动力锂离子电池热分析研究

发布时间：2018-04-10 07:37

  本文选题：锂离子电池　切入点：热安全　出处：《重庆交通大学》2015年硕士论文

【摘要】：锂离子电池由于具有高电压、高放电电流、高能量密度和绿色环保等优势,被广泛地应用于电动汽车等动力设备。锂离子电池在充放电过程中会产生大量的热,热量的集聚导致电池温度急骤升高,如果不能及时的将热量散开,会导致电池的充放电性能、寿命和安全性能降低。安全性一直是消费者最为关心的,该性能的好坏与消费者的财产生命安全息息相关。由此可见在锂离子电池设计生产使用过程中,电池组的散热非常重要。研究单体电池和电池组温度场分布情况,进一步找出其影响因素,从而提高动力锂离子电池热安全性能,对提高电动汽车等动力设备的主动安全性具有非常重要的工程价值。本文在广东省引进创新科研团队专项资金(2011N071)—先进储能设备的开发项目的支持下,采用实验和计算流体动力学技术(CFD)相结合,展开对单体软包电池、动力电池组模块的产热与散热分析,在此基础上,对某空调电池箱散热方案的设计与优化进行深入研究。首先,建立锂离子单层电极单元的二维模型,计算电池在工作过程中电极上电场分布规律。计算结果表明,电流主要集中分布在极耳引出端附近。其次,利用实验方法,测量软包电池的部分物性参数,建立软包电池的产热模型。进一步采用CFD技术对单体软包电池进行数值模拟,并利用实验采集软包电池表面温度,验证模型的可靠性。分别以电流为10A和60A对软包电池进行放电模拟,当电池荷电状态(SOC)从1至0的整个放电过程中,10A放电电池表面5个可靠监控点表明模型最大误差不超过0.5℃,60A放电电池表面4个可靠监控点表明模型最大误差不超过2℃。再次,借助于软包电池的产热模型,研究电池单体模块外壳材料、厚度及散热面等对电池模块散热性能的影响。研究表明,材料为钢厚度在2mm左右的电池外壳散热性能较好。此外,针对电池模块后盖对电池组通风散热性能的影响进行研究,结果表明,在电池后盖的设计过程中,将其与电池底部接触面去掉有利于提高电池组的散热性能。最后,以某空调电池箱通风散热开发为例,考虑电池箱内电池组与空气流场的耦合模型,初步提出三种电池箱通风散热方案,对电池箱内电池组进行放电数值模拟。对比分析三个方案电池组温度场,发现方案三的综合散热性能较好。因此,选取方案三进行改进,从而达到控制箱内电池组最高温度和温度分布均匀性的目的。对改进后的电池箱以200A进行放电,在整个放电过程中,电池组最高温度为47.38℃,电池间最大温差略低于5℃。研究结果表明,优化后的方案三在通风散热和电池组温度均匀性方面均达到要求。
[Abstract]:Li-ion batteries are widely used in electric vehicles and other power equipment due to their advantages of high voltage, high discharge current, high energy density and green environment.A large amount of heat will be produced in the process of charging and discharging of lithium-ion batteries, and the accumulation of heat will lead to a sharp rise in the battery temperature. If the heat is not dispersed in time, the charge-discharge performance, lifetime and safety performance of the battery will be reduced.Safety has always been the most concerned by consumers, and the quality of the performance is closely related to the safety of consumer property.It can be seen that the heat dissipation of the battery pack is very important in the design and production of lithium ion battery.In order to improve the thermal safety performance of Li-ion battery, it is of great engineering value to study the temperature field distribution of single cell and battery pack, and to find out the influencing factors, and to improve the active safety of power equipment such as electric vehicle.In this paper, supported by the development project of advanced energy storage equipment with the special fund of innovative scientific research team introduced by Guangdong Province, this paper combines the experimental and computational fluid dynamics technology (CFDs) to develop the single-cell soft-package battery.On the basis of analysis of heat production and heat dissipation of power battery pack module, the design and optimization of heat dissipation scheme for a certain air conditioning battery box are studied in depth.Firstly, a two-dimensional model of lithium ion monolayer electrode unit is established to calculate the distribution of electric field on the electrode during the operation of the battery.The calculation results show that the current mainly distributes near the polar ear elicitation.Secondly, some physical parameters are measured by the experimental method, and the heat production model of the soft-clad battery is established.Furthermore, the numerical simulation of the single cell was carried out by using CFD technology, and the surface temperature of the cell was collected by experiments to verify the reliability of the model.The current of 10A and 60A was used to simulate the discharge of the soft-clad battery.During the whole discharge process from 1 to 0, the maximum error of the model is less than 0.5 鈩，

本文编号：1730284