进出液方式对全钒液流电池性能影响模拟研究

Simulation study on impact of inlet-outlet ways on performance of VFB

基于有限元技术建立了全钒液流电池的三维数学模型,模型验证表明,模型计算结果与实验结果较吻合;通过该模型,研究了不同进出液方式下电解液的流速、电解液中钒离子浓度的分布规律,考察了流量、SOC对不同进出液方式下电池端电压的影响,结果表明,存在一个流量的临界值,当流量小于此临界值时,端电压受流量影响较大,当流量大于此临界值时,端电压趋于稳定,受流量影响较小;与对角进出液方式相比,平行进出液方式中电解液流速分布更均匀、浓度梯度及过电势更小,能获得更好的电化学性能。

Based on the finite element method, a three-dimensional mathematical model for vanadium flow battery was developed. The model validation shows that the model calculations and experimental results are in good agreement. Based on the proposed model, the electrolyte velocity and distribution of vanadium ion in electrolyte in different inlet-outlet ways were obtained. The impacts of SOC and flow rate on the battery terminal voltage were studied. The results show that a critical value for flow rate exists. When the flow rate is lower than the critical value, the over-potential is largely affected; when the flow rate is higher than the critical value, the over-potential is less affected. Compared with the diagonal model, the parallel way with more uniform distribution of electrolyte velocity, lower over-potential and vanadium ion concentration gradient can get better electrochemical performance.