Thermal Management Technologies Research Articles

Two-Phase Cooling System for Electric Vehicle Battery Based on a 3D Pulsating Heat Pipe

The primary objective pursued in this research is the creation and thorough evaluation of an inventive cooling system designed to uphold optimal temperatures within the batteries employed in electric vehicles. Nowadays, the prevailing equipment underpinning electrical motion hinges on Lithium-Ion cells. These cells frequently necessitate the expeditious delivery of substantial power, thereby giving rise to a consequential generation of heat. Consequently, there is an emergence of elevated operational temperatures, potentially causing noteworthy declines in battery performance, or, in extreme cases, operational failures. Furthermore, deviating from the recommended temperature range (20–40 °C) significantly expedites the aging process of the battery and elevates the probability of premature malfunction. In response to these crucial challenges, the implementation of a battery thermal management system assumes a pivotal role in maximizing battery efficiency. Within the framework of this investigation, we propose the adoption of a cooling system founded on a three-dimensional pulsating heat pipe as the designated thermal management technology for a battery pack. The preliminary phase of our study involved the assessment of the suggested pulsating heat pipe’s performance. Following this, the efficacy of the pulsating heat pipe is subjected to rigorous scrutiny through practical experimentation on an authentic electric battery. The empirical findings conclusively highlight the substantial cooling capacity of the proposed system, thereby presenting a robust and efficacious solution for the thermal management challenges faced by electric vehicle batteries.

Optimization and working performance analysis of liquid cooling plates in refrigerant direct cooling power battery systems

Refrigerant direct cooling is currently being considered as an efficient thermal management technology in power battery systems. In this paper, four types of liquid cooling plates for power battery modules are designed and the computational model is constructed. With the model being validated, it is applied to analyze the effects of the cooling plate structure and cooling channel on the cooling and heat dissipation performances. The results reveal that for the conventional cooling method, i.e., when the cooling plate is placed on the bottom of the battery pack, a significant temperature gradient in the vertical direction is observed. On the contrary, adopting a serpentine cooling plate structure in the main wall or parallel cooling channels in the narrow side wall could significantly reduce the temperature difference of the battery pack, which can keep the temperature difference within 5 °C even under extreme conditions. Further, a detailed analysis of the heat dissipation performance based on the optimal cooling plate structure is performed to determine the safe operating range of the battery pack. It is shown that as the humidity is less than 0.73 and the evaporation temperature is below 15.43 °C, the battery pack can operate safely. However, beyond this condition range the heat dissipation characteristics of the battery pack cannot satisfy the operating requirements. This work sheds light upon the potential of refrigerant direct cooling strategy in power battery thermal management systems by properly arranging the cooling plate.

Recent advancements in thermal management technologies for cooling of data centers

Recent advancements in thermal management technologies for cooling of data centers

Analysis on battery thermal management system based on flat heat pipe at high discharging rate

Power batteries are the core power source for electric vehicles. However, battery thermal management technology for electric vehicles will face more severe challenges in the future. Flat heat pipe has gradually received much attention in the field of battery thermal management due to its high heat conduction coefficient and lightweight structure. This paper focuses on the influence of flat heat pipe structural parameters on battery thermo-electrical performance by establishing simulation model of the battery cooling system, which makes contribution to the flat heat pipe structure design on optimizing battery overall performance. Based on the mechanism of working medium flow effect of flat heat pipe on the battery electrochemical heat generation, a coupled model of flat heat pipe-based battery system is established according to the relationship between battery electrochemical heat generation performance and flat heat pipe heat transfer characteristics. The accuracy of system model is further verified by experiment, and the battery thermo-electrical characteristics under different discharging conditions is simulated. The flat heat pipe-based battery thermal management system can effectively reduce the battery maximum temperature while improving the uniformity of battery temperature and state of charge (SOC). The reduction of the vapor chamber thickness causes the uneven distribution of vapor thermal resistance, so the battery maximum temperature and maximum temperature difference will become larger, which will further cause the uneven distribution of battery internal resistance, and this will finally increase the non-uniformity of battery module discharging current distribution. A structural design method of the flat heat pipe-based battery thermal management system is developed with the battery thermo-electrical coupling performance as the design objective and the flat heat pipe structural parameters (total thickness, vapor chamber thickness, total length) as the optimization variables. Compared with the original scheme, the battery maximum temperature can be reduced by 6.4% under transient high-rate discharging conditions with the modified flat heat pipe based on the proposed design method, while the battery maximum temperature and SOC difference can also be reduced by 18.4% and 16.3%, respectively.

