Mini-channel Cold Plate Research Articles

Numerical simulation for comparison of cold plate cooling and HFE-7000 immersion cooling in lithium-ion battery thermal management

In this work, fluorinated liquids can be used as a new immersion coolant for effective battery thermal management (BTM) because of their insulating and non-flammable inert characteristics. In this research, the liquid chosen for immersion cooling is HFE-7000, characterized by a boiling point of 34 °C. The analysis of bubble kinetics is employed to investigate the heat transfer mechanism in two-phase immersion cooling by examining the behavior of bubbles during the boiling process. The square ternary Li-ion batteries are subjected under loads of 2C and 3C cooled by immersion cooling and a mini-channel cold plate as a comparison. It turns out that immersion liquid cooling modules offer superior thermal performance. Under constant current (CC), the peak temperature is reduced by 4.89 °C and 9.31 °C compared with the mini-channel cold plate cooling (CPC). Under dynamic load conditions, the maximum temperature rise of the battery is reduced by 29.89 % and 43.89 % compared to CPC. As a passive heat dissipation method, two-phase immersion cooling reduces the design requirements for active control. Also, it delivers an efficient battery thermal management system (BTMS) designed for upcoming electric vehicles (EVs).

Simulations on hybrid thermal management of mini-channel cold plate and PCM for lithium-ion batteries under discharging and thermal runaway conditions

In this study, we compared the performance of different structures of mini-channel cold plate (MCP) - phase change material (PCM) hybrid thermal management on discharge and thermal runaway. The heat transfer structures for them can be categorized into three types: (a) uncoupled, (b) semi-coupled, and (c) fully coupled. Among these, the semi-coupled design B exhibits the best performance. Specifically, in the high rate discharge condition, the structure can control the battery temperature at 44.37 °C at low coolant mass flow rate, and the temperature at 36.47 °C at high mass flow rate, while the temperature difference (TD) of a single cell does not exceed 2.01 °C. In a low-multiplier discharge zero-energy system, the pack temperature rise can be limited to no more than 10 °C in 35 °C environment. Under external short-circuit conditions, a lower coolant mass flow rate is sufficient to keep the pack temperature at 43.22 °C. Under internal short-circuit thermal runaway (TR), lower coolant mass flow rate can prolong the TR of the adjacent cell up to 521 s, and higher mass flow rate can completely inhibit the occurrence of TR. The objective of this study is to offer valuable references for the design and implementation of hybrid MCP-PCM cooling systems.

Numerical simulations on hybrid thermal management of mini-channel cold plate and PCM for lithium-ion batteries

This study presents a novel hybrid thermal management system (HTMS) leveraging the mature technology of mini-channel cold plates (MCPs) and the superior thermal properties of phase change material (PCM). For single-cell scales to study their hybrid structures, it is found that the structure of 3channel and 5 mm PCM can reduce the battery temperature from 64.45 °C to 42.83 °C for a 2C discharge by 33.55 %. Furthermore, this study investigates the influence of coolant flow rate, temperature, and PCM thickness on the thermal management system. The findings indicate that HTMS can fulfill thermal management tasks that are not possible with the single-side PCM cooling system, while simultaneously saving 13 times the energy compared to the single-side MCPs cooling system to achieve the similar effect. For battery-pack scales to study their coupled structures, and the results show that the PCM alone effectively cools the battery, reducing its temperature from 55.34 °C to 42 °C at an ambient temperature of 35 °C during low-multiplication discharge. Furthermore, under the New European Driving Cycle (NEDC) condition, the battery pack temperature is maintained within 30 °C with a temperature difference of 0.03 °C, highlighting the exceptional performance of HTMS.

