阀控密封铅酸电池正极板栅在不同硫酸电解液中的电化学行为

Electrochemical behavior of positive-electrode grid for VRLA battery in different density sulfuric acid electrolyte

摘要:

为研究正极板栅的腐蚀对阀控密封铅酸(VRLA)蓄电池失效的影响,分别采用循环伏安(CV)、电化学阻抗谱(EIS)和塔菲尔曲线研究了VRLA电池正极板栅在不同硫酸密度电解液的电化学行为．结果表明: 氧化峰和还原峰的峰值电势均随硫酸密度的降低发生正移,说明Pb向PbSO₄转化变困难,而PbSO₄还原为Pb变得更容易;峰电流值随着硫酸密度的降低而增大,说明硫酸密度越小转化速率越快．酸密度影响正极板栅腐蚀膜的导电性,硫酸密度在1.30 g·cm-3左右时,板栅腐蚀膜的导电性较好．适当降低酸密度对提高板栅腐蚀膜的导电性有利．

Abstract:

To investigate the effect of positive-electrode grid on the failure of valve-regulated lead acid (VRLA) battery, the electrochemical behavior of positive-electrode grid for VRLA battery in the different density sulfuric acid electrolyte is studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel curves, respectively. The result shows that the peak potential of oxidation and reduction peaks move to positive direction with the decrease of sulfuric acid density, indicating that lead can difficultly convert into lead sulfate, but lead sulfate easily convert into lead. The peak current increases with the decrease of sulfuric acid density, revealing that the lower sulfuric acid density is, the faster rate of conversion is. The acid density affects the conductivity of positive grid corrosion film, and the conductivity of positive grid corrosion film is good when the sulfuric acid density is about 1.30 g·cm-3. It is beneficial to improve the conductivity of grid corrosion film by decreasing the acid concentration.