锌镍单液流电池离子传质极化分析

Analysis of ion mass transfer polarization in nickel-zinc single flow battery

基于流动传质、电荷守恒以及涉及氢氧根离子、锌离子反应的反应动力学方程,建立锌镍单液流电池二维瞬态模型,研究离子浓度对电池传质极化的影响。与实验数据对比,验证模型的正确性,然后研究电池极化过程,着重考察离子进口浓度以及放电电流密度对电池负极极化过电位的影响。增大离子进口浓度,电极表面和溶液本体浓度趋同,传质极化减小,而高电流密度下,由于较高的传质阻力,传质极化严重,将导致更大的电压损失。

Based on flowing mass transfer,charge conservation and reaction kinetic equation involving the reaction of hydroxide ions and zinc ions,a two-dimensional transient model of nickel-zinc single flow battery was established to study the effect of ion concentration on the mass transfer polarization of the battery. The correctness of the model was verified by comparing with the experimental data. The polarization process of batteries was studied;the effects of ion import concentration and discharge current density on the negative polarization over-potential of the battery were emphatically investigated. Increasing the ion import concentration,the concentration of electrode surface and the solution bulk converge,the concentration polarization decreased,at high current density,due to the higher mass transfer resistance,the concentration polarization was severe,which would led to greater voltage loss.