Preparation Method of Back-Contact Heterojunction Battery

Abstract

The present disclosure relates to the technical field of solar cells, and specifically provides a method for manufacturing a back-contact heterojunction cell, aiming to solve the problem that the material layer is easily damaged during the manufacturing process of the existing back-contact heterojunction solar cell. For this purpose, the method for manufacturing a back-contact heterojunction solar cell provided by the present disclosure includes: sequentially forming a first intrinsic passivation layer structure, a first doped layer structure, and a first protective layer structure on a first region; sequentially forming a second intrinsic passivation layer structure and a second doped layer structure on a third region and a second region; removing the first protective layer structure on the first region outside the third region. By providing a first protective layer on the first doped layer, during the etching process of the second doped layer and the second intrinsic passivation layer, the first protective layer structure can protect the first doped layer structure and prevent damage to the first doped layer structure.

Description

Technical Field

[0001] The present disclosure relates to the technical field of solar cells, and specifically provides a method for manufacturing a back-contact heterojunction cell. Background Art

[0002] The back-contact heterojunction solar cell (Heterojunction-IBC, abbreviated as HBC) has broad application prospects because the electrodes are arranged on the backlight side of the cell, which can effectively reduce the short-circuit current loss.

[0003] At present, the manufacturing method of the back-contact cell needs to fabricate a P-type region and an N-type region on the back, and it is easy to damage the material layer of the heterojunction cell during the process, thus affecting the performance of the back-contact heterojunction solar cell. Summary of the Invention

[0004] The present disclosure aims to solve the above technical problems, that is, to solve the problem that the material layer is easily damaged during the manufacturing process of the existing back-contact heterojunction solar cell.

[0005] In a first aspect, the present disclosure provides a method for manufacturing a back-contact heterojunction cell, including: providing a substrate, the substrate including a first surface, the first surface including a first region, a second region, and a third region located on the first region and adjacent to the second region; sequentially forming a first intrinsic passivation layer structure, a first doping layer structure of a first doping type, and a first protection layer structure on the first region, and exposing the first surface located on the second region; sequentially forming a second intrinsic passivation layer structure and a second doping layer structure of a second doping type on the third region and the second region, and exposing the first protection layer structure located on the first region outside the third region, the second doping type being opposite to the first doping type; removing the first protection layer structure located on the first region outside the third region.

[0006] In some exemplary embodiments, a first intrinsic passivation layer, a first doping layer of a first doping type, and a first protection layer are sequentially formed on the first surface; the first intrinsic passivation layer, the first doping layer, and the first protection layer are patterned to form a first intrinsic passivation layer structure, a first doping layer structure, and a first protection layer structure located on the first region, and expose the first surface located on the second region.

[0007] In some exemplary embodiments, patterning the first intrinsic passivation layer, the first doping layer, and the first protective layer includes: performing primary patterning on one or more of the first intrinsic passivation layer, the first doping layer, and the first protective layer that are farthest from the first surface by means of laser etching, and removing one or more of the first intrinsic passivation layer, the first doping layer, and the first protective layer that are farthest from the first surface and located on the second region; performing secondary patterning on the first intrinsic passivation layer, the first doping layer, and the first protective layer by means of wet etching or dry etching, and removing the remaining film layers of the first intrinsic passivation layer, the first doping layer, and the first protective layer located on the second region.

[0008] In some exemplary embodiments, after performing secondary patterning on the remaining film layers of the first intrinsic passivation layer, the first doping layer, and the first protective layer by means of wet etching or dry etching, etch the substrate located in the second region so that a groove is formed in the substrate at the second region.

[0009] In some exemplary embodiments, a second intrinsic passivation layer and a second doping layer of a second doping type are sequentially formed on the first protective layer structure and the first surface located in the second region; the second intrinsic passivation layer and the second doping layer are patterned to form a second intrinsic passivation layer structure and a second doping layer structure located on the third region and the second region, and expose the first protective layer structure on the first region outside the third region.

