Hybrid channeling of Cu-Al cold plates for thermal management devices

Cu-Al cold plates,as a novel type of cold plate that combines the high thermal conductivity of copper with the low production cost of aluminum,are among the best options for enhancing the heat dissipation capacity of battery thermal management systems.Hybrid channeling of Cu-Al cold plates was proposed for thermal management devices with the combination of friction stir welding+channeling.The highest flexural strength of the Cu-Al interfaces reached 127.5 MPa with the optimized parameters.Due to the close-row welds adjacent to the channels,high-efficiency heat dissipation was realized with the fully bonded interfaces.No leakage of coolants occurred under the pressure of 0.85 MPa during the hydrostatic tests,indicating a sound sealing performance of the channels.Compared to the conventional Al cold plates,the heat sink capacity of the Cu-Al cold plates was enhanced by 16.3%.The results indicated that hybrid channeling not only en-hanced the interfacial strength of Cu-Al cold plates but also significantly improved the heat dissipation capacity,offering a new technical pathway for optimizing battery thermal management systems.

Design and analysis of a high loss density motor cooling system with water cold plates

Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were studied.To compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling structures.Consequently,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main dimensions.The results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the motor.Considering a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.

Investigation on the Transient Thermal Performance of a Mini-Channel Cold Plate for Battery Thermal Management

Cold plate is an important component for a liquid battery thermal management system.In order to study the transient thermal performance of the cold plate under conditions with sharply increasing heat loads,the numerical model of a battery cold plate is established.The validation experiment shows that the error between the simulation and experiment is around 2.5%to 5%.Effects of the coolant flow rate,the increase in heat flux,and the channel number are analyzed to study the transient thermal performance of the cold plate.Results show that the average temperature of the cold plate at 540 s is lowered from 28.3℃ to 26.9℃ when the coolant flow rate is raised from 0.065 kg/s to 0.165 kg/s.The temperature deviation is decreased when the coolant flow rate is increased from 0.065 kg/s to 0.115 kg/s;however,it is slightly increased if the coolant flow rate is further increased.Both average temperature and temperature deviation are raised if the final heat flux is increased from11000 W/m^(2) to 16500 W/m^(2),which are 2 and 3 times of the initial,respectively.In addition,increasing the channel number has slightly positive effect on the average temperature of the cold plate,while the temperature deviation is increased when the channel number is increased from 3 to 11 due to the non-uniform velocity distribution between each channel.The results of this study will be helpful during the design of cold plate for battery thermal management,especially for transient conditions with sudden rising heat loads like thermal runaway.

Research on pumped two-phase single-sided cold plate of IGBT for rail transit applications

The use of pumped two-phase cooling to improve the thermal management of insulated gate bipolar transistor(IGBT)in rail transportation is a novel cooling technology.An experimental investigation on pumped two-phase cold plate of IGBT used in HXD1C locomotives was conducted at a mass flow rate of 0.1 kg/s–0.29 kg/s and a heat flux of 6.2 W/cm^(2),with R245fa as the working fluid.The experimental results showed that the base temperature nonuniformity can be controlled within 2.2℃ at flow rates of 0.14 kg/s and 0.19 kg/s,which is of great benefit to the reliability of IGBT.Based on well known correlations for saturated flow boiling in tubes,an analytical model was developed and compared with the experimental data.The model could predict the base temperature data within an error band of±3℃,as well as capture the trend of base temperature as a function of vapour quality and mass flow rate.The performance of the pumped two-phase cold plate of IGBT could be further improved with the aid of the developed model.

Thermal Management Optimization of a Lithium-Ion Battery Module with Graphite Sheet Fins and Liquid Cold Plates

Temperature uniformity of lithium-ion batteries and maintaining the temperature within the range for efficient operation are addressed.First,Liquid cold plates are placed on the sides of a prismatic battery,and fins made of aluminum alloy or graphite sheets are applied between battery cells to improve the heat transfer performance.Then a simulation model is built with 70 battery cells and 6 liquid cold plates,and the performance is analyzed according to the flow rate,liquid temperature,and discharge rate.Finally,the results show that temperature differences are mainly caused by the liquid cold plates.The fin surface determines the equivalent thermal conductivity of the battery.The graphite sheets have heterogeneous thermal conductivity,which help improve temperature uniformity and reduce the temperature gradient.With lower density than the aluminum alloy,they offer a lower gravimetric power density for the same heat transfer capacity.In addition to the equivalent thermal conductivity,the temperature difference between the cooling liquid and battery surface is an important parameter for temperature uniformity.Optimizing the fin thickness is found to be an effective way to reduce the temperature difference between the liquid and battery during cooling and improve the temperature uniformity.

