Preparation method of solar cell and solar cell

Abstract

The invention provides a preparation method of a solar cell, and the method comprises the steps: forming a first transition layer, a first conductive amorphous silicon layer and a first protection layer on the front surface of a substrate in a patterning manner, and forming a front surface passivation contact structure which is locally passivated; depositing a second protection layer on the front passivation contact structure and the residual area on the front of the substrate at the same time, and removing the second protection layer plated on the back side in a winding manner; depositing a second transition layer, a second conductive amorphous silicon layer and a third protective layer on the back surface of the substrate from which the second protective layer is removed; forming a water film on the third protective layer on the back surface of the substrate; removing the second conductive amorphous silicon layer and the third protection layer which are arranged on the side surface and are plated on the front surface in a winding manner under the condition that the third protection layer on the back surface of the substrate has water film protection; and further removing the second transition layer wound and plated on the front surface and the second protection layer on the front surface by adopting a cleaning process. According to the technical scheme, the photoelectric conversion efficiency of the cell is improved, and the high efficiency and reliability of the manufacturing process are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a solar cell and a solar cell. Background Art

[0002] With the growth of global energy demand and the pressure of environmental protection, solar energy as a clean and renewable energy source has received more and more attention. Solar cells directly convert light energy into electrical energy through the photovoltaic effect and are one of the core technologies for the utilization of solar energy. Improving the conversion efficiency of solar cells and reducing their production costs are the main directions of current technical research.

[0003] In the preparation of solar cells, the existing passivation contact structure is usually composed of ultra-thin silicon oxide and heavily doped polysilicon, which is mainly used for backlight passivation, while the light-receiving side still uses the method of direct metal contact with the semiconductor, which is prone to compound loss at the contact point, limiting the improvement of solar cell performance. Although the double-sided passivation contact structure can reduce compound loss, the light absorption characteristics of the polysilicon layer on the light-receiving side will affect the light absorption efficiency, requiring local passivation. When achieving local passivation, the existing technology involves complex and multiple patterning and plating removal processes, which are not only cumbersome but also easy to damage the battery structure, such as introducing surface defects or uneven passivation, affecting the overall stability and efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a solar cell to solve the technical problem in the prior art that the preparation steps of a double-sided passivation contact structure are complicated and cumbersome and easily damage the cell structure, thereby affecting the overall stability and efficiency of the cell.

[0005] In a first aspect, the present invention provides a method for preparing a solar cell, the method comprising:

[0006] Patterning a first transition layer, a first conductive amorphous silicon layer and a first protective layer on the front side of the substrate to form a front side passivation contact structure, wherein the front side passivation contact structure is a local passivation structure;

[0007] Depositing a second protective layer on the front passivation contact structure and the remaining area on the front side of the substrate at the same time, and removing the second protective layer that is plated around the back side;

[0008] Depositing a second transition layer, a second conductive amorphous silicon layer and a third protective layer on the back side of the substrate from which the second protective layer has been removed;

[0009] forming a water film on the third protective layer on the back side of the substrate;

[0010] In the case where the third protective layer on the back of the substrate is protected by a water film, removing the second conductive amorphous silicon layer and the third protective layer on the side and around the front;

[0011] A cleaning process is further used to remove the second transition layer on the side and around the front surface as well as the second protective layer on the front surface and the side.

[0012] Optionally, the method for preparing a solar cell further includes:

[0013] Performing texturing on the front surface of the substrate;

[0014] After the front side has been textured, the areas of the front side corresponding to the passivation contact structures are polished.

[0015] Optionally, the method for preparing a solar cell further includes:

[0016] Protect the area on the front side corresponding to the passivation contact structure;

[0017] The other areas of the front surface except the area corresponding to the passivation contact structure are textured.

[0018] Optionally, the method for preparing a solar cell further includes:

[0019] Printing a first organic layer, wherein the first organic layer has an opening to expose a region of the front side corresponding to the passivation contact structure;

[0020] The front side passivation contact structure is formed in the exposed area.

