric cooler) input current, air convection heat transfer coefficient, and cooling water flow rate on thermal performance is comprehensively analyzed. The results show that the introduction of thermoelectric cooling into battery thermal management can amplify the cooling ability of traditional air cooling and water cooling, and the cooling power and COP (coefficient of performance) of thermoelectric coolers first increase and then decrease with the increase of input current. Under the air convection heat transfer coefficient of 50 W m−2 K−1, water flow rate of 0.11 m/s, and TEC input current of 5 A, the battery thermal management system reaches the optimal thermal performance, corresponding to the maximum temperature and temperature difference of 302.27 K and 3.63 K respectively. However, the cooling parameters of these three factors interact with each other, and it is vital to select appropriate cooling parameters to balance the thermal performance and energy consumption of the battery thermal management system. More importantly, this work provides a brand-new idea for the thermal management of batteries. [ABSTRACT FROM AUTHOR]

• The coupled BTMS with PCMs and cold plates is designed for performance improvement. • Aerogel is used to replace the unmelted PCMs for weight reduction. • A strategy is developed to optimize the distribution of PCMs/Aerogel. • T max and Δ T are reduced by 1 K and 49 % respectively after the optimization. • The weight of PCMs/Aerogel is reduced by 45 % after the optimization. The thermal management system is critical for battery packs in electrical vehicles. Coupling the battery thermal management system (BTMS) with phase change materials (PCMs) and cold plates (CPs) has demonstrated good cooling performance. However, part of the PCMs inside the existing systems doesn't experience phase change, which contribute less to the cooling performance as the weight load increases. In this study, aerogel as the typical lightweight flame retardant materials (FRMs) is adopted to replace the un-melted PCMs to reduce the weight of the system. An optimization strategy for the distribution of PCMs/FRMs in the coupled BTMS is proposed to improve the cooling performance with the system's volume fixed. By locating PCMs on the high-temperature area, an optimized system can be obtained by taking just a few adjusting steps using the developed strategy. After the optimization, the maximum temperature and temperature difference inside the battery pack are reduced by1.0 K and 49% respectively, with the weight of the filling materials among battery cells decreasing by 45%. The proposed strategy shows great potential for efficient optimization of coupled BTMSs with phase change materials and cold plates, which can improve the cooling and lightweight performance of the system simultaneously. [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]

• Refrigeration system with evaporator mini-channel structure was developed for power batteries. • The effects of refrigerant charge, OTV and heating power were examined. • For OTV from 41.9% to 79.1%, the heat transfer coefficient first increases and then decreases slightly. • Temperature of battery module with heating power of 100 W-200 W can be restrained within 10.8°C -45.7°C by adjusting OTV. The vapor compression refrigeration system possesses excellent thermal performance owing to two phase boiling with large latent heat, which can be a promising option for refrigerant cooling of battery modules. In this work, the battery thermal management equipped with a small-scale refrigeration system was built up, which primarily consisted of the mini-channel evaporator directly mounted with a battery module, compressor, throttle valve and fan-cooled condenser. The influencing factors such as the refrigerant charge, openness of throttling valve (OTV) and the heating power were examined experimentally. It is found that, with the increase in the refrigerant charge, the system coefficient of performance (COP) first increased and then decreased. When the heating power is between 100 W to 200 W, the temperature of the battery module could be controlled in a suitable range, namely 10°C-45°C, by adjusting the OTV within the range of 48.8%-72.1%. As the OTV increased, the heat transfer coefficient of the mini-channels first increased and then levelled off. As the heat power increased, the heat transfer coefficient of the mini-channels first increased and then decreased. The present study helps better understanding of thermal management using the vapor compression refrigeration system in the battery thermal management. [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]

To enhance the cooling and preheating performance of the battery, a novel hybrid battery thermal management system (BTMS) containing bionic spiral fins wrapped with phase change material (PCM) and embedded liquid cooling is proposed. The cylindrical battery is strategically positioned on a spiral fin, the heat of the battery and PCM is transferred to the cold plate through the extended winglets. The thickness (L 1), height (L 2), distance (L 3) and number of winding turns (N) of fin are optimized using the response surface method (RSM). The effects of the liquid cooling duration, flow rate, channel shape and direction of the flow channel on the latent heat recovery of PCM and the cooling performance of the battery module are analyzed. The results demonstrated that at the duration of 600 s and flow rate of 0.09 g/s, the liquid fraction of PCM reduced from 57 % to 26 %. Furthermore, the preheating efficiency of the BTMS was investigated under different parameter configuration and boundary conditions. The preheating temperature increased by 5.6 °C compared with the BTMS without fins. Additionally, the temperature difference (ΔT) of the BTMS with Layout 2 decreases by 0.5 °C compared with 4.1 °C of Layout 1 at flow rate of 0.5 g/s. [ABSTRACT FROM AUTHOR]

Pursuing high cooling-preheating performances of integrated battery thermal management system (BTMS) inevitably complicates the module structure, leading to great decreases in energy densities. To unblock this trade-off relationship, we propose a compact and lightweight integrated-BTMS by introducing bi-functional heating-cooling plates (BF-HCPs) and temperature-equalizing strategies based on differentiated inlet velocities (v I and v II) and heating powers (P I and P II). Firstly, the skillful design of BF-HCPs simplifies the structure of BTMS by reducing individual heating/cooling accessories. Subsequently, multi-objective optimization of v I , v II , P I , P II and channel width ratio (WR) realizes temperature equalization in large modules. The optimal WR locates at 0.60–0.65; differentiated v I and v II is fixed at large values of 0.25 and 0.16 m·s−1, respectively; the total P I + P II is preferably larger than 695 W with a narrow P II / P I of 0.53–0.56. Consequently, the obtained BTMSs demonstrate outstanding comprehensive performances. In cooling mode, the maximum temperature and temperature difference can be controlled below 30 and 3 °C at 4-C discharge. In preheating mode, the preheating time is lower than 500 s with a temperature difference < 3 °C. Furthermore, the obtained battery module possesses higher energy densities of 143.6 Wh·kg−1 and 332.2 Wh·L−1 than the reported battery modules with existing integrated BTMSs. [ABSTRACT FROM AUTHOR]

