Laser boron-doped selective emitter TOPCon cell, photovoltaic module and laminated cell

Abstract

The utility model is suitable for the technical field of solar power generation, and provides a laser boron-doped selective emitter TOPCon cell, a photovoltaic assembly and a laminated cell, the laser boron-doped selective emitter TOPCon cell comprises a silicon substrate, a boron-doped layer, at least one layer of front passivation contact structure, a first electrode, at least one layer of back passivation contact structure and a second electrode, the at least one layer of front passivation contact structure and the boron doping layer are arranged on the front surface of the silicon substrate, the front passivation contact structure comprises a first silicon oxide layer and a first doping layer, and the back passivation contact structure comprises a second silicon oxide layer and a doped polycrystalline silicon layer. Through the arrangement, the first electrode does not need to be in direct contact with the boron-doped layer, the front contact recombination is reduced, the cell conversion efficiency is improved, meanwhile, the front passivation contact structure can be directly prepared on the boron-doped layer, the front does not need a mask, the front passivation contact structure and the back passivation contact structure can be formed in one step, the preparation process is simplified, and the production cost is reduced. The preparation efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar power generation, and in particular relates to a laser boron doped selective emitter TOPCon cell, a photovoltaic component and a laminated cell. Background Art

[0002] TOPCon (Tunnel Oxide Passivating Contact) cells are tunnel oxide passivated contact solar cells with silicon substrate as substrate. The existing laser boron selective emitter TOPCon cells are made by texturing and cleaning the silicon substrate c-Si and then performing boron diffusion to form a high surface concentration p+ layer and BSG (Back Surface Field Silicon Wafer). The boron diffusion includes BSG deposition at 750-950°C and boron advancement at 800-1000°C. The high surface boron concentration is then used for laser doping to form a p++ region. A post-oxidation treatment at 900-1100°C is then performed to reduce the surface concentration, reduce surface recombination and eliminate laser loss. After the post-oxidation treatment, the p+ layer and BSG on the back are removed, and subsequent back n-poly deposition and phosphorus diffusion (800-950°C) are performed to generate SiO on the back. x The passivation contact structure of the (silicon oxide) layer and the N-poly (doped polysilicon) layer and PSG (Phosphorus-doped Silicon Wafer, phosphorus-doped silicon wafer), further remove the BSG on the front and PSG on the back, RCA cleaning, and then the front and back passivation films (SiN x ) deposition, screen printing grid line (Ag), thereby preparing the laser boron selective emitter TOPCon cell. The preparation process is as follows Figure 1 shown.

[0003] The preparation process of the laser boron selective emitter TOPCon cell includes three high-temperature steps, namely boron diffusion, post-oxidation treatment and phosphorus diffusion steps. Three different high-temperature equipment are required, which has high energy consumption and high preparation cost. Utility Model Content

[0004] The embodiment of the utility model provides a laser boron doped selective emitter TOPCon battery, aiming to solve the problem of high energy consumption in the preparation of the existing laser boron doped selective emitter TOPCon battery.

[0005] The embodiment of the utility model is implemented as follows: a laser boron-doped selective emitter TOPCon cell comprises a silicon substrate, a first boron-doped layer, a first electrode, at least one back passivation contact structure and a second electrode;

[0006] The silicon substrate comprises a front side and a back side opposite to each other, the first boron doped layer is generated by boron diffusion on the front side of the silicon substrate, the first boron doped layer is provided with a heavily doped region, the heavily doped region is generated by laser boron doping in the first boron doped layer, and the first electrode is connected to the heavily doped region;

[0007] At least one back passivation contact structure is stacked on the back of the silicon substrate. The back passivation contact structure includes a first silicon oxide layer and a first doped polysilicon layer sequentially arranged in a direction away from the silicon substrate. The second electrode is connected to the doped polysilicon layer.

[0008] Further, the first boron doped layer is disposed in a local area of ​​the front surface of the silicon substrate.

[0009] Furthermore, the TOPCon cell further includes a back passivation film, which is arranged on a side of the back passivation contact structure away from the silicon substrate, and the second electrode passes through the back passivation film and is connected to the doped polysilicon layer.