[0021] Optionally, the first organic layer is used as a mask layer to heavily dope the region corresponding to the passivation contact structure on the front side of the substrate to increase the doping concentration of the region corresponding to the passivation contact structure.

[0022] Optionally, the method for preparing a solar cell further includes:

[0023] Using the first organic layer as a mask layer, depositing the first transition layer, the first conductive amorphous silicon layer and the first protective layer;

[0024] removing the first organic layer to form a front passivation contact structure;

[0025] The side surface of the front passivation contact structure is trimmed.

[0026] Optionally, the width of the region corresponding to the passivation contact structure is greater than the width of the passivation contact structure.

[0027] Optionally, the method for preparing a solar cell further includes:

[0028] The second protective layer including a multi-layer structure is formed by adopting multiple deposition steps, and the density gradually increases from the outside to the inside.

[0029] Optionally, the thickness of the deposited second protection layer is greater than twice that of the front passivation contact structure.

[0030] In a second aspect, the present invention provides a solar cell prepared by the above-mentioned method for preparing a solar cell.

[0031] According to the technical solution of the present invention, by optimizing the preparation process of the passivation contact structure and adopting simplified processes such as patterned deposition and water film protection, the cumbersome steps in the preparation process and the damage to the battery structure during the removal of the plating are effectively reduced. This method ensures the uniformity and integrity of the passivation layer and avoids the problem of efficiency reduction caused by structural damage in traditional processes. At the same time, by locally passivating the front and back contact structures, the recombination loss is significantly reduced and the carrier collection efficiency is improved. Ultimately, the prepared solar cells show higher stability and conversion efficiency, providing reliable technical support for the production of high-performance batteries.

[0032] By introducing the texturing and polishing steps, the present invention further optimizes the surface structure of the front side of the substrate and improves the light absorption efficiency; the area of ​​the passivation contact structure is protected and partially texturized, effectively avoiding unnecessary surface damage and ensuring the quality of the passivation contact. By printing the first organic layer and using it as a mask layer for patterned deposition and heavy doping operations, not only the process flow is simplified, but also the doping concentration and the size of the passivation structure are accurately controlled, greatly improving the effect of local passivation. In addition, by adopting a multi-layer protection structure with gradually increasing density and adjusting the thickness of the protective layer, the stability and damage resistance of the overall structure are further enhanced. Ultimately, these improvements significantly reduce surface recombination losses and improve the carrier selective collection efficiency, resulting in significant improvements in the photoelectric conversion efficiency and long-term stability of solar cells.

[0033] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic flow chart of a method for preparing a solar cell according to an embodiment of the present invention is shown;

[0035] Figure 2 A schematic structural diagram of a substrate and a front passivation contact structure thereof according to an embodiment of the present invention is shown;

[0036] Figure 3 A schematic diagram of a structure after a second protective layer is deposited on a substrate according to an embodiment of the present invention is shown;

[0037] Figure 4A schematic structural diagram of a substrate after step S200 is performed according to an embodiment of the present invention is shown;

[0038] Figure 5 A schematic structural diagram of a substrate after step S300 is performed according to an embodiment of the present invention is shown;

[0039] Figure 6 A schematic structural diagram of a substrate after step S400 is performed according to an embodiment of the present invention is shown;

[0040] Figure 7 A schematic structural diagram of a substrate after step S500 is performed according to an embodiment of the present invention is shown;

[0041] Figure 8 A schematic structural diagram of a substrate after step S600 is performed according to an embodiment of the present invention is shown;

[0042] Fig. 9 A schematic structural diagram of a substrate according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] Figure 1FIG. 1 is a schematic flow chart of a method for preparing a solar cell according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0047] Step S100 , patterning a first transition layer 102 , a first conductive amorphous silicon layer 103 and a first protective layer 104 on the front surface of the substrate 101 to form a front passivation contact structure, which is a local passivation.

