Solar cell, method of making, and photovoltaic module

1 . A solar cell, comprising:

a substrate, having a first surface and a second surface opposite to the first surface;

a plurality of first doped portions, on the first surface;

a plurality of second doped portions on the first surface, wherein the plurality of second doped portions and the plurality of first doped portions are alternatingly distributed on the first surface along a first direction, and doping elements in the plurality of first doped portions are of a first type and doping elements in the plurality of second doped portions are of a second type different from the first type; and

a plurality of isolation trenches, wherein a respective isolation trench of the plurality of isolation trenches is formed between a respective first doped portion of the plurality of first doped portions and an adjacent second doped portion of the plurality of second doped portions, wherein the respective isolation trench has opposing first sidewall and second sidewall that extend along a second direction, at least one of the first sidewall and the second sidewall has a corrugated structure that undulates while extending along the second direction, and the second direction intersects with the first direction,

wherein at least one of the first sidewall and the second sidewall transitions to a top surface of the respective first doped portion or a top surface of the adjacent second doped portion via a rounded corner,

wherein a ratio of a height of the rounded corner along a thickness direction of the substrate to a height of the first sidewall along the thickness direction of the substrate is less than or equal to 3:20.

2 . The solar cell according to claim 1 , wherein the corrugated structure has a maximum width in the first direction that is less than or equal to 15 μm.

3 . The solar cell according to claim 1 , wherein the corrugated structure includes grooves and ridges alternating along the second direction; and

a tangent line of one of the ridges extending along a direction perpendicular to the second direction includes an angle of 45° to 90° with the first direction.

4 . The solar cell according to claim 1 , wherein each of the plurality of isolation trenches has a bottom surface, the bottom surface includes a first region, a second region, and a third region disposed sequentially along the first direction;

wherein in a thickness direction of the substrate, a second distance is less than a first distance and a second distance is less than a third distance; wherein the first distance is a distance between the bottom surface of each of the plurality of isolation trenches corresponding to the first region and the second surface, the second distance is a distance between the bottom surface of each of the plurality of isolation trenches corresponding to the second region and the second surface, and the third distance is a distance between the bottom surface of each of the plurality of isolation trenches corresponding to the third region and the second surface.

5 . The solar cell according to claim 1 , wherein the first sidewall and the second sidewall each have the corrugated structure extending along the second direction.

6 . The solar cell according to claim 1 , wherein a bottom of each of the plurality of first doped portions facing the substrate is higher than a top of any of the plurality of second doped portions facing away from the substrate.

7 . The solar cell according to claim 1 , further comprising a first passivation layer over the plurality of first doped portions and the plurality of second doped portions and covering the first side wall, the second side wall and a bottom surface of the isolation trench.

8 . The solar cell according to claim 7 , further comprising a first electrode penetrating through the first passivation layer and electrically connected to the plurality of first doped portions; and a second electrode penetrating through the first passivation layer and electrically connected to the plurality of second doped portions.

9 . The solar cell according to claim 1 , further comprising a first passivation layer located on the second surface.

10 . The solar cell according to claim 1 , wherein the first surface of the substrate is a polished surface.

11 . The solar cell according to claim 1 , wherein the second surface of the substrate has a textured structure.

12 . A photovoltaic module, comprising:

at least one cell string, formed by connecting a plurality of solar cells according to claim 1 ;

at least one encapsulation layer, each configured for covering a surface of the at least one cell string; and

at least one cover plate, each configured for covering a surface of the at least one encapsulation layer facing away from the at least one cell string,

wherein the at least one encapsulation layer includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of a front surface and a back surface of the at least one cell string, and the second encapsulation layer covers the other.

13 . The photovoltaic module according to claim 12 , wherein a maximum width of the corrugated structure in the first direction is less than or equal to 15 μm.

14 . The photovoltaic module according to claim 12 , wherein the corrugated structure includes grooves and ridges alternating along the second direction; and

a tangent line of one of the ridges extending along a direction perpendicular to the second direction includes an angle of 45° to 90° with the first direction.

15 . The photovoltaic module according to claim 12 , wherein the plurality of isolation trenches each have a bottom surface, the bottom surface includes a first region, a second region, and a third region disposed sequentially along the first direction;

wherein in a thickness direction of the substrate, a second distance is less than a first distance and a second distance is less than a third distance; wherein the first distance is a distance between the bottom surface of each the plurality of isolation trenches corresponding to the first region and the second surface, the second distance is a distance between the bottom surface of each the plurality of isolation trenches corresponding to the second region and the second surface, and the third distance is a distance between the bottom surface of each the plurality of isolation trenches corresponding to the third region and the second surface.

16 . The photovoltaic module according to claim 12 , wherein the first sidewall and the second sidewall each have the corrugated structure extending along the second direction.