[0010] In some exemplary embodiments, after a second intrinsic passivation layer and a second doping layer are sequentially formed on the first protective layer structure and the first surface located in the second region, a second protective layer is formed on the second doping layer; before patterning the second intrinsic passivation layer and the second doping layer, pattern the second protective layer to protect some of the second intrinsic passivation layer and the second doping layer to be retained.

[0011] In some exemplary embodiments, patterning the second protective layer includes: forming a mask on the second protective layer, the mask being located on the third region and the second region; etching away the second protective layer not covered by the mask to form a second protective layer structure; patterning the second intrinsic passivation layer and the second doping layer includes: etching away the second intrinsic passivation layer and the second doping layer not covered by the second protective layer structure to expose the first protective layer structure on the first region outside the third region.

[0012] In some exemplary embodiments, during the process of etching away the second intrinsic passivation layer and the second doped layer that are not covered by the second protective layer structure, the mask is removed.

[0013] In some exemplary embodiments, while removing the first protective layer structure on the first region that is outside the third region, the second protective layer structure is removed.

[0014] In some exemplary embodiments, the first intrinsic passivation layer structure, the first doped layer structure, the first protective layer structure, the second intrinsic passivation layer structure, and the second doped layer structure on the third region are removed.

[0015] In some exemplary embodiments, before removing the first intrinsic passivation layer structure, the first doped layer structure, the first protective layer structure, the second intrinsic passivation layer structure, and the second doped layer structure on the third region, an electrode material layer is formed on the exposed first doped layer structure and the exposed second doped layer structure, and the electrode material layer on the third region is removed.

[0016] In some exemplary embodiments, a third intrinsic passivation layer and an antireflection layer are sequentially formed on the second surface of the substrate opposite to the first surface.

[0017] In some exemplary embodiments, before forming the first intrinsic passivation layer and the third intrinsic passivation layer, the method further includes: texturing the first surface and the second surface; or, texturing the second surface and polishing the first surface.

[0018] Compared with the prior art, the present disclosure has the following beneficial effects:

[0019] The method for preparing a back-contact heterojunction solar cell provided by the present disclosure includes: providing a substrate, the substrate including a first surface, the first surface including a first region, a second region, and a third region located on the first region and adjacent to the second region; sequentially forming a first intrinsic passivation layer structure, a first doped layer structure of a first doping type, and a first protective layer structure on the first region, and exposing the first surface on the second region; sequentially forming a second intrinsic passivation layer structure and a second doped layer structure of a second doping type on the third region and the second region, and exposing the first protective layer structure on the first region outside the third region, the second doping type being opposite to the first doping type; removing the first protective layer structure on the first region outside the third region. A first protective layer is provided on the first doped layer, and during the etching process of the second doped layer and the second intrinsic passivation layer, the first protective layer structure can protect the first doped layer structure and prevent damage to the first doped layer structure. Brief Description of the Drawings

[0020] The following describes the preferred embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figures 1A to 1E is a cross-sectional structure diagram of a back-contact heterojunction solar cell provided by the present disclosure during the preparation process;

[0022] Figure 2 is a flowchart of the preparation method of the back-contact heterojunction solar cell provided by the present disclosure;

[0023] Figures 3A to 3I is another cross-sectional structure diagram of a back-contact heterojunction solar cell provided by the present disclosure during the preparation process.

[0024] Description of the Reference Numerals in the Drawings:

[0025] 1. Substrate; 11. First surface; 12. Second surface; 13. First region; 14. Second region; 15. Third region; 2. First intrinsic passivation layer; 2a. First intrinsic passivation layer structure; 3. First doped layer; 3a. First doped layer structure; 41. First protective layer; 41a. First protective layer structure; 42. Second protective layer; 42a. Second protective layer structure; 5. Second intrinsic passivation layer; 5a. Second intrinsic passivation layer structure; 6. Second doped layer; 6a. Second doped layer structure; 7. Third intrinsic passivation layer; 8. Antireflection layer; 9. Electrode material layer; 91. First electrode layer; 92. Second electrode layer; 93. Electrode; 10. First mesa structure; 20. Second mesa structure; 30. Isolation groove; 40. Mask. Detailed Embodiments

