动力电池成组液流热管理系统设计分析

发布时间：2018-05-11 09:50

本文选题：动力电池成组 + 热管理　；参考：《吉林大学》2014年硕士论文

【摘要】：随着能源和环境问题的日益严峻，作为新能源汽车典型的电动汽车，，无疑是汽车发展进程中的一个重要标志。动力电池是电动汽车发展的巨大难题，不过新材料和电化学技术的飞速发展使新型电池应运而生，给电动汽车带来了生机和发展机遇。但是，电池工作的电化学效能与温度紧密相关，它需要严格的热控，否则制约电动汽车在高温和低温气候环境下高效应用。本文设计了动力电池成组液流换热系统，并利用CFD仿真方法对其低温预热和高温冷却问题进行了研究。研究工作在总结电动汽车及其动力电池的发展概况的基础上，进一步归纳了国内外有关动力电池热管理技术的研究工作进展。目前为止，动力电池热管理系统的冷却方式主要有：空气冷却、液体冷却、热管冷却及相变材料冷却，工程应用以风冷形式为主，逐步开始有液体循环冷却；并逐步关注电池热管理的加热作用。鉴于液流循环冷暖热控的电池成组热管理系统，本文对研究内容、研究方法及研究意义进行了阐述。针对成组电池，设计了对称叉排A型和错列叉排B型两种电池液流换热结构，力求在保证良好热管理和冷暖热控的基础上，实现轻量化和紧凑化目标，为大规模大容量多叠层组合应用提供潜力。研究工作围绕成组电池液流系统构建模型，包括模型建立、数值模拟、计算方法和分析评价方法等。其中，系统研究了模型简化、边界条件和工况条件，开展了模型和计算方法的实验验证，以保证计算精度。以B型换热系统为算例，对其换热特性、流动特性及电池表面温度均匀性进行了分析。结果表明，换热系统中两端区域流道的传热量、换热系数及流量均大于中间区域的流道，不同位置特征点进入温度稳定状态的时间也不一致。不同电池单体上的表面温差几乎无差异，同一电池单体上表面温差也保证在合适的温度范围内。采用A型和B型两种换热系统对比的方式分析了热流变主要影响因素作用特性。结果表明，对于同一液流换热系统，常规流量和初始温度对电池表面温度均匀性影响不大，低流量、电池单体发热量和电池导热系数对电池表面温度均匀性有一定影响，液流入口温度对电池表面温度有影响，对电池表面温度均匀性影响很小，改变电池表面扁管间的间距，对电池表面的温度均匀性、流动阻力和流动均匀性均有影响；两种液流换热系统相比较而言，B型优于A型。本文还提出了提升电池表面温度均匀性的措施，即在电池表面加薄层高导热系数的石墨片，结果发现同等条件下，可以将电池单体表面的温差缩小为原来的二分之一，大幅度的提高了电池表面的温度均匀性。针对B型液流换热系统，分析了在低温预热及高温急速冷却下的性能。结果表明，常规流量对低温预热和高温急速冷却影响不大；低温预热过程中入口温度越高，同样的时间内电池升高的温度越快；高温急速冷却过程中入口温度越低，同样的时间内温度下降的越快，冷却效果越好。实验结果表明，在低温和高温工况下，本文设计的液流换热系统可以在短时间内将电池温度调整到正常的工作温度范围。
[Abstract]:As energy and environmental problems become more and more serious , as a typical electric vehicle for new energy vehicles , it is no doubt an important symbol in the development of electric vehicles . However , the rapid development of new materials and electrochemical technologies has brought new batteries to life and has brought vitality and development opportunities for electric vehicles . However , the electrochemical efficiency of the new materials and electrochemical technologies is closely related to the temperature .

On the basis of summarizing the development of EV and its power battery , the research work of power battery thermal management is summarized . So far , the cooling mode of power battery thermal management system mainly includes air cooling , liquid cooling , heat pipe cooling and phase change material cooling . The application of power battery is mainly in air - cooled form , and liquid circulation cooling is gradually started .
In view of the battery group thermal management system , the research contents , research methods and research significance are described in this paper .

In this paper , two types of battery liquid flow heat transfer structures are designed for the group of batteries , which can realize the objective of light weight and compactness on the basis of ensuring the good thermal management and the cold and warm thermal control , and provide the potential for the large - scale large - capacity multi - stack combined application . The research works around the model of the group battery flow system , including model establishment , numerical simulation , calculation method and analysis and evaluation method , etc . The experimental verification of the model and the calculation method is carried out in the system , and the calculation precision is guaranteed .

The heat transfer characteristics , flow characteristics and the uniformity of the surface temperature of the battery were analyzed by taking the B - type heat exchange system as an example . The results show that the heat transfer , the heat transfer coefficient and the flow rate of the flow channels at both ends of the heat exchange system are larger than those in the middle region .

The results show that the influence of the flow inlet temperature on the uniformity of the surface temperature of the battery is affected by the influence of the flow inlet temperature on the surface temperature uniformity of the battery , and the temperature uniformity , the flow resistance and the flow uniformity of the surface of the battery are affected .
The results show that the temperature difference between the surface of the cell and the surface of the battery can be reduced to one - half of the original one , and the temperature uniformity of the surface of the battery can be greatly improved .

For B - type liquid heat transfer system , the performance of low temperature preheating and high temperature rapid cooling is analyzed . The results show that the conventional flow has little effect on low temperature preheating and high temperature rapid cooling ;
the higher the inlet temperature during the low temperature preheating , the faster the temperature of the battery rises in the same time ;
The higher the inlet temperature during the high temperature rapid cooling process , the faster the temperature drop in the same time , the better the cooling effect . The experimental results show that the flow heat exchange system designed in this paper can adjust the battery temperature to the normal operating temperature range in a short time under the conditions of low temperature and high temperature .

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

【参考文献】