[0010] Furthermore, the TOPCon cell further comprises at least one front passivation contact structure, wherein the at least one front passivation contact structure is stacked on the first boron-doped layer;

[0011] The front passivation contact structure comprises a second silicon oxide layer and a second doped polysilicon layer arranged in sequence along a direction from the silicon substrate to away from the silicon substrate, and the first electrode is connected to the second doped polysilicon layer.

[0012] Furthermore, the front passivation contact structure and the back passivation contact structure have the same polarity.

[0013] Furthermore, the TOPCon cell further includes a front passivation film, which is disposed on the first boron-doped layer, and the first electrode passes through the front passivation film and is connected to the heavily doped region.

[0014] Further, the front passivation film and the back passivation film include at least one of silicon nitride, aluminum oxide, silicon oxynitride and silicon oxide.

[0015] Furthermore, the front side of the silicon substrate and / or the back side of the silicon substrate is a polished surface or a velvet surface.

[0016] In a second aspect, the present application also provides a photovoltaic module, including the laser boron doped selective emitter TOPCon cell as described above.

[0017] In a third aspect, the present application also provides a stacked cell, including a perovskite cell and a laser boron-doped selective emitter TOPCon cell as described above.

[0018] The beneficial effect of the present application is that the laser boron doped selective emitter TOPCon cell of the present application includes a silicon substrate, a first boron doped layer, a first electrode, at least one back passivation contact structure and a second electrode, wherein the silicon substrate includes a relative front and back, the first boron doped layer is generated by boron diffusion on the front of the silicon substrate, the first boron doped layer is provided with a heavily doped region, the heavily doped region is generated by laser boron doping in the first boron doped layer, the first electrode is connected to the heavily doped region, at least one back passivation contact structure is stacked and arranged on the back of the silicon substrate, the back passivation contact structure includes a first silicon oxide layer and a first doped polysilicon layer sequentially arranged in a direction away from the silicon substrate from the silicon substrate, and the second electrode is connected to the doped polysilicon layer. Through the above arrangement, the first boron doped layer is generated by boron diffusion on the front of the silicon substrate, and laser boron doping is performed on the basis of the first boron doped layer to generate a heavily doped region, and then the first electrode is directly prepared to be connected to the heavily doped region, and no post-oxidation step is required, which reduces the use of high-temperature equipment, thereby reducing energy consumption and controlling preparation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the battery structure during the preparation process of the existing laser boron doped selective emitter TOPCon battery;

[0020] Figure 2 It is a schematic diagram of the battery structure during the preparation process of one embodiment of the laser boron doped selective emitter TOPCon battery provided in the present application;

[0021] Figure 3 It is a schematic structural diagram of a back-side passivation contact structure of one embodiment of a laser boron-doped selective emitter TOPCon cell provided in the present application;

[0022] Figure 4 It is a schematic diagram of the structure of a 2-layer back passivation contact structure of an embodiment of a laser boron doped selective emitter TOPCon cell provided in the present application;

[0023] Figure 5 It is a schematic structural diagram of a three-layer back-side passivation contact structure of an embodiment of a laser boron-doped selective emitter TOPCon cell provided in the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the utility model, and cannot be understood as limiting the utility model. In addition, it should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0025] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0027] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0028] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0029] The disclosure below provides many different embodiments or examples for realizing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the utility model. In addition, the utility model can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the utility model provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0030] The laser boron doped selective emitter TOPCon cell of the present application includes a silicon substrate, a first boron doped layer, a first electrode, at least one back passivation contact structure and a second electrode, wherein the silicon substrate includes a relative front and back, the first boron doped layer is generated by boron diffusion on the front of the silicon substrate, the first boron doped layer is provided with a heavily doped region, the heavily doped region is generated by laser boron doping in the first boron doped layer, the first electrode is connected to the heavily doped region, at least one back passivation contact structure is stacked and arranged on the back of the silicon substrate, the back passivation contact structure includes a first silicon oxide layer and a first doped polysilicon layer sequentially arranged in a direction away from the silicon substrate from the silicon substrate, and the second electrode is connected to the doped polysilicon layer. Through the above arrangement, the first boron doped layer is generated by boron diffusion on the front of the silicon substrate, and laser boron doping is performed on the basis of the first boron doped layer to generate a heavily doped region, and then the first electrode is directly prepared to be connected to the heavily doped region, without the need for a post-oxidation step, reducing the use of high-temperature equipment, thereby reducing energy consumption and controlling the preparation cost.

