Journal of Applied Electrochemistry

, Volume 48, Issue 6, pp 639–649 | Cite as

Capacity balancing for vanadium redox flow batteries through electrolyte overflow

  • Katharina SchafnerEmail author
  • Maik Becker
  • Thomas Turek
Research Article


The vanadium crossover through the membrane can have a significant impact on the capacity of the vanadium redox flow battery over long-term charge–discharge cycling. The different vanadium ions move unsymmetrically through the membrane and this leads to a build-up of vanadium ions in one-half cell with a corresponding decrease in the other. In this paper, a dynamic model is developed based on different crossover mechanisms (diffusion, migration and convection) for each of the four vanadium ions, water and protons in the electrolytes. With a simple to use approach, basic mass transport theory is used to simulate the transfer of vanadium ions in the battery. The model is validated with own measurements and can therefore predict the battery capacity as a function of time. This is used to analyse the battery performance by applying a continuous overflow from one-half cell to the other. Different overflow rates were analysed with regard to an impact of the performance and electrolyte stability. It was observed that a continuous overflow increases the capacity significantly but that the electrolyte stability plays an essential role using a membrane with a big vanadium crossover. Even with a good performance, a complete remixing of the tanks is necessary to prevent electrolyte precipitations.

Graphical Abstract


Vanadium redox flow battery Mathematical model Crossover Self-discharge Capacity balancing 



The authors gratefully acknowledge thyssenkrupp Industrial Solutions AG for financial support and the Energy Research Center of Clausthal University of Technology (EFZ) for technical assistance during this project.


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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute of Chemical and Electrochemical Process EngineeringClausthal University of TechnologyClausthal-ZellerfeldGermany
  2. 2.Energy Research Centre of Clausthal University of Technology (EFZ)GoslarGermany

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