Battery management system and battery system

The invention relates to a control circuit for monitoring and controlling the operation of a rechargeable battery, in particular a lithium- Ion battery, comprising a plurality of interconnected battery cells (1) which are connected to at least one pol connection (3) of the battery by at least one circuit element (2) such that it can be electrically decoupled (2). Said control circuit comprises at least one first cell monitoring device (4) and at least one second cell monitoring device (5) which are designed to detect operational parameters of at least one battery cell (1) and to guide them to a control device. The at least one first cell monitoring device (4) is connected to a first control device (12) by means of a first interface (7), and the at least one second cell monitoring device (5) is connected to a second control device (13) by means of a second interface (8). The first control device (12) is designed to determine battery properties by evaluating captured operational parameters. The second control device (13) is designed to control the at least one circuit element (2). The invention also relates to a battery system comprises the claimed control circuit.