Effect of electrode intrusion on pressure drop and electrochemical performance of an all-vanadium redox flow battery

• Published in: Journal of power sources 2017-08, Vol.360, p.548-558
• Main Authors: Kumar, S., Jayanti, S.
• Format: Article
• Language: English
• Subjects: Electrode compression; Electrolyte circulation; Flow field; Power density; Pressure drop; Vanadium redox flow battery
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.06.045

In this paper, we present a study of the effect of electrode intrusion into the flow channel in an all-vanadium redox flow battery. Permeability, pressure drop and electrochemical performance have been measured in a cell with active area 100 cm2and 414 cm2 fitted with a carbon felt electrode of thickness of 3, 6 or 9 mm compressed to 1.5, 2.5 or 4 mm, respectively, during assembly. Results show that the pressure drop is significantly higher than what can be expected in the thick electrode case while its electrochemical performance is lower. Detailed flow analysis using computational fluid dynamics simulations in two different flow fields shows that both these results can be attributed to electrode intrusion into the flow channel leading to increased resistance to electrolyte flow through the electrode. A correlation is proposed to evaluate electrode intrusion depth as a function of compression. •Effect of electrode intrusion into flow channels studied experimentally.•Study covers three electrode thicknesses, two flow fields and two cell sizes.•Pressure drop and polarization behavior measured.•Supporting CFD simulations carried out for many cases.•Correlation for electrode intrusion depth proposed.