Design Of Thermal Management System Research Articles

Integrated design of multi-circuit thermal management system with battery waste heat utilization for new energy vehicle and performance assessment

A multi-circuit integrated thermal management system for new energy vehicle is proposed to realize the different coupling relationship between the heat exchanger for the cabin and the chiller for the battery through the four-way reversing valves and the solenoid valves. The effects of circuit selection, ambient temperature, driving test conditions and waste heat utilization on thermal management performance are discussed. The results indicate that thermal management can be carried out through three circuits in the system for heating conditions. The cabin is heated first in Circuit 1 and Circuit 3, while the battery has a higher priority in Circuit 2. The energy consumption in Circuit 1 is close to that in Circuit 2 at different ambient temperature. Compared with the other two circuits, Circuit 3 is more power-efficient, with energy consumption reduced by 14.81 %, and energy efficiency increased by 0.11 and 0.13 respectively at 10 °C of ambient temperature. The thermal management performance of Circuit 2 is least affected by the driving test conditions, and the maximum time difference of battery heating completion under different conditions is 284 s. High vehicle speed is beneficial to the waste heat utilization of the battery, for intense driving conditions, the energy consumption reduction ratio in Circuit 1 and Circuit 2 is more than 19.50 % and exergic efficiency is increased by more than 1.01 % in each circuit. Circuit 1 and Circuit 2 are better for intense driving conditions, and Circuit 3 is a good choice for urban driving conditions.

Promotion of practical technology of the thermal management system for cylindrical power battery

Amidst the industrial transformation and upgrade, the new energy vehicle industry is at a crucial juncture. Power batteries, a vital component of new energy vehicles, are currently at the forefront of industry competition with a focus on technological innovation and performance enhancement. The operational temperature of a battery significantly impacts its efficiency, making the design of a reliable Thermal Management System (TMS) essential to ensure battery safety and stability. Cylindrical power batteries are widely utilized in the industry. This article outlines the four main structures and their drawbacks of TMS for cylindrical power batteries. Among these structures, air cooling falls short in meeting high heat dissipation requirements. Liquid cooling is expensive, intricate, and adds considerable weight. Phase Change Materials (PCM) are not yet prevalent in practical applications. Similarly, heat pipes are relatively uncommon in large high-power battery packs. To better align with the new energy vehicle industry’s demands for top-notch performance, cost-effectiveness, eco-friendliness, and reliability, this paper strongly recommends delving deeper into composite cooling solutions. The construction of an economically viable and fully optimized composite cooling method is poised to become a significant scientific challenge for future research endeavors.

Wave and straight plenum effects on thermal management system performance

The need to offset heat generated by batteries in electric vehicles (EVs) necessitated the design and development of battery thermal management systems (BTMS), one of which adopt air cooling technique. The redesign of plenums of the BTMS has been beneficial in the enhancement of the BTMS's performance. In view of these, this study considered wave and straight design of plenums in an attempt to enhance the performance of the system. The proposed designs were investigated using Computational Fluid Dynamics (CFD) methodology. The CFD methodology was validated by first investigating the conventional Z-design of BTMS with straight plenums and the results were compared with existing results from experiments in literature. Findings from the study revealed that by replacing straight-horizontal plenum with straight-inclined plenum, maximum temperature (Tmax), and maximum temperature difference (ΔTmax) of the Z-design was reduced by 3.47 K and 6.82 K, respectively, with increase in pressure drop (ΔP) by 2.24 Pa and pumping power (Pp) by 0.01 W.Furthermore, by adopting wave-inclined plenum design, Tmax, and ΔTmax were reduced by 4.61 K and 8 K, respectively when compared with the conventional Z-design BTMS. More so, the pressure drop (ΔP) and pumping power (Pp) increased by 3.17 Pa and 0.0133 W, respectively. The study generally revealed that careful redesign of divergence plenum with inclined straight and wave-like structure will enhance the thermal performance of BTMS.

