Solar cell and production method thereof, photovoltaic module

A photovoltaic module, comprising:

• a cell string including a plurality of solar cells, wherein the plurality of solar cells are electrically connected in sequence;
• an encapsulation layer configured to cover a surface of the cell string;
• and
• a cover plate configured to cover a surface of the encapsulation layer facing away from the cell string;
• wherein each of the plurality of solar cells comprise:
• an N-type substrate;
• a P-type emitter formed on a first surface of the N-type substrate;
• and
• a tunnel layer and a doped conductive layer sequentially formed over a second surface of the N-type substrate in a direction away from the N-type substrate;
• wherein the P-type emitter comprises a first portion and a second portion, the first portion has first pyramid structures formed on a top surface of the first portion and the second portion has second pyramid structures formed on a top surface of the second portion;
• wherein a transition surface is respectively formed on at least one edge of each first pyramid structure, the at least one edge has irregular deformation, the transition surface is joined with two adjacent inclined surfaces of the each first pyramid structure, and the transition surface is concave or convex relative to a center of the each first pyramid structure;
• wherein a substructure is formed on each of top surfaces of at least a part of the first pyramid structures, and a shape of the substructure is spherical or spherical-like;
• wherein edges of each second pyramid structure are straight;
• and
• wherein a sheet resistance of the first portion ranges from 10 ohm/sq to 500 ohm/sq, a doping concentration at the top surface of the first portion ranges from 1E17 atoms/cm3 to 8E19 atoms/cm3;
• a sheet resistance of the second portion ranges from 100 ohm/sq to 1000 ohm/sq, and a doping concentration at the top surface of the second portion ranges from 1E16 atoms/cm3 to 5E19 atoms/cm3.