The invention relates to a battery management system (1) for monitoring and regulating the operation of a rechargeable battery, comprising a plurality of battery cells, said rechargeable battery comprising a control device unit (2), a plurality of cell monitoring units (3), each assigned to at least one battery cell, a communication system (5) for transmitting and/or receiving data, and an isolating apparatus (4) for galvanic isolation of the battery from a consumer and/or a charging apparatus, wherein the isolating apparatus (4) is designed to receive data. The isolating apparatus (4) comprises an evaluating unit, which evaluates data received by the isolating apparatus (4) in respect of a demand to separate the battery from a consumer and/or a charging apparatus. The invention further relates to a battery system having a rechargeable battery which comprises a plurality of battery cells and a battery management system (1) according to the invention for monitoring and regulating the operation of the battery.