Study on Real‐Time Temperature of a 35 kW Vanadium Stack and Its Influences on the Performance of a Vanadium Redox Flow Battery

Abstract

AbstractThe temperature is a very important parameter for an operating vanadium redox flow battery (VRFB). During charging and discharging, the temperature of VRFB is constantly changing. In this paper, a self‐made 35 kW vanadium stack was charged & discharged at the current density of 100 and 120 mA cm−2 to investigate the change trend of real‐time operating temperature. The results show that the temperature decreases during charging and increases during discharging. And the average temperature of each cycle increases with continuous charge‐discharge cycles. The influences of real‐time temperature on performance of columbic efficiency (CE), voltage efficient (VE), over‐potential, capacity, energy, state of charge (SOC), and pressure loss were further investigated. The results show that the temperature fluctuation largely affects the electrochemical properties of VRFB. With the real‐time average temperature increased from 16.02 °C to 29.91 °C, the VE, capacity, energy and the SOC range of the battery increased, while the CE, the over‐potential and the average pressure loss decreased. This work not only gives data support to temperature management of VFB, but also provides direction to the engineering application of all flow batteries.