Integration of LFP-second life batteries as a storage in a smart microgrid

Abstract

In recent years, there has been an increasing commitment to give batteries a second life, as they are being consumed for different uses and the recycling methods are not defined. This work aims to show how a storage system based on disused Lithium Iron Phosphate (LFP) batteries has been recovered and integrated into the CE.D.E.R- CIEMAT smart microgrid over a period of ten years during which the operation of the system has been affected. During the recovery process, the cells have been classified according to their voltage, and a series of charge-discharge processes have been carried out on them at different voltages to determine their state of health and capacity. Once characterised, the system was assembled and commissioned with the appropriate cells. In addition, for the storage system, a Supervisory Control And Data Acquisition (SCADA) has been developed in Home Assistant for its integration into the CE.D.E.R.'s microgrid management system. This allows the microgrid to be managed more efficiently, storing surplus energy from distributed generation sources and discharging the stored energy during peak consumption periods to reduce peaks, reduce discharges to the distribution grid and reduce the cost of electricity bills.