Back-contact solar cell
This application discloses a back contact solar cell, relating to the field of solar cell technologies. In one implementation, a back contact solar cell includes a semiconductor substrate, a first doped semiconductor layer, and a second doped semiconductor layer. The semiconductor substrate includes a first surface and a second surface opposite to the first surface. The second surface includes a first region having a first convex structure and a second region having a second convex structure. A morphology of a convex of the first convex structure is different from a morphology of a convex of the second convex structure. The first doped semiconductor layer is formed in or on the first region. The second doped semiconductor layer is formed in or on the second region. A conductivity type of the second doped semiconductor layer is opposite to a conductivity type of the first doped semiconductor layer.
1 . A back-contact solar cell, comprising:
a semiconductor substrate having a first surface and a second surface opposite to the first surface, wherein the second surface comprises a first region and a second region arranged in a direction of the second surface, and an isolation region between the first region and the second region, wherein a surface of the first region has a first convex structure, and a surface of the second region has a second convex structure, wherein a morphology of the first convex structure is different from a morphology of the second convex structure;
a first doped semiconductor layer, formed on the first region, wherein the first doped semiconductor layer is on the first convex structure; and
a second doped semiconductor layer, formed on the second region, wherein the second doped semiconductor layer is on the second convex structure, wherein a conductivity type of the second doped semiconductor layer is opposite to a conductivity type of the first doped semiconductor layer, wherein a side length of a first convex of the first convex structure is less than a side length of a second convex of the second convex structure, and wherein a doping concentration of the first doped semiconductor layer is lower than a doping concentration of the second doped semiconductor layer;
a passivation layer covering the first doped semiconductor layer and the second doped semiconductor layer, wherein a first portion of the passivation layer is on the first doped semiconductor layer, and a second portion of the passivation layer is on the second doped semiconductor layer, and wherein a thickness of the second portion of the passivation layer is greater than a thickness of the first portion of the passivation layer;
a first electrode on the first doped semiconductor layer; and
a second electrode on the second doped semiconductor layer, wherein the first electrode and the second electrode comprise a conductive material.
2 . The back-contact solar cell according to claim 1 , wherein the second surface comprises more than one first region and more than one second region alternatively arranged along the direction of the second surface.
3 . The back-contact solar cell according to claim 1 , wherein the first convex structure comprises a first pyramid base structure obtained through polishing treatment, and wherein the second convex structure comprises a second pyramid base structure obtained through polishing treatment.
4 . The back-contact solar cell according to claim 1 , wherein a surface of the first convex structure facing away from the semiconductor substrate is in a shape of one or more first polygons, wherein a surface of the second convex structure facing away from the semiconductor substrate is in a shape of one or more second polygons.
5 . The back-contact solar cell according to claim 4 , wherein a side length of a first polygon of the one or more first polygons is different from a side length of a second polygon of the one or more second polygons.
6 . The back-contact solar cell according to claim 5 , wherein the side length of the first polygon ranges from 0.5 μm to 20 μm, the side length of the second polygon ranges from 10 μm to 50 μm.
7 . The back-contact solar cell according to claim 1 , wherein a height of the first convex of the first convex structure is different from a height of the second convex of the second convex structure.
8 . The back-contact solar cell according to claim 5 , wherein the side length of the first polygon is less than the side length of the second polygon, and a height of the first convex is greater than a height of the second convex.
9 . The back-contact solar cell according to claim 7 , wherein the height of the first convex of first convex structure ranges from 0.5 μm to 5 μm, and the height of the second convex of the second convex structure ranges from 0.5 μm to 10 μm.
10 . The back-contact solar cell according to claim 4 , wherein the first convex structure and the second convex structure each comprise a top surface facing away from the semiconductor substrate and a bottom surface opposite to the top surface, and
wherein a side length of a first polygon of the one or more first polygons is less than a side length of a second polygon of the one or more second polygons, and the top surface of the second convex structure is closer to the first surface of the semiconductor substrate than the top surface of the first convex structure.
11 . The back-contact solar cell according to claim 1 , wherein the first convex of the first convex structure comprises a top portion and a bottom portion that is further away from the first doped semiconductor layer than the top portion, wherein the second convex of the second convex structure comprises a top portion and a bottom portion that is further away from the second doped semiconductor layer than the top portion,
wherein an area of the top portion of the first convex is smaller than an area of the bottom portion of the first convex, and
wherein an area of the top portion of the second convex is smaller than an area of the bottom portion of the second convex.
12 . The back-contact solar cell according to claim 11 , wherein a cross section of the top portion and a cross section of the bottom portion of the first convex are in a shape of a polygon, and
wherein a cross section of the top portion and a cross section of the bottom portion of the second convex are in a shape of a polygon.
13 . The back-contact solar cell according to claim 1 , wherein a surface of the isolation region has one of a regular pyramid textured structure, or an inverted pyramid textured structure.
14 . The back-contact solar cell according to claim 1 , wherein the first convex structure comprises a first convex and a first concave adjacent to the first convex, wherein the second convex structure comprises a second convex and a second concave adjacent to the second convex,
wherein a surface of each of the first convex, the first concave, the second convex, and the second concave is in a shape of one or more polygons,
wherein a side length of a polygon of the first convex is a1, a side length of a polygon of the first concave is b1, a side length of a polygon of the second convex is a2, and a side length of a polygon of the second concave is b2, and
wherein 0.5b1<a1<1.5b1, and 0.5b2<a2<1.5b2.
15 . The back-contact solar cell according to claim 14 , wherein a2>a1, and b2>b1.
16 . The back-contact solar cell according to claim 15 , wherein a2>1.5a1, and b2>1.5b1.
17 . The back-contact solar cell of claim 1 , wherein the first convex structure comprises a plurality of first convexes protruding away from the semiconductor substrate, and the second convex structure comprises a plurality of second convexes protruding away from the semiconductor substrate,
wherein a morphology of the first convex structure is different from the second convex structure.
18 . The back-contact solar cell of claim 1 , wherein a morphology of a surface of the first doped semiconductor layer facing away from the semiconductor substrate is different from a morphology of a surface of the second doped semiconductor layer facing away from the semiconductor substrate.
19 . The back-contact solar cell of claim 1 , wherein a surface of the second doped semiconductor layer facing away from the semiconductor substrate is closer to the semiconductor substrate than a surface of the first doped semiconductor layer facing away from the semiconductor substrate.
20 . The back-contact solar cell of claim 1 , wherein the first doped semiconductor layer and the second doped semiconductor layer comprise polycrystalline silicon.
21 . The back-contact solar cell of claim 1 , wherein a surface of the isolation region has a height difference relative to surfaces of the first region and the second region.