LITHIUM ION SECONDARY BATTERY, BATTERY PACK, HYBRID ELECTRIC VEHICLE, BATTERY PACK SYSTEM, AND CHARGE-DISCHARGE CONTROL METHOD

摘要

A lithium ion secondary battery (100) has a property of securing a flat charge-discharge capacity range (FC) in which fluctuation of terminal voltage is 0.2 V or lower in both the cases where the battery is charged and discharged with electric current having a current value of 1 C over a capacity range of 50% or more of the electric capacity range having a theoretical electric capacity as an upper limit.