A Practical Guide for the Characterization of Lithium-Ion Battery Internal Impedances in PHM Algorithms

Abstract

This article aims at describing the most important aspects to be considered when using the concept of battery internal impedances in algorithms that focus on characterizing the State-of-Health (SOH) degradation of lithium-ion (Li-ion) batteries. The first part provides a brief literature review that will help the reader to interpret the outcome of typical Li-ion discharge and/or degradation tests. The second part of the paper shows preliminary results for accelerated degradation experiments performed on a Li-ion cell under controlled conditions. Results show changes on electrochemical impedance spectroscopy test that can be linked to battery degradation. This knowledge may be of great value when implementing algorithms aimed at predicting the battery End-of-Life (EoL) in terms of temperature, voltage, and discharge current measurements.