PURPOSE: To suppress deterioration of initial capacity in slow discharge cycle, by immersing a grid in aqueous solution containing hydrogen perioxide and phosphoric acid then applying lead paste.
CONSTITUTION: Lead paste is applied on a grid immersed in aqueous solution containing hydrogen peroxide and phosphoric acid, then dried, cured and formation charged to produce a protection layer of fine phosphoric compound on the surface of the grid, and when it is charged during the cycle it will suppress diffusion of sulfuric acid to the grid interface thereby pH in the vicinity of the interface will approach to the neutral region to form α-PbO2 layer having high electron conductivity, slow reaction and high binding force with high probability thus to maintain binding with the active substance. Prior to reaction of the portion near to the grid, β-PbO2 on the plate surface or at the fine hole inlet will react to be covered with lead sulfate to complete discharge where the protection layer in the vicinity of the grid will not concern to the charging reaction considerably thus to maintain the tightness and conductivity between the grid and active substance.
TAKAHASHI KATSUHIRO
HOSHIHARA NAOTO
FUKUDA SADAO