Hybrid cooling system with phase change material and liquid microchannels to prevent thermal runaway propagation within lithium-ion battery packs

Thermal runaway propagation in battery pack can cause catastrophic hazards without timely countermeasures. This paper presents the establishment of lumped thermal resistance model for battery pack and introduces an innovative hybrid thermal management system designed to suppress thermal runaway propagation. First, a heat generation model describing the reaction dynamics of cell thermal runaway is developed and validated by experiment. Subsequently, a lumped thermal resistance network is formulated for the large-scale battery pack using electrical circuit elements and simulation studies for the thermal runaway propagation are carried out. The results reveal that the thermal runaway propagation progress triggered by four cells can accelerate by nearly 40 % compared to that initiated by a single cell. Consequently, a hybrid thermal management incorporating phase change material and liquid microchannels is designed. Comparative analysis with individual cooling systems demonstrates the superior effectiveness of the proposed system in suppressing the first round of thermal runaway propagation. The temperatures of neighbor cells only have a marginal climb to about 80 ℃ in the initial 600 s, which is well below the thermal runaway triggering temperature. This work can provide valuable insights into the structural design of thermal management systems for battery packs in practical applications.

Exploring the reactivity of Na3V2(PO4)3/C and hard carbon electrodes in sodium-ion batteries at various charge states

The interest in post-lithium batteries as an alternative to lithium-ion batteries boosted recently due to their substantial abundance, low cost, inherent safety, and sustainability. In recent years, the crucial need for the improvement of battery safety has been emphasized and safety remains a critical barrier for post-lithium technology. Therefore, the thermal stability and reaction enthalpies of electrochemically de-sodiated sodium vanadium phosphate (Na3V2(PO4)3/C) positive electrode and commercial coconut-shell derived hard carbon (HC) at various states of charge (SOCs) were systematically investigated. This study employed the 3D Tian-Calvet calorimeter (C80) and thermogravimetric analysis coupled with mass spectrometry (TGA-MS), to gain comprehensive insights into the thermodynamic aspects of these materials. Thermal stability of electrode materials at distinct sodiation / de-sodiation states draws great attention in cell design and is one of the reasons for the strong state of charge (SOC) dependence of the thermal runaway phenomenon, which represents the most critical safety issue for batteries. This combined experimental approach provides a comprehensive understanding of thermal stability and associated reactions in both, sodium vanadium phosphate (NVP) and hard carbon (HC) electrodes. NVP/C reacts with the electrolyte between 150 and 300 °C, releasing ∼400 J/g heat, although it thermally decomposed beyond 150 °C. The sodiated HC initiates decomposition at 100 °C, releasing ∼750 J/g heat in two steps in a reaction to the electrolyte. These data can facilitate optimizing the design of thermal management systems according to the cell's thermal performance.

Heat transfer performance of copper foam/paraffin composite phase change material under different centrifugal forces-A visual experimental study

Copper foam is used to enhance the heat transfer of phase change material (PCM) due to its high thermal conductivity. However, its porous structure can restrict the convection of PCM. The natural convection of PCM embedded in copper foam under external force remains unclear. A visual experimental system was established to investigate the effect of copper foam on the heat transfer process of PCM under external force. The phase interface, temperature distribution, and heat storage rate of composite PCM (CPCM) were conducted under centrifugal forces from -5 g to 5 g. Results indicate that there is a significant difference in the melting rate and temperature distribution of PCM under different forces. Under forward force, the convection of PCM is inhibited, and the isotherm is parallel to the end-state isobars line, increasing the total melting time of CPCM and creating a large temperature gradient near the heat source. Conversely, under the backward force, the melting rate of CPCM is increased due to the enhanced natural convection of liquid PCM. The development of isotherms is influenced by buoyancy, which results in a more uniform temperature distribution of CPCM. However, the enhancement effect of the backward force is limited when it exceeds -3 g. In general, CPCM exhibits more apparent improvement in heat transfer performance under the backward force. This article provides references for the optimization design of thermal management systems.

