CN-122028514-A - Back contact battery, preparation method thereof, laminated battery and photovoltaic module

CN122028514ACN 122028514 ACN122028514 ACN 122028514ACN-122028514-A

Abstract

The application relates to the technical field of photovoltaics, in particular to a back contact battery, a preparation method thereof, a laminated battery and a photovoltaic module. The back contact battery comprises a substrate, wherein the first surface of the substrate comprises a first region, a third region and a second region which are alternately arranged, the first region is at least covered with a tunneling oxide layer and an N-type polycrystalline silicon layer, the second region is at least covered with a P-type graded doped amorphous silicon layer, and the third region is covered with a first passivation layer and a first anti-reflection layer. The film layer of the third region can reduce the composite loss of the surface of the substrate, realize electrical isolation between the first region and the second region and be beneficial to improving the electrical performance of the back contact battery. Meanwhile, at least part of the surface of the N-type polycrystalline silicon layer presents a first pyramid structure, the second area presents a second pyramid structure, and the third area presents a third pyramid structure, so that the reflectivity of incident light is reduced, the equivalent optical path of the incident light is increased, the absorptivity of the substrate to the incident light is improved, and the optical performance of the back contact battery is improved.

Inventors

WANG QIAN
SUN YUFENG
DUAN WEIYUAN
YANG JIE
ZHANG XINYU

Assignees

浙江晶科能源有限公司

Dates

Publication Date: 20260512
Application Date: 20260407

Claims (17)