[0048] Figure 2 FIG. 2 shows a schematic structural diagram of a substrate and a front passivation contact structure according to an embodiment of the present invention. Figure 2 As shown, a layer of transition material is deposited on a local area of ​​the front side of the substrate 101 to form a first transition layer 102. This material is usually a dielectric material with low defect density and good electrical properties, such as silicon oxide or silicon nitride. A first conductive amorphous silicon layer 103 is deposited on the first transition layer 102 to achieve effective current collection in a specific area. A layer of protective material, such as transparent oxide zinc oxide, is covered on the first conductive amorphous silicon layer 103 to form a first protective layer 104 for protecting the conductive layer during subsequent processing. The first transition layer 102, the first conductive amorphous silicon layer 103 and the first protective layer 104 constitute a front passivation contact structure.

[0049] The first transition layer 102 improves the interface quality between the substrate 101 and the conductive layer, reduces interface defects, and thus improves the electron transfer efficiency of the battery. The first protective layer 104 effectively prevents damage to the conductive layer in subsequent steps, such as corrosion, scratches or oxidation, which is crucial to maintaining the stability of battery performance. By forming a local passivation structure on the front side, surface recombination is reduced, which means that the probability of electrons and holes recombinating on the surface is reduced, thereby improving the open circuit voltage and overall efficiency of the solar cell.

[0050] Step S200 , depositing a second protective layer 105 on the front passivation contact structure and the remaining area on the front side of the substrate 101 at the same time, and removing the second protective layer 105 that is plated around to the back side.

[0051] Figure 3 A schematic structural diagram is shown after a second protective layer is deposited on a substrate according to an embodiment of the present invention. Figure 4 FIG. 2 shows a schematic structural diagram of a substrate after performing step S200 according to an embodiment of the present invention. Figure 3 As shown, a second protective layer 105, such as silicon nitride or aluminum oxide, is deposited on the front passivation contact structure and other front areas of the substrate 101 to protect the front structure from subsequent steps and external influences. Figure 4As shown, the second protective layer 105 plated around the back is removed by a selective removal process to ensure that the processing of the back in subsequent steps will not be affected. The deposition of the second protective layer 105 in step S200 further reduces the potential damage to the front battery structure by the environment and subsequent steps, especially in subsequent thermal or chemical treatment steps. Removing the excess second protective layer 105 plated around the back can prevent unnecessary accumulation of materials, which helps to ensure the smooth progress of subsequent processes on the back and improve the flexibility and efficiency of the back process.

[0052] Step S300 , depositing a second transition layer 106 , a second conductive amorphous silicon layer 107 and a third protective layer 108 on the back side of the substrate 101 from which the second protective layer 105 has been removed.

[0053] Figure 5 FIG. 4 is a schematic diagram showing the structure of a substrate after performing step S300 according to an embodiment of the present invention. Figure 5 As shown, after removing the second protective layer 105 that is plated around the back of the substrate 101, a second transition layer 106, a second conductive amorphous silicon layer 107 and a third protective layer 108 are deposited on the back of the substrate 101. The second transition layer 106, the second conductive amorphous silicon layer 107 and the third protective layer 108 will be plated around the side and front of the substrate 101. The second transition layer 106 is used to improve the adhesion and interface electrical properties between the back conductive layer and the substrate 101. The second conductive amorphous silicon layer 107 is deposited on the second transition layer 106, and this layer will serve as a current collection and conduction layer on the back. The third protective layer 108, such as oxide or nitride, is deposited on the second conductive amorphous silicon layer 107 to protect the second conductive amorphous silicon layer 107 on the back from the external environment or processing steps.

[0054] Step S400 , forming a water film 109 on the third protective layer 108 on the back side of the substrate 101 .

