Comparing Power Processing System Approaches in Second-Use Battery Energy Buffering for Electric Vehicle Charging

TL;DR

This paper evaluates a new power processing method, LS-HiPPP, for second-use battery systems in electric vehicle charging, showing significant improvements in energy utilization and reliability over conventional methods.

Contribution

Introduces LS-HiPPP, a novel power processing approach for 2-BESS, enabling higher energy utilization and better performance metrics compared to traditional architectures.

Findings

LS-HiPPP achieves 94% energy utilization versus 78% for C-PPP.

LS-HiPPP has a derating of 84.3%, higher than 63.1% for C-PPP.

LS-HiPPP's captured value is 79.8%, outperforming 51% for C-PPP.

Abstract

The heterogeneity in pack voltages and capacity of aged packs limits the performance and economic viability of second-use battery energy storage systems (2-BESS) due to issues of reliability and available energy. Overcoming these limitations could enable extended use of batteries and improve the environmental impacts of electric vehicles by reducing the number of batteries produced. This paper compares Lite-Sparse Hierarchical Partial Power Processing (LS-HiPPP), a new method for power processing in 2-BESS, to conventional power processing architectures using a stochastic EV charging plaza model. This method for performance evaluation allows a fair comparison among power processing architectures for 2-BESS. Results show that LS-HiPPP increases the battery energy utilization to 94% as compared to 78% for conventional partial power processing (C-PPP) and 23% for full power processing. These results were obtained with 25% heterogeneity in individual battery capacities and 20% power processing within the 2-BESS. Derating and captured value are two derived performance metrics for comparing LS-HiPPP and C-PPP in this work. The derating for LS-HiPPP is 84.3% in comparison to 63.1% for C-PPP. The captured value for LS-HiPPP is 79.8% versus 51% for C-PPP.