Pseudo-random sequences for low-cost operando impedance measurements of Li-ion batteries

TL;DR

This paper introduces pseudo-random sequences for low-cost, fast, and efficient operando impedance measurements of Li-ion batteries, enabling better monitoring with simple hardware and data processing.

Contribution

The work presents novel pseudo-random sequences with properties that allow efficient drift compensation in battery impedance measurements, validated through simulations and experiments.

Findings

Effective drift and transient suppression demonstrated

Fast impedance measurements during battery charging

Low-cost hardware implementation feasible

Abstract

Operando impedance measurements are promising for monitoring batteries in the field. In this work, we present pseudo-random sequences for low-cost operando battery impedance measurements. The quadratic-residue ternary sequence and direct-synthesis ternary sequence exhibit specific properties related to eigenvectors of the discrete Fourier transform matrix that allow computationally efficient compensation for drifts and transients in operando impedance measurements. We describe the application of pseudo-random sequences and provide the data processing required to suppress drift and transients, validated on simulations. Finally, we perform experimental operando impedance measurements on a Li-ion battery cell during fast-charging, demonstrating the applicability of the proposed method. It's low-cost hardware requirements, fast measurements, and simple data-processing make the method practical for embedding in battery management systems.