摘要
全釩氧化還原液流電池是一種用來儲存電力的電池。由於全釩電池在充放電過程中可以快速轉換，所以通常都與再生能源作為蓄電池搭配使用作為調和尖離峰與穩定負載之用，如太陽能發電與風力發電。然而，在電解液循環放電過程中，電解液中反應離子濃度越來越少導致質傳現象增加影響電池操作性能。 所以本研究主要探討其電解液濃度對質傳係數之影響。一般全釩電池在操作中，電解液是在儲存桶中循環操作。在本實驗中為了固定其電解液濃度，所以電解液採用非循環操作。在實驗方法上，首先配置不同充電狀態之電解液用於單電池實驗獲得的極化曲線。然後用實驗得到的極化曲線進行極限電流密度分析。 實驗結果顯示，極限電流密度與質傳係數會因電解液充電狀態與計量比的提升而升高。在本研究結束時，質傳係數和電解液流速之間的關係被建立。其結果可以預測質傳過電位，以增加數學模型預測電池性能之精準度。
並列摘要
A vanadium redox flow battery (VRFB) is used for energy storeage and integrated with renewable energy, such as solar and wind power energies. A VRFB plays the role of peaking shaving and load leveling because it can quickly switch between charing and discharging processes. During discharging process, the concentration of reaction ions in the electrolyte will decrease, enhancing the effect mass transfer overpotential on cell performance. In this study, the effects of vanadium ion concentration and electrolyte flow rate on the mass transfer coefficient are experimentally study. The normal VRFB is operated with recirculated electrolytes, causing variation of electrolytle concentration. In order to fix the electrolyte concentration during experiment, the electrolyte is not recirculated. Firstly, electrolyte solutions with different state of charges (SOCs) prepared and used for a single cell to obtain the polarization curves. Then, the polarization curves of overpotential are analyzed for limiting current density. Experimental results show that the limiting current density and mass transfer coefficient increases with increasing state of charge and stoichiometric ratio. At the end of this study, the relationship between the transfer coefficient and electrolyte velocity is established. The result helps predict the effect of operating condition on the cell performance in a mathematical model.