Patent ID: 8771871

Claim:
A lead storage battery which is operable to be used in a partial state of charge where the state of charge is confined within a range of more than 70% to less than 100%, comprising: a group of plates housed in a battery jar, and an electrolytic solution comprising metal ions dissolved in an aqueous solution of sulfuric acid contained in the battery jar; wherein the group of plates are formed of a stack constituted by (i) a plurality of negative substrates comprising grid substrates filled with a negative active material, (ii) a plurality of positive substrates comprising grid substrates filled with a positive active material, and (iii) a porous separator interposed between negative electrodes and positive electrodes; and wherein the metal ions consist essentially of: 0.01 to 0.1 mol/L of aluminum ions; 0.005 to 0.02 mol/L of sodium ions; and unavoidable impurities.