Rapid Lithium-Ion Battery Impedance Measurements Using Binary Sequence With Optimized Frequency Components

Abstract

Battery impedance provides rich information that facilitates battery state estimation and failure diagnosis, yet the current impedance measurement techniques are quite laborious and difficult to implement. This motivates us to propose a comprehensively optimized binary sequence (COBS) for the fast measurement of broadband battery impedance responses. The minimum signal-to-noise ratio requirement of each frequency component of the excitation signal is first derived by analyzing the quantitative relationship between the impedance deviation and the sampling error. The optimal amplitudes and phase angles of all frequency components are then resolved by applying a comprehensive optimization framework to form the COBS for battery impedance response extraction. The effectiveness of the proposed method is verified experimentally in comparison with two prior arts. The results demonstrate the superior performance in measuring broadband battery impedance, where the total normalized root-mean-square errors are below 0.49%.