Energy storage system and method for operating an energy storage system

1. An energy storage system for a motor vehicle having a first electric motor and a second electric motor, the energy storage system comprising:

first and second energy storage cells arranged in the motor vehicle;

electrical connections between the first and second electric motors and the first and second energy storage cells, the electrical connections being configured so that, in a traction mode, the first energy storage cell is connected electrically with the first electric motor and the second energy storage cell is connected electrically with the second electric motor, the first and second electric motors being configured for driving at least one axle of the motor vehicle; and

a monitoring and control unit that is configured so that the first and second energy storage cells can be charged at:

a first charging station that has first and second dedicated charging devices that are separate and independent of one another and that are provided respectively with first and second cables running between the first and second charging devices and the motor vehicle so that the first charging device charges the first energy storage cell and so that the second charging device charges the second energy storage cell; and

a second charging station that has a single charging device with a single cable running between the single charging device and the motor vehicle so that the single charging device charges both the first and second energy storage cells, wherein

the monitoring and control unit further configured to determine a charging infrastructure when in a charging mode and then depending on the determined charging infrastructure:

disconnects the first energy storage cell from the second energy storage cell to accommodate a charging infrastructure at the first charging station,

connects the first and second energy storage cells in series to accommodate a charging infrastructure at the second charging station supplying a first predetermined charging voltage, and

connects the first and second energy storage cells in parallel to accommodate a charging infrastructure at the second charging station supplying a second predetermined charging voltage.

2. The energy storage system of claim 1 , wherein, in the charging mode, the first energy storage cell is coupled to a first charging device and the second energy storage cell is coupled to a second charging device that is separate from the first charging device.

3. The energy storage system of claim 2 , wherein the first charging device comprises the first cable running between the motor vehicle and the charging station, and wherein the second charging device comprises the second cable running between the motor vehicle and the charging station.

4. The energy storage system of claim 2 , wherein the first charging device comprises a first charging regulator arranged on the charging station and wherein the second charging device comprises a second charging regulator arranged on the charging station.

5. The energy storage system of claim 2 , wherein the first charging device comprises a first charging regulator arranged on the motor vehicle and wherein the second charging device comprises a second charging regulator arranged on the motor vehicle.

6. A method for operating the energy storage system of claim 1 , the method comprising the steps of:

establishing the traction mode by electrically connecting the first energy storage cell with the at least one first electric motor and electrically connecting the second energy storage cell with the at least one second electric motor, and subsequently terminating the traction mode; and

establishing the charging mode by electrically connecting the first and second energy storage cells with respectively first and second charging devices of the first charging station or electrically connecting the first and second energy storage cells in series with the single charging device of the second charging station.

7. The method of claim 6 , further comprising depending on the determined charging infrastructure, manually or automatically electrically connecting the first and second energy storage cells with the respectively dedicated charging device separately and independently of one another, or electrically connecting the first and second energy storage cells in series with the common charging device.

8. The energy storage system of claim 1 , wherein the second predetermined charging voltage is half of the first predetermined charging voltage.