Lead Storage Battery Oxides with Metallic Additions

Abstract

Oxides were produced from lead containing various added metals. The concentrations more than covered the range of impurities ordinarily present in primary lead used in manufacturing battery oxides. The influence of these metals, both singly and combined, on battery performance has been studied. Battery capacity and life are unaffected by any of the added metals. Shelf life is unaffected by Bi, Ag, and Cu and is shortened by Ni, Sb, and Te. With the exception of Bi, each of these elements depressed the initial end-of-charge voltage, Te being particularly effective. The effect on end-of-charge voltage is more than additive when several added metals are present.Data on the effects of impurities on storage battery performance are limited. Gillette (1) has studied the effects of a number of elements while Vinal (2) has carried out tests under rather special conditions. Willihnganz (3) recently evaluated the effects of Fe.In all of these studies the impurity was added to the electrolyte. Sb which is present in grid metal is anodically corroded and deposits on the negative active material. In the latter state, it may be considered as an impurity and its effects are well understood. Zachlin (4) along with others has shown the part played by the concentration of Sb in the grid metal on the self-discharge rate.No data are available showing the effects of impurities when present in the Pb from which the oxides are made. Such information is required for a better understanding of the lead-acid battery and this is the reason for the present investigation. ExperimentalThis study was confined to the more common elements associated with Pb, viz., Bi, Ag, Cu, Ni, Sb, and Te. Impurities were introduced in concentration ranges which would more than cover the percentages usually found in Pb used for storage battery oxides. With the exception of Te, alloys were made by adding the proper amount of each element to U.S.S. electrolytic Pb. Metals were added singly or in combination with others as required. The alloys were then converted to high metallic litharges in a small size Barton pot. Each oxide was analyzed spectrographically for the added elements. Results were close to the anticipated concentrations.The oxides containing Te as a single added impurity were prepared by blending TeO~ with pure oxide made from the electrolytic metal. Oxides were also prepared from alloys consisting of corroding Pb and added Te. Because of the mode of preparation, the results obtained with the Te-bearing oxides are not strictly comparable with results corresponding to the other oxides. However, this does not obviate the validity of the conclusions. Te has been investigated because of its presence in corrosionresistant grid metal.Oxides were processed into batteries of the standard height, 100 amp-h~, 15 plate, 6 v automobile TABLE I. Composition of grid and post alloys Metal Per cent Grid Post Sb 8.4 4.4 Cu 0.028 0.05 As 0.023 0.017 Sn 0.38 0.33 Ag 0.0034 0.0033 Bi 0.017 0.017 Fe <0.001 --Ni <0.001 <0.001 Cd <0.0005 <0.001 Zn <0.001 --type. Both the p...