Management device, electric storage device, electric storage system and electric apparatus for managing charging and discharging of a plurality of electric storage cells connected in series

An electric storage system comprising:

• a plurality of electric storage cells connected in series to each other;
• a plurality of electric storage devices, each of the plurality of electric storage devices being connected in series to each other, each of the plurality of electric storage devices includes:
• a corresponding plurality of electric storage cells from among the plurality of electric storage cells;
• and
• a management device configured to manage charging and discharging of the corresponding plurality of electric storage cells;
• an electric power line electrically connectable to each of a plurality of management devices;
• and
• a controller;
• wherein
• the electric power line includes a low potential bus and a high potential bus, a first electric storage device among the plurality of electric storage devices further includes:
• a first terminal equipotentially connected to the low potential bus and a negative pole end of the corresponding plurality of electric storage cells;
• and
• a second terminal equipotentially connected to the high potential bus and a positive pole end of the corresponding plurality of electric storage cells;
• each of one or more other electric storage devices except for the first electric storage device, among the plurality of electric storage devices further include:
• an insulated bidirectional DC-DC converter,
• wherein two terminals of a primary side of the insulated bidirectional DC-DC converter are connected to a positive pole end and a negative pole end of the corresponding plurality of electric storage cells, and two terminals of a secondary side of the insulated bidirectional DC-DC converter are connected to the low potential bus and the high potential bus;
• and
• the controller is configured to control an operation of the DC-DC converter.