[0055] Figure 6 FIG. 4 is a schematic diagram showing the structure of a substrate after performing step S400 according to an embodiment of the present invention. Figure 6 As shown, a thin water film 109 is formed on the third protective layer 108 on the back side, which is usually achieved by a humidification process, such as steam or liquid water coating. The water film 109 can play a protective role when it comes into contact with chemical reagents or other processing steps, preventing the back side material from being chemically corroded or thermally damaged. The water film 109 acts as a physical barrier to reduce friction and mechanical damage, and is particularly critical for protecting sensitive layers when removing excess materials.

[0056] Step S500 , when the third protective layer 108 on the back side of the substrate 101 is protected by the water film 109 , the second conductive amorphous silicon layer 107 and the third protective layer 108 which are plated on the side and the front side are removed.

[0057] Figure 7 FIG. 4 is a schematic diagram showing the structure of a substrate after performing step S500 according to an embodiment of the present invention. Figure 7 As shown, the water film 109 protects the second conductive amorphous silicon layer 107 and the third protective layer 108 on the back of the substrate 101, and the redundant second conductive amorphous silicon layer 107 and the third protective layer 108 on the side and plated on the front are removed by selective etching or physical removal. The water film 109 protects the second conductive amorphous silicon layer 107 and the third protective layer 108 on the side and the front, thereby reducing the error or damage to the back of the substrate 101 during the removal process, ensuring that only unnecessary material parts are removed to prevent them from affecting the optical and electrical properties of the solar cell, especially reducing light reflection and current loss.

[0058] In step S600, a cleaning process is further performed to remove the second transition layer 106 on the side and the front surface and the second protective layer 105 on the front surface.

[0059] Figure 8 The schematic diagram of the structure of the substrate after step S600 according to one embodiment of the present invention is shown. The second transition layer 106 and the second protective layer 105 that are not needed on the side and around the front are removed by chemical cleaning, such as acid cleaning or alkali cleaning, to obtain the substrate. Figure 8 The back structure shown. Cleaning removes unnecessary layers, leaving the front side free of excess coverage, thereby maximizing light incidence and current generation efficiency. Through thorough cleaning, the impact of residual impurities on cell efficiency is reduced, and the surface electrical and optical properties of solar cells are optimized.

[0060] In the above steps, the second conductive amorphous silicon layer 107 and the third protective layer 108 on the side and plated around the front are removed by step S500, while the second transition layer 106 plated around the front and the second protective layer 105 on the front are removed in a further step S600. Different material layers react differently to chemical cleaning and physical etching. The second conductive amorphous silicon layer 107 and the third protective layer 108 may require specific removal methods, such as specific chemical solvents or etching conditions to ensure efficient removal without damaging other layers on the back. Removing these two layers separately from other layers can accurately control the removal process of each material to prevent over-etching or residue. By first removing the second conductive amorphous silicon layer 107 and the third protective layer 108 on the side and plated around the front by step S500, the cleaning process of the front processing can be avoided to complicate, so that the subsequent steps can focus more on the removal of other layers on the front, simplify the process flow and improve the stability of the operation. Therefore, by first removing the second conductive amorphous silicon layer 107 and the third protective layer 108 in step S500, and removing other layers in subsequent steps, this step-by-step arrangement can optimize the removal process conditions of each layer, reduce damage to key functional layers, and improve the accuracy and stability of the entire process. This method can not only better protect the structural integrity of the solar cell, but also maximize the photoelectric conversion efficiency of the cell.

[0061] According to the above embodiment, by optimizing the preparation process of the passivation contact structure and adopting simplified processes such as patterned deposition and water film 109 protection, the cumbersome steps in the preparation process and the damage to the battery structure during the removal of the plating are effectively reduced. This method ensures the uniformity and integrity of the passivation layer and avoids the problem of efficiency reduction caused by structural damage in traditional processes. At the same time, by locally passivating the front and back contact structures, the recombination loss is significantly reduced and the carrier collection efficiency is improved. Ultimately, the prepared solar cells show higher stability and conversion efficiency, providing reliable technical support for the production of high-performance batteries.

