POWER MANAGEMENT SYSTEM

A power management system which carries out charge-discharge control according to lack of storage cell pack characteristic uniformity. A power storage device (14) comprises a power storage unit (16), a power system switching circuit (20), and a power management unit (22). The power management unit (22): acquires charge information (for example, charge rate SOC) on each of a plurality of storage cell packs contained in the power storage unit; compares the size of said charge information according to the minimum and maximum values thereof respectively with an upper bound and a lower bound, and switches a charge switch and a discharge switch of the power system switching circuit (20) ; and transitions the power storage unit (16) between a charge-discharge state, a charge state, and a discharge state.