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EP-4742858-A1 - BACK CONTACT SOLAR CELL AND PHOTOVOLTAIC MODULE

EP4742858A1EP 4742858 A1EP4742858 A1EP 4742858A1EP-4742858-A1

Abstract

The present disclosure relates to a back contact solar cell and a photovoltaic module. The back contact solar cell includes a silicon substrate (1), a first passivation layer (5), a protective layer (4), a first electrode (2), and a second electrode (3). The silicon substrate has a first surface (11) and a second surface (12) opposite to each other. A P-type conductive section (121) and an N-type conductive section (122) spaced apart from each other are provided at a side of the second surface of the silicon substrate. The first passivation layer is disposed on the first surface of the silicon substrate. The protective layer is disposed on a side of the first passivation layer facing away from the silicon substrate. The first electrode is electrically connected to the P-type conductive section. The second electrode is electrically connected to the N-type conductive section.

Inventors

  • CHEN, YUBIN
  • XIA, Danwei
  • XIA, Zhipeng
  • Huang, Jide
  • LIU, CHANGMING

Assignees

  • JINKO SOLAR CO., LTD
  • Jinko Solar (Haining) Co., Ltd.

Dates

Publication Date
20260513
Application Date
20250314

Claims (15)

  1. A back contact solar cell (100), comprising: a silicon substrate (1) having a first surface (11) and a second surface (12) opposite to each other, a P-type conductive section (121) and an N-type conductive section (122) spaced apart from each other being provided at a side of the second surface (12) of the silicon substrate (1); a first passivation layer (5) disposed on the first surface (11) of the silicon substrate (1); a protective layer (4) disposed on a side of the first passivation layer (5) facing away from the silicon substrate (1); a first electrode (2) electrically connected to the P-type conductive section (121); and a second electrode (3) electrically connected to the N-type conductive section (122).
  2. The back contact solar cell (100) according to claim 1, wherein in a thickness direction (Z) of the back contact solar cell (100), a projected area of the protective layer (4) is 2% to 3% of a projected area of the silicon substrate (1).
  3. The back contact solar cell (100) according to claim 1 or claim 2, wherein the protective layer (4) has a thickness of H 1 , where 5 µm ≤ H 1 ≤ 60 µm.
  4. The back contact solar cell (100) according to any one of claims 1 to 3, wherein the protective layer (4) comprises a plurality of support members (41) spaced apart from each other and disposed on the side of the first passivation layer (5) facing away from the silicon substrate (1).
  5. The back contact solar cell (100) according to any one of claims 1 to 4, wherein a distance between geometric centers of any two adjacent support members (41) is greater than 0 mm and smaller than or equal to 20 mm.
  6. The back contact solar cell (100) according to claim 4, wherein a cross-sectional shape of the support members (41), perpendicular to a thickness direction (Z) of the back contact solar cell (100), is a circular shape, a semicircular shape, an annular shape, a rectangular shape, a triangular shape, a rhombic shape, a W shape, a V shape, or any combination thereof.
  7. The back contact solar cell (100) according to claim 4, wherein a cross-sectional shape of the support members (41), perpendicular to a thickness direction (Z) of the back contact solar cell (100), is a circular shape having a radius of R 1 , where 0 < R 1 ≤ 4 mm.
  8. The back contact solar cell (100) according to claim 4, wherein a cross-sectional shape of the support members (41), perpendicular to a thickness direction (Z) of the back contact solar cell (100), is a strip shape formed by combing a semicircular shape and a rectangular shape; the semicircular shape has a radius of R 2 , where 0 < R 2 ≤ 2 mm; and the rectangular shape has a length of L, where 1 ≤ L/R 2 ≤ 5.
  9. The back contact solar cell (100) according to claim 8, wherein the strip shape is formed by one rectangular shape with two semicircular shapes disposed at two opposite ends of the one rectangular shape in a length direction of the one rectangular shape, preferably, the one rectangular shape has a width the same as a diameter of the two semicircular shapes.
  10. The back contact solar cell (100) according to any one of claims 1 to 9, wherein the protective layer (4) is a transparent protective layer.
  11. The back contact solar cell (100) according to any one of claims 1 to 10, wherein a material of the protective layer (4) is acrylic resin, epoxy resin, polyurethane, silicone, or any combination thereof.
  12. The back contact solar cell (100) according to any one of claims 1 to 11, further comprising: a first doped conductive layer (6) disposed in the P-type conductive section (121) at the second surface (12) of the silicon substrate (1); a second doped conductive layer (7) disposed in the N-type conductive section (122) at the second surface (12) of the silicon substrate (1); and a second passivation layer (8) disposed on a side of the first doped conductive layer (6) and a side of the second doped conductive layer (7) that face away from the silicon substrate (1), and disposed on at least a portion of the second surface (12); optionally, the first doped conductive layer (6) forms a PN junction structure with the silicon substrate (1); optionally, each of the second doped conductive layer (7) and the silicon substrate (1) contains a doping element, and a concentration gradient of the doping element is formed between the second doped conductive layer (7) and the silicon substrate (1); optionally, the first electrode (2) penetrates through the second passivation layer (8) to be electrically connected to the first doped conductive layer (6), and the second electrode (3) penetrates through the second passivation layer (8) to be electrically connected to the second doped conductive layer (7).
  13. The back contact solar cell according to claim 12, further comprising: a first tunneling dielectric layer (10a) disposed between the first doped conductive layer (6) and the silicon substrate (1); and a second tunneling dielectric layer (10b) disposed between the second doped conductive layer (7) and the silicon substrate (1).
  14. The back contact solar cell according to claim 12 or claim 13, further comprising an anti-reflection layer (9) disposed between the first passivation layer (5) and the protective layer (4); preferably, a thickness between a surface of the second passivation layer (8) facing away from the silicon substrate (1) and a surface of the first passivation layer (5) or the anti-reflection layer (9) facing away from the silicon substrate (1) is 90 µm to 210 µm.
  15. A photovoltaic module, comprising: a cell string (110) formed by a plurality of back contact solar cells connected to each other, wherein each of the plurality of back contact solar cells is the back contact solar cell (100) of any one of claims 1 to 14; an encapsulation layer (120) configured to cover a surface of the protective layer (4) of each of the plurality of back contact solar cells of the cell string (110); and a cover plate (130) configured to cover a surface of the encapsulation layer (120) away from the cell string (110).