[0026] In some examples, the present disclosure provides a method for preparing a back-contact heterojunction solar cell, including: sequentially forming a first intrinsic passivation layer 2 and a first doped layer 3 of a first doping type on the first surface 11 of the substrate 1 (as Figure 1A shown); patterning the first intrinsic passivation layer 2 and the first doped layer 3 to remove the first intrinsic passivation layer 2 and the first doped layer 3 outside the first region 13 to form a first intrinsic passivation layer structure 2a and a first doped layer structure 3a, and exposing the first surface 11 in the second region 14, and the first intrinsic passivation layer structure 2a and the first doped layer structure 3a form a first mesa structure 10 (as Figure 1B shown); sequentially forming a second intrinsic passivation layer 5 and a second doped layer 6 of a second doping type on the first mesa structure 10 and the first surface 11 exposed in the second region 14 (as Figure 1Cas shown); pattern the second intrinsic passivation layer 5 and the second doping layer 6 to form a second mesa structure 20 located in a third region 15 adjacent to the second region 14 in the first region 13 and including a first intrinsic passivation layer structure 2a, a first doping layer structure 3a, a second intrinsic passivation layer structure 5a, and a second doping layer structure 6a, and remove the second intrinsic passivation layer 5 and the second doping layer 6 in the first region 13 outside the third region 15 (as Figure 1D shown); then remove the second mesa structure 20 to achieve PN zoning (as Figure 1E shown).

[0027] In the above preparation method, if the first intrinsic passivation layer 2 and the first doping layer 3 in the second region 14 are patterned by laser etching, the laser will penetrate through the first intrinsic passivation layer 2 and the first doping layer 3, thereby damaging the substrate 1 in the second region 14. In addition, if the second intrinsic passivation layer 5 and the second doping layer 6 in the first region 13 outside the third region 15 are removed by laser etching, the laser will penetrate through the second intrinsic passivation layer 5 and the second doping layer 6, thereby damaging the first intrinsic passivation layer 2 and the first doping layer 3 in the first region 13 outside the third region 15, and even damaging the underlying substrate 1; if the second intrinsic passivation layer 5 and the second doping layer 6 in the first region 13 outside the third region 15 are removed by dry etching or wet etching, it is possible to damage the first doping layer 3 in the first region 13 outside the third region 15.

[0028] In view of this, an embodiment of the present disclosure provides a preparation method for a back-contact heterojunction solar cell, as Figure 2 shown, the preparation method includes: providing a substrate, the substrate includes a first surface, the first surface includes a first region, a second region, and a third region located on the first region and adjacent to the second region; sequentially forming a first intrinsic passivation layer structure, a first doping layer structure of a first doping type, and a first protective layer structure on the first region, and exposing the first surface on the second region; sequentially forming a second intrinsic passivation layer structure and a second doping layer structure of a second doping type on the third region and the second region, and exposing the first protective layer structure on the first region outside the third region, the second doping type being opposite to the first doping type; removing the first protective layer structure on the first region outside the third region.

[0029] As Figure 3AAs shown, a substrate 1 is provided first. The material of the substrate 1 is silicon, and the doping type of the substrate 1 is not specifically limited. For example, the substrate 1 can be an N-type doped silicon substrate, or a P-type doped silicon substrate. The substrate 1 includes a first surface 11 and a second surface 12 opposite to the first surface 11. The first surface 11 is the backlight surface, also called the back surface; the second surface 12 is the light-facing surface, also called the front surface.

[0030] For the convenience of description, the first surface 11 of the substrate 1 is divided into a first region 13, a second region 14, and a third region 15. The first region 13 and the second region 14 are adjacent, and the third region 15 is located within the first region 13 and adjacent to the second region 14. It should be particularly noted that the first region 13, the second region 14, and the third region 15 are not pre-divided on the first surface 11, but are defined according to the layout of the multilayer structure after the multilayer structure is formed on the first surface 11. The present disclosure only introduces the concepts of the first region 13, the second region 14, and the third region 15 in advance for the convenience of description, so as to facilitate the understanding of the solution of the present disclosure, and does not limit the preparation method provided by the solution of the present disclosure.

