Back-contact solar cells, photovoltaic modules

Abstract

The present invention provides a back-contact solar cell and photovoltaic module that can reduce minority carrier recombination, decrease light loss, and improve the light absorption efficiency on the back surface of the battery. [Solution] The semiconductor substrate 1 has a front and back surface that are placed opposite each other, the back surface of the semiconductor substrate 1 has an N-type conductive region 2 and a P-type conductive region 3, the N-type conductive region 2 has a plurality of first texture structures 21, the P-type conductive region 3 has a plurality of second texture structures 31, there is a height difference between the first texture structures 21 and the second texture structures 31, the height of the first texture structure 21 is lower than the height of the second texture structure 31, and the one-dimensional dimension of the bottom surface of the first texture structure 21 is larger than the one-dimensional dimension of the bottom surface of the second texture structure 31. The semiconductor substrate 1 also includes a first passivation layer 5 located on the front surface of the semiconductor substrate 1, a second passivation layer 6 located on the back surface of the semiconductor substrate 1, a first electrode 7, and a second electrode 8.

Claims

1. A semiconductor substrate having a front and back surface facing each other, the back surface of the semiconductor substrate having an N-type conductive region and a P-type conductive region, the N-type conductive region having a plurality of first texture structures, the P-type conductive region having a plurality of second texture structures, there being a height difference between the first texture structures and the second texture structures, the height of the first texture structures being lower than the height of the second texture structures, and the one-dimensional dimension of the bottom surface of the first texture structures being larger than the one-dimensional dimension of the bottom surface of the second texture structures, A second passivation layer located on the back surface of the semiconductor substrate, A first electrode that penetrates the second passivation layer and forms an ohmic contact with the P-type conductive region, The device comprises a second electrode that penetrates the second passivation layer and forms an ohmic contact with the N-type conductive region, A back-contact solar cell characterized by the following features.

2. The one-dimensional dimension of the bottom surface of the first texture structure is 40 nm or less. The back-contact solar cell according to feature 1.

3. The one-dimensional dimension of the bottom surface of the second texture structure is 30 nm or less. The back-contact solar cell according to feature 1.

4. Within at least a portion of the N-type conductive region, two adjacent first texture structures have a height difference, and this height difference is 1 μm or less. The back-contact solar cell according to feature 1.

5. The N-type conductive region includes a first N-type conductive region and a second N-type conductive region located on one side of the first N-type conductive region, wherein the second N-type conductive region is located between the first N-type conductive region and the P-type conductive region, and the height of the first texture structure located within the first N-type conductive region is greater than the height of the first texture structure located within the second N-type conductive region. The back-contact solar cell according to feature 1.

6. Within at least a portion of the P-type conductive region, two adjacent second texture structures have a height difference, and the height difference between the two adjacent second texture structures is 1 μm or less. The back-contact solar cell according to feature 1.

7. The P-type conductive region includes a first P-type conductive region and a second P-type conductive region located on one side of the first P-type conductive region, wherein the second P-type conductive region is located between the first P-type conductive region and the N-type conductive region, and the height of the second texture structure located within the first P-type conductive region is lower than the height of the second texture structure located within the second P-type conductive region. The back-contact solar cell according to feature 1.

8. Within the N-type conductive region, the first texture structure includes a first substructure and a second substructure installed adjacent to each other, the first substructure and the second substructure partially overlap, and there is a gap between a portion of the first substructure and the second substructure. The first substructure has a first side wall facing the second substructure, the second substructure has a second side wall facing the first substructure, and the first side wall and the second side wall have a first angle. The back-contact solar cell according to feature 1.

9. Within the P-type conductive region, the second texture structure includes a third substructure and a fourth substructure that are installed adjacent to each other, the third substructure and the fourth substructure partially overlap, and there is a gap between a portion of the third substructure and the fourth substructure. The third substructure has a third side wall facing the fourth substructure, the fourth substructure has a fourth side wall facing the third substructure, and the third and fourth side walls have a second angle. The back-contact solar cell according to feature 1.

10. The value of the first angle is less than or equal to the value of the second angle, and / or the first angle is between 40° and 60°, and / or the second angle is between 45° and 70°. The back-contact solar cell according to feature 9.

11. The spacing between two adjacent N-type conductive regions or between two adjacent P-type conductive regions is 0.5 mm to 1.3 mm, the distribution ratio of the N-type conductive regions on the back surface of the semiconductor substrate is 50% to 85%, and the distribution ratio of the P-type conductive regions on the back surface of the semiconductor substrate is 15% to 50%. The back-contact solar cell according to feature 1.

12. The shape of the first texture structure and / or the shape of the second texture structure includes a non-pyramidal shape, The back-contact solar cell according to feature 1.

13. The shape of the bottom surface of the first texture structure and / or the second texture structure includes at least one of a rhombus, a quadrilateral, a trapezoid, a similar rhombus, a similar quadrilateral, and a similar trapezoid. The back-contact solar cell according to feature 1.

14. The device comprises a cover plate, a sealing material layer, and a solar cell string, wherein the solar cell string includes a back-contact solar cell according to any one of claims 1 to 13. A photovoltaic module characterized by the following features.

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