锂离子电池产热特性和散热管理的研究

发布时间：2018-04-29 12:39

本文选题：电芯模型 + 热模型　；参考：《电子科技大学》2016年硕士论文

【摘要】：锂离子电池因其自身的优点在电子产品、电动汽车中广泛应用,在实际应用中,电池的工作温度不仅影响电池的安全性,而且严重影响电池的寿命、老化、能量的利用率等性能。为了对电池进行有效的热管理,本文结合实验测试、仿真模拟、解析计算来研究电池的产热分布和散热管理。主要内容和结论如下:1、产热分析以锰酸锂电池为依据,使用COMSOL软件建立一维电芯模型,计算电芯的产热率。单独计算极耳和集流体的产热率,在计算集流体上的产热分布时,建立一种新的解析方法计算集流体上不同位置的产热率,并将集流体、极耳和电芯这三部分的产热导入到热模型中,计算电池的温度分布。并通过实验测试对比,验证了模型的可靠性,同时说明,使用此解析方法计算集流体的产热是合理准确的。在此模型基础上,分析电芯的正极、负极和电解质不同位置的产热率大小,结果表明,负极的产热率大于正极,而且产热率最高的地方在负极和电解质的接触面上。说明在锂电制备和电池老化监测中,需要特别注意负极和电解质的界面。此外,本文还分析了不同放电倍率时,可逆反应热和不可逆欧姆热对电芯单元总产热的影响。结果表明,小倍率放电时,可逆热占总产热的比例大于欧姆热,而随着放电倍率的增加,可逆热和欧姆热都迅速增大,但是欧姆热的增加幅度大于可逆热,最终导致欧姆热在总产热的比例超过可逆热。2、散热管理电池的散热管理方面分为两部分,第一部分是从电池本身结构出发,研究极耳的位置、尺寸以及电池的长宽厚对电池温度的影响,六种极耳配置结果表明,极耳放置在电池相对的两条长边中点,最有利于降低电池的局部温差,但不利于降低最高温度;将两个极耳往边缘移动,可以有效降低最高温度。极耳越宽,越有利于降低电池的最高温度。通过增大长宽厚对原电池容量进行扩容,以此研究电池长宽厚度对电池温度的影响。结果表明,保持厚度不变,增大电池长宽面积扩容的方法,可以有效降低电池的最高温度,但是会增大局部温差;而保持电池面积不变,增加厚度来扩容时,可以有效降低电池的温差,但是增大了电池的平均温度。当兼顾电池的长度、宽度、厚度来扩容时,既可以降低电池的最高温度,又可以减小电池的温差。第二部分散热管理是借助外界的冷却方式来对电池进行散热处理。对扩容后的大面积锰酸锂单体电池以及由此并联组成的电池包分别进行空气冷却、相变冷却以及二者的结合冷却。结果表明:(1)风冷散热中,加大换热系数,可以有效降低电池的平均温度,但是对减小电池的局部温差,效果不明显,如果散热通道数量比较少,则会增大电池的局部温差。(2)相变散热也可以降低电池的平均温度和温差,但如果相变材料的量不足,在相变材料开始融化和完全融化之间,电池的温差增幅会迅速增大,而电池的平均温度会保持在相变温度范围内。当相变材料完全融化后,电池的平均温度继续升高,而温差的变化有所下降。(3)风冷和相变的结合散热效果,比单一的风冷散热和相变散热效果好。
[Abstract]:Lithium ion battery is widely used in electronic products and electric vehicles because of its own advantages. In practical applications, the working temperature of the battery not only affects the safety of the battery, but also seriously affects the battery life, aging, the utilization of energy and so on. In order to manage the battery effectively, this paper combines experimental test, simulation and simulation. The main contents and conclusions are as follows: 1, on the basis of the lithium manganate battery, the thermal analysis is based on the lithium manganate battery, and the COMSOL software is used to establish the one dimension core model and calculate the heat production rate of the core. The heat production rate of the polar and collecting fluids is calculated separately, and a new kind of heat distribution is established in the calculation of the heat production distribution on the fluid collection. An analytical method is used to calculate the heat production rate of different positions on the collector fluid, and the heat production of the three parts of the fluid collection, the polar ear and the electric core are introduced into the thermal model, and the temperature distribution of the battery is calculated. The reliability of the model is verified by the experimental test and comparison. At the same time, it is proved that the heat production of the collector is reasonable and accurate by using this analytical method. On the basis of the model, the heat production rate of the positive electrode of the electric core, the negative electrode and the electrolyte in different positions is analyzed. The results show that the heat production rate of the negative electrode is greater than the positive pole, and the place of the highest heat production rate is on the contact surface of the negative electrode and electrolyte. The effect of reversible heat and irreversible ohmic heat on the total heat production of the core unit is also analyzed. The results show that the ratio of reversible heat to total heat production is greater than ohm heat when the discharge rate is small, but with the increase of discharge ratio, the reversible heat and Ohm heat increase rapidly, but the increase of ohmic heat is greater than that of the reversible heat. Finally, the proportion of Ohm heat in total heat production exceeds the reversible heat.2. The heat dissipation management of the heat dissipation battery is divided into two parts. The first part is the study of the position, size and the influence of the length and thickness of the battery on the cell temperature from the structure of the battery itself. The six kinds of polar ear configuration results show that the polar ear is placed in the relative two of the battery. The middle point of long edge is most beneficial to reducing the local temperature difference of the battery, but it is not conducive to reducing the maximum temperature. The maximum temperature can be reduced effectively by moving the two pole ears to the edge. The wider the polar ear is, the more beneficial to reducing the maximum temperature of the battery. By increasing the length and thickness of the battery capacity, the capacity of the battery can be expanded to study the cell temperature and the cell temperature. The results show that the method of keeping the thickness constant and increasing the length and width of the battery can effectively reduce the maximum temperature of the battery, but it will increase the local temperature difference, while keeping the cell area constant and increasing the thickness to dilate the battery can effectively reduce the temperature difference of the battery, but increase the average temperature of the battery, when the battery length is taken into account. When the width and thickness are expanded, the maximum temperature of the battery can be reduced and the temperature difference of the battery can be reduced. The second part of the heat dissipation management is to heat the battery with the aid of the external cooling mode. The air cooling and phase change cooling of the large area of the large area lithium manganese monomer battery and the battery package which is made up in parallel are cooled. And the combined cooling of the two shows that: (1) increasing the heat transfer coefficient can effectively reduce the average temperature of the battery, but the effect of reducing the local temperature difference of the battery is not obvious. If the number of heat dissipation channels is less, the local temperature difference will be increased. (2) the phase change heat dissipation can also reduce the average temperature and temperature of the battery. But if the amount of phase change materials is insufficient, the temperature difference increase rapidly between the phase change material and the complete melting, and the average temperature of the battery is kept within the range of phase transition temperature. When the phase change material is completely melted, the average temperature of the battery continues to rise, and the temperature difference decreases. (3) air cooling and phase change Combined with the cooling effect, the cooling effect is better than single cooling and heat transfer.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM912

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