[0062] In some embodiments, the method for preparing a solar cell further comprises the following steps:

[0063] The front side of the substrate 101 is textured.

[0064] Texturing is to form a random or directional pyramid structure of micrometer level on the front side of substrate 101 by chemical corrosion, such as alkaline solution of isopropyl alcohol, sodium hydroxide, etc. This microstructure can significantly reduce the reflectivity of the surface. The surface microstructure after texturing can effectively scatter the incident light, thereby reducing the reflection loss and improving the capture efficiency of the incident light.

[0065] After the front side has been textured, the areas of the front side corresponding to the passivation contact structures are polished.

[0066] After the front surface is textured, the local area corresponding to the passivation contact structure is polished. This step usually uses chemical mechanical polishing or wet chemical polishing to remove the microstructure formed during the texture process and make the surface of the area flat. Polishing can remove the pyramid microstructure in the textured area and form a smooth surface in the passivation contact structure area, which helps to improve the quality of the local passivation contact, reduce the interface state density and recombination rate, and improve the carrier collection efficiency in the local area.

[0067] By texturing the entire front surface, the light absorption rate can be increased, thereby improving the photoelectric conversion efficiency of the battery; and the polishing of the passivation contact structure area further optimizes the local electrical performance. This surface treatment method with a clear division of labor can achieve a balance between different functional areas, that is, while reducing light reflection, it also maintains good electrical performance in key areas. At the same time, by precisely controlling the surface structure and optical properties, the overall manufacturing process of solar cells is optimized, providing better surface conditions for subsequent process steps.

[0068] In some other embodiments, the above-mentioned operation of texturing the front surface of the substrate 101 can also be another method, and the steps are as follows:

[0069] The area of ​​the front side corresponding to the passivated contact structure is protected.

[0070] A layer of protective material, such as photoresist, silicon oxide, silicon nitride or other protective layer that can resist the texturing process, is deposited on the local area corresponding to the passivation contact structure. The position and shape of the protective layer are precisely controlled by photolithography or mask technology to ensure that only the passivation contact area is covered without affecting other areas. The protective material can effectively prevent the corrosive solution from affecting the passivation contact structure area during the texturing process, keeping the surface of these areas flat and smooth. By protecting the passivation contact area, it is ensured that these areas are not disturbed during the texturing process, thereby maintaining its efficient passivation performance. This helps to reduce local surface recombination, improve open circuit voltage and overall battery efficiency. Through selective protection, it is possible to precisely control which areas are texturized and which areas remain flat, thereby optimizing the functions and characteristics of different areas.

[0071] The other areas of the front side other than the area corresponding to the passivation contact structure are textured.

[0072] Texturing outside the passivation contact area can significantly reduce light reflection loss, increase solar energy absorption, and improve the short-circuit current density of the battery. By protecting the passivation contact structure area and texturing other areas, the local and overall performance of the battery is optimized. The passivation contact area remains smooth to reduce recombination losses, while other areas are texturized to improve light absorption.

[0073] Fig. 9FIG. 2 shows a schematic diagram of the structure of a substrate according to another embodiment of the present invention. Fig. 9 As shown, the formation of the front passivation contact structure of the substrate 101 includes the following steps:

[0074] The first organic layer 201 is printed, and the first organic layer 201 has an opening to expose the area corresponding to the passivation contact structure on the front side.

