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The hybrid fuel cell/battery technology is an attractive option for a sustainable mobility with zero emissions. In fact, this solution owns system scalability features and high efficiency and, compared to battery electric solutions, it offers advantages in terms of flexibility of use and fast charging times. However, the thermal management for the battery in this type of powertrain is a crucial issue, since operating temperatures can significantly affect safety and performance. In this study, an innovative system aimed at providing high storage energy density and improving the battery pack performance of hybrid fuel cell/battery vehicles is investigated for use on-board of a plug-in fuel cell electric bike. The proposed system, developed by the authors in previous studies, integrates the battery pack with a hydrogen storage based on metal hydrides. The idea behind this solution is to exploit the endothermic desorption processes of hydrogen in metal hydrides to cool down the battery pack during operation. An experimental analysis is conducted to assess the thermal management capabilities of this system: by considering a typical duty cycle designed on the base of road test measurements, battery pack temperature profiles are evaluated and compared against those from a control experiment where no battery thermal management is enabled (i.e. no hydrogen desorption from the metal hydride tank). The results show that, beside enhancing the on-board stored energy capacity, the proposed system represents an effective solution to provide an efficient thermal management for the battery pack, with significant advantages in terms of attainable riding range. • Plug-in fuel cell electric bicycle with greater riding range than e-bike. • On-board storage system integrating metal hydrides tank and battery pack. • Enhanced volumetric and gravimetric on-board energy storage density. • Optimal thermal management of battery pack and metal hydride tank. [ABSTRACT FROM AUTHOR]

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

[Display omitted] • The thermal application of carbon nanotube from waste plastic was firstly studied. • The thermal conductivity of phase change composite material increased by 104%. • Latent heat capacity of phase change composite material retains 90.7%. • The produced carbon nanotube shows similar potential as commercial carbon nanotube. • This phase change nanocomposite is promising for battery thermal management. Carbon nanotube (CNT), has been demonstrated as a promising high-value product from thermal chemical conversion of waste plastics and securing new applications is an important prerequisite for large-scale production of CNT from waste-plastic recycling. In this study, CNT, produced from waste plastic through chemical vapor deposition (pCNT), was applied as a nanofiller in phase change material (PCM), affording pCNT-PCM composites. Compared with pure PCM, the addition of 5.0 wt% pCNT rendered the peak melting temperature increase by 1.3 ℃, latent heat retain by 90.7%, and thermal conductivity increase by 104%. The results of morphological analysis and leakage testing confirmed that pCNT has similar PCM encapsulation performance and shape stability to those of commercial CNT. The formation of uniform pCNT cluster networks allowed for a large CNT loading into the PCM on the premise of free phase change, responsible for the high thermal conductivity inside the homogeneous phase. Thus, the resulting capillary forces retained a high latent heat capacity and suitable melting temperature and prohibited PCM leakage from the matrix to the outside during re-melting as the pCNT loading ratio increased. Therefore, the as-prepared pCNT-PCM composite is believed to have similar potential to cCNT and shows prominent performance as a flowable conductive filler for battery thermal management systems. [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]

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

• The heat generation model for cylindrical Li-ion battery was built. • A liquid immersion cooling battery pack containing 60 batteries were established. • At 2C discharge rate, 0.5 L/min flow rate was recommended. • The battery pack can address localized high-rate discharge events (4.5C or 6.5C). • Liquid immersion cooling BTMSs have great heat dissipation performance. With the increasingly severe challenges of the thermal management of battery packs for electric vehicles, the liquid immersion cooling technology has gradually attracted more attention due to its superior characteristics such as high heat dissipation efficiency, well temperature uniformity and low risk of thermal runaway. To investigate the heat transfer characteristics of the liquid immersion cooling BTMSs, the 3D model of the 60-cell immersion cooling battery pack was established, and a well-established heat generation model that leveraged parameters derived from theoretical analysis and experiments was incorporated into the 3D simulation to analyze the thermal characteristics of battery pack. The simulation results showed that under the discharging rate of 2C, even with the lowest coolant flow rate in this work (0.2 L/min), no localized abnormal overheating within the battery pack was observed, and the highest temperature was 34.22 °C. The temperature uniformity within the battery pack improved with the increase of the coolant flow rate. It was recommended to maintain a flow rate above 0.5 L/min to ensure a temperature difference below 5 °C. The experimental apparatus of the immersion cooling battery pack was also developed to explore the heat dissipation and temperature uniformity at 2C discharge rate. The simulation results were in well agreement with the experimental results, with the deviation less than 0.43 °C when the flow rate exceeded 0.6 L/min. The effect of the localized high-rate discharge events (4.5C and 6.5C) at different battery pack locations on temperature distribution and uniformity was further discussed based on the verified 3D model. The results suggested that liquid immersion cooling systems offered promising potential for achieving both efficient heat dissipation and preventing thermal runaway in battery packs. [ABSTRACT FROM AUTHOR]

