A battery storage and/or a wind turbine including the battery storage. A generator for generation of an electric current. An electric flow path configured for conducting the electric current to an electric grid via a power converter, the power converter. The battery storage electrically connected to the electric flow path, the battery storage comprising a plurality of battery cells, each battery cell comprising at least one battery element and at least two semiconductor switches. A controller is configured for selectively controlling the voltage over the battery storage by controlling the status of the at least two semiconductor switches of a plurality of the battery cells, and thereby whether a current path through the battery storage is bypassing the at least one battery element or passing through the at least one battery element of one or more of the plurality of battery cells.