Patent ID: 9601931
Date: 2017-03-21
CPC Classifications: H02J

Claim:
1. A device for monitoring and balancing cell voltages of at least two electrical energy storage cells of a multi-cell energy storage stack comprising: at least one capacitive energy storage element; a voltage measuring unit; a first combinatorial circuit having an input side selectively connected to each energy storage cell and first and second output lines connected to the voltage measuring unit; a second combinatorial circuit comprising a first switching element selectively directly connecting the first output line with a positive electrode of the energy storage element, a second switching element selectively directly connecting the second output line with the positive electrode of the energy storage element, a third switching element selectively directly connecting the first output line of the first combinatorial circuit with a negative electrode of the energy storage element, and a fourth switching element selectively directly connecting the second output line of the first combinatorial circuit with the negative electrode of the energy storage element, the second combinatorial circuit connected to the voltage measuring unit via the first and second output lines; and a control unit, which is connected to the voltage measuring unit, and controls the first and second combinatorial circuits, the control unit comprising a computer readable storage medium with non-transitory code for transferring a portion of an electrical charge from a first arbitrary cell to a second arbitrary cell via the energy storage element once or a plurality of times by directly coupling the first arbitrary cell with the energy storage element and then directly coupling the second arbitrary cell with the energy storage element.