To address the bottleneck of easy leakage and low thermal conductivity of phase change materials (PCMs) for battery thermal management. Phase change composite (PCCs) with paraffin (PA) as the PCM, styrene ethylene butylene styrene (SEBS) as the supporting skeleton, and boron nitride (BN) as the thermally conductive filler were fabricated by the sacrificial template method. Compared with the composite prepared by melt-blending method, the thermal conductivity of PCC was improved by 27.6 % and the leakage rate was reduced by 82.4 % because the BN was rubbed with Na 2 SO 4 under the shear provided by internal mixer. As a result, the maximum temperature and maximum temperature difference of the battery pack with PCC cooling were 35.8 % and 62.5 % lower than those without PCC cooling at 2C discharge rate. In total, this work offers a strategy for improving the thermal conductivity and the leakage-proof ability of PCCs as well as for large-scale fabrication. [Display omitted] • The SEBS-BN@PA composites are prepared by the sacrificial template method. • The prepared composites have good leakage-proof ability and shape stability. • The composite has higher thermal conductivity than those prepared by melt-mixing method. • The composite presents excellent performances for battery thermal management. [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]

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

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]

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]

The introduction of a high-thermal-conductivity porous medium stands as an effective strategy for enhancing the heat transfer rate within battery thermal management using phase change material (PCM). In this study, we have delved into the investigation of heat transfer augmentation in battery thermal management through the implementation of toroidal porous medium. The exploration encompasses the effects of Rayleigh numbers, thicknesses of the toroidal porous medium, different kinds of porous medium and PCM. By comparing the liquid fraction, dynamic temperature and the latent heat ratio, we found the effect of Rayleigh number and thickness of porous medium on the property of the battery thermal management. The results indicate that by applying thicker toroidal porous medium could weaken the heat accumulation derived by high Rayleigh numbers. Case of d = 0.273R exhibits superior performance for a significant portion of the entire process compared to other cases with thickness of 0.235R, 0.326R, 0.408R and uniform distributed, while the dominant position is difficult to hold due to the heat accumulation. The conclusion is universal for different porous medium and PCM materials. The optimal distribution of porous medium should seek a balance between enhancing heat conduction and weakening thermal convection. A more scattered distributed porous medium could weaken the effect of heat convection and rises the latent heat ratio. [ABSTRACT FROM AUTHOR]

The performance of the battery is affected by temperature, and the battery thermal management (BTM) system consumes considerable energy to maintain the temperature in the suitable range. The unnecessary acceleration and deceleration of electric vehicles (EVs) during driving causes higher energy consumption in the powertrain. The emergence of connected and automated vehicle (CAV) technology provides an opportunity for predictive control of thermal and energy management. To explore the coordination optimization between battery thermal and vehicle energy management, this article proposes a two-level optimization framework for the speed and BTM of EVs, which improves energy efficiency and battery safety. Each level consists of a sequential optimization of speed and battery thermal. In the upper layer, speed planning based on iterative dynamic programming (IDP) is first proposed to reduce powertrain energy consumption using intelligent traffic information. Then, based on the BTM system and the battery thermodynamics features, the long-term optimal trajectory of the battery temperature is derived according to optimized speed. In the lower layer, the model predictive controllers (MPC) are designed to track reference speed and temperature trajectories in real-time and enforce energy saving. Meanwhile, to improve the prediction accuracy of the system model, we integrate the Gaussian process (GP) model in the MPC and build the learning-based MPC strategy. Simulation results verify the performance of the proposed method which reduces the powertrain energy consumption by 20.95%. In the high and low temperature environment, compared with normal MPC, PID-based and Rule-based, it reduces BTM energy consumption by up to 15.69%, 29.68% and 38.73%. [Display omitted] • A two-level optimization strategy is proposed for speed and thermal management. • Global reference trajectory of speed and battery temperature for connected and automated vehicle is planned. • Speed following and temperature tracking based on model predictive control are realized. • The Gaussian process model is integrated into the model predictive control to improve the estimation accuracy. [ABSTRACT FROM AUTHOR]