[0031] Embodiment 1

[0032] like Figures 2 to 5 As shown, an embodiment of the present application provides a laser boron-doped selective emitter TOPCon cell, comprising a silicon substrate 100, a first boron-doped layer 200, a first electrode 300, at least one back passivation contact structure 400 and a second electrode 500;

[0033] The silicon substrate 100 includes a front side and a back side opposite to each other. The first boron-doped layer 200 is formed by boron diffusion on the front side of the silicon substrate 100. The first boron-doped layer 200 is provided with a heavily doped region 210. The heavily doped region 210 is formed by laser boron doping on the first boron-doped layer 200. The first electrode 300 is connected to the heavily doped region 210.

[0034] At least one layer of back passivation contact structure 400 is stacked on the back side of the silicon substrate 100, and the back passivation contact structure 400 includes a first silicon oxide layer 410 and a first doped polysilicon layer 420 sequentially arranged in a direction from the silicon substrate 100 to away from the silicon substrate 100, and the second electrode 500 is connected to the first doped polysilicon layer 420.

[0035] During implementation, the silicon substrate 100 can be an N-type silicon wafer or a P-type silicon wafer, wherein the N-type silicon wafer is obtained by adding a pentavalent element (such as phosphorus) to intrinsic semiconductor silicon, and the P-type silicon wafer is obtained by adding a trivalent element (such as boron, gallium or indium) to intrinsic semiconductor silicon, which will not be elaborated herein.

[0036] The silicon substrate 100 has a front side and a back side, wherein the front side of the silicon substrate 100 corresponds to the light-receiving side of the solar cell, and similarly, the back side of the silicon substrate 100 corresponds to the backlight side of the solar cell.

[0037] A first boron-doped layer 200 is provided on the front side of the silicon substrate 100. The first boron-doped layer 200 is a P+ layer with a high surface boron concentration generated by boron diffusion on the basis of the silicon substrate 100. That is, the first boron-doped layer 200 is a P-type silicon layer generated by doping the silicon substrate 100 with boron elements.

[0038] After the boron diffusion process is performed on the silicon substrate 100 , a first boron doped layer 200 and a BSG layer may be generated on the front surface of the silicon substrate 100 . Alternatively, a first boron doped layer 200 and a BSG layer may be generated on the front surface of the silicon substrate 100 .

[0039] After the boron diffusion, laser doping is further performed using a high surface boron concentration to form a heavily doped region 210 , which is a p++ region.

[0040] In some embodiments, after laser doping is performed to form the heavily doped region 210 , the first boron doped layer 200 and BSG on the back side need to be removed.

[0041] During implementation, the first boron-doped layer 200 and BSG on the back side can be removed by etching, for example, the laser-doped silicon substrate 100 is placed in an etching solution to remove the first boron-doped layer 200 and BSG on the back side. The etching solution can be an aqueous solution of H2SO4 (sulfuric acid) plus HF (hydrofluoric acid) or a solution that can etch the first boron-doped layer 200 and BSG on the back side, without limitation.

[0042] In some possible embodiments, in order to prevent the etching solution from causing damage to the front and / or side surfaces of the silicon substrate 100, the front and / or side surfaces of the laser-doped silicon substrate 100 may be first covered with a layer of water film, and then the silicon substrate 100 covered with the water film may be placed in the etching solution to remove the first boron-doped layer 200 and BSG on the back side.

[0043] After removing the first boron-doped layer 200 and BSG on the back side, a high-temperature n-poly process is directly performed to prepare at least one layer of back passivation contact structure 400 on the back side of the silicon substrate 100. These back passivation contact structures 400 are stacked layer by layer on the back side of the silicon substrate 100 in a stacked manner.

