钒电池充放电过程离子变化规律研究

Study on the ion change rule of all vanadium battery during charge and discharge process

采用电位滴定法测定了钒离子浓度,并与钒化学分析方法(GB)测定结果进行了对比。在此基础上,研究了钒电池在一定充电深度下充放电过程中正负极不同价态钒离子浓度变化规律。结果表明,在钒电池多次循环过程终态时,无论是充电状态,还是放电状态,正负极电解质中钒离子浓度变化规律一致,即正极V5+离子浓度随电池循环次数的增加而升高;负极V2+离子浓度随电池循环次数的增加而降低,并且这种失衡现象严重影响着电池的寿命和效率。因此,若想延长电池循环寿命,保证电池设计容量和效率,如何有效控制正负极电解质中V5+与V2+离子实际浓度与理论值相匹配是电池运行中的关键问题。

The concentration of vanadium was determined by potentiometric titration analysis method and the result was compared with the result obtained by determination of vanadium （GB）. The change rule of the concentration of anodic and cathodic electrolyte under certain state of charge was studied. The results show that the concentration of V^5＋ increases with long cycle of the battery during both charge and discharge process, while the concentration of V^2＋ decreases with cycle,and these facts pose influences greatly on the lifespan and efficiency of the battery. The key problem is how to keep the actual concentration of V^5＋ and V^2＋ with their theoretical concentration in order to prolong the cycle life and remain the designed capacity and the efficiency of the battery.