The use of a hybrid cooling system, which combines phase change material (PCM) and liquid channels, has been extensively researched to mitigate the risk of battery thermal runaway. However, the existing studies on hybrid cooling systems have overlooked the impact of buoyancy-driven natural convection in PCM. This results in a uniform flow rate allocation among liquid channels, leading to inadequate heat dissipation performance. To this end, this paper proposed a prediction-informed adaptive flow rate allocation strategy for the hybrid cooling system considering natural convection in PCM. First, a novel thermal runaway model was developed, followed by a PCM model that considers natural convection. Then, the proposed strategy utilized Bi-directional Long Short-Term Memory (Bi-LSTM) to predict the outlet temperature, which represents the cooling demand. The flow rate was regulated based on the predicted temperature to avoid an initial flow rate of 0 in the liquid channel and achieve a timely response. The results showed that the proposed strategy extended the thermal runaway propagation interval by 60.6% (85.9 s) and reduced the total flow rate by 31.7%. This strategy significantly enhanced the hybrid cooling system's performance, without increasing the parasitic energy or reducing the battery pack's energy density. • Prediction-informed strategy to enhance hybrid cooling systems' performance. • Adaptive flow rate regulation for hybrid cooling systems considering natural convection. • Novel coupled electrochemical–thermal model for thermal runaway analysis. [ABSTRACT FROM AUTHOR]

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

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

• 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]

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

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]

[Display omitted] • Surface modification of hBN was carried out, making hBN more compatible with matrix. • FPCMs with excellent overall performance have been prepared. • Induced SBS/LDPE cross-linking improves the high-temperature resistance of FPCMs. • FPCMs show much better battery thermal management performance. In battery thermal management (BTM), flexible phase change materials (FPCMs) emerge as highly promising substances, owing to their simple installment and low contact thermal resistance. However, FPCMs based on high thermal conductivity fillers and polymers always suffer from the enduring challenges of poor high-temperature resistance and poor filler-matrix compatibility. To solve these problems, a novel strategy is reported in this work, wherein FPCMs with excellent filler-matrix compatibility and satisfactory high-temperature resistance are synthesized by two steps: functionalizing the hexagonal boron nitride (hBN) surface and inducing the inter crosslinking between Styrene-Butadiene-Styrene(SBS) and Low-density polyethylene(LDPE). Vinyltrimethoxysilane (VTMS) molecules were introduced on the surface of raw hBN by hydroxylation and silanization surface modification to improve the compatibility of hBN with the matrix. Concluding from the results, the addition of 6.7 wt% LDPE doubled the high-temperature resistance of FPCMs, enabling them to maintain their structural integrity even at 200 °C for 1 h. The prepared FPCMs also exhibited higher thermal conductivity (increased by 20.5 %), low leakage rate (<0.6 wt% after 70 heating–cooling cycles), high enthalpy (122 J g−1), and strong adhesion (>0.1 MPa), etc. In terms of BTM performance, the FPCMs-based passive cooling BTM presents remarkable temperature control capabilities (maximum temperature reduction by 16.3 ℃) and uniform temperature performance (maximum temperature difference < 2.5 ℃). Collectively, this work will provide a promising approach for the fabrication of high-performance FPCMs in BTM and other thermal management applications for electronic devices. [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]

