A Method for Detecting the Existence of an Over-Discharged Cell in a Lithium-Ion Battery Pack via Measuring Total Harmonic Distortion

This paper deals with a method to detect the existence of an over-discharged cell in lithium-ion battery (LIB) pack by measuring total harmonic distortion (THD) rate voltage response. Over-discharge LIB reduces available capacity irreversible chemical reactions, resulting serious safety risks such as explosions. Even if only one exists pack, it accelerates decomposition other cells. In general, measurement each is required cell. because measured, cannot be distinguished whether uniformly low or specific weak over-discharged. The proposed measures frequency response through at two terminals presence When discharged beyond certain level, system nonlinearity increases, and can detected from increased THD pack. verified simulation measurement.