US Patent 7934576 Bicycle frame with integrated and detachable battery

The present invention concerns a bicycle frame, including a number of frame elements, preferably tubes, where the frame elements are interconnected and constitute a construction with so great rigidity that the cycle frame does not change its geometrical shape under usual load, where an electric battery system is at least partly embedded in the frame, including at least one battery pack for storing electric energy for use in connection with equipment, such as comfort equipment and/or safety equipment on a bicycle, including an electric auxiliary motor, where the part of the frame adapted to mounting a battery pack is constituted by a hollow section, the hollow section being a multiple chamber section, where a battery pack is predominantly arranged in a cutout in the multiple chamber section so that at least one chamber in the multiple chamber section is substantially intact. Thus is obtained a cycle frame with a cutout for a battery pack, where the frame has great rigidity.