Thermal management lithium-ion battery for electric vehicles with using cold plate

Lithium-ion batteries are widely employed as the primary energy storage solution for electric vehicles (EVs). Effective thermal management of these batteries within EVs is important to ensure their safety, optimal performance, and longevity. Lithium-ion batteries are sensitive to fluctuations in temperature, and if not managed correctly, these temperature variations can lead to issues like overheating, reduced efficiency, and even safety risks. This study aims to investigate the effectiveness of a cooling method for a prismatic NMC battery used in electric vehicles. It emphasizes the significance of maintaining the battery's temperature within a specific range, typically between 15 °C and 35 °C, to prevent capacity loss and extend the battery's life. The design of the minichannel cold plate allows for precise thermal control with the 7 °C temperature difference. It efficiently absorbs heat generated during battery operation and releases it, preventing the battery from reaching undesirable temperature levels. Furthermore, the study underscores the importance of optimizing the contact area between the coolant and the battery stack for superior performance of the liquid cooling system. At higher discharge rates of the battery, a greater flow rate is required to achieve efficient cooling, with certain limitations due to the cooling system's efficiency. Overall, the study highlights the advantages of employing a liquid cooling system for proficient temperature regulation and effective heat dissipation in battery stacks for EVs.

A Comparative Numerical Analysis of Cold Plates for Thermal Management of Chips With Hotspots

Abstract Thermal and hydraulic performances of seven water-cooled minichannel cold plates with different internal structures are compared using numerical analysis. Recent increasing demands for high-performance computing have led to serious challenges in the thermal management of electronic devices. In addition to dangerous on-chip temperatures, heterogeneous integration and local regions of elevated temperatures (hotspots) lead to nonuniform chip-level temperature distributions. As a result, the lifespan and reliability of electronic devices are adversely impacted. Due to the limitation of the air-cooled heat sinks, several new methods, such as liquid-cooled microchannel cold plates are developed to remedy these challenges. The objective of this work is to provide a comparative numerical study of the effectiveness of different minichannel cold plate internal structures in the thermal management of a chip with a nonuniform power map and a hotspot. Cold plate thermal resistance, on-chip temperature uniformity, and pump power were the metrics used for this comparison. For four coolant inlet flow rates within the laminar regime, it is seen that increasing the inlet flowrate enhances the thermal resistance of all cold plate designs while creating less uniformity in chip-level temperature distribution relative to the conventional straight microchannels. Concentrating pin fins on the hotspot showed a 7.2% reduction in thermal resistance, despite increasing temperature nonuniformity by about 7.6%. However, it is observed that hotspot-focused pin fins are more effective in lowering the chip's maximum temperature. Obtaining lower chip-level nonuniformity may be possible by modifying the inlet and outlet conditions of the cold plates.

Optimization of Heat Transfer Performance Using Response Surface Methodology-Central Composite Design (RSM-CCD) for Nano-Coolant (Al2O3+EG/W) in Electric Vehicle Battery

The presence of electric vehicles (EVs) must be supported by batteries that have good-quality energy storage. Battery power is critical to the development of electric cars. Temperature affects battery strength, so operating within the optimum temperature range must be ensured. During the charge and discharge processes, the electrochemical reaction generates hot energy, causing an increase in battery temperature. In this research, the solution to the problem is to make a cooling system with a mini channel cold plate and Al2O3 1%vol+EG/W (50:50) nano coolant. Optimization of heat transfer enhancement using Response Surface Methodology-Central Composite Design (RSM-CCD) and experimental tests with various flow rate variations. The research findings revealed that the RSM-CCD results and the outcomes of studies employing test equipment agreed that the highest cooling fluid flow rate was the most optimal condition, the highest T2 temperature drop of 17.63% occurred at a flow rate of 1.7 LPM, and the lowest T2 temperature was 13.13% at a flow rate of 1 LPM.

Experimental study on an integrated system of thermosyphon loop and vapor compression assisted with phase change material for pulse heat load

In order to safely and energy-efficient handle the pulse heat load of avionics, the paper proposes an integrated system of thermosyphon loop and vapor compression cycle, especially assisted with phase change material (PCM). Under low heat load and heat sink temperature, the system operates as a thermosyphon loop (TL) for energy saving; otherwise as a vapor compression cycle (VCC) for safety. A prototype of the integrated system was developed, where a whole three-dimensional (3D) printed structure worked as the evaporator of the system, consisting of a mini-channel cold plate and a high thermal-conductivity matrix containing PCM. The dynamic performance of the proposed system has been experimented under different pulse heat loads and heat sink temperatures, and compared to the integrated system without PCM and a traditional VCC. The proposed system can handle a peak heat load of 1000 W for 120 s without running the compressor, saving 100 % energy compared to traditional VCC. The PCM enhances both the safety and energy efficiency of the integrated system. On the one hand, it reduces wall temperature during the transition from TL to VCC, avoiding overheating issue. On the other hand, it reduces the operating time of VCC, which is more significant with lower peak heat load and heat sink temperature. Overall, the integrated system assisted with PCM is a promising solution for solving pulsating heat loads.

