How do Tafel behavior and float characteristics affect battery life?
Stationary batteries for standby power reserve power are kept fully charged by floating, which means that the batteries are continuously overcharged at a constant voltage slightly higher than the thermodynamically reversible potential. The positive grid corrosion is prevented by keeping an excess potential on the positive plate. The proportion of excess potential over constant float voltage at the positive and negative plates is determined by the Tafel curve of the electrodes. During the float service of a battery, certain organic chemical components in the separator that are leached to the electrolyte will cause he hydrogen overvoltage at the negative plate to be increased. This shifting of fixed float voltage, due to increased hydrogen overvoltage at the negative plate, will deprive the excess voltage at the positive plate which is needed to prevent the positive grid from corroding. The lack of excess polarization at the positive electrode will cause the battery to discharge and shor
