Battery Unit, Method for Electrically Interconnecting Cell Stacks of a Battery Unit and Method for Separating an Electrical Interconnection of Cell Stacks of a Battery Unit

A battery unit of a vehicle includes a plurality of cell stacks which each include a respective plurality of cells electrically interconnected to one another, an electrical attachment contact, and a contact key element. The contact key element has a contact region and is electrically insulating outside of the contact region. In a first contact position of the contact key element the plurality of cell stacks are interconnected electrically to one another via the contact region and in a subsequent second contact position of the contact key element the plurality of cell stacks that are interconnected electrically to one another are electrically connected to the electrical attachment contact.