摘 要

自汽车发明到二十一世纪汽车业的高速发展，汽车成了人们必备的交通工具。汽车简便了人们的生活，但是随之而来的问题是资源短缺、大气污染等。为了应对环境污染问题，节省石油资源，新型的电动汽车登上历史舞台。准确把握电池荷电状态SOC的值是电动汽车技术的核心，电池管理系统也离不开SOC的精准估算，所以对于SOC的估算是动力电池研究的前提和基础。因此，本课题建立动力电池的Thevenin等效电路模型来研究电池荷状态精度。本文介绍了几种典型的电池模型，选取二阶Thevenin模型作为研究工具，以戴维南动力电池为研究目标。对电池进行HPPC实验，再以HPPC实验数据为基础对锂电池进行参数辨识，借助Matlab中cftool工具对试验数据进行多项式拟合。最后Matlab/simulink中搭建仿真模型并将辨识数据输入及电流信号导入，得出仿真结果。仿真下所得电压、电流、SOC值与HPPC试验对比，验证等效电路模型的可靠性。分析了仿真误差增大的原因，提出了进一步提高电池模型参数精确度的方法。结果表明，该模型可以准确地描述不同工况下的锂电池外特性，虽然在SOC小于0.2时误差较大，但仿真结果与HPPC试验结果基本吻合。

关键词：动力电池；等效电路模型；参数辨识

Establishment of Equivalent Circuit Model for Second-order Thevenin Power Battery

ABSTRACT

From the invention of automobile to the rapid development of automobile industry in the 21st century, automobile has become a necessary means of transportation for people. Automobile simplifies people's life, but the following problems are the shortage of resources, air pollution and so on. In order to cope with environmental pollution and save petroleum resources, a new type of electric vehicle has been put on the stage of history. Accurately grasping the SOC value of battery charging state is the core of electric vehicle technology, and battery management system can not do without the accurate estimation of SOC, so the estimation of SOC is the premise and foundation of power battery research. Therefore, the Thevenin equivalent circuit model of power battery is established to study the accuracy of battery charge state. Several typical battery models are introduced in this paper. The second-order Thevenin model is chosen as the research tool and the Thevenin power battery is taken as the research object. HPPC experiments were carried out on batteries, and the parameters of lithium batteries were identified based on HPPC experimental data. The experimental data were polynomially fitted with the help of cftool tool in matlab. Finally, the simulation model is built in MATLAB/simulink and the identification data and current signals are imported to get the simulation results. The simulation results of voltage, current and SOC are compared with HPPC test to verify the reliability of the equivalent circuit model. The reason for the increase of simulation error is analyzed, and a method to further improve the accuracy of battery model parameters is proposed. The results show that the model can accurately describe the external characteristics of lithium batteries under different operating conditions. Although the error is large when the SOC is less than 0.2, the simulation results are basically consistent with the HPPC test results.

Keywords: Power battery; Equivalent circuit model; Parameter identification

目 录

1 绪论 1

1.1 本文研究的背景及意义 1

1.2 国内外研究现状 1

1.3 本文主要研究内容及章节安排 2

2 动力电池工作原理与模型选用 4

2.1 锂离子电池原理 4

2.2 常见等效电路模型的介绍 4

2.3 等效电池模型的比较与选用 6

2.4 本章小结 7

3 基于二阶Thevenin模型参数辨识 8

3.1 锂离子电池HPPC充放电实验 8

3.2 模型参数辨识 10

3.2.1 开路电压辨识 11

3.2.2 欧姆内阻辨识 11

3.2.3 极化电阻,,极化电容辨识 12

3.3 本章小结 15

4 基于Matlab/simulink的模型仿真及验证分析 16

4.1 仿真模型的搭建 16

4.1.1 实验环境及输入输出模块模型 16

4.1.2 电池等效模型 19

4.2 仿真结果的对比 20

4.3 仿真结果的分析 20

4.4 本章小结 21

5 总结与展望 22

致 谢 23

参考文献 24

第1章 绪论

1.1 本文研究的背景及意义

随着大气污染的加剧、石油资源的匮乏及石油价格的提高，到新能源汽车的诞生，新能源汽车开始逐步成了人们研究的热点。作为一个刚起步的项目，新能源汽车还存在一些问题，比如电池容量低，电池使用寿命短，甚至还存在电池过热自燃爆炸等严重问题。

新能源汽车不是纯粹意义上的纯电动汽车，它还分为许多小类型，比如混合动力汽车及燃料电池电动汽车等^[1]，目前市场上使用最多的是以电力作为主要动力源的纯电动汽车和混合动力汽车，所以其主要输出动力还是以电池输送电力为主。相比于传统的燃油汽车来讲，新能源汽车的主要动力源蓄电池存在许多优点，比如减轻了整车的质量使得耗电量减少行驶里程增加，比如简化了汽车的结构使得汽车内部空间增大，节约了框架的使用材料等。但是它依然存在着许多不足点，又如电池的容量问题，电池过热导致的安全问题，续行驶问题等，这些都需要我们去解决。

新能源汽车的动力源作为新能源汽车技术的核心，需要我们针对它电池过热的安全问题和电池容量及使用寿命问题对电池的工作状态进行监控，那么建立电池管理系统^[2]，是监控了解电池的工作状态的关键。