The era of electric mobility has started, and petrol/diesel vehicles are being replaced by electric vehicles (EVs). The phase change material (PCM) is a trending field of research in its application of energy storage and thermal management. PCM-based thermal management method is found to be quite simple and effective for battery packs. However, its commercialization is difficult due to its low thermal conductivity and extra weight addition to the battery pack. Hence, the present research focuses on the battery performance with PCM. The experimental setup for a 48V, 25Ah battery pack is developed, and its performance is explored with and without PCM. The numerical model for same sized battery pack is developed, and validated with experimental results. The major objective of the present research is to find the optimal gap between two battery cells so that a sufficient amount of PCM can be filled inside the battery pack. Initially, inline and staggered cell arrangements are examined, and no significant difference in thermal performance is found. Further, cell spacing of 5 mm, 3 mm, and 1 mm are examined, and maximum temperature and temperature difference are compared along with the weight and volume of the battery pack. For a single charging process, 1 mm cell spacing is found sufficient, considering the weight of the battery pack and thermal performance. However, with 1 mm cell spacing, temperature increases significantly after each charging and discharging. At the same time, 3 mm and 5 mm are found as feasible solutions considering single and double charging-discharging cycles, respectively. 3 mm cell spacing is better option when weight is a critical issue, while 5 mm cell spacing is better when thermal performance is a critical issue. The current study offers guidance in the advancement of battery packs, particularly in cases where space constraints are a concern. • The research focuses on utilization of optimal amount of PCM. • The battery charging experiments are carried out on 48V, 25Ah battery pack. • PCM OM42 reduced battery temperature by 18 %. • The inline and staggered arrangements are found equally effective. • 3 mm cell spacing is found sufficient with limited weight increment. [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]

A powerful thermal management scheme is the key to realizing the extremely fast charging of battery electric vehicles. In this scheme, a water-cooled plate is set at the bottom of the battery modules, which has a remarkable heat dissipation ability but increases the temperature difference between the top and bottom of the battery. This temperature difference problem is more obvious during the high-rate charge/discharge process; in particular, in the area of battery tabs, which are usually located far from the cooling plate, heat accumulates, risking thermal runaway. To address this problem, a thermal management method based on an ultrathin vapour chamber (UTVC) is proposed in this paper to improve temperature uniformity and reduce the highest temperature of batteries. According to the number of applied UTVCs, a unilateral UTVC (U-UTVC) and a bilateral UTVC (B-UTVC) cooling approach were presented, the effectiveness of which was verified by a set of thermal performance experiments. The test data show that the temperature differences in the batteries under the U-UTVC and B-UTVC schemes are 39.77% and 73.54% lower than those under the traditional method at a 25 °C ambient temperature and a 1.39C charge rate, respectively. The temperature difference on the battery surface with the B-UTVC scheme is approximately 3 °C at 25 °C and 40 °C ambient temperature. • An ultra-thin vapour chamber-based power battery thermal management is proposed to improve the temperature uniformity. • The methods have limited effect on battery volumetric specific energy, and the volumetric specific energy of battery is only reduced by 1.2% which is far less than reported investigations. • Temperature difference and maximum temperature of battery module of the presented scheme are reduced by 15.49% and 73.54%, respectively. [ABSTRACT FROM AUTHOR]

