Design, development, and techno-economic analysis of extreme fast charging topologies using Super Capacitor and Li-Ion Battery combinations

Abstract

In the past few decades, it has been observed that Renewable Energy System (RES) coupled with a grid is a potential option for fulfilling the fast-growing load demand. However, the intermittent nature of renewable energy resources limits the performance of RES and prevents it from being properly utilized. This results in power quality issues and grid system instability. To address this issue, it is a common practice to combine RES with effective energy storage technologies, including the latest storage system based on Lithium-Ion Batteries (LIB) and Super Capacitors (SC). However, the fast charging of LIB and slow discharging of SC are still debatable. Time taken for charging LIB is usually sky-high that the Cost of Energy (CoE) becomes unprofitable. On the other side, although the charging of SC is faster, but undergoes quick discharging. Hence, in this paper, a cutting-edge model of LIB, i.e., an extreme Fast Charging LIB (FCLIB) is developed, where LIB is integrated with fast charging SC. This reduces the charging time of storage systems in comparison with conventional systems. In the current paper, six alternative topologies of FCLIB are developed and analyzed for CoE estimation, using real commercial load profiles and resource data. It is observed that the proposed FCLIB with the best topology is achieving 80 % of its State of Charge (SoC) in 5.84 min and 100 % of SoC in 13.5 min. The Optimized Electric Renewable Model (OERM) was employed to analyze the techno-economic analysis of the proposed FCLIB. It is estimated that the proposed topology of FCLIB has a CoE of 0.32$/kWh with fast charging, which is approximately equal to the CoE of a conventional slow charging LIB (estimated as 0.33$/kWh). Thus, the designed FCLIB provides an optimal storage solution for RES to overcome the intermittent nature of renewable energy resources to meet the load demand.