Instability analysis of pressure drop and flow characteristics in mini-channel heat sink with phase-separated configuration

Improving flow boiling stability is crucial for ensuring the safety in fields such as thermal management and microfluidic technology. Based on vapor–liquid separation analysis, multiple-pore phase-separated configurations have been proven to effectively enhance the stability of flow boiling in mini-channels. However, these structures primarily focus on expelling vapor from the mini-channel outlet, and vapor–liquid separation between adjacent mini-channels has not been addressed. In order to enhance and quantitatively analyze the vapor–liquid separation effect of phase-separated configurations, three phase-separated configurations with porous permeable membranes are prepared and experimentally studied in counter-flow mini-channel heat sinks: multiple-pore phase-separated configuration, sparse-pore phase-separated configuration, and poreless phase-separated configuration. The study found that phase-separated configurations effectively achieve vapor–liquid separation between adjacent mini-channels, thereby improving vapor–liquid distribution within the channels. Compared to sparse-pore and poreless phase-separated configurations, the multiple-pore phase-separated configuration offers greater advantages in enhancing the flow stability of mini-channel systems. Among them, the multiple-pore phase-separated configuration shows a maximum reduction of 24.71 % in the two-phase flow pressure drop, and with the increase in heat flux, this reduction becomes more pronounced compared to the conventional poreless structure. Additionally, the vapor permeation parameter X for the multiple-pore phase-separated configuration is increased by 27.66 % compared to the sparse-pore phase-separated structure, indicating a higher vapor transfer rate per unit time for the multiple-pore phase-separated structure. Simultaneously, the potential physical mechanisms underlying the suppression of flow instability in mini-channels by phase-separated structures are discussed in this study.

Flexible phase change film with motion sensing and tactile recognition for wearable thermal management

Phase change materials (PCMs) have gained significant interest in personal thermal management technologies owing to high latent heat capacity and isothermal phase transitions. However, achieving simultaneous thermal and wearing comfort remains a formidable challenge due to their solid rigidity and liquid leakage. In this work, a polyetheramine-based conductive phase change film was developed by introducing ion transport network and tetradecanol as phase change components encapsulated within the skeleton network. The film possesses adjustable heat storage density (79.5–163.4 J/g) and exceptional flexibility at room temperature. On the basis of desirable thermal regulation ability and ideal wearability, the film was successfully applied in the personal thermal management field and effectively regulated the human body temperature. Moreover, the film realized human motion sensing and object tactile recognition in real time with construction of the inner ion transport channels. This successful exploration provides a promising and scalable route towards intelligent wearable thermal management.

The role of crystallization and annealing on the thermal conductivity of material extrusion additively manufactured parts

Despite the significant research being conducted on the mechanical reliability of additively manufactured parts, comparatively little focus has been paid to the property of thermal conductivity. Additively manufactured thermally conductive parts have the potential to benefit thermal management technologies that are currently a bottleneck of many classes of advanced electronic devices. Creating parts with high thermal conductivities remains a major challenge for the most prevalent form of material extrusion additive manufacturing, fused filament fabrication, which creates parts by extruding multiple layers of molten polymeric extrudate using an automated gantry system. The low thermal conductivity of these parts stems from several types of interfaces and voids inherent to the fused filament fabrication additive process, which create significant internal resistance to the flow of heat through a part. To increase thermal conductivity, many researchers and companies have added thermally conductive particles into the polymeric filaments. Still the achievable properties are largely constrained by the printing defects inherent to the printing process, especially when compared to injection molded parts. In this work, we investigate the role of thermal post-processing to both anneal the printed part and to tune the crystallization state of the polymer. We find that careful thermal post-processing of parts made with commercial filaments can improve thermal conductivity values to 2.5 times the as-printed property values. Further, we detail several correlations between processing conditions and thermal conductivity outcomes that will improve the implementation of fused filament fabrication for addressing thermal management challenges in industry.

Performance analyses on the air cooling battery thermal management based on artificial neural networks