[0075] The first organic layer 201 is deposited on the front of the solar cell substrate 101 using printing technology. The first organic layer 201 is usually a photoresist or other material that can be removed by subsequent processing. Through the exposure and development steps, specific areas in the first organic layer 201 are removed to form precisely controlled openings. The shape and position of these openings correspond to the areas where the passivation contact structure needs to be formed, exposing the surface of the substrate 101. Printing the first organic layer 201 and exposing the specified area through the opening can accurately control the position and size of the passivation contact structure, which helps to optimize local electrical properties. The unopened part of the first organic layer 201 protects other areas from the impact of subsequent processing, avoiding unnecessary passivation and possible waste of materials. Printing technology can quickly and accurately control patterning, which helps to reduce production costs and improve the flexibility and efficiency of the manufacturing process. At the same time, the first organic layer 201 provides a layer of protection, reducing the risk of direct damage and contamination of the substrate 101 when it comes into contact with chemicals or other processing steps.

[0076] A front side passivation contact structure is formed in the exposed area.

[0077] The passivation contact structure is deposited in the area of ​​the substrate 101 exposed by the opening. Local deposition techniques such as chemical vapor deposition, atomic layer deposition, or physical vapor deposition can be used. Commonly used materials include silicon oxide, silicon nitride, aluminum oxide or other combinations of passivation and conductive materials. The deposition method and the materials used are not limited in detail here. After the passivation contact structure is formed, the first organic layer 201 can be completely removed by an organic layer removal step such as stripping or cleaning, leaving only the passivation contact structure.

[0078] Through precise local passivation, the recombination of electrons and holes in key areas can be reduced, the open circuit voltage and current density of the battery can be increased, and the photoelectric conversion efficiency can be significantly improved. At the same time, unnecessary passivation layers are avoided from being formed in non-critical areas, optimizing material costs and usage. Precise patterning and selective processing reduce variables and uncertainties in the process, improve the performance and reliability of the final product, simplify the production process, and reduce potential production defect rates.

[0079] In some embodiments, the first organic layer 201 is used as a mask layer to heavily dope the region corresponding to the passivation contact structure on the front surface of the substrate 101 to increase the doping concentration of the region corresponding to the passivation contact structure.

[0080] Using the first organic layer 201 as a mask layer, the doping area can be accurately located to ensure that only the predetermined passivation contact structure area is heavily doped, thereby avoiding doping diffusion to unnecessary areas. The mask layer protects the areas that do not need to be doped, prevents dopants from diffusing into these areas, and maintains the initial characteristics and performance of other parts of the battery. In the exposed passivation contact structure area, the doping concentration is increased by heavy doping processes such as diffusion doping and ion implantation. Common dopants include phosphorus or boron. Heavy doping can significantly reduce the contact resistance of the passivation contact structure area, improve the current collection efficiency, and enhance the overall electrical performance of the battery. At the same time, increasing the local doping concentration can enhance the conductivity of the area, effectively reduce the recombination rate of electrons and holes, and increase the short-circuit current density of the battery. The use of heavy doping combined with the passivation layer helps to provide a better interface passivation effect in the contact area, improve the collection efficiency of carriers, and reduce the loss of photogenerated carriers. Therefore, by performing heavy doping in a local area, better current conduction and lower contact resistance can be achieved, thereby improving the conversion efficiency of the overall solar cell. The use of organic layer mask technology can quickly adjust the doping area and pattern, simplify the manufacturing process and improve process accuracy, which is suitable for the production needs of a variety of solar cell structures.

[0081] In some embodiments, the formation of the front passivation contact structure further includes the following steps:

[0082] Using the first organic layer 201 as a mask layer, a first transition layer 102 , a first conductive amorphous silicon layer 103 and a first protective layer 104 are deposited.

[0083] In the exposed area, the first transition layer 102 is first deposited to provide surface passivation and serve as a base for the conductive layer. Then the first conductive amorphous silicon layer 103 is deposited to serve as a conduction channel for carriers. Finally, the first protective layer 104 is deposited on the first conductive amorphous silicon layer 103 to protect the underlying structure and enhance the passivation effect.

[0084] The first organic layer 201 is removed to form a front passivation contact structure.

[0085] Through the organic layer removal step, the mask layer is removed, and only the deposited multilayer structure is retained to form a complete front passivation contact structure.

