the activation rate is higher and in regard to the battery internal pressure the performance is evaluated to be higher when the value of the battery internal pressure of the nickel metal hydride storage battery after use under the certain conditions is lower for example when the activation rate is low the portion of the anode that is insufficiently activated is not used effectively and current concentrates at the activated portion of the anode thereby lowering the charging discharging cycle life and shortening the life of the nickel metal hydride storage battery the performance of the nickel metal hydride storage battery is thus evaluated as being higher when the activation rate is higher also for example when the amount of gas generated is high and the battery internal pressure is high the gas generated due to charging is emitted to the exterior from the nickel metal hydride storage battery in accordance with the internal pressure rise and the discharge reserve amount of the nickel metal hydride storage battery thus decreases the nickel metal hydride storage battery after use under the certain conditions is thus judged to be higher in performance when the amount of gas generated in accompaniment with charging is lower that is when the battery internal pressure is lower the inventors thus carried out diligent research on the correlation of the activation rate and battery internal pressure that are measured from the nickel metal hydride storage battery and the amount of cobalt the inventors then determined an evaluation.