Air cooling thermal management technology is a lightweight and cost-effective approach for managing heat in power battery packs for electric ships. However, it suffers from significant drawbacks such as poor temperature control and excessive noise generation. To address these challenges, this study proposes a method that combines fluid dynamics and artificial neural networks (ANNs) to optimize the thermal management and aeroacoustic performance of the air cooling battery thermal management system (BTMS) for marine power batteries. Initially, a thermal-flow coupled model and an acoustic model for the BTMS were developed to investigate the impact of system structural parameters (battery spacing d, and main channel inclination angle θ) and operating parameter (system inlet velocity v) on the thermal management performance indicators (maximum temperature Tmax, and maximum temperature difference ΔTmax) as well as the aeroacoustic performance indicator (overall sound pressure level, OSPL). Subsequently, a relationship between the system structural and operating parameters and performance indicators was established using the 50-layer Residual Network (ResNet-50) model, enabling accurate and rapid prediction of the system thermal management and aeroacoustic performance. Furthermore, by combining ResNet-50 with the evaluation method of Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), this study successfully obtained the optimal system structure and operating parameters. The research indicates that keeping the remaining parameters constant, increasing the battery spacing results in higher maximum temperature and maximum temperature difference, while decreasing the overall system sound pressure level. Conversely, increasing the main channel inclination angle results in lower maximum temperature and maximum temperature difference, but higher overall system sound pressure level. In addition, increasing the inlet velocity will result in higher maximum temperature and maximum temperature difference, as well as higher overall system sound pressure level. The optimal case were found to be a main channel inclination angle θ = 3°, battery spacing d = 2 mm, and inlet velocity v = 10 m⋅s−1. Compared to the base case, the optimal case shows a maximum temperature reduction of 10.63 K, a maximum temperature difference reduction of 9.41 K, and an overall sound pressure level reduction of 4.6 dB. The prediction errors for these values are 0.08 %, 2.64 %, and 1.36 % respectively. This research demonstrates an effective and rapid approach based on fluid dynamics and ANNs in the design and optimization of BTMS.

Design and Optimization of Heat Dissipation for a High-Voltage Control Box in Energy Storage Systems

Abstract To address the issue of excessive temperature rises within the field of electronic device cooling, this study adopts a multi-parameter optimization method. The primary objective is to explore and realize the design optimization of the shell structure of the high-voltage control box, aiming to effectively mitigate the temperature rise in internal components and enhance their thermal management efficacy without altering the fan performance, environmental conditions, or spatial layout. Initially, the study employs computational fluid dynamics methods to investigate the heat dissipation characteristics of the high-voltage control box, subsequently verifying the simulation parameters' accuracy through temperature rise tests. Building upon this foundation, the article conducts a thorough analysis of how the position and shape of the box's openings impact the device's temperature rise. The findings suggest that configuring circular openings on the front and rear sides can optimize the heat dissipation effect. Moreover, the SHERPA algorithm was employed to refine the size and distribution of the openings on the outer shell of the high-voltage control box through multi-parameter optimization, yielding locally optimal structural parameters. Post-optimization, the temperature measurement points within the high-voltage control box exhibited a maximum reduction in temperature rise of 27.16%. The pivotal contribution of this methodology is the application of a data-driven decision-making process for the enhancement of conventional heat dissipation designs. This research offers invaluable practical insights and novel perspectives on the optimization of thermal management designs for box-type electronic devices, significantly advancing the field of thermal management technology in electronic devices.

Self-driven manifold microchannel heat sink for cooling electronics

The advancement of passive, compact, and lightweight thermal management technology for high-power chips is essential for the stable and efficient operation of the next generation of electronic devices. A novel self-driven heat sink based on embedded manifold microchannel heat dissipation technology is proposed, which uses capillary force as the driving force to replace the pump, and minimize pressure drop and thermal resistance between the heat sink and heat source. This design of the embedded self-driven manifold microchannel heat sink allows for the integration and miniaturization of the heat sink and the chip heat source. Through Micro Electromechanical Systems technology, an experimental sink with microchannels with a high aspect ratio was fabricated. A theoretical model is constructed to analyze the influence of the width and depth of the microchannel on the limit heat flux, and the correctness of the model is verified by experiments. The results indicate that the width has a more significant impact on the limit heat flux compared to the depth. An optimal width of 6.5 μm is identified. As the depth increases, the influence of depth on the limit heat flux diminishes. By conducting theoretical calculations on the embedded self-driven manifold microchannel heat sink, it was determined that the device using HFE7100 as the working fluid demonstrates a wider heat load range than ethanol and acetone, and the limit heat flux can reach 41.5W/cm2.

Research Status of New Energy Vehicle Thermal Management

Thermal management of new energy vehicles, as a way to break through the driving range of new energy vehicles and one of the guarantees of safety performance, has been paid more and more attention to. In order to improve the thermal management efficiency of new energy vehicles, the thermal management mode of the whole vehicle should be optimized, so that different parts can work at a suitable temperature, so as to ensure the functional safety and service life of the vehicle. Based on this, this paper analyzes the passenger cabin thermal management system through Positive Temperature Coefficient (PTC) heating air conditioning, heat pump air conditioning and other technologies. This paper introduces the new energy vehicle battery thermal management system from the aspects of direct cooling mode and heating mode, introduces the battery thermal management system through the analysis of flow charts, and introduces the cooling mode of electric control and motor, and pays attention to some cutting-edge research progress, and summarizes the automobile thermal management technology theory.