Investigation of an improved cold plate design with circuitous minichannel: a computational study involving the effect of conjugate heat transfer

Purpose This study aims to investigate a new circuitous minichannel cold plate (MCP) design involving flow fragmentation. The overall thermal performance and the temperature uniformity analysis are performed and compared with the traditional serpentine design. The substrate thickness and its thermal conductivity are varied to analyse the effect of axial-back conduction due to the conjugate nature of heat transfer. Design/methodology/approach The traditional serpentine minichannel is modified into five new fragmented designs with two inlets and two outlets. A three-dimensional numerical model involving the effect of conjugate heat transfer with a single-phase laminar fluid flow subjected to constant heat flux is solved using a finite volume-based computational fluid dynamics solver. Findings The minimum and maximum temperature differences are observed for the two branch fragmented flow designs. The two-branch and middle channel fragmented design shows better temperature uniformity over other designs while the three-branch fragmented designs exhibited better hydrodynamic performance. Practical implications MCPs could be used as an indirect liquid cooling method for battery thermal management of pouch and prismatic cells. Coupling the modified cold plates with a battery module and investigating the effect of different battery parameters and environmental effects in a transient state are the prospects for further research. Originality/value The study involves several aspects of evaluation for a conclusive decision on optimum channel design by analysing the performance plot between the temperature uniformity index, average base temperature and overall thermal performance. The new fragmented channels are designed in a way to facilitate the fluid towards the outlet in the minimum possible path thereby reducing the pressure drop, also maximizing the heat transfer and temperature uniformity from the substrate due to two inlets and a reversed-flow pattern. Simplified minichannel designs are proposed in this study for practical deployment and ease of manufacturability.

Numerical and experimental studies on novel minichannel cold plates for lithium-ion battery thermal management

This paper reports the numerical and experimental studies on two novel minichannel cold plate (MCP) designs viz. D1 (channels with circular slot profile) and D2 (channels with zigzag profile) employed for cooling high-power lithium-ion batteries (LIBs). Detailed 3D CFD simulations are carried out to understand the effect of the parameters viz. coolant inlet velocity (Vin), coolant inlet temperature (Tin) and the number of channels (n), on the cooling performances of the MCPs. Experiments are performed with D2 using a proxy high power battery module for validation and analysis. Detailed flow visualization, and thermo-hydraulic studies are reported. Both simulations and experiments, reveal a strong influence of the parameters on the cooling performance. An increase in the coolant inlet velocity from 0.05 to 0.3 m/s reduces the battery temperature rise by about 5 °C in both the designs whereas increases the pressure drop and pumping power by a factor of 7.5 and 28 with D1 and D2 respectively. It is shown that the number of channels can be limited to five (n = 5) for a better cooling performance. It is recommended to limit Tin to <30 °C for maintaining the LIB module at 40 °C or below. It is evident from the studies that the two MCPs are best suited for the thermal management of high-power lithium-ion battery modules discharging at high C-rates.

Thermal performance of cold plate based on phase change emulsion for Li-ion battery

A battery thermal management system (BTMS) is responsible for the safety performance of lithium-ion batteries. In this paper, different cooling methods based on phase change emulsion (PCE) containing 10 wt% to 40 wt% paraffin were investigated and compared with a water-cooling system. The three-dimensional thermal simulation results showed that the cooling performance of the mini-channel configuration was better than the baffle plate, fin cooling and jacket cooling methods. Based on the optimized structure of the mini-channel cold plate, the operation conditions for cooling Li-ion batteries were determined to keep the maximum temperature limit of 313 K and maximum temperature difference of 5 K at various discharge rates. There was advantage for the PCE cooling in reducing the pump energy consumption for high discharging rates compared with water cooling. The pump power declined by 24% and 36% for 2.0C discharging when applying the PCE with 25 wt% and 40 wt% paraffin as the coolant, respectively. The cooling with the PCE containing 25 wt% paraffin had 16% less energy consumption for 3.0C discharging.