Analysis of Heat Transfer Behaviour of the Conduction Cold Plate System

The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the coolant mass flowrate, the heat load and the hashest cold plate temperature is established.A model is proposed to describe the transient thermal rosponse of the cold plate under thermal shock condition. The analytic solution of the transient heat transfer within the cold plate is provided. The results of this paper agree with those of the finite element method and can be used for the structural design and performance evaluation of cold plate system.

夏热冬冷地区某三甲医院供暖系统运行性能实测研究

医院建筑具有功能复杂、能耗强度高等特点,是节能减排的重要领域。特别是夏热冬冷地区三甲医院通常采用燃气锅炉系统来满足冬季供暖需求,但易出现能源消耗大、能源利用效率低、碳排放较高等问题。以夏热冬冷地区某三甲医院为例,对其燃气锅炉供暖系统运行能耗、供热量及关键设备实际运行性能开展了实测研究,总结出燃气锅炉频繁启停、板式换热器换热性能不佳、水系统存在大流量小温差,以及末端室内环境冷热不均等问题,存在较大的节能优化空间。

高寒地区中深层地源热泵系统运行表现分析

对青海省共和县中深层地源热泵集中供暖系统实际运行情况展开了研究。通过室内外温度、取水与回灌水温度、供回水温度、能耗和性能系数等数据,综合分析了供热系统实际运行表现。研究结果表明,地热水出水温度存在0.078℃/d的衰减率,为维持地热动态平衡,取水上限流量为80 m 3/h。此外,天气转暖过程中室外平均温度5℃可看作热泵机组启停节点,关闭地源热泵机组仅靠板式换热器换热,能使系统综合性能系数最大升至8.7,系统能耗降幅达42.9%。本文可为地热供暖系统优化运行及能效提升提供参考。

动力电池冷板波纹形流道结构的优化

针对动力电池冷却问题,考虑电池模组的布局和散热要求,设计一种具有波纹形流道的冷板,在保证能耗的前提下,控制冷板换热面温度,并具有良好的热均匀性。分析冷板的特征结构,分别讨论波峰波谷高度、流道入射角度及流道宽度对冷板性能的影响。调节流道入射角度可更好地通过流量分配来控制板内压降变化,流道宽度与波峰波谷的设置能改善冷板的热均匀性问题。用最优参数设计的波纹形流道冷板,相比于传统的直流道,换热性能提升8.4%,板内能耗仅提升1.7%。

冷板阻热层对锂电池模组散热均匀性影响

锂电池模组温差过大引发电池间充放电、老化衰减速率不一致,致使其性能变差。为了进一步降低锂电池模组工作温差,提出一种设阻热层的新型冷板,即通过在冷板冷却液入口处与锂电池间增设阻热层增大热阻、抑制锂电池与冷板间热交换改善其散热均匀性。利用新型冷板对锂电池模组3 C放电冷却散热进行建模仿真计算,分析了并行流道、并联蛇形流道以及分叉型流道等3种不同流道冷板增设阻热层对锂电池模组放电散热均匀性影响,以及阻热层材料导热系数、厚度及覆盖面积对锂电池模组冷却散热均匀性影响。结果表明:在3种流道冷板上增设阻热层均能有效降低锂电池模组工作温差。随着阻热层材料导热系数减小,锂电池模组最高温度和温差均先减小后增加。随着阻热层厚度、阻热层覆盖面积增大,锂电池模组工作最高温度和温差均先减小后增大。采用长80 mm、宽80 mm、厚1 mm导热硅胶垫阻热层,分叉型流道冷板冷却锂电池模组3 C放电最高温度和温差降至306.55 K和4.89 K。

Drive Train Cooling Options for Electric Vehicles

Electrification of vehicles intensifies their cooling demands due to the requirements of maintaining electronics/electrical systems below their maximum temperature threshold.In this paper,passive cooling approaches based on heat pipes have been considered for the thermal management of electric vehicle(EV)traction systems including battery,inverter,and motor.For the battery,a heat pipe base plate is used to provide high heat removal(180 W per module)and better thermal uniformity(<5°C)for the battery modules in a pack while downsizing the liquid cold plate system.In the case of Inverter,two phase cooling system based on heat pipes was designed to handle hot spots arising from high heat flux(∼100 W/cm2)–for liquid cooling and provide location independence and a dedicated cooling approach-for air cooling.For EV motors,heat pipebased systems are explored for stator and rotor cooling.The paper also provides a glimpse of development on high-performance microchannel-based cold plate technologies based on parallel fins and multi-layer 3D stacked structures.Specifically,this work extends the concept of hybridization of two-phase technology based on heat pipes with single-phase technology,predominately based on liquid cooling,to extend performance,functionalities,and operational regime of cooling solutions for components of EV drive trains.In summary,heat pipes will help to improve and extend the overall reliability,performance,and safety of air and liquid cooling systems in electric vehicles.