Optimizing Closed Loop Pulsating Heat Pipes (CL-PHPs) using Taguchi method enhancing thermal performance and operational parameters

Closed Loop-Pulsating Heat Pipes (CL-PHPs) are a promising heat transfer technologies known for their efficient and versatile thermal management capabilities. This study presents a comprehensive analysis of CL-PHPs employing Taguchi method. It's a statistical technique to optimization enhance their performance. The research involves the utilizing an 8-turn pulsing heat pipe and a variety of working fluids aqueous mixtures, including Water with acetone, methanol, ethanol and water. An optimal CL-PHP performance was achieved while incorporation of optimization techniques for the selected operational parameters such as thermal resistance, heat supply, angle of orientation, type of fluid and filling ratio. The optimization process aims to improve various operational parameters impact such as the thermal resistance performance of CL-PHPs were examined, including fill ratio, heat input, angle of inclination, working fluid, etc. to attain optimal CL-PHP performance. The performance parameters orthogonal array were studied using ANOVA and analysis of variance. Experiments with changing the input parameters were carried out using the Taguchi L27 orthogonal array. The performance of CL-PHP was mostly effected by heat supply along with inclination angle and fill ratio to some extent. The optimization results indicate that the most important element affecting CL-PHP performance is heat input, which is followed by fill ratio and angle of inclination. This research contributes to the advancement of thermal management technologies and underscores the potential benefits of CL-PHPs in various engineering applications A maximum deviation of with ±8 % divergence from the anticipated values is obtained among the test runs that are considered random.

Research Status and Development Trends of Thermal Management Technologies for Motors

Research Status and Development Trends of Thermal Management Technologies for Motors

Physics of pressurized hydrogen spontaneous ignition in pipes containing bends of different angles

In the context of hydrogen-based energy storage systems, the safeguarding against spontaneous ignition during high-pressure hydrogen release is of paramount importance. This study delves into the thermal safety and management technologies pertinent to such systems by numerically investigating the effects of pipeline geometry on the risk of spontaneous ignition. Employing Large Eddy Simulation (LES) coupled with detailed chemical kinetics and a linear eddy model, the research assesses the impact of different pipe angles and burst pressures on ignition behavior. The simulations are validated against experimental data, ensuring the veracity of the findings. The results demonstrate a significant interplay between the ignition propensity and both the geometrical configuration of the pipeline and the pressure of hydrogen release. Notably, the emergence and interaction of transverse waves in pipe bends are revealed to amplify mixing processes, generating vortices that elevate the temperature and promote a conducive environment for chemical reactions leading to stable flame propagation. The ignition is shown to occur predominantly near the stoichiometric mixture ratio, suggesting a narrow ignition region. These insights are vital for enhancing the safety protocols and thermal management strategies of hydrogen-based energy storage systems, paving the way for safer and more efficient energy solutions.

Improving fluid flow and heat transfer of cryogen spray cooling using sweeping cold air jet

Industrial growth has led to increased electronic component integration, resulting in higher working temperatures and technological failures. Cryogen spray cooling (CSC) could reach cryogenic temperatures with fast-responding, but its heat transfer limitation due to liquid film deposition is potentially challenging. In this study, CSC cooling is incorporated with either a cold air jet (CAJ) or a sweeping jet (SWJ) to enhance heat and fluid flow. A K-type thermocouple is used for measuring the surface temperature, while the improved Duhamel theorem is used to estimate the heat flux. The spray and film intensities are recorded through the Mie-scattering methodology via high-speed camera. The results demonstrated that the CAJ/SWJ exhibited a significant reduction in surface temperature and film intensity, enhanced heat dissipation and spray efficiency compared to CSC cooling. More precisely, it demonstrated a 26%–36% heat transfer coefficient improvement, along with a 52% increase in the corresponding time of the critical heat flux. Meanwhile, the CAJ/SWJ intensifies heat transfer during film and transition boiling, inspired by the fast liquid film evaporations. In contrast, the SWJ is much preferred due to its wider and stable coolant coverage throughout film evaporation, as seen by its greater heat transfer coefficient. The combined results demonstrated the need to promptly eliminate the deposited film, as it holds the potential to serve as a pivotal resolution for the advancement of thermal management technology.