[0044] The back passivation contact structure 400 includes a first silicon oxide layer 410 and a first doped polysilicon layer 420 , wherein the first silicon oxide layer 410 refers to a tunneling oxide layer (SiO 2 ) and the first doped polysilicon layer 420 refers to a doped polysilicon layer (n-poly).

[0045] During implementation, the first silicon oxide layer 410 and the first doped polysilicon layer 420 may be prepared by PECVD (plasma enhanced chemical vapor deposition) or LPCVD (Low Pressure Chemical Vapor Deposition), without limitation.

[0046] In some possible embodiments, the thickness of the tunnel oxide layer is 1.5 nanometers to 4 nanometers, for example, the thickness of the tunnel oxide layer is 2 nanometers, 2.5 nanometers, 3 nanometers or 3.5 nanometers, etc., without limitation.

[0047] Optionally, the back side passivation contact structure 400 may be directly fabricated on the back side of the silicon substrate 100 without using a mask, thereby simplifying the fabrication process and reducing fabrication costs.

[0048] In some embodiments, the back side passivation contact structure 400 may have only one layer, that is, a first silicon oxide layer 410 and a first doped polysilicon layer 420 are disposed on the back side of the silicon substrate 100. Figure 3 shown.

[0049] Optionally, the back passivation contact structure 400 may be provided with multiple layers, such as 2 layers, 3 layers, 4 layers or other number of layers, without limitation. For example, taking the back passivation contact structure 400 including 2 layers as an example, a first silicon oxide layer 410, a first doped polysilicon layer 420, a first silicon oxide layer 410 and a first doped polysilicon layer 420 are sequentially provided on the back side of the silicon substrate 100, i.e., a SiOx / n-poly / SiOx / n-poly structure, such as Figure 4 shown.

[0050] Optionally, taking the back side passivation contact structure 400 including three layers as an example, a first silicon oxide layer 410, a first doped polysilicon layer 420, a first silicon oxide layer 410, a first doped polysilicon layer 420, a first silicon oxide layer 410 and a first doped polysilicon layer 420 are sequentially arranged on the back side of the silicon substrate 100, that is, a SiOx / n-poly / SiOx / n-poly / SiOx / n-poly structure, as shown in FIG. Figure 5 As shown, no further elaboration is given.

[0051] After the n-poly process on the back side, the BSG or PSG is removed, RCA cleaning is performed, and then the gate lines are screen-printed to prepare the first electrode 300 and the second electrode 500 .

[0052] In implementation, when there is only one layer of back passivation contact structure 400, the second electrode 500 is directly connected to the first doped polysilicon layer 420, thereby reducing contact recombination and improving the cell conversion efficiency.

[0053] In some possible embodiments, when a plurality of back passivation contact structures 400 are provided, the other back passivation contact structures 400 except the back passivation contact structure 400 closest to the silicon substrate 100 are provided with perforations (not shown in the figure), and the second electrode 500 passes through the perforations and contacts the first doped polysilicon layer 420 of the back passivation contact structure 400 closest to the silicon substrate 100. Of course, in some possible embodiments, only part of the back passivation contact structure 400 may be provided with perforations, for example, a first back passivation contact structure 400, a second back passivation contact structure 400 and a third back passivation contact structure 400 are sequentially provided in a direction away from the silicon substrate 100, wherein only the third back passivation contact structure 400 is provided with perforations. At this time, the second electrode 500 passes through the perforations and contacts the first doped polysilicon layer 420 of the second back passivation contact structure 400, thereby reducing front contact recombination and improving battery conversion efficiency.

[0054] Optionally, the back passivation contact structure 400 may not be provided with a through hole, and the molten metal paste is burned through the back passivation contact structure 400, and the second electrode 500 is formed after the metal paste is cooled and solidified, which will not be described in detail.

