Battery system and method for producing a battery system

The battery system has several cells that are electrically conductively connected by cell connectors (2). An electronic unit (4) has contact elements (4.1) made ?[deg] f copper for detecting the voltage potentials of the cells. A bonding wire (3) made of aluminum electrically connects cell connectors and contact elements. The contact element is attached to intermediate element (5) by a soldering process. The intermediate element has a first section (5.1) of copper and a second section (5.2) made of aluminum. The bonding wire is contacted on the second section in the ultrasonic bonding process. An independent claim is included for method for manufacturing battery system.