Lithium Iron Phosphate State of Charge Estimation, Cycle Life and Capacity Fading

Abstract

SoC estimation is considered to be the most crucial and complex part of designing any battery powered product as it involves various algorithms and techniques to be implemented. In this paper, the arguments to be considered in order to eliminate SoC Estimation Error are presented by carrying out Charge-Discharge Cycles on 100Ah Lithium Iron Phosphate Cells at different C-Rates and plotting a Voltage vs State of Charge Curve. Measuring the precise values of the remaining Ah of a Cell in percentage for the end user requires several aspects of the Cell Chemistry and its behaviour under the range of operating conditions (Safe Operating Area) to be studied intensively.