1. A back contact battery, the back contact battery comprising: A substrate including a first face and a second face disposed opposite to each other in a first direction, the first face including first regions and second regions alternately arranged in a second direction, and a third region between the first regions and the second regions; the tunneling oxide layer is arranged in the first region, and the N-type polycrystalline silicon layer is arranged on the surface of one side, away from the substrate, of the tunneling oxide layer; The P-type slowly-doped amorphous silicon layer is arranged in the second region; the first passivation layer is arranged in the third region, and the first anti-reflection layer is arranged on the surface of one side, away from the substrate, of the first passivation layer; At least part of the surface of the N-type polycrystalline silicon layer presents a first pyramid structure along a first direction, the second region of the substrate presents a second pyramid structure, and the third region of the substrate presents a third pyramid structure.
2. The back contact battery of claim 1, wherein in a first direction, the first pyramid-like structure is present on at least a portion of a surface of the N-type polysilicon layer on a side facing away from the substrate.
3. The back contact battery of claim 2, wherein the N-type polysilicon layer has a width dimension L1 and the first pyramid-like structure has a width dimension L2 in the second direction, and L1 and L2 satisfy 0.9 +.l 2/L1 +.1.
4. The back contact battery of claim 3, wherein the N-type polysilicon layer comprises pyramid regions and flat regions, the flat regions being distributed on both sides of the pyramid regions in the second direction, the pyramid regions exhibiting the first pyramid-like structure, the flat regions being provided with the P-type graded doped amorphous silicon layer.
5. The back contact battery of claim 4, wherein the flat region has a width dimension L11 in the second direction, and L11 and L1 satisfy 0+.l11/l1+.0.1.
6. The back contact battery of any of claims 1-5, wherein at least a portion of the first pyramid-like structures have a height L14 in a first direction, and L14 satisfies 40nm +.l 14 +.90 nm.
7. The back contact battery of claim 6, further comprising a first transparent conductive layer and a second transparent conductive layer, wherein the first transparent conductive layer is disposed on a surface of the N-type polycrystalline silicon layer on a side facing away from the tunneling oxide layer, and the second transparent conductive layer is disposed on a surface of the P-type graded doped amorphous silicon layer on a side facing away from the substrate, along a first direction; The back contact battery also comprises a first electrode and a second electrode, wherein the first electrode is positioned at one side of the first transparent conductive layer, which is away from the N-type polycrystalline silicon layer, and is electrically connected with the first transparent conductive layer, and the second electrode is positioned at one side of the second transparent conductive layer, which is away from the P-type slowly-doped amorphous silicon layer, and is electrically connected with the second transparent conductive layer; in the second direction, the width dimension of the first region is L3, the width dimension of the first electrode is L4, L3 and L4 satisfy 0.1≤L4/L3≤0.8, the width dimension of the second region is L5, the width dimension of the second electrode is L6, and L5 and L6 satisfy 0.1≤L6/L5≤0.8.
8. The back contact battery of claim 7, wherein in a second direction, both ends of the first passivation layer and the first anti-reflection layer extend toward the first region and the second region, respectively, and cover at least portions of the first transparent conductive layer and the second transparent conductive layer, respectively.
9. The back contact battery of claim 8, wherein in the second direction the N-type polysilicon layer comprises a pyramid region and flat regions on either side of the pyramid region, and in the first direction the projections of the first passivation layer and the first anti-reflection layer cover at least a portion of the flat regions.
10. The back contact cell of claim 6, further comprising a second passivation layer and a second anti-reflection layer, wherein the second passivation layer is disposed on the second face in the first direction, and wherein the second anti-reflection layer is disposed on a surface of the second passivation layer facing away from the substrate.
11. The back contact battery of claim 10, wherein the second passivation layer and the first passivation layer are the same material and the second anti-reflection layer and the first anti-reflection layer are the same material.
12. A method for preparing a back contact battery, the method comprising: providing a substrate, wherein the substrate comprises a first surface and a second surface which are oppositely arranged along a first direction, the first surface further comprises a first area and a second area which are alternately arranged along a second direction, and a third area which is positioned between the first area and the second area; sequentially depositing a tunneling oxide layer and an N-type polycrystalline silicon layer in the first region; Depositing a P-type slowly-doped amorphous silicon layer in the second region; Performing laser treatment on the third region to remove a film layer covering the third region; carrying out acid washing treatment on the third region to clean residual impurities in the third region; sequentially depositing a first passivation layer and a first anti-reflection layer in the third region; The surface of the N-type polycrystalline silicon layer presents a first pyramid structure, the second region of the substrate presents a second pyramid structure, and the third region of the substrate presents a third pyramid structure.
13. The method of claim 12, wherein during the sequentially depositing the tunnel oxide layer and the N-type polysilicon layer in the first region, the method further comprises: Sequentially depositing the tunneling oxide layer and the intrinsic polycrystalline silicon layer on the first surface; performing phosphorus doping on the intrinsic polycrystalline silicon layer to form an N-type polycrystalline silicon layer; Depositing the P-type slowly-doped amorphous silicon layer on the first surface; Performing laser treatment on the first region, wherein the laser treatment firstly adopts a tangential mode to remove the P-type slowly-doped amorphous silicon layer at least partially covering the N-type polycrystalline silicon layer, and then adopts a facula overlapping mode to display the first pyramid-shaped structure on the surface of the N-type polycrystalline silicon layer; And carrying out acid washing treatment on the first surface to remove residual impurities on the surface of the N-type polycrystalline silicon layer.
14. The method of preparing as claimed in claim 13, further comprising, after the step of phosphorus doping the intrinsic polysilicon layer to form the N-type polysilicon layer: Performing laser treatment on the second region and the third region to remove the tunneling oxide layer and the N-type polycrystalline silicon layer which cover the second region and the third region; Texturing the second and third regions to present the second and third pyramid-like structures in the second and third regions, respectively; depositing an intrinsic amorphous silicon layer on the first side; boron doping is carried out on the intrinsic amorphous silicon layer so as to form the P-type slowly-doped amorphous silicon layer; Along a first direction, the P-type graded amorphous silicon layer comprises a low-doped amorphous silicon region and a high-doped amorphous silicon region, and the high-doped amorphous silicon region is located at one side of the low-doped amorphous silicon region, which is away from the substrate.
15. The method of manufacturing according to claim 14, wherein after the step of laser-treating the second region and the third region to remove the tunnel oxide layer and the N-type polysilicon layer covering the second region and the third region, the method of manufacturing further comprises: carrying out acid washing treatment on the second surface to remove the phosphosilicate glass covering the second surface; While the second region and the third region are being textured to present the second pyramid-like structure and the third pyramid-like structure in the second region and the third region, respectively, the manufacturing method further includes: texturing the second surface to present a fourth pyramid-like structure on the second surface; Sequentially depositing a second passivation layer and a second anti-reflection layer on the second surface; And carrying out acid washing treatment on the first surface to remove the second passivation layer and the second anti-reflection layer which cover the N-type polycrystalline silicon layer, the second region and the third region.
16. A laminated cell, characterized in that it comprises a bottom cell employing the back contact cell of any one of claims 1-11 and a wide bandgap top cell located on one side of the bottom cell and electrically connected to the bottom cell.
17. A photovoltaic module comprising a cover plate, an encapsulation layer and at least one cell string, the cover plate being connected to the cell string by the encapsulation layer, the cell string comprising a plurality of back contact cells according to any one of claims 1-11 or a plurality of stacked cells according to claim 16.

