锂离子电池电化学阻抗谱测量方法研究

硕士学位论文

锂离子电池电化学阻抗谱

测量方法的研究

RESEARCH ON MEASUREMENT

METHODS OF ELECTROCHEMICAL

IMPEDANCE SPECTROSCOPY OF

LITHIUM-ION BATTERY

韩晓丽

哈尔滨工业大学

2011年6月

国内图书分类号：TM930.12 学校代码：10213 国际图书分类号：621.3 密级：公开

工学硕士学位论文

锂离子电池电化学阻抗谱

测量方法的研究

硕士研究生：韩晓丽

导 师：王立欣教授

申请学位：工学硕士

学科：电气工程

所在单位：电气工程系

答辩日期：2011年6月

授予学位单位：哈尔滨工业大学

Classified Index: TM930.12

U.D.C: 621.3

Dissertation for the Master Degree in Engineering

RESEARCH ON MEASUREMENT

METHODS OF ELECTROCHEMICAL

IMPEDANCE SPECTROSCOPY OF

LITHIUM-ION BATTERY

Candidate：Han Xiaoli

Supervisor：Prof. Wang Lixin

Academic Degree Applied for：Master of Engineering Speciality：Electronic Engineering Affiliation：Dept. of Electronic Engineering Date of Defence：June, 2011

Degree-Conferring-Institution：Harbin Institute of Technology

哈尔滨工业大学工学硕士学位论文

摘要

随着电子产品向着大规模集成的方向发展，电池作为能源核心部件，其健康状态成为系统正常运行的关键。电池的健康状态反应在它的电化学阻抗谱上。快速、准确测量电池的电化学阻抗谱对电池的寿命预测和健康管理具有重要意义。

本文分别从频率域和时间域测量的两个不同角度，对电化学阻抗谱测量方法进行了研究。

首先，从传统的扫频原理出发，本着集成的原则，在LabVIEW平台上用虚拟的扫频信号发生器代替了传统的信号发生器，用模块化的波形成分检测函数来获取响应信号的幅值和相位，从而代替了传统的相关器或乘法器。

其次，为了解决逐频测量耗时长的问题，研究了基于全相位FFT的测量方法，该方法所用的激励信号是由多个频率的正弦信号叠加而成。数据处理的方法运用全相位FFT，与传统的FFT相比，全相位FFT具有较好的抑制谱泄漏的能力和相位不变性，结果更准确。与扫频方式相比，测量时间大大减少。

最后，研究了基于解析函数Laplace变换的测量方法。文中给定暂态电流阶跃激励，测得系统的时域响应，用半对数法求得时域响应的解析函数表达式形式。然后对求得的解析函数进行Laplace变换，得到频率域的阻抗表达式。测量方法测量时间进一步减少，准确度较高。

为验证上述测量方法，本文针对两种等效电路进行了测试，并把实验测得的结果与理论值和CS阻抗谱测试仪的结果进行了比较，证明了算法的有效性。最后将上述三种方法用于锂离子电池电化学阻抗谱的测量。

对上述三种测量方法的比较分析结果表明，本文所述三种方法都摒弃了传统的信号发生器，乘法器以及相关器等，硬件结构更简单，易于向嵌入式集成方向发展；几种测量方法的横向比较结果表明，基于扫频原理的频率域测量方法，耗时很长，低频时尤其明显。时间域的测量方法可以大大缩短测量时间，其中基于解析函数Laplace变换的测量方法用时最短；除此之外，基于解析函数Laplace变换的测量方法，把采集的离散响应信号转换成了解析函数来进行研究，所得的阻抗谱是连续均匀的，准确度较高。因此，基于Laplace变换的方法能够实现阻抗谱的快速测试，测量结果准确，易于软硬件的嵌入式集成，能够满足应用中对电池性能进行快速测试的要求。

关键词：电化学测量；电化学阻抗谱；扫频；全相位FFT；Laplace变换

哈尔滨工业大学工学硕士学位论文

Abstract

With the development of large-scale integration of electronic products, as the core energy source, the health status of battery is increasingly becoming the keypoint of system operation. Study result found that EIS of battery reprents its health status. Therefore, rapid and accurate measurement fo the battery’s EIS has great significance in life prediction and health management of battery.

This paper has studied on the EIS measurement of battery from frequency domain and time domain.

Firstly, a intergated virtual frequency sweep signal generator is used instead of traditional signal genetrator under the conventional principle fo frequency sweep on the LabVIEW platfrom. Modular waveform detect function is used to obatin the amplitude and phase of responsing signal instead of traditional correlation or multipliers.

Secondly, in order to solve the problem of long time-consuming in frequency-sweeping, this paper has studied a measurement method based on all-phase FFT, the stimulus signal used is componented by multiple frequencies of sinusoidal signal, the data is processed by all-phase FFT. Comparing with the traditional FFT, all-phase FFT is better in spectrum leakge-preventing and phase invariance, the result is much more accurate and measurement time has been reduced.

Finally, another measurement method which is based on the Laplace transform analytic function has been studied. With given transient current step excitation to get time domain of system, and the analytical function expression form of time domain response is obatined by half logarithmic. Then the analytic funtcion is Laplace transformed to get impedance expression in frequency domain. This one has further reduced the measurement time and improved accuracy of result.

To verify the measurement methods described above all, two kinds of equivalent circuits are designed, and experiment result is compared with theoretical value and result obatined by CS impedance tester, the validity of the algorithm has been proved. Finally, it is used in the measurement of lithium-ion battery EIS

Analysis of the three measurement results showed that they are more simple from the software and hardware point of view to implement, as methods described in this article abandoned the traditional signal generators, multipliers, and other related circuit, they are much possible to be embedded. Frequence-sweeping method is much longer in time consuming, especially in low frequencies. Method based on time domain can shorten measurement time greatly, and the Laplace transform of