汽车用SPCC冷轧钢板冲压成形性能比较分析研究

为了评判SPCC冷轧钢板冲压成形性能的优劣性,通过单向拉伸试验、凸耳试验及锥杯试验全面比较了SPCC钢与ZK60板、08Al板、Q235F板、IF板、TRIP600板6种钢板的成形性能。研究结果表明:SPCC的屈服点较低,屈强比σ_(s)/σ_(b)相对较小(约为0.618),断后延伸率δ和硬化指数最高,分别为41.46%与0.265,说明SPCC薄板塑性成形时所需成形力较低,且成形性能也相对较好。SPCC的凸耳率比TRIP600高强钢和IF钢的凸耳率均大,约为6.40%,可通过降温从而减小板材平面各向异性。SPCC的锥杯值与镁合金相近,约为45.3 mm,反映出SPCC具有良好的拉深-胀形综合性能。

多结构形式小通道液冷板散热性能对比研究

小通道冷板作为一种有效的热控装置,已被广泛应用于高热流密度电子器件的热管理领域。文中以通道特征尺寸为2 mm的串行、并行以及射流冲击/小通道混合液冷板为研究对象,旨在获取这3种结构形式冷板的极限散热能力和流动阻力损失的差异。研究结果表明:在相同冷却工质流量条件下,3种冷板的散热功率由大到小依次为串行通道、射流冲击/小通道混合液冷板、并行通道;串行通道冷板的板内阻力损失明显大于其余两者;在综合考虑压力损失和散热性能的基础上,根据不同热源热流密度条件选择合适的冷板结构,有望满足特定应用的需求。该研究可供小通道液冷板的设计和优化参考。

不同封装结构相变蓄冷板用于冷藏库数值模拟研究

目的:研究相变蓄冷在冷库错峰用电中的应用,提出更有效的蓄冷板封装结构。方法:针对冻结物冷藏库,设计多种相变蓄冷板封装结构,并建立相应的数值模型。通过数值模拟,在标准温度下(-18℃)测试不同封装结构蓄冷板的凝固蓄冷及融化放冷过程。比较平板蓄冷板和凹凸蓄冷板的异同,并分析不同蓄冷板对库内温度波动的影响。结果:3种特殊版型的蓄冷板中,30~75 mm规格的蓄冷板蓄冷效果最好,在8 h的蓄冷过程中,可比平板型蓄冷板多储存36.23%的冷量。此外,凹凸型封装蓄冷板的放冷能力也要优于平板封装蓄冷板的,能让冷库内温度更加均匀。结论:研究设计的凹凸面封装相变蓄冷板可以在冷库错峰用电中发挥更加有效的作用,能够稳定库内温度并降低能源消耗。

双层蛇形通道冷板动力电池热管理数值模拟

针对电动汽车高能量密度动力电池,为改善热管理以确保其安全性,对某型镍钴锰酸锂电池模组提出了一种底部布置的双层蛇形通道冷板;通过数值模拟确定了冷却液的最佳流动方案为方案一和通道的最佳宽度为10 mm,依次分析了冷却液质量流量、电池放电倍率和环境温度对电池模组最高温度、温差和冷却液压力损失的影响.结果表明:随着放电倍率和环境温度的增加,电池模组的最高温度和温差均会增加,增加冷却液的流量可以更好地控制电池的最高温度,但会导致压力损失的增加;放电倍率小于0.7 C时,不需要启动液冷系统.

泵驱动的制冷剂相变冷板冷却系统实验研究

元器件的小型化和性能的提升使电子器件功率不断提高,优越的散热性能对于保证电子器件的可靠性具有重要意义。本文搭建了泵驱动的制冷剂相变冷板冷却实验系统,设计加工了4块不同材质(铜、铝)和流道高度(10、15 mm)的相变冷板,对散热功率为200~1000 W、热流密度为4.4~22.2 W/cm^(2)的集中热源在制冷能力为3~11 kW和不同热源位置时的冷板换热性能、阻力特性及泵功耗进行了研究。结果表明:相变冷板换热性能优越,在应对散热量为1 kW、热流密度为22.2 W/cm^(2)的集中热源时,传热系数最高可达26 kW/(m^(2)·℃),在系统总阻力小于20 kPa、制冷剂泵功耗小于20 W时可以实现模拟热源表面与制冷剂温差小于15℃,可以利用天然冷源进行散热,实现节能;相变冷板的换热特性可由翅片效率计算式和Kandlikar传热关联式进行描述,使用理论公式计算出的冷板温差与实际值偏差小于1℃,可以指导冷板流道设计。