Pursuing high cooling-preheating performances of integrated battery thermal management system (BTMS) inevitably complicates the module structure, leading to great decreases in energy densities. To unblock this trade-off relationship, we propose a compact and lightweight integrated-BTMS by introducing bi-functional heating-cooling plates (BF-HCPs) and temperature-equalizing strategies based on differentiated inlet velocities (v I and v II) and heating powers (P I and P II). Firstly, the skillful design of BF-HCPs simplifies the structure of BTMS by reducing individual heating/cooling accessories. Subsequently, multi-objective optimization of v I , v II , P I , P II and channel width ratio (WR) realizes temperature equalization in large modules. The optimal WR locates at 0.60–0.65; differentiated v I and v II is fixed at large values of 0.25 and 0.16 m·s−1, respectively; the total P I + P II is preferably larger than 695 W with a narrow P II / P I of 0.53–0.56. Consequently, the obtained BTMSs demonstrate outstanding comprehensive performances. In cooling mode, the maximum temperature and temperature difference can be controlled below 30 and 3 °C at 4-C discharge. In preheating mode, the preheating time is lower than 500 s with a temperature difference < 3 °C. Furthermore, the obtained battery module possesses higher energy densities of 143.6 Wh·kg−1 and 332.2 Wh·L−1 than the reported battery modules with existing integrated BTMSs. [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]

• An improved FRN model is developed for variable cross-section air-cooled BTMSs. • An efficient method based on FRN model is proposed for design of deflector shape. • The optimized BTMS outperformed those using the previous optimization methods. • Experiments are carried out to verify the effectiveness of the optimization method. Air-cooled systems are widely used for cooling of battery packs in electric vehicles. Optimization method combined with the flow resistance network (FRN) model is effective for system design. However, the local pressure loss of divergence and convergence ducts in the traditional FRN model is ignored, leading to large error when applying the model in systems with variable cross-section channels. In this study, the local loss coefficients of the contractive and diffusive channels are derived and the improved FRN model is developed for velocity calculation of variable cross-section air-cooled systems. The improved model is verified using computational fluid dynamics method. Based on the improved FRN model, the cross-section width distribution of the divergence duct is calculated from the given flow rate distribution. The shape of the divergence deflector is optimized by adjusting the flow rate distribution and using the improved model. The results indicate that the temperature difference of the battery cells decreases by more than 84% after the optimization, with the maximum temperature decreasing by more than 3.8 K. Furthermore, the optimized system performs better than those in the previous studies. Also, experiments are carried out to verify the effectiveness of the developed optimization method based on the improved FRN model. [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]

The current study proposed a heat pipe (HP)-assisted hybrid fin (HF) for inter-cell cooling in a battery thermal management system (BTMS). Its thermal performance was comprehensively investigated under extreme thermal conditions of up to 50 W along with critical variables. A numerical model for the proposed HF-BTMS was developed using the finite difference method and integrated with a performance prediction model based on an artificial neural network. After successfully validating with experimental results, the developed numerical model was intensely used for module-level thermal analysis and multivariate optimization. The proposed HF-BTMS exhibited a better thermal performance, which was experimentally verified by the reduction in the maximum temperature and deviation by 5.4 and 3.8 °C, respectively, than the BTMS with conventional plain fin (PF). The multivariate optimization indicated that the optimized performances of the HF-BTMS were all within the desired temperature ranges. The condensation lengths are known to be most influential rather than other variables related to coolant operating conditions. Finally, under the most thermally harsh condition, compared to PF-BTMS, the HF-BTMS was found out to dramatically reduce the maximum temperature and temperature deviation of the BTMS by over 17.95 °C and 16.37 °C, successfully maintaining within the safety range. [ABSTRACT FROM AUTHOR]

The heat dissipation performance of batteries is crucial for electric vehicles, and unreasonable thermal management strategies may lead to reduced battery efficiency and safety issues. Therefore, this paper proposed an optimization strategy for battery thermal management systems (BTMS) based on linear time-varying model predictive control (LTMPC). To begin, based on the results of three-dimensional thermal flow analysis, a reduced order substitution model for the battery cooling system was established. Next, to address the issue of high computational complexity caused by the nonlinear model in the controller, a linearization method based on staged control was designed. Furthermore, the control parameters were optimized using the particle swarm optimization algorithm. Finally, a BTMS physical model based on SIMSCAPE was established for performance simulation. The performance of the logic threshold controller (LTC), linear model predictive controller (LMPC), and nonlinear model predictive controller (NMPC) was compared and analyzed. LTMPC was found to reduce the average temperature of the battery by up to 2.33 °C and 1.90 °C, and the cumulative temperature difference is reduced by 13.9% and 16.6% compared to LTC and NMPC, respectively. Compared to LMPC, LTMPC reduces thermal management energy consumption by 21.2%. • A complete mathematical model of the liquid cooling cycle circuit was derived through the order reduction method. • Reasonably incorporate future information into the controller to improve robustness of system. • Adopting a staged control strategy to segment the model, establishing a linear time-varying control model, greatly improving computational efficiency. • The upper controller uses the heat exchange between the coolant and the air conditioning system as the control variable, improving control efficiency. • The combination of particle swarm optimization algorithm and pareto curve fully exploits the optimization potential of parameters. [ABSTRACT FROM AUTHOR]