Description

TECHNICAL FIELD The present disclosure relates to the technical field of photovoltaic cells, and in particular to a back contact solar cell and a photovoltaic module. BACKGROUND A solar cell, also known as a "solar chip" or "photovoltaic cell," is a photoelectric semiconductor device that utilizes sunlight to generate electricity directly. The solar cell can instantly output voltage and generate current in the case of a loop, as long as it is exposed to light that meets certain illuminance conditions. An interdigitated back contact (IBC) solar cell has no metal grid lines on its front surface, with positive and negative metal electrodes disposed in an interdigitated pattern on its back surface. The IBC solar cell exhibits a good photoelectric conversion efficiency due to the absence of obstruction from the grid lines on its front surface. However, during the process of printing the metal grid lines on the cell wafers and conveying the cell wafers to an assembling process, the front films of the cell wafers are prone to damage. Currently, an isolation paper is commonly interposed between two adjacent cell wafers. However, in the sorting and collecting process, the risk of scratching the front films of the cell wafers is still increased due to uneven collection of the cell wafers or misalignment of the isolation paper. SUMMARY In view of this, the present disclosure provides a back contact solar cell and a photovoltaic module, to solve the problem that during the process of printing the metal grid lines on the cell wafers and conveying the cell wafers to an assembling process, the front films of the cell wafers are prone to damage. In a first aspect, the present disclosure provides a back contact solar cell, including a silicon substrate, a first passivation layer, a protective layer, a first electrode, and a second electrode. The silicon substrate has a first surface and a second surface opposite to each other. A P-type conductive section and an N-type conductive section spaced apart from each other are provided at a side of the second surface of the silicon substrate. The first passivation layer is disposed on the first surface of the silicon substrate. The protective layer is disposed on a side of the first passivation layer facing away from the silicon substrate. The first electrode is electrically connected to the P-type conductive section. The second electrode is electrically connected to the N-type conductive section. In an embodiment, in a thickness direction of the back contact solar cell, a projected area of the protective layer is 2% to 3% of a projected area of the silicon substrate. In an embodiment, the protective layer has a thickness of H1, where 5 µm ≤ H1 ≤ 60 µm. In an embodiment, the protective layer includes a plurality of support members spaced apart from each other and disposed on the side of the first passivation layer facing away from the silicon substrate. In an embodiment, a distance between geometric centers of any two adjacent support members is d, where 0 < d ≤ 20 mm. In an embodiment, a cross-sectional shape of the support members, perpendicular to a thickness direction of the back contact solar cell, is a circular shape, a semicircular shape, an annular shape, a rectangular shape, a triangular shape, a rhombic shape, a W shape, a V shape, or any combination thereof. In an embodiment, a cross-sectional shape of the support member, perpendicular to the thickness direction of the back contact solar cell, is a circular shape with a radius of R1, where 0 < R1 ≤ 4 mm. In an embodiment, a cross-sectional shape of the support member, perpendicular to the thickness direction of the back contact solar cell, is a strip shape formed by combing a semicircular shape and a rectangular shape. The semicircular shape has a radius of R2, where 0 < R2 ≤ 2 mm. The rectangular shape has a length of L, where 1 ≤ L/R2 ≤ 5. In an embodiment, the protective layer is a transparent protective layer. In an embodiment, a material of the protective layer is acrylic resin, epoxy resin, polyurethane, silicone, or any combination thereof. In a second aspect, the present disclosure provides a photovoltaic module. The photovoltaic module includes a cell string, an encapsulation layer, and a cover plate. The cell string is formed by a plurality of back contact solar cells that are provided according to any one of the above embodiments and connected to each other. The encapsulation layer is configured to cover a surface of the protective layer of each of the plurality of back contact solar cells of the cell string. The cover plate is configured to cover a surface of the encapsulation layer that is away from the cell string. In the present disclosure, the protective layer is disposed on a side of the first passivation layer facing away from the first surface of the silicon substrate. The protective layer can prevent the contact between a surface of the first passivation layer and other stacked back contact solar cell