微米導流柱改良之流道板對全釩液流電池性能影響之分析

Enhanced micro-pillars flow field design for performance gains in vanadium redox flow batteries

羅世偉(Shi-wei Luo)

指導教授 ： 李雄

國立中央大學/工學院/光機電工程研究所/碩士(2014年)

摘要

全釩液流電池 (Vanadium Redox Flow Battery, VRFB)在近年內備受關注，因為其具有體積小、功率大、放電穩定及效率高等特性，被廣泛利用在工商業中。而在本研究中，我們針對電池內之電解液流道進行分析，提出四種不同流道設計並藉由測定電池輸出功率及效率之實驗來驗證各種設計之優劣，其中在流道中安插入微米導流柱的設計顯著的改善了流體在流道中的均勻性，且電池性能與原始設計相比之下增加了13%的功率密度(mW•cm-2)。此外，實驗經過多次的取樣以驗證全釩液流電池的電化學性能以及計算其平均效率，結果證實微米導流柱的設計能有效的改良全釩液流電池之性能，且本研究也進一步針對電池的充放電循環進行測試，電池能穩定地保持在72.5%的高能量效率。另一方面，在本研究的改良流道設計之基礎下，我們對組合全釩液流電池之夾持力進行研究，分析在不同夾持力下電池性能之改變，並證實電池在最適合之夾持力下能大幅提高電池68.5%的電流密度(mA•cm-2)，更能有效增加37.3%的電化學反應面積 (Electrochemical Surface Area, ECSA)。

關鍵字

全釩液流電池 ； 微米導流柱 ； 流場均勻性

並列摘要

In this work, we propose a uniformly distributed electrolytes system based on micro pillars enhanced flow field designs for vanadium redox flow battery (VRFB). Experimental validation is carried out using a power-based efficiency method and measured for four different entrance bypass designs. Results show that a micro pillars flow field at the entrance bypass region can result in a significant improvement of 13% power density, as compared with the original design. In addition, the effect of asymmetry anode/cathode flow rates and the cycling tests are measured for verifying the electrochemical performance and the average efficiency of the VRFB unit cell. From the results, it is clearly indicated that the asymmetry flow rate between each half-cell with the selection of our micro pillars enhanced design can result in an optimal flow rate for each half-cell at which the maximum efficiency can be achieved. Moreover, the charge/discharge cycling tests shows consecutive and consistently smooth curve such that the cyclic performance can be stably maintained and a relatively higher average value of energy efficiency 72.5 % is obtained for our VRFB design.
On the other word, based on the micro-pillars design, the effect of different assembly torque which is used to tighten the bolts surrounded the end plate is investigated. There is an optimal assembly torque can result in a significant improvement of 68.5% current density when compared with the original torque. Furthermore, the effect of cyclic voltammograms (CV) is measured to verify the electrochemical performance of the VRFB unit cell. The results clearly indicate that the optimal assembly torque with enhanced micro-pillars design can result in the 37.3% increment of estimated electrochemical surface area (ECSA).

並列關鍵字

Vanadium Redox Flow Battery ； micro-pillars ； flow uniformity

參考文獻

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