COMMUNICATION SYSTEM, AND RECHARGEABLE BATTERY SYSTEM

A communication system provided with a battery assembly obtained by connecting in series a plurality of battery packs having at least one rechargeable battery cell; a battery management unit for managing the battery packs; and an optical line used for transmitting from the battery packs to the battery management unit, along with battery data, an emergency stop signal for cutting off the connection between the battery assembly and a power conversion system when unsafe conditions are detected by the battery packs.