Experimental and numerical study on two-phase minichannel cold plate for high-power device

In this study, the flow and heat transfer performance of the two-phase minichannel cold plates with 10 kW level heat load is designed and studied. The numerical simulation can guide the optimization of the structure on both channel level and whole level, which roughly matches the experimental results. An abnormal phenomenon that the temperature increase with flow rate is observed and explained by boiling point change. The influence of channel structure, fluid characteristics, flow uniformity, and pressure resistance on cold plate temperature and pressure drop are investigated. The fusiform channel performs better than the rectangular channel and refrigerant R1234ze(E) beats R1233zd(E) in the cold plate. Flow uniformity and pressure drop improvement methods are explained and tested. The cold plate can keep its surface temperature below 80 °C and pressure drop below 0.6 bar when the heating power is 20 kW, utilizing R1234ze(E) with a temperature of 60 °C and a flow rate of 9 L/min. A high-power two-phase cold plate can be designed with reference to this study.

Optimal Design of Minichannel Cold Plate for the Thermal Management of Cylindrical Battery Modules

The application of the minichannel cold plate in a cylindrical battery module encounters the problem of poor heat transfer capability as it cannot match well with the curved surfaces of the cylindrical batteries. Herein, design optimization of a minichannel cold plate is performed to enhance its heat dissipation performance in the cylindrical battery module. In‐depth analyses are made on the thermal behavior of a cylindrical battery module with minichannel cold plates. Influences of different cold plate design parameters, including the size and position of the heat transfer interface between the batteries and the cold plates, the cold plate material, and the cold plate thickness, are examined and compared under various coolant velocities. The results highlight the significance of cold plate design in achieving a high‐performance cooling system for the cylindrical battery module. Based on the results, some general rules are set for the design of minichannel cold plates in the cylindrical battery module, which can provide useful guidance for the future development of minichannel cold plates.

Numerical Simulations for Lithium-Ion Battery Pack Cooled by Different Minichannel Cold Plate Arrangements

In real electric vehicles, the arrangement of liquid-cooled plates not only influences the thermal performance of the battery pack but also relates to the energy consumption of the BTMS and the compactness of the whole battery pack. In this study, design A, design B, design C, and design D, a total of four different arrangement designs of battery thermal management based on liquid-cooled plates with microchannels, are proposed for a 35 V battery pack composed of 12 LiFePO4 pouch battery cells connected in series, and the corresponding three-dimensional electrical-thermal-fluid model is established for numerical study. The cooling effects of the four designs are discussed and compared in terms of discharge rate, contact thermal resistance, and external short circuit. For design D, cold plates are placed in front of each battery cell. The results show that design D achieves the best cooling effect with the lowest power consumption compared to the other three designs under 0.5C, 1.0C, and 2.0C discharge rate. Its maximum temperature is about 30°C, and maximum temperature difference is under 5°C. The reduction in contact thermal resistance has different effects and magnitudes for different designs with different cold plate arrangements, but the overall effect is small. In the extreme condition of external short circuit, for design D, increasing the mass flow rate can reduce the maximum temperature of design D from 76.6°C by 27.5% to 55.5°C and the temperature difference from 35.0°C by 23.4% to 26.8°C. Selecting the proper coolant flow rate can keep the maximum temperature and temperature gradient on the battery pack of design D within tolerable level, and increasing the flow rate helps to enhance the cooling effect. For the other three designs, the maximum temperatures and temperature gradients exceeded 90°C and 40°C under the external short circuit condition, and increasing the flow rate has very little effect on the performance enhancement.