Design and optimization of battery and thermal management system for AC photovoltaic energy module

The utilization of renewable energy sources has increased due to concerns about climate change. However, injecting the power from renewable energy sources into grid-tied systems is challenging. The techno-economic analysis a photovoltaic (PV) energy systems is investigated. As a result, this paper presents AC-PV module for Grid-Tied and Off-Grid Scenarios via optimization, modeling, and test results. Even though the output of a PV panel is DC voltage, a three-port inverter and a lithium-ion battery pack are integrated with the back of the PV panel. They are packaged as a PV system module that makes the module output have AC voltage. Therefore, an optimized AC-PV module can be a solution for residential and commercial use, which are grid-tied systems; it can be very efficient for those without access to electricity, which is an off-grid system. An integrated battery and thermal management strategy is crucial for this AC-PV module. In the article, the battery capacity optimization, the electrical and the thermal model of the battery pack, battery heat generation model are discussed by using stochastic analysis techniques; the battery test results are also obtained to identify the models’ parameters and a control algorithm is proposed to extract the battery information such as temperature, current, voltage, SoC and SoH of the battery pack.

Research and evaluation of the arrangement of heat exchangers in electric vehicle thermal management systems for CO2 refrigerant

The application of transcritical CO2 cycle in the thermal management system of electric vehicles has become increasingly prevalent, but the existing thermal management system architecture has not been optimized to specifically enhance the performance of CO2 refrigerant. This paper analyzes the impact of various heat exchanger arrangements on CO2 thermal management system and evaluates system configurations based on a new performance index, cycle coefficient of performance. The effects of air temperature, ambient temperature, and heat load on system performance are conducted with a high precision model. The chiller is connected in parallel-series with indoor heat exchangers, resulting in a maximum coefficient of performance improvement of 27.89% at an indoor air inlet temperature of 10 °C, and a maximum coefficient of performance improvement of 21.69% at an ambient temperature of 5 °C, under simultaneous heating conditions. The radiator is placed on the windward of gas cooler, leading to a maximum coefficient of performance increase of 4.85% in heating mode, but a maximum coefficient of performance decrease of 9.84% in cooling mode. The evaluation of these configurations across different operating cycles reveals that the parallel-series connection is well-suited for the new European driving cycle, showing an 18.4% improvement in cycle coefficient of performance compared to the series-parallel connection. The windward arrangement of radiator proves effective for highway fuel economy test cycle in winter and the new European driving cycle in summer. This study provides effective instruction for configuration design and evaluation of transcritical CO2 vehicle thermal management systems.

Optimization design of a hybrid thermal runaway propagation mitigation system for power battery module using high-dimensional surrogate models

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.

Electro-thermal performance evaluation of a prismatic battery pack for an electric vehicle

Abstract In recent years, electric vehicles (EVs) have grown in popularity as a viable way to reduce greenhouse gas emissions by replacing conventional vehicles. The need for EV batteries is steadily increasing. An essential and expensive part of electric transportation is the battery. The operating temperature of the lithium-ion (Li-ion) battery significantly impacts the performance of the EV battery pack. Battery packs undergo temperature fluctuations during the charging and discharging procedures due to internal heat generation, necessitating an examination of the temperature distribution of the battery pack. The geometrical spacing between cells is considered larger and identical and is kept open on two sides for free air circulation. A novel battery thermal management system (BTMS) design is required to effectively dissipate heat from the prismatic battery pack module. The electro-thermal behaviour of the prismatic Li-ion battery pack module was investigated based on the high charge/discharge rate. This study presents the development of a three-dimensional free open-source OpenFOAM computational fluid dynamics model for prismatic cell battery packs that simulates heat generation, air flow field, and temperature distribution across the width and depth of the battery pack module. The prismatic battery pack simulation results are compared with the experimental and simulation results of the cylindrical battery pack. It was also revealed that prismatic cells generate more heat on the backside, requiring battery packs to have increased cooling and space between individual cells to ensure sufficient air circulation for cooling and gas removal. The BTMS is improved by designing with increased space among the prismatic battery cells as compared with the conventional prismatic cell battery pack design.