[0055] In some possible embodiments, at least one front passivation contact structure (not shown) is disposed on the back side of the silicon substrate 100, and at least one front passivation contact structure is stacked on the first boron-doped layer 200, wherein the front passivation contact structure includes a second silicon oxide layer and a second doped polysilicon layer sequentially disposed in a direction away from the silicon substrate 100, and the first electrode 300 is connected to the second doped polysilicon layer. In implementation, the front passivation contact structure and the first electrode 300 can refer to the above-mentioned back passivation contact structure 400 and the second electrode 500, and no further description is given.

[0056] Optionally, the front passivation contact structure and the back passivation contact structure 400 have the same polarity, and the front passivation contact structure and the back passivation contact structure 400 can be prepared step by step or simultaneously to reduce the preparation process flow.

[0057] The laser boron-doped selective emitter TOPCon cell of the present application includes a silicon substrate 100, a first boron-doped layer 200, a first electrode 300, at least one back passivation contact structure 400 and a second electrode 500, wherein the silicon substrate 100 includes a relative front side and a back side, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, the first boron-doped layer 200 is provided with a heavily doped region 210, the heavily doped region 210 is generated by laser boron doping in the first boron-doped layer 200, the first electrode 300 is connected to the heavily doped region 210, at least one back passivation contact structure 400 is stacked on the back side of the silicon substrate 100, the back passivation contact structure 400 includes a first silicon oxide layer 410 and a first doped polysilicon layer 420 sequentially arranged in a direction from the silicon substrate 100 to away from the silicon substrate 100, and the second electrode 500 is connected to the doped polysilicon layer. Through the above arrangement, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, and laser boron doping is performed on the basis of the first boron-doped layer 200 to generate a heavily doped region 210, and then the first electrode 300 is directly prepared to be connected to the heavily doped region 210, without the need for a post-oxidation step, thereby reducing the use of high-temperature equipment, thereby reducing energy consumption and controlling preparation costs.

[0058] In some optional embodiments, the first boron doped layer 200 is disposed in a local area of ​​the front surface of the silicon substrate 100 .

[0059] During implementation, the first boron-doped layer 200 can be full-surface or regional contact, that is, the first boron-doped layer 200 can be arranged on the entire front side of the silicon substrate 100, or can be arranged in a partial area of ​​the front side of the silicon substrate 100. Preferably, the first boron-doped layer 200 is arranged in a partial area of ​​the front side of the silicon substrate 100, which can effectively reduce the surface recombination of the non-contact area and improve the battery conversion efficiency.

[0060] In some possible embodiments, the width of the first boron doped layer 200 is smaller than the width of the front passivation contact structure. Through the above configuration, the width of the first boron doped layer 200 is smaller, thereby reducing contact recombination.

[0061] In some optional embodiments, the laser boron-doped selective emitter TOPCon cell provided in the present application further includes a front passivation film 600 , which is disposed on the first boron-doped layer 200 , and the first electrode 300 is connected to the heavily doped region 210 through the front passivation film 600 .

[0062] The front passivation film 600 is a passivation film, which is used to improve the photoelectric conversion efficiency and stability of the solar cell, reduce the surface damage and oxidation reaction of the solar cell, and extend the service life of the solar cell.

[0063] Optionally, the front passivation film 600 may be provided with an opening, and the first electrode 300 passes through the opening of the front passivation film 600 and is connected to the heavily doped region 210 .

[0064] In some other possible embodiments, the front passivation film 600 is not provided with an opening, and the front passivation film 600 is connected to the heavily doped region 210 after being burned through by molten metal paste, and the first electrode 300 is formed after the metal paste is cooled and solidified.

[0065] In some optional embodiments, the laser boron doped selective emitter TOPCon cell provided in the present application further includes a back passivation film 700, which is disposed on a side of the back passivation contact structure 400 away from the silicon substrate 100, and the second electrode 500 passes through the back passivation film 700 and is connected to the first doped polysilicon layer 420. The back passivation film 700 can refer to the front passivation film 600 described above, and no further description is given.

[0066] In some possible embodiments, the passivation film includes at least one of silicon nitride, aluminum oxide, silicon oxynitride and silicon oxide, etc., without limitation. Preferably, the front passivation film 600 and / or the back passivation film 700 can be made of aluminum oxide to ensure light absorption rate.