[0031] The substrate 1 is cleaned to remove the damaged layer and subjected to texturing treatment. Among them, both the first surface 11 and the second surface 12 are cleaned to remove the damaged layer. In some examples, both the first surface 11 and the second surface 12 are subjected to texturing treatment, or the second surface 12 is subjected to texturing treatment and the first surface 11 is polished.

[0032] A third intrinsic passivation layer 7 and an antireflection layer 8 are sequentially formed on the second surface 12 of the substrate 1. Among them, the third intrinsic passivation layer 7 is amorphous silicon, and the antireflection layer 8 is silicon nitride or silicon oxide. For example, the third intrinsic passivation layer 7 and the antireflection layer 8 are formed by PECVD (plasma enhanced chemical vapor deposition).

[0033] As Figure 3A and Figure 3B shown, a first intrinsic passivation layer structure 2a, a first doping layer structure 3a of the first doping type, and a first protective layer structure 41a are sequentially formed on the first region 13, and the first surface 11 located on the second region 14 is exposed. In the examples of the present disclosure, it specifically includes:

[0034] As Figure 3AAs shown in the figure, a first intrinsic passivation layer 2, a first doping layer 3 of a first doping type, and a first protective layer 41 are sequentially formed on the first surface 11 of the substrate 1. Among them, the first intrinsic passivation layer 2 is amorphous silicon, the first doping layer 3 is nanocrystalline silicon, microcrystalline silicon, or amorphous silicon, and the first protective layer 41 is an inorganic film layer, such as silicon nitride or silicon oxide. For example, the first intrinsic passivation layer 2 and the first doping layer 3 are formed by PECVD, and the first protective layer 41 is formed by PVD, PECVD, or evaporation. For example, the doping type of the first doping layer 3 is P-type doping or N-type doping.

[0035] As Figure 3B shown in the figure, the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 are patterned to form a first intrinsic passivation layer structure 2a, a first doping layer structure 3a, and a first protective layer structure 41a located on the first region 13, and the first surface 11 located in the second region 14 is exposed. Specifically, it includes: using laser etching to perform a first patterning on one or more layers of the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 that are farthest from the first surface 11 to remove one or more layers of the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 located in the second region 14; using wet etching or dry etching to perform a second patterning on the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 to remove the remaining film layers of the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 located in the second region 14. Due to the presence of the first protective layer 41, in the stage of laser etching, the laser needs to pass through one more film layer (i.e., the first protective layer 41) to shoot at the substrate 1, thereby reducing the laser intensity shooting at the substrate 1 and reducing the damage to the substrate 1 caused by the laser.

[0036] For example, using laser etching to perform a first patterning only on the first protective layer 41 to remove the first protective layer 41 located in the second region 14 to form a first protective layer structure 41a; using the patterned first protective layer structure 41a as a mask, using wet etching or dry etching to perform a second patterning on the first intrinsic passivation layer 2 and the first doping layer 3 to remove the first intrinsic passivation layer 2 and the first doping layer 3 located in the second region 14, thereby reducing the damage to the substrate 1 caused by laser etching.

[0037] Another example is to use laser etching to perform a first patterning on the first protective layer 41 and the first doping layer 3 to remove the first protective layer 41 and the first doping layer 3 located in the second region 14, and then use wet etching or dry etching to perform a second patterning on the first intrinsic passivation layer 2 to remove the first intrinsic passivation layer 2 located in the second region 14.

[0038] For another example, the first protective layer 41, the first doping layer 3, and the first intrinsic passivation layer 2 are patterned once by laser etching to remove the first protective layer 41, the first doping layer 3, and the first intrinsic passivation layer 2 located on the second region 14.

[0039] In some examples, after patterning the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41, the substrate 1 located in the second region 14 is etched, so that a groove 16 is formed in the substrate 1 at the second region 14. Since at least one of the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 is patterned by laser etching, during the process, the laser will pass through the first intrinsic passivation layer 2, the first doping layer 3, and the first protective layer 41 and shoot at the substrate 1, which will cause damage to the substrate 1. After that, the substrate 1 will be etched, and the damage caused to the substrate 1 by laser etching can be removed.