• An easily-assembled liquid cooling (LC) system is developed by an embedding process. • The system avoids processing tailor-made LC components, reducing cost and complexity. • The flexibility of the silica gel greatly reduces the thermal contact resistance. • A hierarchically thermal conductive skeleton is constructed in the battery module. • The battery module presents superior cooling performance in harsh working condition. Liquid cooling (LC) technology is most widely used in battery thermal management systems. However, for cylindrical battery modules, tailor-made LC components with curved surface and complicated LC structures are required to match the curved surface of the cells. Herein, we design an easily-assembled LC structure by directly embedding thermal conductive silica gel (SG) into a 21.6 V/39Ah cylindrical battery module with thermal conductive plates (TCPs) connected to LC plates (LCPs). This LC strategy avoids the tedious and costly procedure of processing LC components with special specifications, and demonstrates excellent adaptability to battery modules with diversified specifications. By selecting copper plates and flexible SG with 2 wt% expanded graphite as the TCPs and embedding material respectively, a high-efficient thermal conductive skeleton can be constructed, endowing the module center with a greatly reduced thermal resistance of 1.27 × 10−2 m2∙K∙ W −1. In addition, the optimal water inlet velocity and cell distance are determined to be 0.2 m∙ s −1 and 7 mm, respectively. As a result, the maximum temperature (T max) and temperature difference (ΔT max) of the battery module are well maintained within the optimal ranges of 28.9∼41.7 °C and 1.4∼4.7 °C under all working conditions, respectively. Remarkably, even under the harsh working conditions with a 3 C discharge rate under 25, 35 and 40 °C, the T max can be controlled below 31.6, 40.3 and 41.7 °C, while the corresponding ΔT max are only 4.6, 3.8 and 3.8 °C, respectively. [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]

• A computationally efficient model for large-scale battery packs is developed. • Parameters are devised to evaluate the structural designs for the battery pack. • Pros and cons of the alternative structural designs are analyzed. • Interspersed battery pack design is suggested to enhance the thermal performance. In this paper, a comparative study for structural design of battery thermal management system is presented for electric vehicles. A thermal model for the pouch battery pack with liquid cooling is developed for thermal analysis of various pack designs. Typical battery pack with fin-cooling structure is set as a reference design, and thermal behavior of the battery pack is examined in the aspect of cooling performance and temperature uniformity. Numerical results indicate that poor heat conductivity from the bottom of the cell stack to the cooling plate is one of the major barriers to the efficient heat dissipation and asymmetric design of fin-cell arrangement have negative effect on the temperature uniformity of the battery pack. To improve the performance of the thermal management system, various structural designs are suggested and evaluated based on plural criteria. A new structural design for the large-scale battery pack is suggested to enhance the cooling performance and temperature uniformity of the battery pack minimizing the increase in system volume, weight, and pressure drop. [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]

Highlights • The effects of temperature on the performance of batteries were performed. • Battery modeling methods and thermal management strategies were discussed. • A systematic review of liquid based thermal management system was presented. • An integrated system with suitable energy allocation and control unit is desirable. Abstract Electric vehicles with green power system are viable alternatives to reduce greenhouse gas emissions and dependence on fossil energy resources. The power source such as Li-ion battery has high sensitivity to temperature, which is a challenge related to battery thermal management. Battery thermal management system plays a vital role in the high efficiency, dependability and security of these batteries. Modern commercial electric vehicles normally use liquid based battery thermal management system, which has high heat transfer efficiency with the function of cooling or heating. This paper firstly looks at the effects of temperature on the battery performance from three aspects: low temperature, high temperature and differential temperature. Then the battery management system is discussed with the main emphasis on battery modeling methods and thermal management strategies. Further, a systematic review of liquid based system is presented in terms of direct and indirect contact mode. Progress made in liquid channel configuration and heat transfer fluid aiming at improving the overall thermal performance is also discussed. With the function of liquid-gas phase change process, the heat pipe based battery thermal management is feasible and effective for its high heat transfer efficiency. To further facilitate vehicle-mounted energy optimization, an integrated vehicle thermal management system with appropriate energy allocation is required. In addition, the battery thermal management system connected with the other subsystems (e.g., heating ventilation air conditioning system) by utilizing the liquid circulation in vehicle thermal management has great potential in energy-saving and efficiency promotion. [ABSTRACT FROM AUTHOR]

Battery thermal management system (BTMS) is critical to dissipate the heat generated by the battery pack and guarantee the safety of the electric vehicles. Among the various battery thermal management technologies, the air cooling is one of the most commonly used solutions. In this paper, the cooling performance of the parallel air-cooled BTMS is improved through using the secondary vent. Computational fluid dynamics is introduced to calculate the flow field and the temperature field, finally evaluating the cooling performance of the BTMS. Mathematical analysis is conducted to explore the influences of the inlet air temperature and the heat generation rate on the battery cell temperature. The analysis results demonstrate that the temperature rise and the temperature difference of the battery pack are independent of the inlet air temperature, and are proportional to the heat generation rate for the situation of the constant heat generation rate. Subsequently, the influences of the position and the size of the secondary vent on the cooling performance of the BTMS are investigated through using the typical numerical cases. The results show that the position of the secondary vent strongly affects the maximum temperature and the maximum temperature difference of the battery pack. When the vent is on the convergence plenum, it is suggested to be located against the cooling channel around the battery cell with the maximum temperature. Compared to the vent located on the convergence plenum, the one against the outlet performs better. In this situation, the maximum temperature of the battery pack is reduced by 5 K or more, and the maximum temperature difference is reduced by 60% or more compared to the BTMS without vent for the situation of the constant heat generation rate. Moreover, the cooling performance of the BTMS becomes better as the size of the secondary vent increased, and similar conclusion can be obtained when the heat generation rate is unsteady. [ABSTRACT FROM AUTHOR]