基于多目标粒子群优化算法的动力电池仿生冷板结构优化设计

为了提高锂离子电池的冷却效果,提出一种高度对称的仿生网状流道冷板。首先,利用单因子分析法分析了冷板结构参数对其性能的影响,然后,以冷板的平均温度、温度标准差和冷却液压力损失为性能指标,采用多目标粒子群优化(MOPSO)算法对冷板的结构参数进行了优化,得到性能最优时的流道宽度、流道深度和冷板壁厚分别为9.0 mm、1.5 mm和1.4 mm,对应的平均温度、温度标准差和压力损失分别为33.20℃、1.33℃和65.63 Pa,相比于初始结构参数,优化后的平均温度和温度标准差分别下降1.92℃和0.02℃,但压力损失增大27.10 Pa。最后,在电池模组层面验证了优化结果。

基于正交试验的热管换热蓄冷板充冷性能研究

车载蓄冷板是充冷式冷藏车的重要组成部分,缩短蓄冷板充冷时间对提高冷链物流的效率具有重要作用。提出了一种热管换热蓄冷板,模拟研究了蓄冷板充冷冻结过程,并通过实验验证了理论模型的可靠性。利用正交试验方法研究了热管管径、管间距、通道内载冷剂流速、雷诺数对蓄冷板充冷性能的影响。研究表明:常规单层厚度约为50 mm蓄冷板状态下,管径为7 mm、管间距为39 mm、通道内载冷剂流速为1.2 m/s、雷诺数为3.89时(最优参数),平均冻结时间和完全冻结时间分别为45 min和78 min;与现有文献报道的结果相对比,最优参数下热管换热蓄冷板的充冷时间大幅缩短。

冷喷涂Cu包覆AlN增强铜基复合涂层的制备与性能研究

目的 通过冷喷涂技术在铜基体上制备了具有高致密高硬度的Cu/AlN涂层,并研究化学镀预处理工艺对冷喷涂Cu/AlN复合涂层微观形貌、力学性能和耐腐蚀性能的影响。方法 采用冷喷涂技术在铜基体表面分别沉积Cu、Cu-AlN(球磨混合)和Cu-Cu@AlN(化学镀包覆)涂层,通过扫描电子显微镜(SEM)观察了涂层截面的微观形貌,通过能谱仪(EDS)对涂层元素组成进行了检测,并计算了涂层中AlN的沉积量。借助维氏硬度计和电化学工作站分别对涂层进行了显微硬度和电化学腐蚀行为测试。结果扫描电镜结果显示,Cu-Cu@AlN和Cu-AlN涂层有着比纯Cu涂层更加致密的微观组织,并且与基体的结合更好,孔隙更少。能谱仪结果显示AlN在涂层中分布均匀,并且Cu-Cu@AlN涂层中AlN的含量明显大于Cu-AlN涂层。Cu-Cu@AlN涂层具有最高的显微硬度(151.8HV),相比基体提升71%。在模拟海洋环境中的电化学测试结果表明,Cu-Cu@AlN涂层的自腐蚀电位最高(-0.1667V),表明其腐蚀倾向最低,自腐蚀电流密度最低(1.18μA/cm^(2)),相比Cu-AlN涂层降低了1个数量级,表明其具有最佳的耐腐蚀性能。电化学阻抗谱(EIS)测试结果表明,Cu-Cu@AlN涂层具有最高的电荷转移电阻(1625?·cm^(2)),证实其具有最佳的耐蚀性,这与动电位极化测试的结果一致。结论 通过化学镀预处理的粉体制备出的Cu-Cu@AlN涂层致密,AlN含量高,该涂层的显微硬度和耐腐蚀性能最好,有望应用在铜及铜合金制备的船舶构件,从而延长其在海洋环境中的服役寿命。

数据中心液冷散热技术及应用

数字技术的创新演进与蓬勃发展,推动算力需求持续提升,数据中心能耗呈指数型增长。在可持续发展、“双碳”、新型数据中心等政策理念指引下,数据中心制冷技术正式迈入液冷阶段。首先从芯片、设备、机柜散热诉求,机房节能诉求等多个维度,深入探讨液冷技术的必要性与优势,同时针对多种液冷技术方案从架构、原理、关键组成等方面进行深入分析。其次,通过散热能力、节能效果、维护性、技术成熟度等方面的综合对比,短中期单相冷板式液冷将更具优势。最后,探讨了当前数据中心液冷在可靠性、散热强化、低成本等维度的研究趋势。