Life-Cycle Optimization and Flow Control in a Nickel-Zinc Flow Assisted Battery

Nickel-Zinc flow-assisted rechargeable batteries are currently being explored as a potential new generation of large-scale, low-cost energy storage devices. The viability of a commercial nickel-zinc battery has been hindered by the well-known phenomena of dendrite formation and zinc morphology variation over time. Applying electrolyte flow to traditional nickel-zinc battery systems has demonstrated significant life cycle performance improvements by reducing both dendrite formation and morphological variation. It has also been demonstrated that periodic low-current reconditioning discharge further improves cycle life. This thesis examines the effect of eliminating electrolyte flow during discharge of nickel-zinc flow assisted batteries, which would allow a much broader range of applications for these novel batteries, particularly transportation-based applications such as electric vehicle applications. Experiments were further designed to determine the optimal periodicity for low-current reconditioning discharge, examining the effects of reconditioning after 7, 12, 20 and 30 charge-discharge cycles. The results of these experiments demonstrate that electrolyte flow during discharge does provide performance benefits, but it is possible to operate a nickel-zinc flow assisted battery without flow during discharge, when low-charge reconditioning is applied every 7 cycles. It was further found that when electrolyte is flowing continuously, nickel-zinc flow-assisted batteries can operate at high efficiency and minimal performance degradation with periodic reconditioning after 30 cycles