AC impedance and state-of-charge analysis of a sealed lithium-ion rechargeable battery

Shalini, Rodrigues and Munichandraiah, N and Shukla, AK (1999) AC impedance and state-of-charge analysis of a sealed lithium-ion rechargeable battery. In: J Solid State Electrochem, 3 (7-8). pp. 397-405.

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Abstract

A 7.2V, 1.25 Ah sealed lithium-ion rechargeable battery has been studied for estimating its state-of-charge (SOC) by AC impedance. The dispersion of impedance data over the frequency range between 100 kHz and 25 mHz comprises an inductive part and two capacitive parts. As the inductive behaviour of the battery is attributed to the porous nature of the electrodes, only the capacitive components have been examined. The data obtained at several SOC values of the battery have been analyzed by a non-linear least-squares fitting procedure. The presence of two depressed semicircles in the capacitive region of the Nyquist plots necessitated the use of an electrical equivalent circuit containing constant phase elements instead of capacitances. The impedance parameters corresponding to the low-frequency semicircle have been found useful for predicting the SOC of the battery, mainly because the magnitude of these parameters and their variations are more significant than those of the high-frequency semicircle. The frequency maximum (f(max)) of the semicircle, the resistive component (Z') corresponding to f(max), the phase angle (phi) in the 5.0 Hz-0.1 Hz frequency range, the equivalent series resistance (R-s) and the equivalent series capacitance (C-s) have been identified as suitable parameters for predicting the SOC values of the lithium-ion battery.

Item Type:	Journal Article
Publication:	J Solid State Electrochem
Publisher:	Springer-Verlag
Additional Information:	Copyright of this article belongs to Springer-Verlag.
Keywords:	AC impedance;Lithium-ion battery;State-of-charge
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	02 Jan 2009 16:48
Last Modified:	19 Sep 2010 04:58
URI:	http://eprints.iisc.ac.in/id/eprint/17725

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