Batteries, Vol. almost eight, Pages 26: A Technique for Detecting the Existence of a good Over-Discharged Cell in the Lithium-Ion Battery Pack via Testing Total Harmonic Distortion
Batteries doi: 10. 3390/batteries8030026
Authors: Jonghyeon Kim Julia Kowal
This paper works with a method to detect the existence of a good over-discharged cell in a lithium-ion battery (LIB) package by measuring the overall harmonic distortion (THD) rate in the voltage reaction. Over-discharge of the LIB cell reduces the accessible capacity by irreversible chemical reactions, resulting in serious security risks such as explosions. Even if just one over-discharged cell exists in the battery pack, it accelerates the decomposition of other cellular material. In general, the dimension of each cell voltage in a battery power is required to identify one over-discharged cell. This is because if just the voltage of the battery pack is tested, it cannot be recognized whether the voltage of each cell is consistently low or one specific weak cell is over-discharged. The proposed method measures the frequency response via the voltage at only 2 terminals of the battery power to detect the presence of one over-discharged cell. When the battery cell is discharged beyond a certain level, the system nonlinearity of the battery power pack increases, and it can be detected from the increased THD rate associated with the battery pack. The proposed method is verified by simulation and measurement.
