A novel methodology to estimate the state-of-health and remaining-useful-life of a Li-ion battery using discrete Fourier transformation

Abstract

In this work, a multiphysics-based modeling approach is followed, which helps to diagnose the state-of-health (SoH) of the battery by using the discrete Fourier transform (DFT) analysis. The experimentally validated electrochemical model is considered based on the pseudo-2-Dimensional (P2D) porous electrode model. A constant current with a small perturbation (sinusoidal) on it is applied to the cell for testing purposes. The cell testing pulses of different frequencies are applied to the cell, and output responses are measured for the same. The change in battery output voltage response is observed with the contributing factors (SEI layer resistance, active material volume fraction reduction of anode) in the electrochemical model to observe the change in battery output voltage response. The spectrum analysis of the output voltage response is carried out to show the effect of aging on the battery using the DFT algorithm. Mathematical relationships between signal power and cell degrading parameters are formulated. Finally, a methodology is developed based on the obtained signal power values and the cell degrading factors, which concludes the present SoH of the cell and helps to give remarks to the remaining-useful-life (RUL) of the cell.