锂电池化成过程中的热效应分析及散热结构设计

发布时间：2018-03-18 20:21

本文选题：锂电池化成　切入点：温度场　出处：《东华大学》2014年硕士论文　论文类型：学位论文

【摘要】：锂离子电池因其比能量高、循环寿命长、环境污染小等优点正成为新能源汽车的主流动力源。锂离子动力电池作为汽车的关键部件,其充放电性能及可靠性将直接影响整车的成本和性能,而锂电池化成工艺过程的多次充放电的电化学反应使其产生大量的热量,为此充放电过程中对电池以及电池周边工况的散热好坏成为影响锂电池化成效果的关键因素。本课题以实际锂电池化成单元为研究对象,从理论和试验仿真两个方面对锂电池的生热机理、散热方法进行研究,并由此探索散热结构的设计方法,对锂离子电池生产具有重要的实际意义和应用价值。本文的研究内容主要如下： (一)充分调研锂电池的结构组成,电化学原理,化成工艺,以及锂电池充放电过程中的生热机理,为后续开展理论分析和计算仿真提供了理论基础； (二)根据锂离子电池的传热及散热特性,建立了锂电池的热效应模型,计算了锂电池的热物性参数；根据Bernadi D提出的电池生热理论建立了锂电池的生热速率模型,并计算电池在化成过程中的内部生热量； (三)应用Fluent软件对电池生热模型进行流体动力学仿真分析,完成了锂电池温度模型的建模、边界条件设置,计算得到在自然状态下锂电池单体和锂电池组的生热温度场。进一步分析了锂电池化成充放电单元的温度场分布情况,探讨充放电单元空间设计对锂电池组温度场的影响。这些为后续开展散热结构设计提供了分析依据； (四)结合流体力学的基本理论,开展散热结构的设计。提出了上吹风、下抽风、近封闭式通风箱以及变截面通风箱等四种散热设计,并应用Fluent对该四种设计的散热温度场进行数值模拟,完成了对散热结构中影响散热效果的因素的定量分析,从而确定合适的结构参数。论文提出了锂电池化成过程的热场模拟仿真和分析方法,建立了有效的数学模型,并开展了多种散热结构的设计和分析,这些将为锂离子电池化成过程的散热设计提供有效的设计方法和设计依据,也将为锂电池化成自动化生产线的关键部件的设计提供参考借鉴。
[Abstract]:Lithium ion battery is becoming the mainstream power source of new energy vehicle because of its high specific energy, long cycle life and low environmental pollution. The charge / discharge performance and reliability will directly affect the cost and performance of the whole vehicle, while the electrochemical reaction of multiple charges and discharges in the forming process of lithium battery will produce a lot of heat. Therefore, the heat dissipation of the battery and its peripheral conditions in the process of charging and discharging has become the key factor affecting the formation effect of the lithium battery. In this paper, the actual lithium battery formation unit is taken as the research object. The heat generation mechanism and heat dissipation method of lithium battery are studied from two aspects of theory and experiment simulation, and the design method of heat dissipation structure is explored. It has important practical significance and application value for the production of lithium ion battery. The main contents of this paper are as follows:. (1) the structure, electrochemical principle, forming process and heat generation mechanism of lithium battery during charge and discharge are investigated, which provides a theoretical basis for the subsequent theoretical analysis and simulation; (2) according to the heat transfer and heat dissipation characteristics of the lithium ion battery, the thermal effect model of the lithium battery is established, and the thermal physical parameters of the lithium battery are calculated, and the heat generation rate model of the lithium battery is established according to the theory of heat generation proposed by Bernadi D. The internal heat generation of the battery in the process of formation is calculated. (3) using Fluent software to simulate and analyze the heat generation model of the battery, the modeling of the temperature model of the lithium battery and the setting of the boundary conditions are completed. The heat generation temperature field of lithium cell monomer and battery pack is calculated in natural state. The temperature field distribution of the charge / discharge unit of lithium battery is further analyzed. The effect of charging and discharging unit space design on the temperature field of lithium battery pack is discussed. (4) combined with the basic theory of fluid mechanics, the design of heat dissipation structure is carried out. Four kinds of heat dissipation designs, such as upper blow, lower air, near closed ventilation box and variable section ventilation box, are put forward. The numerical simulation of the four designed heat dissipation temperature fields is carried out by using Fluent, and the quantitative analysis of the factors affecting the heat dissipation effect in the heat dissipation structure is completed, and the appropriate structural parameters are determined. In this paper, the thermal field simulation and analysis method of the formation process of lithium battery is put forward, the effective mathematical model is established, and the design and analysis of various heat dissipation structures are carried out. These will provide an effective design method and design basis for the heat dissipation design of Li-ion battery formation process, and will also provide reference for the design of key components of the Li-ion battery formation automation production line.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

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