[0086] The side surfaces of the front passivation contact structure are trimmed.

[0087] The sides of the passivation contact structure are trimmed by physical or chemical methods. Commonly used techniques include laser cutting, plasma etching or wet etching. The trimming can be partial removal or edge trimming to ensure that the sides are smooth and neat. Through the trimming process, the sides of the passivation contact structure are trimmed. The smooth sides help reduce light scattering losses, improve the utilization efficiency of incident light, reduce leakage current and surface recombination in the edge area, and help improve the overall photovoltaic conversion efficiency of the battery. The multi-layer structure and fine cutting process reduce the impact of environmental factors and process defects on the passivation contact structure, and improve the stability and long-term performance of the battery. At the same time, the use of an organic mask layer simplifies the patterning process of multi-layer deposition, and combined with the cutting step, it can achieve higher manufacturing precision and flexibility, which is suitable for large-scale production.

[0088] In some embodiments, a width of the region corresponding to the passivation contact structure is greater than a width of the passivation contact structure.

[0089] The area width of the passivation contact structure is designed to be larger than the actual width of the passivation contact structure, usually to leave a certain edge protection band between the passivation contact area and the non-passivation area, which can effectively reduce the surface recombination velocity, reduce current leakage, and improve the photoelectric conversion efficiency. The edge protection band can avoid irregular deposition or diffusion of the passivation material at the edge during deposition or doping, prevent high recombination rates from occurring at the edge of the passivation contact structure, thereby extending the carrier lifetime, while reducing parasitic current paths and optical occlusion, and increasing the utilization of incident light. In addition, this design can also improve manufacturing tolerance and consistency, reduce performance fluctuations caused by process fluctuations, and ensure production yield and product stability. By reducing thermal mismatch and mechanical stress, the thermal stability and mechanical integrity of the structure are also enhanced, which significantly improves the overall performance and reliability of solar cells.

[0090] In some embodiments, multiple deposition steps are used to form the second protection layer 105 including a multi-layer structure, and the density gradually increases from the outside to the inside.

[0091] The second protective layer 105 adopts a multi-layer structure. Through a phased deposition process, the protective layer is constructed layer by layer, which can better control the thickness, density and material properties of each layer. The design of the multi-layer structure helps to balance the stress between layers and reduce the thermal expansion mismatch and mechanical stress that may be caused by a single thick layer of material. By gradually increasing the density from the outside to the inside, the lower density of the outer layer can provide good flexibility and stress buffering, and the higher density of the inner layer provides strong protection and isolation. This progressive density design can avoid cracks or pores during the deposition process, ensure good adhesion between each layer, and thus enhance the mechanical strength and stability of the overall structure. In the above step S200, the second protective layer 105 is deposited simultaneously on the front passivation contact structure and other areas on the front of the substrate 101. The multi-layer design of the second protective layer 105 can ensure more uniform and effective protection for the passivation contact structure and the surface of the substrate 101, and will not cause stress concentration or insufficient protection problems caused by simple single-layer deposition. At the same time, due to its gradient density design, the protective layer will not significantly increase the complexity and cost of the process while providing protection, and can maintain complete protection of key areas when removing unnecessary plating parts.

[0092] In some embodiments, the thickness of the deposited second protection layer 105 is greater than twice that of the front side passivation contact structure.

[0093] The thickness of the second protective layer 105 is designed to be greater than twice the thickness of the front passivation contact structure, mainly to enhance the mechanical strength and durability of the passivation contact structure, while effectively isolating the intrusion of moisture, oxygen and pollutants from the external environment to ensure the stability of the passivation effect and conductive properties. A thicker protective layer can improve the uniformity and integrity of the deposition, reduce the porosity or microcrack problems caused by thin layer deposition, and reduce the residual risk when removing the part that is plated on the back, avoiding the impact on the back performance. In addition, the increased thickness also improves the electrical insulation performance of the protective layer, prevents electrical short circuits or leakage, and ensures the safety and normal operation of the battery. Ultimately, such a thickness design optimizes process compatibility, allowing the protective layer to provide effective support in subsequent processes, maintain the integrity and functionality of the passivation structure, thereby improving the robustness of the overall production and the reliability of the product.