• A comprehensive model based on battery aging effect is developed for MHP-BTMS. • A framework combing deep learning and multi-objective genetic algorithm. • BTMS shows poor cooling capacity due to SEI formation inside the aged battery. • Two optimization strategies are proposed for multi-objective optimization. • The trade-off between battery temperature and performance is achieved. Battery thermal management and electrochemical performance are critical for efficient and safe operation of battery pack. In this research, a multi-physics model considering the battery aging effect is developed for micro heat pipe battery thermal management system (MHP-BTMS). A novel multi-variables global optimization framework combining multi-physics modeling, deep learning and multi-objective optimization algorithms is established for optimizing the structural parameters of MHP-BTMS to improve battery thermal management and electrochemical performance simultaneously. It is found that MHP-BTMS fails to control the temperature of aged battery pack due to the higher heat generation caused by solid electrolyte interphase formation. After 1000 cycles, the maximum temperature and maximum temperature difference were increased by 3.32 K, 2.49 K, 2.04 K and 1.78 K, 1.46 K, 1.26 K, respectively. It is also found that the battery electrochemical performance during the cycling is highly related to battery thermal behaviors. MHP-BTMS with 0.004/s inlet velocity achieved the best performance in preventing SEI formation and battery aging effect, which was lower by 7.01 nm (SEI) and 1.65% (aging), 2.31 nm and 0.58% as compared to 0.002 and 0.003 m/s cases. Besides, MHP-BTMS with optimized inlet velocity, MHP arrangement and cold plate can improve cooling performance and electrochemical performance. Multi-variables global optimization can provide the optimal structure parameters of MHP-BTMS under the different combinations of weighted coefficients and optimization strategies to achieve the trade-off between battery thermal issues and electrochemical performance. In addition, it is demonstrated that the weighted coefficients and optimization strategies in this novel framework can be changed according to the actual needs in engineering applications. [ABSTRACT FROM AUTHOR]

Heat dissipation capacity is of great importance object for the battery thermal management system (BTMS). To obtain a simple and efficient liquid cooling method for rectangular lithium-ion battery, three types of diamond channel (line, inner arc and outer arc) cold plate were established. Firstly, the temperature rise of line diamond microchannel cold plate under basic conditions were simulated. Then, an experimental device for measuring the surface temperatures of cold plate was designed, and the numerical simulation results were verified. The results showed that the errors between the avenge temperature (T avg) of experiment and simulation were between 0.66% and 2.1%, and the inner arc diamond-type channel cold plate had better cooling effectiveness. Then the effects of the connection form of the intermediate channel, structural parameters and the layout of the inlet and outlet on the cooling performance of the cold plate were discussed. The pressure drop (Δ P) and T avg of the best results reach 5.33Pa and 36.52 °C respectively. Compared with the initial condition, Δ P was decreased by 32.81Pa (86.03%) and T avg was decreased by 0.69 °C (1.9%). The above research results depict that the new diamond-shaped cold plate proposed in this paper could greatly enhance the cooling performance of the liquid-cooling system. • Three new types of diamond channel cold plate were designed. • The errors between experiments and CFD simulations were less than 2.1%. • The optimal internal channel structure parameters were obtained after optimization. • Δ P and T avg were decreased by 32.81Pa (86.03%) and 0.69 °C (1.9%) after optimization. [ABSTRACT FROM AUTHOR]

• New material with room-temperature flexibility and high-temperature shape stability. • The contact thermal resistance of TPS is reduced by 50% compared with that of EPDM. • The maximum temperature is controlled below 56 °C at the discharge rate of 2.5C. • The temperature difference of the CPCM cooling battery module is lower than 4.0 °C. Phase change materials have potential uses in battery thermal management because of their controllable phase change temperature and high latent heat. However, the application of phase change materials is limited by their strong rigidity, difficult assembly, high contact thermal resistance, low thermal conductivity, and leakage. In this study, a novel flexible composite phase change material (CPCM) with good mechanical properties is prepared, which can maintain flexibility at room temperature and shape stability at high temperatures. A thermoplastic styrene-based polymer (TPS) is used as the support material, paraffin is used as the phase change material, and expanded graphite is used as the reinforced thermal conductive filler. Results show that the composites have good flexibility and extensibility at room temperature and can maintain good shape stability at 60 °C and certain pressure. The contact thermal resistance of CPCM is 50% of the contact thermal resistance of similar materials. Thermal management experiments of single battery and square battery modules are designed. After six cycles of 2.5C high-rate discharge, the maximum temperature of the battery module cooled by CPCM is 2 °C and 10.4 °C lower than that of forced air cooling and natural air cooling, respectively. The temperature difference of the battery module is lower than 4.0 °C. This study shows that the new flexible CPCM thermal management system is easy to assemble and can reduce the temperature of battery modules, and this feature is conducive to the application of CPCM. [ABSTRACT FROM AUTHOR]

• The side face owns the largest cooling efficiency. • Thermal-hydraulic performance is improved by even distributed enhanced unit. • The maximum temperature is maintained below 38 °C. • The optimal cold plate owns the highest energy flow percentage. Targeted at addressing cooling concerns of high power Cell-Pack, a novel interlayer battery thermal management system applying Tesla-valve mini-channel is proposed. The effect of cold plate position and Tesla-valve channel parameters is investigated to obtain optimal thermal performance through coupled battery cold-plate simulations with a 2C-discharge rate and wide Re range. Compared to main face cooling, side face cooling demonstrates more favorable thermal performance with decreasing maximum temperature and maximum temperature difference by 5.6 °C and 8.5 °C respectively. With application of forward Tesla-valve mini-channel, the maximum temperature decreases by 3.8 °C compared to straight mini channel at a moderate Re of 500. This prior thermal performance is corresponded to the even distributed heat transfer enhancement zones with flow fluctuations. Furtherly, the thermal–hydraulic performance is optimized by channel number, Tesla valve number and contraflow design with doubled Nusselt number and normalized thermal performance factor, maintaining the maximum temperature below 38 °C at a higher discharge current of 210 A. Consequently, the optimal forward Tesla-valve mini-channel owns considerable cooling efficiency factor of 369 and the highest energy flow percentage of 59.2% compared to the straight mini-channel, demonstrating the improved thermal–hydraulic performance and cooling efficiency. [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]

• 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]