[0067] In some optional embodiments, the front and / or back of the silicon substrate 100 is a polished surface or a velvet surface. Generally, before the silicon substrate 100 is subjected to the boron diffusion process, the silicon substrate 100 may be polished or velvet-treated. Among them, the polishing process of the silicon substrate 100 may be performed by mechanical polishing, chemical mechanical polishing, electrochemical polishing, photocatalytic assisted chemical mechanical polishing, etc., in order to enhance the polishing effect, improve the surface roughness of the silicon substrate 100, and increase the material removal rate. The velvet treatment refers to the use of a specific process (such as a chemical wet process) to process the front and / or back of the silicon substrate 100 to form a pyramid-shaped velvet surface on the front and / or back. The light trapping principle of the velvet surface is used. When light is incident on a slope at a certain angle, the light will be reflected to a slope at another angle, forming secondary or multiple absorption, thereby increasing the absorption rate, reducing the reflectivity of light, and increasing the short-circuit current, thereby improving the photoelectric conversion efficiency.

[0068] In some embodiments, taking a layer of back passivation contact structure 400 and a layer of back passivation contact structure 400 as examples, the preparation process of the laser boron doped selective emitter TOPCon cell provided in the present application includes the following steps:

[0069] Step 1, cleaning the silicon substrate 100, and then performing texturing or polishing on the silicon substrate 100;

[0070] Step 2: performing boron diffusion on the silicon substrate 100 to generate a first boron-doped layer 200 and BSG with a high surface concentration on both the front and back sides of the silicon substrate 100;

[0071] Step 3: laser doping is performed using a high surface boron concentration to form a heavily doped region 210;

[0072] Step 4, removing the first boron-doped layer 200 on the back side and the BSG on the back side;

[0073] Step 5: Perform a high-temperature n-poly process on the back side to form a back SiOx / n-poly passivation contact plus a back PSG;

[0074] Step 6: Remove the BSG on the front and the PSG on the back, and then perform RCA cleaning;

[0075] When implemented, the RCA cleaning method mainly includes two steps:

[0076] SC1 cleaning: This is an alkaline solution, the main purpose of which is to remove particles, metals and organic matter. Through the strong oxidizing effect of hydrogen peroxide and the alkaline corrosion effect of ammonium hydroxide, particles and organic pollutants on the surface of silicon wafers can be effectively removed.

[0077] SC2 cleaning: This is an acidic solution, the main function of which is to remove metal ions. The metal impurities on the surface of the wafer can be removed through the oxidation of hydrogen peroxide and the acid corrosion of hydrochloric acid.

[0078] In addition, the RCA cleaning method also includes several other cleaning solutions, such as a mixture of H2SO4+H2O2 (sulfuric acid plus hydrogen peroxide) for removing metals and organic matter, and diluted hydrofluoric acid for removing oxide films on the surface of silicon wafers. The order and conditions of using these cleaning solutions are selected according to specific cleaning requirements and material properties, and are not limited.

[0079] In order to improve the effect of RCA cleaning, it can also be combined with megasonic cleaning technology. Megasonic cleaning uses high-frequency sound waves in liquid media to generate tiny cavitation bubbles. When these bubbles burst, local shock waves are generated, thereby effectively removing pollutants on the surface of silicon wafers. The above combined method can ensure the cleanliness of silicon wafers.

[0080] Step 7: depositing the front and back passivation films 700 to prepare the front passivation film 600 and the back passivation film 700;

[0081] Step 8: Screen-printing the gate lines to prepare the first electrode 300 and the second electrode 500, thereby preparing a laser boron-doped selective emitter TOPCon cell.

[0082] In some possible embodiments, light injection and laser enhanced contact processing can be performed after screen printing and grid line sintering. After the light injection, laser irradiation and reverse bias current are applied simultaneously to optimize the paste contact.

[0083] Embodiment 2

[0084] In some optional embodiments, the present application provides a photovoltaic module, including the laser boron doped selective emitter TOPCon cell as described above.