Review of heat pipes for power batteries of new energy vehicles

With the global energy crisis becoming one of the most concerned topics, the application of new energy systems has become the most popular research at present. In addition, with the emerging new energy vehicles, problems such as high calorific value and insufficient heat dissipation performance of lithium batteries for new energy vehicles have not been solved, so the research on thermal management technology of lithium batteries is essential. Based on the analysis of heat pipe research, this paper summarizes heat pipe from three aspects, including structure and arrangement of the heat pipe, wall materials of the heat pipe and phase change materials of the heat pipe. This paper puts forward new insights and provides a reference for the research on the thermal management of lithium batteries for new energy vehicles.

Experimental Analysis on Enhancement of Heat Transfer in Compact Heat Exchanger Using Nano Particles

This experimental study focuses on enhancing heat transfer in compact heat exchangers through innovative methods. Various augmentation techniques, including surface modifications, vortex generators, and advanced fluids, are systematically tested in a carefully designed experimental setup. The research aims to quantify the impact of these enhancements on heat transfer rates, pressure drop, and overall thermal performance. Controlled parameters such as fluid flow rates and temperatures are measured to assess heat transfer coefficients and effectiveness under different operating conditions. Results aim to provide valuable insights into the feasibility of implementing these techniques, offering practical guidelines for optimizing compact heat exchanger design. The study contributes to advancing thermal management technologies, promoting energy efficiency, and reducing environmental impact in industrial applications.

Observation of nonvolatile magneto-thermal switching in superconductors

Applying a magnetic field to a solid changes its thermal-transport properties. Although such magneto-thermal-transport phenomena are usually small effects, giant magneto-thermal resistance has recently been observed in spintronic materials and superconductors, opening up new possibilities in thermal management technologies. However, the thermal conductivity conventionally changes only when a magnetic field is applied due to the absence of nonvolatility, which limits potential applications of thermal switching devices. Here, we report the observation of nonvolatile thermal switching that changes the electron thermal conductivity when a magnetic field is applied and retains the value even when the field is turned off. This unconventional magneto-thermal switching arises in commercial Sn-Pb solders and is realized by phase-separated superconducting states and resultant nonuniform magnetic flux distributions. This result confirms the versatility of the observed phenomenon and aids the development of active solid-state thermal management devices.

Thermal Interface Hydrogel Composites Mechanically Compliant with Curvy Skins and Rigid Electronic Modules

AbstractThe evolution of wearable electronic devices has drawn attention to personal thermal management (PTM) technologies encompassing the sensing and regulation of body temperature and/or harnessing human body heat for energy harvesting. However, solid PTM devices encounter inherent limitations concerning thermal contact and mechanical compatibility with the human body. This study introduces a thermal interface hydrogel exhibiting high thermal conduction and mechanical compatibility with human skin. Employing a strategic design approach, the mechanical and thermal properties of the hydrogel are assessed. This hydrogel is a structured composite incorporating alumina microplatelets embedded layer‐by‐layer within a densified polymer matrix. Incorporating aligned alumina platelets in the layered structure, combined with a densified polymer matrix ensuring close contact and packing of polymer chains, enhances the thermal conductivity of the hydrogel. Simultaneously, it maintains mechanical flexibility and robustness. Subsequently, the resulting hydrogel is showcased as a thermal interface material sandwiched between flexible human skin and a rigid Peltier module for a cooling device affixed to the human skin. Anticipated applications of the hydrogel‐based thermal interface material include advanced bioelectronics with added functionalities in PTM, all without inducing mechanical or physical discomfort.

Improving the performance of heat sinks through the integration of fins and the utilization of graphene-mixed latent heat energy storage

Effective thermal management is significant to ensure the safety of all operating systems. However, these systems demand innovative thermal management technology. A heat sink with improved thermal conductivity is one of the passive heat management techniques. This study focuses on enhancing thermal management in devices by evaluating the performance of a heat sink with and without fins integrated with high thermal conductivity graphene-incorporated phase change material. Paraffin wax with a melting temperature of 58 °C was used as the phase change material. The study examines how the addition of graphene nanoparticles improves heat transfer capacity and extends the heat sink's working duration. The findings revealed that the phase change material extends the heat sink's working duration while adding nanoparticles improves performance. The performance of the phase change material and mixture of the nanoparticles was examined using a finned heat sink under constant heat input. The heating and cooling cycle of the heat sink was examined. The performance of the heat sink with fins and nano PCM was increased by 30 % compared to the baseline heat sink at 15 W heat input. This performance was increased to 45 % when the heat input changed to 30 W. The results indicated that nanoparticles in the phase change material augment the heat sink's recovery time, irrespective of the influence of fins.