In this study, a hybrid liquid cold plate design containing Z-type parallel cooling channel and PCM/aluminum foam composite, in conjunction with a novel delayed cooling strategy, is proposed to provide a compact, lightweight, and energy efficient solution for battery thermal management systems (BTMSs). A total of nine different cold plate designs, including one baseline cold plate without PCM composite and eight hybrid cold plates containing PCM composite, are analyzed systematically to demonstrate the superior cooling performance of the proposed cooling design. Specifically, the average temperature of battery surface and total power consumption performance of each design are analyzed and compared at a battery discharging rate of 1C under both continuous and delayed cooling schemes. Subsequently, two selected designs with superior cooling performance as well as the baseline cold plate are further investigated to discuss the effectiveness of hybrid liquid cold plates for cooling batteries at high discharge rates. The results show that the optimum hybrid cold plate design, which only weighs half of the baseline cold plate, can provide more than 50% reduction in the total pumping power while achieving the same cooling performance (i.e., with the average battery temperature controlled within 40 °C) compared with the baseline cold plate at battery discharging rates of 1C, 2C and 3C. These results can potentially provide important guidance to the design of advanced cooling systems for lithium-ion batteries. • A compact and lightweight battery thermal management system is proposed. • A delayed cooling strategy is proposed and analyzed. • Cooling performances were compared between different designs numerically. • Optimum cooling system allows >50% reduction in power consumption and weight. [ABSTRACT FROM AUTHOR]

• Common factors of inefficient cooling invoke the formation of universal solutions. • Airflow uniformity is the dominant factor for battery air-cooling. • Increased air residence time improves the uniformity of air distribution. Inspired by the ventilation system of data centers, we demonstrated a solution to improve the airflow distribution of a battery energy-storage system (BESS) that can significantly expedite the design and optimization iteration compared to the existing process. A defective cooling system of a BESS decreases the overall operational efficiency and increases the risk of thermal runaway, but current design optimizations rely on a case-by-case approach. The solutions of this fashion are both time-consuming and costly because of the laborious recursive process. The desire to eliminate the time for development motivates us to pursue a more general path for design optimization. In this work, we identified the similarity of geometry between the data center and the BESS, as well as the factors that induced the unbalanced airflow distribution. Inspired by the data-center thermal management, we propose a generalized solution of layout arrangement that we applied to the BESS design. We performed a quantitative analysis of cooling performance and investigated the flow patterns under given operating configurations. After modification, the maximum temperature difference of the battery cells drops from 31.2°C to 3.5°C, the average temperature decreases from 30.5°C to 24.7°C, and the coefficient of performance (COP) increases four-fold. The modification shows an improvement in temperature uniformity, overall temperature and COP. The cooling solution applicable to the general container BESS design demonstrates the enormous potential for an effective and rapid design optimization. [Display omitted] [ABSTRACT FROM AUTHOR]

A kind of new hybrid thermal management system combining phase change materials with a series of liquid cooling is designed. The characteristics of the temperature change is studied experimentally and numerically when the ambient temperature is 25 °C to 40 °C. The results indicate that the temperature of phase change cooling system is reduced by 44.2%, 30.1% and 5.4%, respectively, compared with air cooling system, liquid cooling system and pure phase change material cooling system. To further enhance heat transfer, copper fins are added around the battery, the results shows that the maximum longitudinal difference of the battery temperature decreased by 69.7%. The research of this paper provides a theoretical basis for the thermal characteristics of hybrid cooling system and a design method with higher cooling efficiency and better temperature uniformity for the design of power battery thermal management system. • A new hybrid thermal management system combining phase change materials with liquid cooling is designed. • The simulation results are in good agreement with the experimental results. • The design structure of BTMS is optimized and validated again with experiments and simulation. • Hybrid thermal management system improves the temperature uniformity of the battery pack. [ABSTRACT FROM AUTHOR]

An efficient and safe thermal insulation structure design is critical in battery thermal management systems to prevent thermal runaway propagation. In this paper, using a common real-life overcharge as a trigger for battery runaway, we investigate the runaway response of the battery module without thermal insulation and with various thermal insulation materials. The experimental results indicate that the thermal insulation has the effect of stopping the thermal spread of the battery module and reducing the maximum temperature. By comparing the temperature change of the batteries, it is discovered that the fiber-based material has a temperature drop efficiency of 71.83%, while the aerogel materials are at least 13% more efficient in temperature reduction than fibrous materials. Meanwhile, it is demonstrated that by examining the capacity characteristics of the damaged battery and the characteristics of the insulation material, the pre-oxidized silk aerogel has the best thermal spread suppression effect and the TG (thermogravimetric) variation withstood high temperatures of up to 746 °C. SEM (scanning electron microscope) morphology for different insulation materials before and after combustion show that pre-oxidized silk aerogel maintains a strong thermal insulation capacity in the thermal spreading. It is expected to have a guidance for the design of thermal insulation in lithium-ion battery modules. • The greater the overcharge multiplier, the higher the temperature following thermal runaway. • The battery is highly susceptible to TR when the surface temperature exceed 200 °C. • The fiber material have a temperature drop efficiency of 71.83%. • The aerogel materials are at least 13% in temperature reduction than fibrous materials. • The pre-oxidized silk aerogel have the best thermal spread suppression effect. [ABSTRACT FROM AUTHOR]

• A novel liquid-cooled BTMS with TPMS sheet structure for cylindrical LIB is proposed. • The BTMS with TPMS sheet structure can improve thermal performance than that with the straight tube. • The inner skeleton structure improves the cooling performance of BTMS than the outer skeleton structure. • The temperature consistency of the battery module is enhanced by the gradient design of parameter c along the flow direction. As an effective cooling method, liquid-cooled battery thermal management system (BTMS) is crucial to maintain the performance of the battery packs. Triply periodic minimal surface (TPMS) is a mathematically described surface with large surface area and tortuous regions. These features allow the TPMS-based structures to be used as the internal filling structures of the heat exchangers for thermal performance improvement. In this study, the TPMS-based internal filling structures in the liquid-cooled BTMS are proposed. The results demonstrate that the cooling performance and temperature consistency of the battery module can be enhanced by filling the TPMS-based structures in the cooling channel. Compared with the conventional straight tube, at the inlet flow rate of 0.003 kg/s, the maximum temperature and temperature difference of the battery module in the BTMS with the sheet structure decrease by 9.0% and 59.8%, respectively. In addition, the gradient sheet structure is designed to alleviate the temperature gradient of the coolant in the flow direction. The results illustrate that the temperature difference of the battery module in the gradient sheet structure decreases by 15.7% than that in the uniform sheet structures (c = ±0.5). This study can provide a new approach for thermal performance enhancement of the liquid-cooled BTMS. [ABSTRACT FROM AUTHOR]

