Lifetime estimation of grid connected LiFePO4 battery energy storage systems

Abstract

Battery Energy Storage Systems (BESS) are becoming strong alternatives to improve the flexibility, reliability and security of the electric grid, especially in the presence of Variable Renewable Energy Sources. Hence, it is essential to investigate the performance and life cycle estimation of batteries which are used in the stationary BESS for primary grid applications. In this paper, a new approach is proposed to investigate life cycle and performance of Lithium iron Phosphate (LiFePO4) batteries for real-time grid applications. The proposed accelerated lifetime model is based on real-time operational param eters of the battery such as temperature, State of Charge, Depth of Discharge and Open Circuit Voltage. Also, performance analysis of LiFePO4 battery system has been carried out for different grid-scale applications. Proposed methodology helps to design the size of the battery system for particular grid applications. Applicability and reliability of the developed life cycle estimation model are demonstrated on the practical 500 kW/250kWh LiFePO4 battery system installed at 230/110/22 kV grid connected substation at Puducherry, India. The real-time operational challenges are addressed and recommendations made based on the field data.