Performance Analysis of Wet Porous Moving Fin under the Influence of Spherical Shaped TiO2- Ag Hybrid Nanoparticles in a Water Based Fluid

The study investigates the flow characteristics of spherical shaped TiO2 –Ag hybrid nanofluid with water as a base fluid passing through a wet porous rectangular moving fin with a focus on understanding the effects of nanoparticle concentration on the heat transfer rate. The fin under consideration are subjected to boundary conditions, insulated and convective tips. Hybrid nanofluid that combine nanoparticles with conventional base fluids have potentially enhanced thermal conductivity and heat transfer properties in engineering applications. The energy balance equation containing the parameters that effect the flow of heat transfer rate is non- dimensionalized and solved numerically using 3-stage Lobatto - IIIa formula with appropriate boundary conditions. The simulation result shows the impact of different parameters on the flow and heat transfer properties of the hybrid nanofluid obtained by mixing spherical shaped TiO2 –Ag hybrid nanoparticles with water as base fluid. It is observed that the fin shows significant heat transfer rate in a convective tip relative to an insulated tip. The findings contribute to the understanding of hybrid nanofluid flow and its potential application in the design and optimization of thermal management system. It also facilitates the ground work for research in the field of nano fluid based cooling system. The observation from the graphical illustration shows that the rise in the thermal conductivity of the base fluid by 23% increases the conduction heat transfer as well as the temperature distribution by 10%. The natural convection and radiation are the key parameters that determines the heat transfer rate from the surface to the surrounding. In our investigation, enhancing the Nc,Nr parameters by 50% and 25%, the temperature distribution profile is reduced by about 13% and 6% respectively. The increase in the Pe number by 100% results in a rise in the temperature distribution by 8%.

Simulation of an aircraft thermal management system based on vapor cycle response surface model

The modern aircraft Thermal Management System (TMS) faces significant challenges due to increasing thermal loads and limited heat dissipation pathways. To optimize TMS during the conceptual design stage, the development of a modeling and simulation tool is crucial. In this study, a TMS simulation model library was created using MATLAB/SIMULINK. To simplify the complexity of the Vapor Cycle System (VCS) model, a Response Surface Model (RSM) was constructed using the Monte Carlo method and validated through simulation experiments. Taking the F-22 fighter TMS as an example, a thermal dynamic simulation model was constructed to analyze the variation of thermal response parameters in key subsystems and elucidate their coupling relationships. Furthermore, the impact of total fuel flow and ram air flow on the TMS was investigated. The findings demonstrate the existence of an optimal total fuel flow that achieves a balance between maximizing fuel heat sink utilization and minimizing bleed air demand. The adaptive distribution of fuel and ram air flow was found to enhance aircraft thermal management performance. This study contributes to improving modeling efficiency and enhancing the understanding of the thermal dynamic characteristics of TMS, thereby facilitating further optimization in aircraft TMS design.

Optimization Design and Thermodynamic Analysis of Thermal Management System for New Energy Vehicle Power Batteries

Optimization Design and Thermodynamic Analysis of Thermal Management System for New Energy Vehicle Power Batteries

Experimental study on the thermal management performance of lithium-ion battery with PCM combined with 3-D finned tube