• A novel design for BTMS is proposed to separate the propagation of thermal runaway. • Th BTMS unites phase change cooling, liquid cooling and thermal insulation material. • The electrochemical-thermal and heat transfer-laminar flow coupling model is built. • The influence of coolant flow rate on the novel BTMS in the extreme case is analyzed. Nowadays, electric vehicles attract much attention due to the advantages of low energy consumption and zero emission. As the power source of electric vehicles, the safe and stable operation of lithium ion battery is very important. However, owing to overcharge, mechanical collision, overheating or other conditions, the battery may occur thermal runaway, which can cause serious accidents such as fire or explosion. To solve this problem, an efficient and energy-saving battery thermal management system becomes a necessary choice. In this paper, a novel integrated battery thermal management system with multi-measure prevention strategy is designed and analyzed, which is mainly composed of the composite phase change material, aerogel and cooling-channel. Firstly, the electrochemical-thermal coupling mathematical model is established, and then the reliabilities of thermal runaway model, phase change cooling model and liquid cooling model are verified, respectively. Next the numerical simulation including the effect of different operating modes, extreme case and coolant flow rate on the battery thermal management system is carried out, and finally the results are discussed in detail. The results show that the battery thermal management system can not only quickly take away the accumulated heat and separate the propagation of thermal runaway, but also maintain the temperature uniformity of battery. [Display omitted] [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are extremely sensitive to their temperature and therefore, require a battery thermal management system (BTMS). BTMS is commonly employed to prevent thermal runaway of the LIB pack by controlling their operating temperature. This review paper provides various cooling strategies, including active and passive approaches, utilized in BTMSs. Air-cooled, liquid-based, and PCM-cooled techniques are first reviewed. This article presents an assessment of the application of nanofluids and nano-phase change materials (nano-PCMs) in BTMSs to improve heat dissipation from the LIB pack. This work emphasizes the utilization of these materials to intensify their thermal conductivity and suggests further investigations on their application in BTMSs. • Lithium-ion batteries are extremely sensitive to their temperature. • BTMS is employed to prevent battery thermal runaway by controlling its temperature. • Providing various cooling strategies for BTMS: active and passive approaches. • Presenting an assessment of the application of nanofluids and nano-PCMs) in BTMSs. [ABSTRACT FROM AUTHOR]

Mini channeled cold plates (MCCP) are an impressive choice for electric vehicles with a liquid-based thermal management system to keep the battery temperature within the desired range and to achieve a homogeneous temperature distribution. This paper came up with an optimum solution for maximum battery temperature (MBT), maximum temperature difference on the battery surface (MTD) and pressure drops in the channels (ΔP), which are vital parameters. Multi-objective optimization of geometric parameters and coolant flow rate of a designed MCCP which is experimentally investigated is carried out using the Desirability Function Approach. Firstly, the design of experiments (DoE) is generated using response surface method after determining the input variables and their levels. Then, each sample of DoE are modeled and analyzed numerically. Furthermore, the regression equations of the objective functions (MBT, MTD and ΔP) depending on the design parameters are developed and their variance analyzes are performed. Prediction accuracies of model equations developed for MBT, MTD and ΔP are 97.75%, 95.49% and 97.15%, respectively. As a result, optimum values of design variables, namely channel width (mm), distance between branches (mm), channel depth (mm), number of crossovers in branches and coolant flow rate (l/min) are 5, 5, 10, 13 and 0.7061, respectively. • Multi-objective optimization of a mini channeled cold plate. • Simulation of temperature distribution on the battery surface for different cases. • Deriving regression equations for the optimization output variables. • Achieving a minimum prediction accuracy rate of 95.49% for the response parameters. [ABSTRACT FROM AUTHOR]

Despite significant advances in battery thermal management system (BTMS), current electric vehicles (EVs) still lag behind user expectations in terms of battery performance and safety. A reliable, low-cost, and lightweight system is crucial for an effective BTMS that enables the battery's operation within a reasonable temperature range. In this study, a novel U-shaped lightweight liquid cooling method is introduced to optimize the thermal safety and weight of a prismatic battery cell. Numerical calculations are first carried out to investigate the effects of different fluid flow directions, flow rates, channel dimensions, fluid media, and discharge rates on the battery's temperature, and the results reveal that these factors simultaneously influence both the maximum temperature and temperature uniformity. To save computational costs and avoid the overwhelming complexity of the numerical measurements, a neural network-based regression model was constructed on the basis of 125 sets of simulation data, which comprised of four kernel functions with two outputs: maximum temperature and temperature difference. Each kernel function had a desirable testing accuracy (99.1 % , 97.0 % , 97.8 % , 98.4 %) after training, which indicates that the Gaussian Process Regression (GPR) with Matern 5/2 kernel function can better express complex non-linear relations for the prediction of maximum temperature and temperature difference with minimal errors between the simulated and predicted values compared with other kernel functions. Additionally, applying the GPR model to all cases studied, it is observed that Case 1 decreases the maximum temperature of the battery cell by 21 % and lowers the weight of the cooling plate by 45 % compared to the conventional liquid-cooled BTMS. Hence, it is chosen as the optimal design. The newly introduced BTMS can contribute to the development of lightweight and thermally safe battery cells. [ABSTRACT FROM AUTHOR]

