Battery system for operating an electric motor of vehicles , in particular of cars and / or trucks, comprising at least one battery exchange module , wherein the battery exchange module comprises a plurality of battery elements and is constructed in modular manner therefrom, wherein the battery elements are electrically coupled to the battery exchange module ; wherein the battery elements each have a unit size or a multiple of the unit size and can be combined flexibly to attain a predetermined length, wherein the battery exchange module can be introduced into a first accommodation space of the vehicle, wherein the battery exchange module is designed to supply the electric motor with electrical current, wherein each of the battery elements has an electrical contact and an electrical contacting means with each of a first and a second power line, wherein the battery elements mechanically abut each other at their respective end faces and form a plug connection, that the electrical contact of a first battery element is introduced into the electrical contacting means of a second battery element , wherein the first and the second battery elements form at least a section of the plug connection, and that the mechanically coupled battery elements are connected in series or in parallel characterized in that the respective first power lines and the respective second power lines of the battery elements are connected to each other electrically, wherein the battery elements have corresponding circuits, so that the battery elements can be switched optionally in parallel or in series by an intelligent controller of the vehicle, and form either an electrical parallel circuit or a serial circuit. at least one battery exchange module , wherein the battery exchange module comprises a plurality of battery elements and is constructed in modular manner therefrom, wherein the battery elements are electrically coupled to the battery exchange module ; wherein the battery elements each have a unit size or a multiple of the unit size and can be combined flexibly to attain a predetermined length, wherein the battery exchange module can be introduced into a first accommodation space of the vehicle, wherein the battery exchange module is designed to supply the electric motor with electrical current, wherein each of the battery elements has an electrical contact and an electrical contacting means with each of a first and a second power line, wherein the battery elements mechanically abut each other at their respective end faces and form a plug connection, that the electrical contact of a first battery element is introduced into the electrical contacting means of a second battery element , wherein the first and the second battery elements form at least a section of the plug connection, and that the mechanically coupled battery elements are connected in series or in parallel characterized in that the respective first power lines and the respective second power lines of the battery elements are connected to each other electrically, wherein the battery elements have corresponding circuits, so that the battery elements can be switched optionally in parallel or in series by an intelligent controller of the vehicle, and form either an electrical parallel circuit or a serial circuit. <EOS>