关键词: 阻抗谱, 快速测量, 伪随机二进制序列, 估计算法, 电化学能源

Abstract:

With the extensive application of impedance spectroscopy, the time-consuming issue of its traditional testing methods has become more and more serious, which limits its application range. In the study of accelerating impedance measurement or reconstruction, the synthesis of wideband excitation signals and the design of high efficiency estimation algorithms have been identified as important ways. In view of the purpose of rapid impedance reconstruction, Pseudo-Random Binary Sequence (PRBS) has the advantages of flat power spectrum and easy generation, and has a good application prospect. This paper reviews three core issues in rapid reconstruction of impedance spectrum: PRBS signal types, different fast algorithms, and their typical applications in the field of electrochemical energy. For the PRBS signal types, namely, the maximum length sequence signal, the hybrid PRBS, the discrete interval binary sequence and the orthogonal PRBS, their respective characteristics and application ranges are discussed. For the fast algorithms corresponding to different PRBS excitation signals, namely, the discrete Fourier transform/Fast Fourier transform, wavelet transform, fast m-sequence transform, parameter estimation algorithm based on system identification, and their respective characteristics and application scope, this paper has carried out in-depth analysis on computation efficiency and calculation precision for fast reconstruction of impedance spectrum. For the application of rapid impedance spectrum measurement based on PRBS, the electrochemical energy sources such as lead-acid batteries, lithium-ion batteries, proton exchange membrane fuel cells and supercapacitors are taken as examples to verify the feasibility of its application. In order to promote the further improvement of technology, this paper summarizes and analyzes the challenges in rapid measurements or reconstruction of impedance spectrum based on PRBS signals, and proposes the future research strategy necessary to overcome these challenges: 1) design hardware test system according to specific application scenarios; 2) choose the optimal estimation algorithms based on the test object; 3) balance the complexity between excitation signal generation and impedance estimation algorithms.

Key words: impedance spectroscopy, fast measurement, pseudo-random binary sequence, estimation algorithm, electrochemical energy