This study proposes a new approach for dealing with the thermal management of batteries in fuel cell hybrid electric vehicles, by introducing a new concept of on-board energy storage system which integrates the battery pack with a metal hydride tank. The rationale behind this solution is to use the exothermic absorption and endothermic desorption processes of hydrogen in metal hydrides for heating and cooling the battery pack, respectively, thus ensuring an optimal thermal management control. An experimental investigation is carried out on a prototype in order to proof the concept and preliminary assess its feasibility for actual implementations. The results show that the system is capable to effectively control the temperature variations within the battery pack: for 1C and 1.5C constant-current discharge tests, a desorption of 30%–40% of hydrogen, over the total amount stored into the metal hydride tank of the system, allows the final average temperature of the battery pack to be around 15 °C lower than the one reached without thermal management. Moreover, it is found that the system is potentially capable of providing a suitable thermal management for more than four hours under realistic driving conditions. The proposed energy storage system also achieves inherently high gravimetric and volumetric energy densities, with theoretical values equal to 182 Wh/kg and 530 Wh/L, respectively. These estimates represent reference values for further design improvements. • New concept of hybrid energy storage system for plug-in fuel cell electric vehicles. • The hybrid system integrates metal hydrides for hydrogen storage and battery pack. • Experimental proof of concept for a hybrid energy storage system prototype. • Effective and efficient battery thermal management. • On-board energy storage system with enhanced energy density. [ABSTRACT FROM AUTHOR]

Liquid-cooled battery thermal management system with cold plate shows great potential for cooling battery packs in electric vehicles due to its merits of large heat transfer coefficient and good sealing performance. However, current design of cold plate leads to large temperature difference in battery packs, especially in the case with large battery packs. Besides, the pump energy consumption is usually high, which shortens the endurance of electric vehicles. In this paper, a parallel mini-channel cold plate (PMCP) for large battery packs is designed to reduce the temperature difference of the system. Numerical method is adopted to evaluate the performance of the PMCP, which is further demonstrated by experiment. Then a bidirectional symmetrical cold plate is designed to reduce both temperature difference and energy consumption. Positions of the outlets of the bidirectional symmetrical cold plates are adjusted to further improve the system performance. Finally, the designed cold plates are used for cooling large battery packs. Compared with systems equipped with traditional PMCP, the temperature difference in battery pack and the energy consumption of the system with designed PMCP are reduced by 77% and 82%, which shows that the designed PMCP significantly improves the system cooling and energy saving performance. • PMCP is used to cool large-scale battery packs at a high discharge rate. • Experiments are done to study the PMCP performance and verify the numerical method. • Performance of PMCP is improved by constructing bidirectional symmetrical system. • Influence of the outlet position on the performance of designed PMCP is studied. • Δ T avg-b and W P of designed BTMS are reduced by at least 76% and 81%, respectively. [ABSTRACT FROM AUTHOR]

• A direct optimization strategy for efficient design of parallel BTMS is developed. • Field synergy equation is employed to obtain the optimal flow rate distribution. • Flow resistance network model is used to directly calculate the optimal parameters. • Experiments are carried out to demonstrate the effectiveness of numerical method. • >The optimized BTMSs in this study exhibited remarkably enhanced cooling performance. Air-cooled battery thermal management system (BTMS) is critical for the safety and performance of electric vehicles. The system design needs to be optimized to achieve best thermal stability and uniformity. The current optimization methods for system design require empirical adjustment and contain randomness, which impedes to get the optimal system design. In this work, a direct optimization strategy based on field synergy equation is proposed for the optimal design of BTMS. Field synergy equation is introduced to calculate the optimal flow rate distribution in the system, which is combined with flow resistance network model to obtain the optimized structural parameters of the system. The developed strategy is adopted to optimize the parallel channel width distribution and plenum angle of BTMS. Computational fluid dynamics method and experiment are utilized to evaluate the cooling performance of BTMS. The results show that the temperature difference (Δ T max) in battery pack after parallel channel width optimization is reduced by at least 49% without pressure drop increased, while Δ T max after plenum angle optimization is reduced by at least 56% with pressure drop slightly increased. Mechanism of convective heat transfer optimization is taken into consideration by using field synergy equation in the proposed direct optimization strategy, which thus eliminates the burden of repeated adjustment of structural parameters and exhibits high efficiency for design of parallel cooling system. The developed optimization strategy is believed to guide the thermal design of battery packs to enhance their performance and safety. [ABSTRACT FROM AUTHOR]

• A multifunction flexible composite phase change material (CPCM) has been proposed. • Ethylene-Propylene-Diene Monomer (EPDM) based CPCM has excellent anti-leakage property. • Thermal contact resistances of rigid and flexible CPCMs under vibration are compared. • Flexible CPCM with EPDM for battery module has prominent anti-vibration performance. From the assembly and application perspective, battery thermal management system with phase change material has been highly desirable but remains significant challenges, including phase change material leakage, high rigidity and low thermal conductivity. In this study, a novel anti-leakage and anti-vibration thermally induced flexible composite phase change material has proposed which is utilized Ethylene-Propylene-Diene Monomer to increase the crosslinking of styrene-butadienestyrene block copolymer, so as to improve the adsorption of paraffin. The results revealed that the mass retention rate of thermally induced flexible composite phase change material with 3 wt% Ethylene-Propylene-Diene Monomer and 5 wt% expanded graphite was still more than 99% after heating (60 °C, 10 h) condition. Besides, the maximum temperature of battery module with the flexible composite phase change materials can be still controlled below 50 °C at 1C discharge rate, the corresponding temperature difference was effectively maintained within 2 °C. With these prominent performances, the battery module with designed thermally induced flexible composite phase change material can provide insights into the passive thermal management and other energy storage fields. [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]

