Solar power applications and integration of lithium iron phosphate batteries in off-grid photovoltaic system

Abstract

Lithium iron phosphate battery is a type of rechargeable lithium battery that has lithium iron phosphate as the cathode material and graphitic carbon electrode with a metallic backing as the anode. It is a relatively new emerging energy storage battery that is Cobalt-free and Nickel-free. However, its integration with solar PV systems and the specific precautions for its use is not well known to most technicians and installers, especially in developing countries. In this paper, the issues on the applications and integration/compatibility of lithium iron phosphate batteries in off-grid solar photovoltaic systems are discussed. Also, the characteristics, properties, advantages, and disadvantages of the battery are presented. From the study, it is shown that if the battery operates with a charge control algorithm specially set for long charge durations, the energy storage system is an ideal choice for an off-grid photovoltaic system. This is due to their high energy density, long cycle life, relatively low cost compared to Li-ion, high safety, low toxicity, low risk of thermal runaway or combustion, low self-discharge rate, high capacity, lightweight, lower environmental impact, low maintenance, high cell voltage, fast charging, high-temperature stability, high discharge power, a good lifetime when deep cycled, etc. Additionally, the advantages have made the battery to be highly valued in energy storage, backup power, vehicle use utility-scale stationary applications, electric vehicles, commercial batteries , solar power, and other renewable energy applications, etc.