[0040] Combined Figures 3C to 3F As shown, a second intrinsic passivation layer structure 5a and a second doping layer structure 6a of a second doping type are sequentially formed on the third region 15 and the second region 14, and the first protective layer structure 41a on the first region 13 outside the third region 15 is exposed. The second doping type is opposite to the first doping type. Specifically, it includes:

[0041] As Figure 3C shown, a second intrinsic passivation layer 5 and a second doping layer 6 of a second doping type are sequentially formed on the first protective layer structure 41a located on the first region 13 and the first surface 11 located on the second region 14. For example, when the first doping layer 3 is N-type doped, the second doping layer 6 is P-type doped; when the first doping layer 3 is P-type doped, the second doping layer 6 is N-type doped. The second intrinsic passivation layer 5 is amorphous silicon, and the second doping layer 6 is nanocrystalline silicon, microcrystalline silicon, or amorphous silicon. For example, the second intrinsic passivation layer 5 and the second doping layer 6 are formed by PECVD.

[0042] A second protective layer 42 is formed on the second doping layer 6. The second protective layer 42 is an inorganic film layer, such as silicon nitride or silicon oxide, and the second protective layer 42 is formed by PVD, PECVD, or evaporation.

[0043] As Figure 3D and 3E shown, the second protective layer 42 is patterned to remove the second protective layer 42 on the first region 13 outside the third region 15, and a second protective layer structure 42a is formed to protect a part of the second intrinsic passivation layer 5 and the second doping layer 6 to be retained (i.e., the second intrinsic passivation layer 5 and the second doping layer 6 covered and protected by the second protective layer 42). In the examples of the present disclosure, as Figure 3DAs shown, first, a mask 40 is formed on the second protective layer 42. The mask 40 is located on the third region 15 and the second region 14. The second protective layer 42 can isolate the mask 40 from the second doped layer 6, preventing the mask 40 from damaging or contaminating the second doped layer 6; as Figure 3E shown, then, the second protective layer 42 that is not covered by the mask 40 is etched away to form a second protective layer structure 42a. For example, the mask 40 is an organic layer, such as peelable glue, dry film, photoresist, etc.

[0044] As Figure 3F shown, the second intrinsic passivation layer 5 and the second doped layer 6 are patterned to form a second intrinsic passivation layer structure 5a and a second doped layer structure 6a located on the third region 15 and the second region 14, and the first protective layer structure 41a on the first region 13 outside the third region 15 is exposed. Specifically, it includes: using an alkaline etching solution to etch away the second intrinsic passivation layer 5 and the second doped layer 6 that are not covered by the second protective layer structure 42a to expose the first protective layer structure 41a on the first region 13 outside the third region 15. During the process, the first protective layer structure 41a can cover the first doped layer structure 3a throughout the process to protect the first doped layer structure 3a, preventing the etching solution from damaging the first doped layer structure 3a.

[0045] In some possible examples, during the process of etching away the second intrinsic passivation layer 5 and the second doped layer 6 that are not covered by the second protective layer structure 42a (i.e., during the process of patterning the second intrinsic passivation layer 5 and the second doped layer structure 6a), the mask 40 is removed, thus saving process steps. For example, an alkaline etching solution (such as sodium hydroxide, potassium hydroxide, etc.) is used to etch the second intrinsic passivation layer 5 and the second doped layer 6. At the same time, the alkaline etching solution will also corrode and remove the mask 40 that is an organic layer.

[0046] As Figure 3G shown, the first protective layer structure 41a on the first region 13 outside the third region 15 and the second protective layer structure 42a are removed, thus exposing the first doped layer structure 3a and the second doped layer structure 6a. In some possible examples, the materials used for the first protective layer structure 41a and the second protective layer structure 42a are the same and are removed in the same wet etching process. For example, during the process of removing the first protective layer structure 41a on the first region 13 outside the third region 15 and the second protective layer structure 42a, the etching rate of the etching solution for the first doped layer structure 3a is slow, and the damage to the first doped layer structure 3a is small, thus reducing the damage to the first doped layer structure 3a during the preparation of the back contact heterojunction solar cell. For example, the etching solution used to remove the first protective layer structure 41a on the first region 13 outside the third region 15 and the second protective layer structure 42a is an acidic etching solution (such as hydrofluoric acid).

