Maintenance-free Lead-acid Battery Positive Plate Grid Material

As the most important non-active components, grid alloys impose great effects on increasing specific energy, power and extending the cycle life of lead-acid batteries. The composition and characteristics of grid alloys in common use was reviewed. The development and characteristics features of grid alloy for lead-acid battery were reviewed in this paper. In the point of metallurgy and electrochemical principles, experimental alloys were designed, then the mechanical properties and electrochemical performances of different alloys were studied systematically. On the basis of past grid alloy Pb-Ca-Sn-Al, the fifth element such as Bi,Ag,Zn and Ce are added into the alloy after the theoretical analysis and early experiments. Several performances of grid alloy are researched and analysised, such as metallograph, hardness, oxygen overpotentials, corrosion resistance and Tafel curves, and the corrosion layers on the surface of different grid alloys were investigated by cycle voltammetry,X-ray Diffraction and SEM. In the end, batteries with different grid alloys were designed and assembled, then the performances of the batteries were tested and the tested data were analyzed and discussed.The result of mechanical tested shows that the addition of Ag,Zn and Ce all can improve the hardness, but the effect of Ce is best distinctness.The results of electrochemical tests shows that the effect of Bi on oxygen overpotentials and corrosion resistance properties of grid alloy is very complex. Addition Ag,Zn and Ce can increased the corrosion resistance of grid alloy, and the overpotentials of oxygen evolution were increased after the addition of Bi and Ce, but the oxygen overpotentials is failed after the addition of Ag. Besides, the results of tests also shows after the addition of Ag and Zn, the conductivity of the corrosion film on the alloy is improved and reduced the polarization resistance of alloy. While the addition of Bi and Ce can decreased the conductivity of the corrosion film.Different grid alloys with better performances are put into batteries, the results of tests shows that after the addition of Ag and Zn, the performances of the batteries are improved, and the cycle life of the batteries are prolonged. But after the addition of Bi and Ce, the performances of the batteries are decreased, and the cycle life of the batteries are shortened.