Description

Back contact battery, preparation method thereof, laminated battery and photovoltaic module Technical Field The application relates to the technical field of photovoltaics, in particular to a back contact battery, a preparation method thereof, a laminated battery and a photovoltaic module. Background For the Back contact battery (Back-contact solar cell), the Back surface is usually an N region and a P region which are alternately arranged and an isolation region between the N region and the P region, and the junction of the isolation region and the N region and the P region is at risk of electric leakage, so that the parallel resistance is reduced, and the loss of electrical performance is caused. Disclosure of Invention In view of the above, the application provides a back contact battery, a preparation method thereof, a laminated battery and a photovoltaic module, so as to solve the technical problem of weakening of the back contact battery in the prior art. The application provides a back contact battery, which comprises a substrate, a tunneling oxide layer, an N-type polycrystalline silicon layer, a P-type slowly-doped amorphous silicon layer, a first passivation layer and a first anti-reflection layer. The substrate includes a first face and a second face disposed opposite each other in a first direction, the first face including first regions and second regions alternately arranged in a second direction, and a third region between the first regions and the second regions. The tunneling oxide layer is arranged in the first region, and the N-type polycrystalline silicon layer is arranged on the surface of one side, away from the substrate, of the tunneling oxide layer. The P-type slowly-doped amorphous silicon layer is arranged in the second region. The first passivation layer is arranged in the third region, and the first anti-reflection layer is arranged on the surface of one side, away from the substrate, of the first passivation layer. Along the first direction, at least part of the surface of the N-type polycrystalline silicon layer presents a first pyramid-shaped structure, a second area of the substrate presents a second pyramid-shaped structure, and a third area of the substrate presents a third pyramid-shaped structure. In one possible embodiment, the first pyramid-like structure is present on at least part of the surface of the side of the N-type polysilicon layer facing away from the substrate in the first direction. In one possible embodiment, the width dimension of the N-type polysilicon layer is L1, the width dimension of the first pyramid-like structure is L2, and L1 and L2 satisfy 0.9≤L2/L1≤1 in the second direction. In one possible implementation manner, the N-type polysilicon layer includes a pyramid region and a flat region, the flat region is distributed on two sides of the pyramid region along the second direction, the pyramid region presents a first pyramid-shaped structure, and the flat region is provided with a P-type graded doped amorphous silicon layer. In one possible embodiment, the width dimension of the flat region is L11 in the second direction, and L11 and L1 satisfy 0≤L11/L1≤0.1. In one possible embodiment, at least part of the first pyramid-like structures have a height L14 in the first direction, and L14 satisfies 40 nm≤L14≤90 nm. In one possible implementation manner, the back contact battery further includes a first transparent conductive layer and a second transparent conductive layer, wherein the first transparent conductive layer is disposed on a surface of the N-type polysilicon layer on a side facing away from the tunneling oxide layer, and the second transparent conductive layer is disposed on a surface of the P-type graded doped amorphous silicon layer on a side facing away from the substrate along the first direction. The back contact battery also comprises a first electrode and a second electrode, wherein the first electrode is positioned on one side of the first transparent conductive layer, which is away from the N-type polycrystalline silicon layer, and is electrically connected with the first transparent conductive layer, and the second electrode is positioned on one side of the second transparent conductive layer, which is away from the P-type graded doped amorphous silicon layer, and is electrically connected with the second transparent conductive layer. Along the second direction, the size of the first region is L3, the size of the first electrode is L4, L3 and L4 meet 0.1-0.8, the size of the second region is L5, the size of the second electrode is L6, and L5 and L6 meet 0.1-0.6/5-0.8. In one possible embodiment, both ends of the first passivation layer and the first anti-reflection layer extend toward the first region and the second region, respectively, and cover at least portions of the first transparent conductive layer and the second transparent conductive layer, respectively, in the second direction. In one possible embodiment, the N-type poly