[0047] As Figure 3H shown, an electrode material layer 9 is formed on the exposed first doped layer structure 3a and the second doped layer structure 6a. For example, the electrode material layer 9 can be formed by PVD, RPD (rapid plasma deposition), evaporation, or the like. For example, the electrode material layer 9 can be a single-layer structure or a multi-layer structure. For example, the material of the electrode material layer 9 is TCO (Transparent Conductive Oxides), and the material of each layer in the electrode material layer 9 can specifically be ITO (Indium tin oxide), ICO (indium oxide doped with cadmium), IWO (indium oxide doped with tungsten), SnO 2 , AZO (aluminum-doped zinc oxide), or the like.

[0048] As Figure 3I shown, the first intrinsic passivation layer structure 2a, the first doped layer structure 3a, the first protective layer structure 41a, the second intrinsic passivation layer structure 5a, the second doped layer structure 6a, and the electrode material layer 9 located on the third region 15 are removed to form an isolation groove 30, so that the first doped layer structure 3a on the first region 13 outside the third region 15 is insulated and separated from the second doped layer structure 6a on the second region 14, and the electrode material layer 9 on the first doped layer structure 3a and the electrode material layer 9 on the second doped layer structure 6a are electrically insulated, thereby achieving PN zoning. The electrode material layers 9 on both sides of the isolation groove 30 are the first electrode layer 91 and the second electrode layer 92, respectively. The first electrode layer 91 is electrically connected to the first doped layer structure 3a, and the second electrode layer 92 is electrically connected to the second doped layer structure 6a. It should be particularly noted that during the process of removing the first intrinsic passivation layer structure 2a, the first doped layer structure 3a, the first protective layer structure 41a, the second intrinsic passivation layer structure 5a, the second doped layer structure 6a, and the electrode material layer 9 located on the third region 15, a part of the film layers on the first region 13 and the second region 14 outside the third region 15 may be removed.

[0049] Electrodes 93 (including the first electrode and the second electrode) are respectively formed on the first electrode layer 91 and the second electrode layer 92. The first electrode and the second electrode can be specifically formed by screen printing, laser transfer printing, or copper electroplating.

[0050] In summary, the main advantages of the above preparation method of the back-contact heterojunction battery are as follows:

[0051] (1) During the process of patterning the first protective layer 41, the first doped layer 3, and the first intrinsic passivation layer 2, due to the presence of the first protective layer 41, during the laser etching stage, the laser needs to pass through one more film layer (i.e., the first protective layer 41) to reach the substrate 1, thereby reducing the laser intensity reaching the substrate 1 and reducing the damage caused by the laser to the substrate 1.

[0052] (2) When the first protective layer 41 is disposed on the first doped layer 3 and the second doped layer 6 and the second intrinsic passivation layer 5 are etched, the first protective layer structure 41a can protect the first doped layer structure 3a and prevent damage to the first doped layer structure 3a.

[0053] (3) During the process of removing the first protective layer structure 41a on the first region 13 outside the third region 15, the etching solution used has a relatively slow corrosion rate for the first doped layer structure 3a, thereby reducing the damage to the first doped layer structure 3a.

[0054] (4) The entire set of processes uses the organic mask printing process that is prone to damaging and contaminating the solar cell material layer only once, which can ensure higher efficiency to a greater extent, and the overall process flow is simple and easy to mass-produce.

[0055] The present disclosure also provides another method for manufacturing a back contact heterojunction battery, which is basically the same as the previous embodiment, except that the second protective layer 42 is not provided during the process of manufacturing the back contact heterojunction battery. The main function of the second protective layer 42 is to prevent damage or contamination to the second doped layer 6 during the formation of the mask 40. On the premise of not considering the damage or contamination caused by the mask 40 to the second doped layer 6, the second protective layer 42 can be not provided to simplify the manufacturing process of the back contact heterojunction battery.

[0056] So far, the technical solutions of the present disclosure have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present disclosure is obviously not limited to these specific embodiments. Without departing from the principle of the present disclosure, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present disclosure.

