基于锁定放大器和Levy辨识法的锂电池阻抗参数在线测量

On-line Measurement of Impedance Parameters of Lithium Batteries Based on Lock-in Amplifier and Levy Method

根据磷酸铁锂电池各类型内阻的产生原因和影响因素,建立电池内阻等效模型,确定电化学阻抗谱法对电池内阻进行测量,并以此提出了磷酸铁锂电池内阻在线式检测系统的总体设计方案。对系统中的各部分以及整体系统进行了仿真测试,得到了电池模型的电化学阻抗谱,将测量值与设定值进行对比,通过使用Levy法精确辨识出等效模型的各个参数。模拟实际电路情况,在仿真模型中加入噪声干扰,探究噪声对内阻测量精准度的影响。从仿真测试的情况可以看出,磷酸铁锂电池内阻在线式检测系统的测试指标满足系统的设计要求。

In this paper,the internal resistance equivalent model of lithium iron phosphate battery is established according to the causes and influencing factors of the battery internal resistance,and the method of electrochemical impedance spectroscopy is adopted to measure the battery internal resistance.The electrochemical impedance spectrum of the battery model is obtained by simulation test of each part of the system and the whole system.Then,the measured values are compared with the set ones,and the parameters of the equivalent model are accurately identified by Levy method.To simulate the actual circuit,noise interference is added into the simulation model to explore the influence of noise on the accuracy of internal resistance measurement.Finally,it can be seen from the simulation test that the test index of the on-line detection system for the internal resistance of lithium iron phosphate battery meets the design requirements of the system.