• High-stable CPCM for battery thermal management is prepared via one-pot strategy. • 3D nano-framework is in-situ constructed to obtain high shape stability of CPCM. • Nano-framework stacks into a developed mesoporous structure to suppress leakage. • The obtained CPCM shows outstanding cooling performance for the battery module. • No leakage trace is detected on the battery module during accelerated aging tests. Mainstream phase change material (PCM) for the thermal management of battery modules has been suffering from the leakage issue due to the weak capillary condensation from its micron-scaled polymer framework. Therefore, in this work, we design a high-stable and leakage-proof composite PCM (CPCM) by in-situ constructing a nano-scaled resorcinol-furfural polymer framework (RF-PF) in PCM via a one-pot strategy. Compared to classical micron-scaled framework of epoxy resin, the nano-scaled RF-PF stacks into a three-dimensionally mesoporous structure, and thus provides a much more intensive adsorbability towards PCM to prevent leakage. The mass retention rate of the RF-PF-based CPCM (RF-CPCM) during the leakage tests is up to 99.84 wt%. Combining with the suitable thermo-physical properties including a phase change enthalpy of 107.18 J g−1, phase change temperature region of 40– ∼ 55 °C and thermal conductivity of 1.58 W m−1 K−1, the RF-CPCM demonstrates effective and stable thermal management performances towards the pouch and cylindrical battery modules. For example, the temperature of the pouch battery module can be controlled below 41.15, 44.16 and 46.82 °C during 0.5-C, 1-C and 2-C discharges, respectively. During the accelerated aging test, the leakage trace appearing on the traditional CPCM module, is effectively overcome in the RF-CPCM module. [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]

The phase change immigration of flame retardant Composite Phase Change Material (CPCM), especially the temperature aging effect during multicycle process, greatly restricted its application in power battery pack of electric vehicle and energy storage system. In this study, the properties of flexible flame-retardant CPCMs before and after temperature aging were investigated, and the battery thermal management effects of battery modules were compared. The results revealed that flexible CPCMs with styrene block copolymers exhibited little volume change owing to their elastic and anti-leakage properties, effectively alleviating flow and agglomeration. In addition, battery modules with flexible flame-retardant CPCMs exhibited prominent battery thermal management. These mechanisms in flame-retardant CPCMs can profoundly affect the design and preparation of multifunction CPCMs, providing novel insights into passive thermal management of battery systems. [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]

The phase change immigration of flame retardant Composite Phase Change Material (CPCM), especially the temperature aging effect during multicycle process, greatly restricted its application in power battery pack of electric vehicle and energy storage system. In this study, the properties of flexible flame-retardant CPCMs before and after temperature aging were investigated, and the battery thermal management effects of battery modules were compared. The results revealed that flexible CPCMs with styrene block copolymers exhibited little volume change owing to their elastic and anti-leakage properties, effectively alleviating flow and agglomeration. In addition, battery modules with flexible flame-retardant CPCMs exhibited prominent battery thermal management. These mechanisms in flame-retardant CPCMs can profoundly affect the design and preparation of multifunction CPCMs, providing novel insights into passive thermal management of battery systems. [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]

Improper battery temperature will lead to reduced battery discharge efficiency and electric vehicle driving range. Endeavors to find an efficient and precise battery temperature control method for the transcritical CO 2 thermal management system of electric vehicles, two evaporation temperature control methods for battery cooling were proposed. First, the effects of the control methods on battery temperature, optimal discharge pressure and coefficient of performance (COP) were simulated under typical operating conditions. Subsequently, a comparative simulation was conducted on the battery temperatures and COP of the two control methods under full cooling conditions. The results revealed that equal evaporation temperature control induced a reduction in battery temperature to 11 °C (suboptimal levels) under conditions of low ambient temperature and vehicle speed. Conversely, while unequal evaporation temperature control could maintain the battery temperature within the optimal range of 20–45 °C, it would result in a maximum COP drop of more than 20% under certain conditions. Furthermore, the effects of the two control methods on driving range under different ambient temperatures and vehicle speeds were studied. The reasults indicated that the ultimate influence of uneuqal evaporation temperature control on the quarterly average driving range was virtually negligible, peaking at 1.35%. Given the dual-objective constraints pertaining to the driving range and the battery cooling performance, it was concluded that uneuqal evaporation temperature control was the optimal choice for direct battery cooling. • A transcritical CO 2 battery direct cooling thermal management cycle is studied. • The effects of battery temperature controls on driving range of EVs are evaluated. • Coupling effects of operation conditions and controls on driving range of EVs is revealed. • The optimal option for battery temperature control is recommended. [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]

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

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]

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

• 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]

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]

• 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]