[0094] According to the above-mentioned embodiment, by introducing the steps of texturing and polishing, the present invention further optimizes the surface structure of the front side of the substrate 101 and improves the light absorption efficiency; the area of ​​the passivation contact structure is protected and partially texturized, which effectively avoids unnecessary surface damage and ensures the quality of the passivation contact. By printing the first organic layer 201 and using it as a mask layer for patterned deposition and heavy doping operations, not only the process flow is simplified, but also the doping concentration and the size of the passivation structure are accurately controlled, which greatly improves the effect of local passivation. In addition, by adopting a multi-layer protection structure with gradually increasing density and adjusting the thickness of the protective layer, the stability and damage resistance of the overall structure are further enhanced. Ultimately, these improvements significantly reduce surface recombination losses and improve the carrier selective collection efficiency, so that the photoelectric conversion efficiency and long-term stability of solar cells are significantly improved.

[0095] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a solar cell, characterized in that: The method comprises: Patterning a first transition layer, a first conductive amorphous silicon layer and a first protective layer on the front side of the substrate to form a front side passivation contact structure, wherein the front side passivation contact structure is a local passivation structure; Depositing a second protective layer on the front passivation contact structure and the remaining area on the front side of the substrate at the same time, and removing the second protective layer that is plated around the back side; Depositing a second transition layer, a second conductive amorphous silicon layer and a third protective layer on the back side of the substrate from which the second protective layer has been removed; forming a water film on the third protective layer on the back side of the substrate; In the case where the third protective layer on the back of the substrate is protected by a water film, removing the second conductive amorphous silicon layer and the third protective layer on the side and around the front; A cleaning process is further used to remove the second transition layer on the side and around the front surface as well as the second protective layer on the front surface and the side.

2. The method for preparing a solar cell according to claim 1, characterized in that: Also includes: Performing texturing on the front surface of the substrate; After the front side has been textured, the areas of the front side corresponding to the passivation contact structures are polished.

3. The method for preparing a solar cell according to claim 1, characterized in that: Also includes: Protect the area on the front side corresponding to the passivation contact structure; The other areas of the front surface except the area corresponding to the passivation contact structure are textured.

4. The method for preparing a solar cell according to claim 1, characterized in that: Also includes: Printing a first organic layer, wherein the first organic layer has an opening to expose a region of the front side corresponding to the passivation contact structure; The front side passivation contact structure is formed in the exposed area.

5. The method for preparing a solar cell according to claim 4, characterized in that: The first organic layer is used as a mask layer to heavily dope the region corresponding to the passivation contact structure on the front side of the substrate, thereby increasing the doping concentration of the region corresponding to the passivation contact structure.

6. The method for preparing a solar cell according to claim 4, characterized in that: Also includes: Using the first organic layer as a mask layer, depositing the first transition layer, the first conductive amorphous silicon layer and the first protective layer; removing the first organic layer to form a front passivation contact structure; The side surface of the front passivation contact structure is trimmed.

7. The method for preparing a solar cell according to claim 4, characterized in that: The width of the region corresponding to the passivation contact structure is greater than the width of the passivation contact structure.

8. The method for preparing a solar cell according to claim 1, characterized in that: Also includes: The second protective layer including a multi-layer structure is formed by adopting multiple deposition steps, and the density gradually increases from the outside to the inside.

9. The method for preparing a solar cell according to claim 8, characterized in that: The thickness of the deposited second protection layer is greater than twice that of the front passivation contact structure.

10. A solar cell, characterized in that: The solar cell is prepared by the method for preparing the solar cell according to any one of claims 1 to 9.

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