Development and testing of mechanically stable Vanadium redox flow battery
Molchanov, Bogdan (2016)
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This thesis work is concerned with electrochemical energy storage and conversion technology based on vanadium chemistry. This thesis is continuation of a work done at Arcada in summer 2015 and is expected to become a foundation for future research in the flow battery area. The major objective of this study was to build a prototype of vanadium flow battery that is robust enough to be analyzed and compared against flow batteries of other research groups. The work is broken down into four smaller parts. In the first part a literature review of flow batteries was compiled. The working principles and history of flow batteries and their electrolyte compositions were reviewed. In the second part, vanadium electrolyte production and monitoring methods were studied. The method of producing stock electrolyte from available reagents was established and UV-Vis spectra of the four pertinent oxidation states of vanadium were obtained. The spectra were found to match closely those reported by other research groups. The UV-Vis spectra were then correlated to electrolyte compositions and methods for electrolyte state of charge monitoring were developed. In the third part, improvements to the design and assembly of a battery test station and its components were conceived, evaluated and in some cases implemented. Modifications to the existing battery test station were favored over building a completely new test station. The modifications aimed primarily at eliminating notable electrolyte leakage in the reaction center and other critical spots. In the fourth part, experiments were performed to characterize the battery by undergoing charging and discharging cycles. Electrical data were analyzed to determine the power and efficiency of the battery. The peak power was found to be 0.15 W/cm2, which is close to what other groups have reported. The efficiency of the battery was 60%, which is lower than the 90% efficiencies reported by other groups.