Determination of suitable parameters for battery analysis by Electrochemical Impedance Spectroscopy

Electrochemical Impedance Spectroscopy (EIS) is one of the most powerful tools for the study of batteries. The applied AC current, range of frequency sweep, points per decade represented, length of the pause time after a change in the state of charge (SOC) and length of the pause time after a change in the ambient temperature must have suitable values to obtain useful results from EIS tests. A method to determine and optimize these parameters is presented in this paper. It is based on the limits imposed by the battery, the tests carried out, the instruments employed and the use of Kramers-ICronig relations. The method has been checked using two kinds of lithium batteries: a lithium iron phosphate (LFP) battery and a lithium cobalt oxide (LCO) battery. (C) 2017 Elsevier Ltd. All rights reserved.