Vanadium redox flow battery (VRFB) is one of the promising technologies suitable for large-scale energy storage in power grids due to high design flexibility, low maintenance cost and long-life cycle. Vanadium redox flow cell consists of two porous electrodes with serpentine flow channels and electrolyte solutions which is separated by an ion-exchange membrane. The temperature has been set to 298 K for the electrolytes which is composed of 1500 mol/m³ initial vanadium concentration with 4000 mol/m³ initial HSO concentration. We developed a three-dimensional model to scrutinize the complexities of fluid dynamics and electrochemical reactions when considering different electrode thickness sizes, electrode porosity and electrolyte flow rates. In this study, a three-dimensional numerical simulation have been performed in order to investigate the effect of electrode thickness and electrode porosity on the performance of VRFB. The impact of electrolyte solution flow rate on the VRFB electrical characteristics and efficiencies are also numerically investigated. The results show that the cell voltage increases with increasing the electrolyte flow rate and electrode porosity during discharging process of VRFB. Increasing the initial vanadium concentration, the VRFB cell voltage is significantly increased due to reduced overpotential in the porous electrodes. The maximum power-based efficiency of 96.8% is calculated with the electrode thickness of 1 mm at 10 ml/min, while the power-based efficiency of 96.4% is calculated with the electrode thickness of 4 mm at 50 ml/min. This work gives comprehensive insights on electrode configurations for VRFBs.

中文翻译：

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全钒氧化还原液流电池电极厚度和孔隙率影响的数值研究

全钒氧化还原液流电池（VRFB）由于设计灵活性高、维护成本低和生命周期长，是适合电网大规模储能的有前途的技术之一。钒氧化还原流通池由两个带有蛇形流道的多孔电极和由离子交换膜分隔的电解质溶液组成。对于由 1500 mol/m3 初始钒浓度和 4000 mol/m3 初始 HSO 浓度组成的电解质，温度设置为 298 K。我们开发了一个三维模型，以在考虑不同的电极厚度尺寸、电极孔隙率和电解液流速时仔细检查流体动力学和电化学反应的复杂性。在本研究中，进行了三维数值模拟，以研究电极厚度和电极孔隙率对 VRFB 性能的影响。还对电解质溶液流量对 VRFB 电气特性和效率的影响进行了数值研究。结果表明，VRFB放电过程中，电池电压随着电解液流量和电极孔隙率的增加而增加。增加初始钒浓度，由于多孔电极中的过电势降低，VRFB 电池电压显着增加。当电极厚度为1mm、流量为10ml/min时，计算得到的最大功率效率为96.8%；当电极厚度为4mm、流量为50ml/min时，功率效率为96.4%。这项工作对 VRFB 的电极配置提供了全面的见解。