The invention discloses a back
electrode, a
solar battery, and preparation methods of the back
electrode and the
solar battery. The preparation method of the
solar battery back
electrode comprises thefollowing steps of preparing a
photoresist layer on a substrate, preparing a plurality of first graving regions which penetrate through the thickness of the
photoresist layer and are arranged at intervals on the
photoresist layer, preparing an insulating layer on the surfaces of the substrate and the photoresist layer, preparing a
nonmetal layer on the insulating layer, removing the photoresist layer and the insulating layer and the
nonmetal layer on the photoresist layer by a cleaning process, preparing a back electrode layer on the substrate and the
nonmetal layer, and removing the nonmetallayer and the back electrode layer on the nonmetal layer by a cleaning process. According to the method, division of the back electrode is completed by replacing
laser graving with a photetching technology, so that damage of the
laser graving to the substrate can be avoided; and insulating medium filling is performed in graving lines of the first graving regions (P1), so that the area of an deadregion can be reduced, the area of a power generation region can be increased, and the power generation efficiency can be improved.