摘 要

二十一世纪以来，世界各国皆在努力研发新能源载具的相关技术，同时电动载具是新能源载具中的主流产品，且电池作为核心技术，其容量以及管理技术的要求越来越高。而其中锂离子电池是目前被广泛运用的动力电池，分析其电化学和热稳定性对整体性能起到关键作用。本文通过仿真技术，建立一维电化学模型，在考虑电化学热和欧姆热的前提下，与锂离子电池三维模型耦合，建立其温度场模型。根据仿真模型分析锂离子电池不同方向的散热，外壳与内部电池形成的三层材料的散热以及集柱的欧姆热，以此加深对锂离子电池热管理的研究。

根据研究结果可得出：在电池进行充放电循环过程中，电池在生热速率是非线性的，并且在放电时生热率高，在充电时生热率较低；电芯的平均生热率在充放电过程中呈增加的趋势，且由于对流换热，电池中心的热量不能及时传递出去，故而中心的温度更高；

在垂直于电池极片的方向上，随着尺寸的增大，电极极片的增加，产生了显著的温度梯度。

关键词：锂离子电池；热电化学耦合模型；热管理

ABSTRACT

Since the 21st century, all countries in the world are trying to develop new energy vehicle technology, and electric vehicle is the mainstream of new energy vehicle products, and battery as the core technology, its capacity and management technology requirements are getting higher and higher.Among them, lithium ion battery is the power battery which is widely used at present. The analysis of its electrochemical and thermal stability plays a key role in the overall performance.In this paper, a one-dimensional electrochemical model was established by means of simulation technology. On the premise of considering electrochemical heat and ohmic heat, it was coupled with a three-dimensional model of lithium ion battery to establish its temperature field model.According to the simulation model, the heat dissipation of lithium ion battery in different directions, the heat dissipation of the three-layer material formed by the shell and the internal battery and the ohmic heat of the collecting column are analyzed, so as to deepen the research on the heat management of lithium ion battery.

According to the research results, it can be concluded that in the process of battery charging and discharging, the heat generation rate of battery is non-linear, and the heat generation rate is high when discharging, and low when charging; the average heat generation rate of battery cell is increasing in the process of charging and discharging, and because of convection heat exchange, the heat of battery center can not be transferred out in time, so the temperature of battery center is higher; in vertical In the direction of the electrode, with the increase of the size of the electrode, there is a significant temperature gradient.

Keywords:Lithium-ion batteries;Thermoelectric chemical coupling model;Thermal management

目录

第 1 章：绪论..................................................................................................................................1

第 2 章：电动汽车发展趋势对动力电池的要求....................................................................2

第 3 章：锂离子电池的组成及原理..........................................................................................3

3.1锂离子电池的组成及结构................................................................................................3

3.2锂离子电池的工作原理......................................................................................................4

3.3锂离子电池的产热原理.....................................................................................................4

第 4 章：构建锂离子热-电化学耦合模型................................................................................5

4.1理论思路................................................................................................................................5

4.2电化学模型............................................................................................................................6

4.3热平衡....................................................................................................................................7

4.4 三维模型构建.....................................................................................................................7

4.5热-电化学模型耦合............................................................................................................8

第 5 章：分析结果与讨论............................................................................................................9

5.1总体温度特性分析..............................................................................................................9

5.2各方向上的温度梯度分析..............................................................................................10

5.3极耳温度特性分析............................................................................................................11

5.4电池结构不同材料的温度分析.....................................................................................12

第 6 章：结论..................................................................................................................................13

致谢....................................................................................................................................................14

参考文献...........................................................................................................................................15

第1章：绪论

电动载具在国内有着巨大前景，而动力电池是其技术的核心，也是研究者们的重点。如今对动力电池的要求越来越高，主要着重在更大的能量密度，更长的循环寿命，充放电的安全性，更大的单体容量上。而锂离子电池是如今被广泛关注的动力电池，它的整体性能很强，拥有能量密度大，储能高，安全性能好的特点。然而锂离子电池在充放电过程中伴随着很复杂的电化学反应，电池的反应热和运行工况等皆影响着它的综合性能。当电池分布的不均匀时，或者过热过冷时，温度的不均匀会使得电池组之间的平衡性被破坏，有可能使电池损毁，引起安全事故。锂离子电池是由多个电化学单元组成的复杂系统，其电化学和热稳定性对电子器件的性能和使用性能起着至关重要的作用。迄今为止，人们已经进行了大量的研究工作，通过开发新的电极化学和设计不同的电池几何形状来促进锂离子电池技术的发展。然而由于相应的热管理设计不够成熟，导致大规模锂离子电池组没有得到成熟的发展，所以针对锂离子电池，开展温度特性的分析研究成了重点。

就锂离子电池的热管理而言，影响电池温度分布有诸多因素，电池的电化学反应是否充分，电池的尺寸，外壳和结构。其中电池的外壳和结构的不同会导致电池内部的热传递以及电流分布的变化。根据电池尺寸结构的对比分析，我们可以得到更高效更安全的大型方型锂离子电池的尺寸参数，为动力电池交通工具打下夯实的基础。