Abstract Based on thermodynamic calculations a potential/pH diagram for the Pb/H2SO4/H2O system is plotted. It defines the pH ranges of formation of the different phases and electrode systems, but the system Pb/H2SO4/H2O is kinetically controlled as well. During the anodic polarization of a lead plate immersed in sulfuric acid solution, the following electrode systems form: 1. Lead sulfate electrode (Pb/PbSO4) in the potential region from −0.97 to −0.40V versus Hg/HgSO4 reference electrode; 2. Lead oxide/lead sulfate electrode (Pb/PbO/PbSO4) at potentials from −0.40 to +0.95V; 3. Lead dioxide electrode (Pb/PbO2) at potentials above +0.95V. Pb/PbO/PbSO 4 electrode: In the lead oxide/lead sulfate potential region, a PbSO4 crystal layer forms first. It acts as a semipermeable membrane, which causes alkalization of the solution at the boundary between Pb and PbSO4 and the solution in the pores of PbSO4 layer. The Pb/PbO/PbSO4 electrode has photoelectrochemical properties, and when exposed to electrochemical oxidation above +0.95V, PbO is oxidized to α-PbO2 and PbSO4 to β-PbO2. Pb/PbO 2 electrode: Electrochemically obtained PbO2 contains crystal (PbO2) and hydrated (PbO(OH)2) (gel) zones. During discharge of the battery, the reduction of PbO2 proceeds in the gel zones by a proton–electron mechanism. On anodic polarization of the Pb/PbO2 electrode, oxygen is evolved. It penetrates through the PbO2 layer and oxidizes the lead, i.e., a corrosion layer of PbO and PbOn (1<n>2) forms. The lead alloy composition (i.e., Sb, Sn, Bi, Ag, As, and other additives) affects the rate of oxidation of PbO to PbO2 and the electrochemical properties of the corrosion layer. At high overvoltage of the Pb or PbO2 electrodes, hydrogen and oxygen evolve, and hydrogen (H+/H2) and oxygen (H2O/O2) electrode systems form. This chapter presents also general notes on lead–acid cell/battery design and on the technological schemes for battery manufacture.