Abstract: A battery system includes: a plurality of battery cells electrically connected to each other in series between a first node and a second node; an intermediate node dividing the plurality of battery cells into a first subset of battery cells and a second subset of battery cells; a step-down converter connected in parallel with the plurality of battery cells between the first node and the second node and having an output node; a first diode, an anode of which is connected to the intermediate node and a cathode of which is connected to the output node; and a control unit interconnected between the output node and the first node and configured to control the step-down converter.

Abstract: A plurality of battery cells arranged as a cell stack with adjacent lateral walls forming a row includes a case including two lateral walls from among the lateral walls, and a cap assembly capping the case, and including a positive terminal and a negative terminal, and a solid state switch arranged as an element in the cell stack of battery cells and for switchably connect the battery module with an external power grid, the solid state switch including a switch circuit board including a power MOSFET for providing a power stage for performing switching, a back cover and a front cover, the back and front covers forming a housing of the solid state switch and including lateral walls in the same size and shape as the lateral walls of the case of each battery cell.