Studies on pressure losses and flow rate optimization in vanadium redox flow battery
Studies on pressure losses and flow rate optimization in vanadium redox flow battery
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DOI：
10.1016/j.jpowsour.2013.09.071
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发表时间：
2014-02-15
影响因子：
9.2
通讯作者：
Skyllas-Kazacos, Maria
中科院分区：
文献类型：
--
作者：
Tang, Ao;Bao, Jie;Skyllas-Kazacos, Maria
钒氧化还原液流电池运行中的过早断压在很大程度上与高荷电状态(SOC)或放电状态(SOD)下浓度过电位的上升有关。高恒定体积流量的使用将降低浓度过电势，但可能会消耗过多的泵送能量，从而降低系统效率。另一方面，任何不适当的流量降低也会限制运行的SOC，并导致电池效率下降。需要减少流动电池组中的分流电流，这就需要使用又长又窄的通道和歧管，从而进一步加剧了压降损失。本文将浓度超电势模拟为流量的函数，通过对压力损失和总泵浦能量的分析，确定了能够产生较高系统效率的合适的可变流量。40节电堆在预设电压截止极限下的模拟结果表明，对于给定的系统设计，可变流量优于恒定流量，对于不同的充放电操作，使用相对于理论流量7.5的流量因数可以达到整体较高的系统效率。(C)2013爱思唯尔B.V.保留所有权利。
Premature voltage cut-off in the operation of the vanadium redox flow battery is largely associated with the rise in concentration overpotential at high state-of-charge (SOC) or state-of-discharge (SOD). The use of high constant volumetric flow rate will reduce concentration overpotential, although potentially at the cost of consuming excessive pumping energy which in turn lowers system efficiency. On the other hand, any improper reduction in flow rate will also limit the operating SOC and lead to deterioration in battery efficiency. Pressure drop losses are further exacerbated by the need to reduce shunt currents in flow battery stacks that requires the use of long, narrow channels and manifolds. In this paper, the concentration overpotential is modelled as a function of flow rate in an effort to determine an appropriate variable flow rate that can yield high system efficiency, along with the analysis of pressure losses and total pumping energy. Simulation results for a 40-cell stack under pre-set voltage cut-off limits have shown that variable flow rates are superior to constant flow rates for the given system design and the use of a flow factor of 7.5 with respect to the theoretical flow rate can reach overall high system efficiencies for different charge-discharge operations. (C) 2013 Elsevier B.V. All rights reserved.