Optimization and Design of the Minimal Architecture Zinc-Bromine Battery Using Insight from a Levelized Cost of Storage Model

Abstract

This work demonstrates how a levelized cost of storage (LCOS) model can be used to optimize the performance of the minimal architecture zinc bromine battery (MA-ZBB). Cycling data is collected at charge times ranging from 4 to 48 hours and capacities ranging from 320 to 4000 mAh using scaled-up versions of the MA-ZBB. An LCOS model for the entire MA-ZBB system is proposed and used to demonstrate how the energy efficiency/discharge energy trade-off within the system can be exploited to minimize LCOS. The present, unoptimized cell is shown to approach an LCOS of $0.08 kWh−1 as electricity purchase prices approach $0.02 kWh−1. At all purchase prices, greater than 60% of the LCOS comes from the capital cost, where the main contributors are the carbon foam electrode and zinc bromine electrolyte in the cell (both accounting for 20% of the total capital cost). In addition, two case studies are conducted which show how the LCOS model can be used to determine the optimal electrode spacing (0.4 cm) and electrolyte concentration (1.0 M) in the cell. Finally, a comparison with existing technologies is conducted, indicating the system-level cost of the MA-ZBB is competitive with lithium-ion, lead-acid, vanadium redox flow, and zinc bromine redox flow batteries.