Storage battery control device, energy storage system, and storage battery control method

An energy storage system, comprising:

• a plurality of storage batteries connected in series;
• a plurality of bypass units configured to bypass the storage batteries respectively;
• a current sensor configured to detect a charge and discharge current flowing from or into the storage batteries;
• and
• a storage battery control device configured to control the plurality of bypass units and perform offset correction of the current sensor, wherein
• each of the plurality of bypass units comprises:
• a bypass line configured to bypass the storage battery of a corresponding bypass unit among the plurality of bypass units;
• a bypass switch configured to connect and cut off the bypass line;
• and
• a cutoff switch configured to connect and cut off the storage battery of the corresponding bypass unit;
• and
• the storage battery control device is configured to
• detect, in a case that both the bypass switch and the cutoff switch are in a cutoff state in at least one of the plurality of bypass units, a zero current state in which the charge and discharge current does not flow from or into the storage batteries;
• and
• perform the offset correction of the current sensor based on an output of the current sensor when the zero current state is detected.

A storage battery control method for controlling an energy storage system using a computer, wherein

• the energy storage system includes a plurality of storage batteries connected in series, a plurality of bypass units that bypass the storage batteries respectively, and a current sensor that detects a charge and discharge current flowing from or into the storage batteries, and each of the plurality of bypass units includes a bypass line that bypasses the storage battery of a corresponding bypass unit among the plurality of bypass units, a bypass switch that connects and cuts off the bypass line, and a cutoff switch that connects and cuts off the storage battery of the corresponding bypass unit;
• and
• the storage battery control method comprising:
• detecting, in a case that both the bypass switch and the cutoff switch are in a cutoff state in at least one of the plurality of bypass units, a zero current state in which the charge and discharge current does not flow from or into the storage batteries;
• and
• performing offset correction of the current sensor based on an output of the current sensor when the zero current state is detected.