Thermal performance of a lithium-ion battery thermal management system with vapor chamber and minichannel cold plate

An effective battery thermal management system is essential to maintain the operating temperature of lithium-ion batteries for electric vehicles in the optimum range and excellent temperature uniformity. In this work, a novel battery thermal management system based on a vapor chamber and minichannel cold plate is proposed to cool and preheat the battery module. A transient numerical simulation is developed and verified by experiments. The thermal characteristics of three battery thermal management systems are analyzed: natural convection cooling, minichannel cold plate cooling, and mixed minichannel cold plate and vapor chamber cooling. Subsequently, the effects of the discharge rate (1C, 2C, 3C), the arrangement and width of the minichannel cold plate, the coolant inlet velocity and coolant temperature on the cooling performance of the systems are investigated. The research results reveal that compared with natural convection cooling and minichannel cold plate cooling, mixed minichannel cold plate and vapor chamber cooling method exhibits lower maximum temperature and more uniform temperature distribution. When the batteries are discharged at 2C and the coolant temperature is 25 °C, the maximum temperature and temperature difference of the batteries can be maintained at 29.6 °C and 3.5 °C respectively. In addition, the preheating performance of the battery module at subzero temperature is also discussed. The results indicate that the proposed battery thermal management system with vapor chamber and minichannel cold plate also exhibits rapid heating capacity and excellent temperature uniformity.

Experiments and Simulation on the Performance of a Liquid-Cooling Thermal Management System including Composite Silica Gel and Mini-Channel Cold Plates for a Battery Module

Lithium batteries in the electric vehicles (EVs) reveal that the operating temperature and temperature uniformity within the battery pack significantly affect its performance. An efficient thermal management system is urgently needed to protect the battery module within suitable temperature range. In this study, the composite silica gel (CSG), coupled with cross-structure mini-channel cold plate (MCP) as the cooling system, has been proposed and applied in a battery module, which can provide a reliable method of controlling battery temperature with low energy consumption. The experimental and simulation results reveal that a composite silica gel-based liquid system can control the temperature below 45 °C and maintain the temperature difference within 2 °C at a 3C discharge rate. Besides, the CSG, coupled with the structure of reciprocal chiasma channels for the battery module, presents an optimum temperature-controlling performance among various cooling structures during the charge and discharge cycling process. This research is expected to provide significant insights into the designing and optimization of thermal management systems.

A numerical study on the battery thermal management system with mini-channel cold plate considering battery aging effect

Battery aging is critical for the batteries in electric vehicles, significantly affecting both thermal characteristics and electrochemical performance. In this research, a more realistic and generic model combining the electrochemistry, capacity fade and heat transfer is developed for the design of battery thermal management system (BTMS) to ensure efficient and durable operation of batteries. The thermal behaviors and electrochemical characteristics in different working cycles of BTMSs with X direction and Y direction mini-channels are analyzed and compared. It is found that BTMSs only provide effective cooling to batteries in their initial working cycles but fail to control the battery temperature after 1000 cycles due to the higher heat generation rate of aged battery caused by solid electrolyte interphase (SEI) formation. In addition, BTMS with Y direction mini-channels always provides more effective cooling to batteries to achieve good electrochemical performance with acceptable higher pressure loss during battery cycling. Furthermore, the optimization schemes are proposed for BTMS with Y direction mini-channels to further enhance cooling of the battery for high performance and durable operation of the batteries. The results show that optimizing mini-channel arrangement, arranging circular pin fins (CPF) and dispersing nanoparticles into coolant can be helpful for BTMS to provide effective thermal manage, achieve higher average potential and prevent SEI formation and capacity fade even after 1000 cycles, although the pressure loss is also higher.

New design of U-turn type minichannel cold plate with hybrid fins for high temperature uniformity

The thermo-hydraulic performance of cold plates is strongly influenced by the channel profiles and fin shapes. First, a shape optimization of U-turn type liquid cold plates is performed employing a discrete adjoint method in this work. The better uniformity of flow rate in minichannel cold plates is obtained by applying the optimized design of structures for entrance and baffle regions. Compared with the baseline design, the standard deviation of the flow rate for the optimal design decreases by 82.76%. The temperature uniformity of liquid cold plates can be further improved by using an asymmetric design of the double flow paths. The standard deviation of the temperature of the heating wall surface in the optimal design decreased by 20.75% compared with that of the conventional design. Furthermore, the roles of fin shape (rectangular, discontinuous, and wavy), fin thickness, and amplitude, wavelength and phase difference of sinusoidal wavy fin on the thermal performance of liquid cold plates having the asymmetric design with the curved baffle proposed are evaluated in detail. The results reveal that the larger amplitude, the smaller wavelength, the greater phase difference of wavy units may contribute to the greater heat transfer performance and the better temperature uniformity of cold plates. The heat transfer augmentation is attributed to the formation of vortices in the channel caused by the wavy fins and the increase of heat transfer surface area caused by the corrugated walls. As a result, two novel designs of minichannel cold plate were presented. New design of minichannel cold plate with wavy fins exhibits better heat transfer performance, while the other design with hybrid fins has more advantages to enhance temperature uniformity. The obtained results demonstrate that the new designs proposed have better temperature uniformity than the initial design of cold plates having straight rectangular minichannels.