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

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

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

Aiming at the problems of irreversible decay and shortened life of the battery caused by high temperature during the operation of power battery pack, a novel composite phase change material based on metal-organic framework (MOF) was proposed in this work. MIL-101-NH 2 , an amino functionalized MOF material, was grown in situ on expanded graphite (EG) to synthesize hierarchical structure-based loading material for efficient loading of phase change material lauric acid (LA). The microstructure and structure of the composite phase change materials, thermal properties such as phase change temperature and latent heat, thermal conductivity, thermal stability, thermal cycling properties, as well as thermal stability and thermal cycling properties were tested. The results show that amino functionalization of the loading materials is helpful to further improve the loading rate and latent heat of the composite phase change materials. LA/MIL-101-NH 2 and LA/EG@MIL-101-NH 2 can be loaded up to 70% and have high phase change latent heat (97.74 J/g and 94.55 J/g). When applied to battery thermal management, LA/EG@MIL-101-NH 2 can reduce the battery temperature by 4.5–22.3% under the discharge conditions of 1C, 2C, 3C, 4C and the cycle condition, and keep the safe temperature below 50 °C, which provides a new idea for passive thermal management of batteries. • A composite phase change material based on metal-organic skeleton is proposed. • Thermophysical parameters of composite phase change materials is tested. • A new idea for passive thermal management of batteries is provided. [ABSTRACT FROM AUTHOR]

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

Thermal management of power battery is important to ensure the safety of electric vehicle. Coupling phase change materials (PCMs) with liquid cooling technology is an efficient temperature uniformity strategy. In this paper, a self-made microencapsulated PCM (MPCM) was used to prepare MPCM slurry (MPCMS), and three base liquids (water, ethanol, and silicone oil) were evaluated, which confirmed that the silicone oil could maintain slurry without sedimentation for 7 days, providing the best stability. Also, graphene (GE) was introduced to increase the heat transfer rate of slurry. Then the prepared slurries were applied to the prismatic lithium-ion battery module to verify their thermal management performance. The results indicated that the prepared slurries' latent heat, thermal conductivity, and specific heat capacity were all rose with the increase of MPCM concentration. In addition, the slurries' viscosity changed little when the concentration was below 40 wt%. Compared with the blank module, GE-MPCMS-Si could reduce the battery module temperature and the temperature variance by 14.49 °C and 3.8 °C2, respectively. Besides, the influence of flow rate was further investigated, which showed 6 mL/s is the most economical and efficient flow rate option. • Phase change microcapsule slurry was prepared for battery thermal management. • The stabilities of slurries with three base liquids were compared. • The thermal performance of the slurry was raised by introducing graphene. • Prepared slurry can reduce the maximum temperature and improve uniformity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The single battery model is representative of the battery module at large flow rate. • Characteristic melting stages are identified for novel conjugated cooling of battery module. • Conjugated cooling can significantly reduce the battery temperature and ramp-up rate. • Increasing thermal column size or heat spreading plate thickness improves heat dissipation significantly. • Good agreement is found between numerical analysis and experimental test. Abstract A novel conjugated cooling configuration using phase change material (PCM) and liquid cooling techniques is proposed, and its thermal performance is investigated for a battery module. 106 cylindrical batteries are connected to the cold plate at the bottom through a heat spreading plate and the adjacent thermal columns, with PCM filled in between the gaps, which forms the cooling configuration. Three-dimensional numerical models are established for the cooling of the representative battery and battery module, which includes the battery connected to a liquid cooled mini-channel cold plate through the heat spreading plate and thermal column structures. The thermal characteristics of the battery incorporating the PCM melting and liquid cooling are examined at large flow rate. The geometrical parameters such as the size of the thermal column, the thickness of the heat spreading plate and the spacing of the batteries are investigated for the present conjugated cooling configuration. Both the battery temperature ramp-up rate and the steady-state battery temperature are significantly reduced by the conjugated cooling, in comparison with single PCM or liquid cooling conditions. The effects of various structure parameters on the thermal performance can be visualized by plotting the working time t 50 vs the heat density based on the PCM volume. A comparison of the numerical simulation with the preliminary experiment work shows good agreement. This work can be useful in the design of conjugated configurations for the battery thermal management. [ABSTRACT FROM AUTHOR]

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