bicycle drive as well as to a battery unit insertable therein to provide an easy operation and at the same time a highly stabilized placement of the battery it is suggested that said tube section is provided with a lateral opening substantially extending in the direction of extension of said tube section wherein said battery unit is insertable into said interior space through said lateral opening application_number US 72759610 A description in fig1 an electromotively driven bicycle 1 of the prior art is shown with a bicycle frame 2 on the down tube of which a battery enclosure 3 for receiving a battery unit is mounted the latter supplying the energy for an electric motor 4 arranged on the rear wheel such a known electric motor 4 may be used both as a full bicycle drive and as a hybrid drive where the cyclist 39 s muscular force is assisted depending on the drive force transmitted to the rear wheel by the pedal drive fig2 shows a bicycle frame 5 of the invention the frame is essentially composed of a seat tube 6 a top tube 7 and a down tube 8 arranged in a triangular shape as well as of a head tube 9 on the front side and two seat stays 10 and two chain stays 11 arranged on the frame on the rear side thereof as compared to seat tube 6 and top tube 7 down tube 8 has a cross sectional shape that is extended in the plane of the frame thereby creating.