Performance analysis and improvement of lithium-ion battery thermal management system using mini-channel cold plate under vibration environment

The battery pack is often subjected to various vibrations and shocks from the road during operation of the vehicle. As one of the core components in the power battery, battery thermal management system (BTMS) also works in a vibration environment. Considering that the vibration may have an impact on heat transfer, the performance of mini-channel cold plate in the liquid cooling system under vibration condition was investigated in this paper. Numerical simulations were performed on the influence of vibration frequency, amplitude and inlet mass flow rate. A method to further improve the heat transfer enhancement effect of vibration was proposed by adding fillets to the square cross-section of the channel. The results indicated that vibration had the effect of enhancing the heat transfer capacity of the cold plate, which was related to the frequency, amplitude and mass flow rate. Under the vibration of 10 Hz and 0.8 mm, when mass flow rate was set to 5 g/s, the maximum temperature of the cold plate was reduced by 4.35 K while the temperature difference was reduced by 3.03 K simultaneously, compared to the static condition. The heat transfer enhancement effect of vibration can be amplified by adding fillets to cross-section of the channel. The overall performance of the cold plate was improved by 33.7% with a fillet of R1.0 mm compared to the original square cross-section.

A new battery thermal management system employing the mini-channel cold plate with pin fins

Batteries are critical for energy storage and electrical vehicles. In this study, a new battery thermal management system (BTMS) is proposed by employing a mini-channel cold plate with pin fins. The performance of BTMS is evaluated by a 3D numerical model. The heat transfer characteristics, pressure loss and flow structure in the BTMS are analyzed, and the performance of BTMS is evaluated using efficiency index (EI) which considers both heat transfer performance and pressure loss. It is found that pin fins can improve the heat transfer performance of BTMS with acceptable pressure loss. Therefore, the EI of BTMS with pin fins is always greater than 1. It is also found that the BTMS with 4 × 3 staggered arranged pin fins outperforms that with the 3 × 4 staggered arrangement and 4 × 4 inline arrangement in EI. Although the horizontally arranged pin fins greatly enhances heat transfer, the pressure loss by the pin fins is also significant. As a result, EI of BTMS with vertically arranged pin fins was 4.54% higher than that of BTMS with horizontally arranged pin fins.

Comparative assessment among several channel designs with constant volume for cooling of pouch-type battery module

Liquid cooling is an effective thermal management technique in reducing the peak temperature of lithium-ion batteries. To meet the development of the battery thermal management system's compact design, a liquid-based mini channel cold plate is utilised. Although several researchers proposed numerous designs of mini channels across the cold plate, a comparative assessment among these designs is limited. Therefore, a three-dimensional numerical method is introduced to explore the laminar flow of liquid coolant in six distinct mini channel designs. This includes serpentine, U-bend, straight, pumpkin, spiral, and hexagonal designs under a constant channel volume. Their cooling ability is evaluated in terms of pressure drop, temperature variation, a non-dimensional j/f factor, average temperature, uniformity factor, and cooling performance factor for varying mass flow rate and a fixed discharge rate of 3C. Results signify that the serpentine and hexagonal geometries could significantly improve temperature homogeneity, whereas the pumpkin model maintains a lower pressure drop and pumping power. Furthermore, a detailed analysis is conducted with all the channel designs for an ambient temperature and discharge rate varying from 25 °C to 45 °C and 1C to 5C, respectively. Also, a realistic drive cycle data US06 is utilised to assess the performance of optimal design serpentine channel-based battery module for on-road driving conditions.