Accurately monitoring state-of-charge (SoC) is vital for any rechargeable battery system. It is important to monitor the SoC of both half-cells simultaneously because of imbalances which occur due to side reactions and unwanted vanadium transfer across the membrane. The electrolyte may be rebalanced by various techniques but only if the SoC of each half-cell is accurately known. There are multiple possible techniques to monitor the SoC of each half-cell. We measure SoC in-situ by analysing the absorbance spectra of the vanadium electrolytes as they are charged and discharged. We also accurately measure volume changes throughout the cycle to study the water transfer through the nafion membrane. This accurate SoC data which is obtained will be compared with other SoC techniques. It will also be used to study the performance characteristics of the battery.

Acknowledgements:

This research was funded by the Sustainable Energy Authority of Ireland (Award Number 18/RDD/341).