随着电动汽车的大力发展，退役动力锂电池的回收、处理、再利用成为了亟待解决的问题。利用储能系统对退役锂电池进行梯次利用，既能大幅延长锂电池的寿命周期，又能降低储能系统建设中的电池成本，提升储能系统经济效益。但锂电池全寿命周期中的参数离散性也给储能系统带来了运行安全性的问题，由此需要寻找一种基于电化学机理的、不影响储能系统正常工作的锂电池状态参数的监测方法。本文基于电化学阻抗谱的方法，研究了锂离子电池等效阻抗模型的构建及阻抗参数的辨识与监测，设计了一种锂电池考虑电池荷电状态（State of Charge，SOC）变化的电池健康状态（State of Health，SOH）估算方法，具体内容如下：首先，利用电化学工作站测量18650型三元锂电池在不同SOC、不同SOH下的电化学阻抗谱，根据被测锂电池电化学阻抗谱形貌，与基本阻抗元件、基本阻抗环节的阻抗形貌相对比，构建了锂电池基于电化学阻抗谱的等效阻抗模型，并对所建立的模型进行了拟合验证。其次，基于Levenberg-Marquardt算法结合被测锂电池的电化学阻抗谱数据，对其等效阻抗模型中的阻抗参数进行拟合辨识，其中针对L-M等最小二乘拟合算法初值选取不合理导致计算偏差或不收敛的问题，提出了一种基于阻抗谱数据的分段解析拟合的初值确定方法，解决了阻抗参数辨识中的初值选取问题。而后通过对比不同电池电阻参数与电池SOH的关联性，选取电荷转移电阻用来估算电池的SOH，并通过锂电池的电化学反应机理推导电荷转移电阻与电池SOC之间的关系，最终提出了一种考虑电池SOC变化的SOH估计方法，并对该方法进行了拟合验证，该方法展现出了较好的准确度。最后，通过进一步观察被测锂电池的电化学阻抗谱数据，发现锂电池的阻抗谱中存在不随电池状态参数变化的特征频率点，且特征频率点阻抗实部之差近似等于对应频段的电池电阻参数。利用DRT方法对被测阻抗谱做进一步分析，验证了上述发现，并提出了基于特征频率阻抗的锂电池快速SOH估计方法。同时考虑到电化学工作站由于体积等原因难以在储能系统中测量电池阻抗，因此基于阻抗测量芯片AD5941设计了电化学阻抗谱测量装置，并与电化学工作站对比测量结果验证精度，对电化学阻抗谱法在实际储能系统应用中做了硬件尝试。

With the vigorous development of electric vehicles, recycling, treatment and re-use of retired power lithium ion batteries has become an urgent problem. Energy storage systems use retired lithium ion batteries as energy storage carriers for the secondary utilization of lithium ion batteries, which can not only significantly extend the life cycle of lithium ion batteries, but also reduce the cost of batteries in the construction of energy storage systems and enhance the economic benefits of energy storage systems. However, the use of secondary lithium ion batteries also brings safety problems to the energy storage system, so it is necessary to find a method to monitor the state parameters of the batteries based on the electrochemical mechanism, which does not affect the normal operation of the energy storage system. In this paper, based on the method of electrochemical impedance spectroscopy, the construction of the equivalent impedance model of lithium ion batteries and the identification and detection of impedance parameters are studied, and the state of health (SOH) estimation method of lithium ion batteries considering the change of state of charge (SOC) of batteries is designed, as follows.Firstly, the electrochemical impedance spectroscopy of 18650 ternary lithium ion battery is measured under different SOC and SOH by using electrochemical workstation, and the equivalent impedance model of the lithium ion battery is constructed based on the shape of the measured lithium ion battery electrochemical impedance spectroscopy, compared with the impedance shape of basic impedance components and basic impedance links, and the established model is fitted and verified.Secondly, based on the Levenberg-Marquardt algorithm, the impedance parameters in the equivalent impedance model are identified by combining the measured electro-chemical impedance spectroscopy data. In response to the problem of calculation deviation or non-convergence due to unreasonable initial value selection of least-squares fit-ting algorithms such as the L-M algorithm, an initial value determination method for segmental analytical fitting based on electrochemical impedance spectroscopy data is proposed to solve the initial value selection problem in impedance parameter identification. Then, by comparing the correlation between different cell resistance parameters and the SOH of the battery, the charge transfer resistance is selected to estimate the SOH of the battery, and the relationship between the charge transfer resistance and the SOC of the battery is deduced through the electrochemical reaction mechanism of the lithium ion battery. At last the SOH estimation method considering the variation of the SOC of the battery is proposed, and the method is validated by fitting, which shows a good accuracy.Finally, by further observing the electrochemical impedance spectroscopy data of the tested lithium ion battery, it is found that there are characteristic frequency points in the impedance spectroscopy of the lithium ion battery that do not vary with the battery state parameters, and the difference of the real part of the impedance of the characteristic frequency points is approximately equal to the battery resistance parameters in the corresponding frequency band. Further analysis of the measured impedance spectroscopy by DRT method verifies the above findings, and proposes a fast SOH estimation method for lithium ion battery based on the characteristic frequency impedance. Meanwhile, considering that the electrochemical workstation is hard to measure the battery impedance in the energy storage system due to its size, an electrochemical impedance spectroscopy measurement device is designed based on the impedance measurement chip AD5941, and the measurement results are compared with the electrochemical workstation to verify the accuracy.