Patent ID: 8575886

Claim:
A power storage apparatus in connection with a power generation system using natural energy having a generation power which changes with time, the power storage apparatus mitigates changes to the generation power of the power generation system, the power storage apparatus comprising: a plurality of electricity storage devices, where the plurality of electricity storage devices are composed of converters and secondary batteries, and the converters include a charge rate detector for detecting a charge rate of the secondary batteries; and a control unit including a power station output target value calculator for calculating a target value of power station output, a charge and discharge power calculator for calculating a change relief charge and discharge instruction for executing charging and discharging by each of the plurality of electricity storage devices on the basis of the target value of the power station output, a charge rate target value calculator for calculating a charge rate target value of the plurality of electricity storage devices, and a charge rate management charge and discharge instruction calculator for correcting the change relief charge and discharge instruction on the basis of the charge rate target value and the charge rate detected by the charge rate detector and calculating a correction value of a charge and discharge power instruction for instructing the charging and discharging of the electricity storage devices, wherein the converters are configured to control a charge and discharge power of the secondary batteries so as to follow the charge and discharge power instruction from the control unit and to mitigate changes to a combined power formed by adding the power outputted from the power generation system and the charge and discharge power outputted from the power storage apparatus, and wherein the control unit includes a deterioration index calculator for calculating a correction value of the charge rate target value of the power storage apparatus according to characteristics or an operation history of the plurality of secondary batteries and instructing the charge rate target value calculator of the correction value.