As an important intermediary between the green energy and human society, the lithium-ion battery has promising prospects in the new energy vehicles, energy storage, and green development fields. However, lithium-ion batteries can generate a large amount of heat during operation. In addition, excess temperature or big temperature difference of the surface of the lithium-ion battery can reduce its performance, which also results in reducing its operational life and even triggers incidents such as fires and explosions. Therefore, studying efficient thermal management methods for lithium-ion batteries is crucial for increasing their application range. This paper proposes a novel thermal management method by combining 3-D finned tubes with PCM. The thermal management system maintains a battery operating temperature less than 45 °C and a maximum temperature difference less than 2.4 °C. The influence of different fin structure parameters on the melting dynamics of PCM and the heat transfer performance is then discussed. The obtained results show that under each solid–liquid ratio of PCM, the heat transfer performance increases with the increases of the fin height, while it initially decreases and then increases with the increase of the width and axial spacing. Moreover, the heat transfer performance of the 3-D finned tube with different PCM liquid–solid ratios is investigated. The obtained results demonstrate that for constant fin parameters, the heat transfer reaches its highest performance for a PCM liquid–solid ratio greater than 2:2. The findings of this study lay a foundation for the design of efficient thermal management systems incorporating PCM applications.

An Overview of the Recent Advances in Pool Boiling Enhancement Materials, Structrure, and Devices.

This review attempts to provide a comprehensive assessment of recent methodologies, structures, and devices for pool boiling heat transfer enhancement. Several enhancement approaches relating to the underlying fluid route and the capability to eliminate incipient boiling hysteresis, augment the nucleate boiling heat transfer coefficient, and improve the critical heat flux are assessed. Hence, this study addresses the most relevant issues related to active and passive enhancement techniques and compound enhancement schemes. Passive heat transfer enhancement techniques encompass multiscale surface modification of the heating surface, such as modification with nanoparticles, tunnels, grooves, porous coatings, and enhanced nanostructured surfaces. Also, there are already studies on the employment of a wide range of passive enhancement techniques, like displaced enhancement, swirl flow aids, and bi-thermally conductive surfaces. Moreover, the combined usage of two or more enhancement techniques, commonly known as compound enhancement approaches, is also addressed in this survey. Additionally, the present work highlights the existing scarcity of sufficiently large available databases for a given enhancement methodology regarding the influencing factors derived from the implementation of innovative thermal management systems for temperature-sensitive electronic and power devices, for instance, material, morphology, relative positioning and orientation of the boiling surface, and nucleate boiling heat transfer enhancement pattern and scale. Such scarcity means the available findings are not totally accurate and suitable for the design and implementation of new thermal management systems. The analysis of more than 100 studies in this field shows that all such improvement methodologies aim to enhance the nucleate boiling heat transfer parameters of the critical heat flux and nucleate heat transfer coefficient in pool boiling scenarios. Finally, diverse challenges and prospects for further studies are also pointed out, aimed at developing important in-depth knowledge of the underlying enhancement mechanisms of such techniques.

Investigation on the heat generation and heat sources of cylindrical NCM811 lithium-ion batteries

High temperature may cause the degradation of capacity and lifespan for the batteries, and even possibly triggers the thermal runaway. Therefore, in order to safe use of batteries, investigation on the heat generation characteristics of lithium-ion batteries is essential to guard the design of thermal management system (TMS). In this work, the heat generation rate (HGR) and heat sources of the 18650 NCM811 battery is investigated by both the isothermal calorimetry test and calculation using the modified Bernardi model, respectively. It is revealed that during charging or discharging, the irreversible heat increases rapidly at low SOC due to large internal resistance, while the reversible entropic heat becomes more important at about 40–60 % SOC due to high entropy coefficient therein. Moreover, the ratio between heat sources has been revealed. The irreversible heat is dominated among the heat sources during charging/discharging with a proportion of 76.33–96.65 %. Wherein, the ohmic heat contributes the most heat generation. Meanwhile, the reversible heat accounts for the smallest proportion of 3.25–23.67 %. It should be noted that current is the main influence factor to the HGR of the lithium-ion battery. With increasing the current, the irreversible HGR, especially ohmic heat, increases much faster than that of reversible heat, resulting in higher ratio. The calculation data are validated to be well consistent with experimental results, giving insights to the investigation of the heat generation of the lithium ion battery.

