Influence of fumed silica and additives on the gel formation and performance of gel valve-regulated lead-acid batteries

The gel electrolyte is an important factor that controls both the manufacturing process and the performance of gel valve-regulated lead-acid (gel VRLA) batteries. In this study, the influence of the concentration of fumed silica and four additives in the gel electrolyte formulation on the gelling process, electrochemical behavior and battery performance was investigated. Higher fumed silica concentrations and the presence of polyacrylamide and vaniline led to a shorter gelling time and a firmer gel. Of the gel formulations studied, gel VRLA batteries with or without 0.005% (w/v) vaniline had a higher discharge capacity than the conventional liquid VRLA battery.