• A novel battery thermal management system (BTMS) was proposed, which utilizes the excess high-pressure turbocharged air. • The BTMS performance and corresponding enhancement mechanisms were experimentally and numerically explored. • The average and maximum Nusselt number were increased by 0.43-16.55, 5.73-34.42 times, depending on the jet pressure. • Vortexes and jet deflection by the mainstream was quantified with the jet pressure. • The thermal boundary layer thickness was quantitively compared, which was much thinned by the jet. The novel concept of impinging jet cooling, i.e., an active-passive air cooling strategy, was proposed to achieve improved battery thermal management in hybrid vehicles, and this method is supported by excess high pressure discharged air. To comprehensively realize the active-passive combined cooling behavior, a rectangular channel with a jet impingement hole was utilized to experimentally and numerically study the flow characteristics and thermal performance of the joint cooling mechanism. The numerical results were confirmed by the experimental data in this work, the maximum deviations of the offset and Nusselt numbers are 18.8% and 7.5%, respectively. The thermal transport performs much better under the interaction between the mainstream and impinging jet, i.e., the average Nusselt number and maximum Nusselt number can be increased by 0.43-16.55, 5.73-34.42, respectively, at inlet pressures of the impinging jet in the range of 1–6 bar. The values of Nu/Nu 0 /(f/f 0) 1/3 are improved by 1.52–3.33. The jet fluid was deflected under the influence of the mainstream and a vortex can be induced, which is beneficial for the heat transfer performance. The jet fluid closely reached the heated plane at a relatively large volume flow rate and the heat transfer performance was excellent once the jet fluid touched the heated plane. The thermal boundary layer becomes thinned under the impact of the impinging jet but the magnitude of the reduction is relatively slight. [ABSTRACT FROM AUTHOR]

• A battery thermal management system based on heat pipe-cooling is designed. • Multiple structure parameters of the aluminum sheet are investigated and optimized. • Impacts of factors on the cooling performance are analyzed by an orthogonal design. • Primary influential factors are obtained through fuzzy grey relational analysis. An efficient thermal management system is essential to maintain its good performance of a power battery pack. Evaluating the impacts of influential factors on the system cooling performance helps guide the design of the battery thermal management system. In the present work, a battery thermal management system based on heat pipes combined with a liquid-cooling plate is proposed. Orthogonal design and fuzzy grey relational analysis are employed as evaluating methods, and numerical simulations are carried out to investigate the influence of four structure parameters of the aluminum sheet (the height, the thickness, the covering angle to battery, and the covering angle to heat pipe) on the temperature distribution of the battery pack. Results show that, in order to keep a good operating temperature range of the battery, the values of the height, the thickness, the covering angle to battery and the covering angle to heat pipe of the aluminum sheet are suggested to be above 50 mm, 2 mm, 75° and 60°, respectively. The covering angle of aluminum sheet to battery has the most influential impact on the system cooling performance, and the covering angle to heat pipe has the slightest influence. The optimal value of the maximum temperature is 37.58 °C and the temperature difference is 3.67 °C. [ABSTRACT FROM AUTHOR]

• Shark-skin bionic heat sink containing phase change material is developed. • The value of T max and ΔT of bionic heat sink are reduced by 5.49 K and 4.11 K. • The optimization method for the bionic structure height is proposed. • The ΔT of battery model is reduced to 1.22 K after the structure height optimized for seven times. • Environmental adaptability of the battery thermal management is studied. To improve the cooling efficiency and temperature consistency of battery module, a novel heat sink inspired by shark-skin microstructure is proposed to apply in battery thermal management system (BTMS), which is combined with axial air cooling and phase change material (PCM). The surface of the shark-skin bionic heat sink shows a number of regularly arranged and hollow raised structures. The cavities of these raised structures are filled with PCM. The effect of the structure parameters of shark-skin bionic structure on the cooling performance is investigated using validated computational fluid dynamic method. When the shape, height, length and interval of shark-skin bionic structure are triangular, 3 mm, 7 mm and 2.5 mm, respectively, the maximum temperature (T max) and temperature difference (ΔT) of battery module are control to 308.98 K and 3.21 K, while the consumption energy is 34.57 J. As compared with the normal case, the T max and ΔT of shark-skin bionic sink are reduced by 5.49 K and 4.11 K, respectively. Then, a method is proposed to optimize the height distribution of bionic structure. After the height distribution of bionic structure for battery module is optimized for seven times, its ΔT and energy consumption are reduced to 1.22 K and 26.81 J, while its T max is 309.19 K. Furthermore, the BTMS exhibits reliable cooling performance under different ambient temperatures and dynamic conditions. [ABSTRACT FROM AUTHOR]

• Dynamic battery thermal model integrated with vehicle dynamics is newly developed. • Transient traits of the electric motor and regenerative brake system are reflected. • Comparative analysis between two steady and dynamic operation modes are conducted. • The proposed model is highly applicable to any driving conditions and EV models. • The dynamic thermal effects are non-negligible large despite the cooling effects. Accurate thermal analysis of batteries for realistic operating conditions is a key requirement to develop an effective battery thermal management system of electric vehicles (EV), which ensures battery safety. In this context, a dynamic battery thermal model is developed to investigate the thermal characteristics of the battery module under dynamic EV operating conditions. The comprehensive modeling on EV dynamics is firstly conducted to determine the power demands with driving cycle applications. The efficiencies of components within the EV powertrain are closely considered, and the power consumed or regenerated in traction or brake mode is estimated. The battery thermal model considering both the joule and entropic heats is developed to predict the heat generation rates and temperature profiles following the dynamic battery loads. The developed models are validated within 3.98% for the EV dynamics model and 0.76% for the battery thermal model in relative error, respectively, allowing precise power and thermal simulation under the realistic operating conditions of the EV battery. A comparative analysis between the dynamic and steady modes for the same power loads to confirm the effects of the dynamic patterns is conducted for ten continuous cycles. As a result, the maximum differences between steady and dynamic modes are discovered about 3.57 times in heat generation, and 4.58 °C in temperature. These differences remain significant even with the thermal management, turning out more active cooling is required for normal operation under dynamic operating conditions. [ABSTRACT FROM AUTHOR]