Experimental study on 18650 lithium-ion battery-pack cooling system composed of heat pipe and reciprocating air flow with water mist

Lithium-ion batteries (LIBs) are critical power sources for portable devices, electric vehicles, power grids, and energy-storage systems. Effective thermal management is mandatory for achieving optimal battery performance. Although the air-cooling method has been investigated extensively owing to its simple structure, convenient maintenance, and low cost, it is insufficient for cooling large-scale battery packs because of its limited air-cooling capacity and unsatisfactory temperature uniformity. Thus, a reciprocating spray cooling system comprising a reciprocating air flow channel, heat pipe array, and spray nozzle is proposed herein for the efficient cooling of 18,650 LIB packs. The effects of the inlet air speed, spray frequency, and spray duty cycle on the cooling performance of the reciprocating mist cooling system and the corresponding optimal operating parameter range are analyzed. Additionally, the competitive mechanism between forced air convection and evaporative cooling is discussed. The results indicate that, compared with the case of natural convection cooling, the temperature increment of the battery pack decreases by 32.1 % under reciprocating mist cooling. Meanwhile, the maximum temperature difference reduces to approximately 3.41 °C with 3C of discharge. The spray frequency minimally affects the overall heat dissipation but induces surface temperature fluctuations in individual batteries. Increasing the spray duration per 10 s in a single spray duty cycle can reduce the average temperature of the battery pack by approximately 2 °C. Additionally, the power-allocation scheme affects the heat dissipation of the system. Decreasing the flow rate of spray cooling water and increasing the inlet air speed promote the evaporation of water mist inside the system, thus further improving heat dissipation. This study provides new insights into the design of air-cooled thermal management systems for battery packs.

Neural network and physical enable one sensor to estimate the temperature for all cells in the battery pack

The performance of lithium-ion batteries (LIBs) is sensitive to the operating temperature, and the design and operation of battery thermal management systems reply on accurate information of LIBs' temperature. This study proposes a data-driven model based on neural network (NN) for estimating the temperature profile of a LIB module. Only one temperature measurement is needed for the battery module, which can assure a low cost. The method has been tested for battery modules consisting of prismatic and cylindrical batteries. In general, a good accuracy can be observed that the root mean square error (RMSE) of esitmated temperatures is less than 0.8 °C regardless of the different operating conditions, ambient temperatures, and heat dissipation conditions.

A numerical and statistical study to determine the effect of thermophysical properties of phase change material for lithium-ion battery thermal management

Lithium-ion batteries’ performance is quite sensitive to temperature, leading to capacity fade, acceleration of aging effect, and possible thermal runaway. The temperature of lithium-ion batteries increases under operating conditions of high discharge rates. The heat released by the battery can be effectively removed using phase change material (PCM). The thermophysical properties of the PCM affect the heat removal performance of the PCM. In this study, the effect of thermophysical parameters such as thermal conductivity, latent heat, specific heat, and density on maximum battery temperature and battery temperature uniformity was numerically investigated. The dominant factors for PCM to prevent temperature increase in a prismatic LiMn2O4 lithium-ion battery were identified by orthogonal design to improve the thermophysical properties of PCM. The thermophysical properties of PCM were changed by incorporating the expanded graphite. Based on what was observed in the current study, the influence of the thermal conductivity of PCM was higher than other thermophysical properties, while the influence of the latent heat on both maximum battery temperature and temperature uniformity was negligible. Density was the second crucial factor that could help reduce the maximum battery temperature and keep the temperature distribution uniform. The results obtained from this study can allow the design of effective battery thermal management systems by improving the thermophysical properties of the PCM.

Investigations of Li-Ion Battery Thermal Management Systems Based on Heat Pipes: A Review

Investigations of Li-Ion Battery Thermal Management Systems Based on Heat Pipes: A Review