Method for producing a nickel metal-hydride storage battery

Abstract

A method for producing a nickel metal-hydride storage battery includes: (i) assembling a battery by enclosing the positive electrodes, the negative electrodes, separators, and an electrolyte in a case; (ii) charging the battery with electric current in a range of 0.05 C (ampere) to 0.2 C (ampere) until a state of charge rises to a range of 10% to 30%; (iii) overcharging the battery that has been subjected to the charging, with electric current in a range of 0.2 C (ampere) to 1 C (ampere), and thereafter discharging the same until the state of charge lowers to 10% or below; and (iv) subjecting the battery after overcharging to a plurality of charging-discharging cycles, each charging-discharging cycle being composed of charging the battery that has been subjected to the overcharging, with electric current in a range of 0.2 C (ampere) to 5 C (ampere) until the state of charge rises to a range of 60% to 95%, and discharging the same until a battery voltage lowers to a range of 0.70 V to 1.05 V. In this method, in the charging-discharging cycles, the battery is cooled with a coolant at a temperature in a range of 30° C. to 60° C. This method makes it possible to produce a nickel metal-hydride storage battery at high productivity and low cost.

Dependencies are inferred from the claim text.