Optimal Design of Zinc-iron Liquid Flow Battery Based on Flow Control

Zinc-iron liquid flow batteries have high open-circuit voltage under alkaline conditions and can be cyclically charged and discharged for a long time under high current density, it has good application prospects in the field of distributed energy storage. The magnitude of the electrolyte flow rate of a zinc-iron liquid flow battery greatly influences the charging and discharging characteristics of the battery, and the battery's energy efficiency changes significantly with the change in flow rate. In this paper, the effect of electrolyte flow rate on battery capacity and energy efficiency is experimentally investigated under the conditions of circulating pump output for different engineering applications. The experimental method verifies that the electrolyte flow rate is an important factor affecting the energy efficiency of the battery. In this paper, the experimental and energy efficiency calculations of the charge/discharge characteristics of a single cell, a single stack battery, and a 200 kW overall energy storage module are analyzed, and the optimal pump output and flow rate are optimized and compared step by step. The experimental operation results show that the overall energy efficiency of the stack remains good under the conditions of 42-46 m3/h. However, along with the increase in the number of charge and discharge cycles and the increase in the number of stacks, the stability of the single stack battery affects the battery capacity and charge and discharge characteristics of the whole battery module.