Back-contact solar cell, back-contact solar cell assembly, and photovoltaic system

A back-contact solar cell, comprising:

• a silicon wafer, wherein the silicon wafer has a light-receiving face and a shady face which are mutually opposed, and the shady face is provided with a plurality of groove structures and a plurality of non-groove areas spaced at intervals, and the plurality of non-groove areas and the plurality of groove structures are disposed alternately;
• a first doped layer that is disposed on the silicon wafer at a first non-groove area of the plurality of non-groove areas, wherein,
• at a predetermined position in a first groove structure of the plurality of groove structures, the first doped layer includes a first portion extending above the first groove structure of the plurality of groove structures,
• the first doped layer is disposed on the shady face of the silicon wafer opposite to the light-receiving face of the silicon wafer, and
• the first portion of the first doped layer has a first surface facing towards the first groove structure of the plurality of groove structures and a second surface facing away from the first groove structure of the plurality of groove structures;
• a first dielectric layer formed on the first surface, wherein a first part of the first dielectric layer has a tunneling function and is thinner than a second part of the first dielectric layer;
• and
• a second doped layer that is disposed within the first groove structure of the plurality of groove structures and has a polarity opposite to the first doped layer, wherein,
• at the predetermined position, the second doped layer has a wrapping portion disposed along a side wall surface of the first groove structure of the plurality of groove structures and covers the first and second parts of the first dielectric layer,
• the first surface intersecting the side wall surface of the first groove structure of the plurality of groove structures, and
• the first groove structure includes an opening at the shady face over the second doped layer, the opening is formed inside the silicon wafer and has a depth along a direction from the shady face to the light-receiving face.