Storage battery system

A battery system comprising:

• a plurality of storage battery modules, each comprising an assembled battery including a plurality of battery cells, a first wireless communication module configured to transmit and receive radio waves based on a BLE standard, and a battery monitoring unit configured to control operation of the first wireless communication module;
• and
• a battery management unit comprising a plurality of second wireless communication modules configured to transmit and receive radio waves based on the BLE standard and an arithmetic processing device configured to control operation of the plurality of second wireless communication modules,
• wherein a first identifier is preset in the first wireless communication module, and
• when a connection is started between the second wireless communication module and the first wireless communication module, the first wireless communication module in which a value of a second identifier included in an advertising packet transmitted from the second wireless communication module is a value of the first identifier becomes a broadcaster and transmits the advertising packet.