The invention discloses a preparation method of a main-grid-free
solar cell, which belongs to the technical field of solar cells, and comprises the following steps: replacing a second
machine and a fourth
machine of a silk screen with a main-grid-free
screen printing plate, and not turning on a first
machine and a third machine; a TOPCon process flow is carried out; the positive and negative
electrode grid lines of the
solar cell piece comprise a plurality of parallel fine grid lines, and no main grid line is arranged, that is, when the grid line
screen printing plate pattern is designed, no main grid line is arranged; after the grid line
screen printing plate pattern is designed, the
solar cell positive
electrode grid line is printed on the surface of the
cell positive
electrode. According to the preparation method of the main-grid-free solar
cell, cost reduction is achieved mainly through silver reduction, efficiency improvement, reduction of the thickness of a
silicon wafer and the use amount of an
adhesive film, a main grid is replaced with a
welding strip, so that part of
silver paste of the main grid is saved, efficiency improvement is achieved through reduction of a shading area and shortening of a current transmission path, and the module power can be improved by more than 5W; the problems of hidden cracks and grid breakage caused by
welding after
thinning can be solved, and breakthrough of a battery piece with the thickness within 100 micrometers can be achieved.