Simulating a novel Electrochemical Impedance Spectroscopy measurement system

We present a novel methodology for Electrochemical Impedance Spectroscopy (EIS) applied to lithium-ion cells, along with a digital model that simulates the measurement system. This innovative approach incorporates the nonlinear behavior of the cell using Volterra filter theory. The digital model, referred to as the Digital Twin (DT), is employed to demonstrate both the strengths and weaknesses of the proposed method. The methodology involves stimulating the cell with a specific current signal. By analyzing the Fourier transform of the impulse response in our nonlinear system — i.e., the first-order kernel of the Volterra model — we obtain the impedance spectrum of the cell. The DT serves as a controlled and customizable environment, acting as a reference system for pre-verifying the measurement equipment before conducting tests on the cell.