State-of-charge indication in portable applications

Abstract

Abstract-The known methods of State-of-Charge (SoC) indication in portable applications are not accurate enough under all practical conditions. The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the remaining run-time with an accuracy of 1 minute or better under all realistic user conditions, including a wide variety of load currents and a wide temperature range. The basis of the proposed algorithm is current measurement and integration during charge and discharge state and voltage measurement during equilibrium state. One of the main problems in designing an accurate SoC indication system is aging of the battery. A simple method of adapting the maximum battery capacity used in the system with the aging effects will be presented in this paper. A first set of experimental results shows the effectiveness of our novel approach for improving the accuracy of the SoC indication.

Modeling Battery Behavior for Accurate State-of-Charge Indication

“…[1][2][3][4][5][6][7][8][9][10][11] However, the battery does not behave like a linear capacitor. This implies that not all charge supplied to the battery can actually be retrieved under all conditions.…”

“…[1][2][3][4][5][6] The purpose of the system is to inform the user of a portable device of accurate SOC and remaining run-time indications in order to provide maximum utility and to prolong the lifetime of the battery. Modeling methods for the EMF and overpotential functions have been developed.…”

An effective method for state-of-charge estimation in wireless sensor networks

“…The battery's EMF (Electro-Motoric Force) which is the open-loop voltage of the battery, is known to be a robust measure for the relative State-of-Charge (SoC) of the battery [3]. The load current of a WSN node with RF communication switched off is close to this open-loop condition of the battery.…”

Smart and Accurate State-of-Charge Indication In Portable Applications

“…The DC/DC converter is in turn leads to an earlier wear-out of the battery. The effect of used to efficiently condition the unregulated battery voltage (3 inaccuracy of SoC indication can be even worse when the SoC V -4.2 V in a Li-ion chemistry) for compatibility with value is also used to control charging. The battery is either not stringent load requirements (see Fig.…”

“…The its history. The battery capacity has been learned during the first charge cycle by using the method described in [3]. A 40408 maximum capacity of 1176 mAh has been obtained.…”