Abstract
During storage of partially wet‐charged and dry‐charged lead‐acid batteries, processes take place which lead to self‐discharge and passivation of the plates. In the case of partially wet‐charged batteries, 
crystals form in the separators during storage. When the battery is subjected to charge and overcharge they transform into Pb and 
and cause short circuits between the plates and the failure of the battery. Self‐discharge reactions are presented for the two kinds of plates. The capacity loss during storage is reversed upon charge of the battery. The passivation phenomena are determined by the structure of the two kinds of plates. The passivation of the positive plate manifests itself by an abrupt fall of its discharge potential. It is assumed that this is due to the formation of a nonstoichiometric oxide following a reaction between the grid and 
of the corrosion layer. This oxide has a high electric resistivity. Upon charge it is oxidized to 
by the O atoms and O− radicals which have first formed upon anodic polarization. They penetrate through the corrosion layer and oxidize it. The plate is depassivated with a sharp rise of its discharge potential. The passivation of the negative plate brings about the shortening of the discharge time without changing substantially the discharge potential. It is assumed that passivation is caused by the formation of a 
film at the interface between the skeleton and energetic structures of the lead active mass. These films interrupt the electric contact thus decreasing the plate capacity. Upon charge the 
film is reduced to lead and the electronic contact between the two structures is restored. The plate capacity increases and the latter is depassivated.