Alkaline storage battery system

An alkaline storage battery system comprising:

• an alkaline storage battery including:
• an electrode group having a hydrogen storage alloy negative electrode using a hydrogen storage alloy as a negative electrode active material, a nickel positive electrode using nickel hydroxide as a main positive electrode active material, and a separator;
• an alkaline electrolyte;
• and
• an outer can accommodating the electrode group and the alkaline electrolyte;
• and
• a partial charge-discharge controller;
• in the nickel positive electrode, zinc (Zn) being added to nickel hydroxide that is the main positive electrode active material with an addition amount of 8% by mass or less with respect to the mass of nickel in the positive electrode active material,
• the hydrogen storage alloy having a crystal structure of an A5B19 type structure, with a stoichiometric ratio (B/A) representing the molar ratio of component B to component A of the A5B19 type structure ranging from 3.6 to 3.9, inclusive, and being represented by a general formula of Ln1-xMgxNiy-aMa (where Ln is an element selected from rare earth elements including yttrium (Y), and M is at least one kind of element selected from Al, Co, Mn, and Zn) in which the content of the element M is 1.0% by mass or less,
• the alkaline electrolyte having a concentration of 6.5 mol/L or less,
• the alkaline electrolyte containing lithium (Li) of 0.3 mol/L or more, and
• the alkaline storage battery system being arranged to control partial charging-discharging.