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

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.