Claims

1. A method for preparing a back contact heterojunction battery, characterized in that: include: Providing a substrate, the substrate comprising a first surface, the first surface comprising a first area, a second area, and a third area located on the first area and adjacent to the second area; forming a first intrinsic passivation layer structure, a first doping layer structure of a first doping type, and a first protection layer structure in sequence on the first region, and exposing the first surface located on the second region; Sequentially forming a second intrinsic passivation layer, a second doping layer of a second doping type, and a second protective layer on the first protective layer structure and the first surface located on the second region; Patterning the second protective layer to form a second protective layer structure covering the second area and the third area; Patterning the second intrinsic passivation layer and the second doping layer to sequentially form a second intrinsic passivation layer structure and a second doping layer structure of a second doping type on the third region and the second region, and exposing the first protection layer structure on the first region outside the third region, wherein the second doping type is opposite to the first doping type; removing the first protective layer structure on the first area outside the third area; The first intrinsic passivation layer structure, the first doping layer structure, the first protection layer structure, the second intrinsic passivation layer structure, and the second doping layer structure located on the third region are removed.

2. The method for preparing a back contact heterojunction battery according to claim 1, characterized in that: forming a first intrinsic passivation layer, a first doping layer of a first doping type, and a first protective layer on the first surface in sequence; The first intrinsic passivation layer, the first doping layer and the first protection layer are patterned to form a first intrinsic passivation layer structure, a first doping layer structure and a first protection layer structure located on the first region, and the first surface located in the second region is exposed.

3. The method for preparing a back contact heterojunction battery according to claim 2, characterized in that: Patterning the first intrinsic passivation layer, the first doping layer, and the first protective layer includes: Patterning one or more layers of the first intrinsic passivation layer, the first doped layer, and the first protective layer that are farthest from the first surface by laser etching, and removing one or more layers of the first intrinsic passivation layer, the first doped layer, and the first protective layer that are farthest from the first surface and located on the second region; The first intrinsic passivation layer, the first doping layer and the first protective layer are secondarily patterned by wet etching or dry etching to remove the remaining film layers of the first intrinsic passivation layer, the first doping layer and the first protective layer located on the second area.

4. The method for preparing a back contact heterojunction battery according to claim 3, characterized in that: After patterning the first intrinsic passivation layer, the first doping layer, and the first protection layer, the substrate located in the second region is etched to form a groove in the substrate at the second region.

5. The method for preparing a back contact heterojunction battery according to claim 1, characterized in that: Patterning the second protective layer includes: forming a mask on the second protective layer, wherein the mask is located in the third area and the second area; Etching and removing the second protective layer not covered by the mask to form a second protective layer structure; Patterning the second intrinsic passivation layer and the second doping layer includes: The second intrinsic passivation layer and the second doping layer that are not covered by the second protection layer structure are removed by etching to expose the first protection layer structure on the first region outside the third region.

6. The method for preparing a back contact heterojunction battery according to claim 5, characterized in that: In the process of etching and removing the second intrinsic passivation layer and the second doping layer not covered by the second protection layer structure, the mask is removed.

7. The method for preparing a back contact heterojunction battery according to claim 5, characterized in that: The second protection layer structure is removed while the first protection layer structure on the first area outside the third area is removed.

8. The method for preparing a back contact heterojunction battery according to claim 1, characterized in that: Before removing the first intrinsic passivation layer structure, the first doping layer structure, the first protective layer structure, the second intrinsic passivation layer structure and the second doping layer structure located on the third region, an electrode material layer is formed on the exposed first doping layer structure and the exposed second doping layer structure, and the electrode material layer located on the third region is removed.

9. The method for preparing a back contact heterojunction battery according to claim 1, characterized in that: A third intrinsic passivation layer and an anti-reflection layer are sequentially formed on a second surface of the substrate opposite to the first surface.

10. The method for preparing a back contact heterojunction battery according to claim 9, characterized in that: Before forming the first intrinsic passivation layer and the third intrinsic passivation layer, the method further comprises: texturing the first surface and the second surface; or, The second surface is textured, and the first surface is polished.

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