電池設計及操作條件對全釩液流電池性能影響之模擬研究

Modeling the effects of battery design and operating condition on the performance of all-vanadium redox flow batteries

黃裕婕(Yu-Chieh Huang)

指導教授 ： 陳永松

國立中正大學/工學院/機械工程學系/碩士(2015年)

摘要

全釩氧化還原液流電池(以下簡稱全釩電池)近年來已應用於再生能源，與太陽光電發電及風力發電機結合，以作為平衡負載及儲能之用。全釩電池具有較低之電流密度，因此需將其應用於較大之碳氈電極則可提升其電流密度及電池之性能。當碳氈電極之活性區大，電池性能會受到電解液分佈之影響，而其電池之設計及操作條件皆會影響電解液分佈之均勻性，因此本研究探討電池設計和操作條件對電解液分佈及電池性能的影響。
本研究第一部分是以模擬方式探討支流設計對電解液在碳氈電極流動均勻性的影響。由於支流設計參數繁多，本研究對支流設計之探討主要著重於主支流及次支流的設計。模擬結果顯示，主支流設計對電解液分佈之影響較為顯著。第二部分則先以小面積之碳氈電極模型進行分析，並與參考文獻之實驗數據進行比對，探討模擬之可行性。接著以較大面積之碳氈電極進行不同操作條件對濃度分佈及局部電流密度之探討。模擬結果表示，流率較高且操作電流密度較低，濃度分佈及電流密度分佈皆為較均勻。第三部分為探討石墨板之無流道及直向流道設計於不同操作條件下對電池性能之影響。由結果得知，其流道設計寬度較小且深度越深，能有較佳之電池性能。

關鍵字

局部電流密度 ； 流場設計 ； 電解液 ； 全釩氧化還原液流電池

並列摘要

All-vanadium redox flow batteries (VRFB) are currently used for load leveling, peak shaving, and energy storing in renewable energy systems (e.g. solar and wind). The VRFB has low current density, so it requires a larger active area of the carbon felt electrode in practical applications. When the active area is large, battery performance could be affected by electrolyte distribution, which is related to battery design and operating condition. As a results, understanding the effect of battery design and operating condition on electrolyte distribution and battery performance is essential in the development of VRFBs.
The first part of this study was to simulate the electrolyte distribution inside the battery. The stream line, velocity field, and pressure distribution of electrolyte within different distribution channel designs were investigated. Modeling results showed that the primary distribution channel has a significant impact on electrolyte distribution within the active area. In the second part, a mathematical model which can describe local current density was developed and calibrated using experimental data. Then the effect of operating condition on electrolyte concentration and local current density was studied using the calibrated model. The results showed that higher electrolyte flow rate and the lower operating current density can improve electrolyte utilization and battery performance. In the third part, the effect of flow channel design on battery performance was investigated. The results showed that more channel number and deeper channel depth improved battery performance.

並列關鍵字

electrolyte ； local current density ； All-vanadium redox flow battery ； flow field design

參考文獻

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