[0085] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the photovoltaic assembly described above can refer to the corresponding structure and implementation principle in the aforementioned embodiment 1, and will not be repeated here.

[0086] The laser boron-doped selective emitter TOPCon cell of the present application includes a silicon substrate 100, a first boron-doped layer 200, a first electrode 300, at least one back passivation contact structure 400 and a second electrode 500, wherein the silicon substrate 100 includes a relative front side and a back side, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, the first boron-doped layer 200 is provided with a heavily doped region 210, the heavily doped region 210 is generated by laser boron doping in the first boron-doped layer 200, the first electrode 300 is connected to the heavily doped region 210, at least one back passivation contact structure 400 is stacked on the back side of the silicon substrate 100, the back passivation contact structure 400 includes a first silicon oxide layer 410 and a first doped polysilicon layer 420 sequentially arranged in a direction from the silicon substrate 100 to away from the silicon substrate 100, and the second electrode 500 is connected to the doped polysilicon layer. Through the above arrangement, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, and laser boron doping is performed on the basis of the first boron-doped layer 200 to generate a heavily doped region 210, and then the first electrode 300 is directly prepared to be connected to the heavily doped region 210, without the need for a post-oxidation step, thereby reducing the use of high-temperature equipment, thereby reducing energy consumption and controlling preparation costs.

[0087] Embodiment 3

[0088] In some optional embodiments, the present application also provides a stacked cell, including a perovskite cell and a laser boron-doped selective emitter TOPCon cell as described above.

[0089] In practice, perovskite cells, i.e., perovskite solar cells, are solar cells that use perovskite-type organic metal halide semiconductors as light-absorbing materials. The tandem cells provided in this application are perovskite-silicon-based tandem solar cells. Perovskite-silicon-based tandem cells utilize the wide bandgap structural characteristics of perovskite cell materials, and place perovskite cell materials above silicon-based cells, which can absorb high-energy photons in the short-wave band that are difficult for silicon-based cells to absorb, thereby making greater use of solar incident light, thereby improving the conversion efficiency of photovoltaic cells, and having a higher theoretical efficiency limit, which will not be elaborated on.

[0090] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the structure and implementation principle of the laminated battery described above can refer to the corresponding structure and implementation principle in the aforementioned embodiments 1 and 2, and will not be repeated here.

[0091] The laser boron-doped selective emitter TOPCon cell of the present application includes a silicon substrate 100, a first boron-doped layer 200, a first electrode 300, at least one back passivation contact structure 400 and a second electrode 500, wherein the silicon substrate 100 includes a relative front side and a back side, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, the first boron-doped layer 200 is provided with a heavily doped region 210, the heavily doped region 210 is generated by laser boron doping in the first boron-doped layer 200, the first electrode 300 is connected to the heavily doped region 210, at least one back passivation contact structure 400 is stacked on the back side of the silicon substrate 100, the back passivation contact structure 400 includes a first silicon oxide layer 410 and a first doped polysilicon layer 420 sequentially arranged in a direction from the silicon substrate 100 to away from the silicon substrate 100, and the second electrode 500 is connected to the doped polysilicon layer. Through the above arrangement, the first boron-doped layer 200 is generated by boron diffusion on the front side of the silicon substrate 100, and laser boron doping is performed on the basis of the first boron-doped layer 200 to generate a heavily doped region 210, and then the first electrode 300 is directly prepared to be connected to the heavily doped region 210, without the need for a post-oxidation step, thereby reducing the use of high-temperature equipment, thereby reducing energy consumption and controlling preparation costs.

[0092] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser boron doped selective emitter TOPCon cell, characterized in that: It includes a silicon substrate, a first boron-doped layer, a first electrode, at least one back-side passivation contact structure, and a second electrode; The silicon substrate comprises a front side and a back side opposite to each other, the first boron doped layer is generated by boron diffusion on the front side of the silicon substrate, the first boron doped layer is provided with a heavily doped region, the heavily doped region is generated by laser boron doping on the first boron doped layer, and the first electrode is connected to the heavily doped region; At least one layer of the back passivation contact structure is stacked on the back side of the silicon substrate, and the back passivation contact structure includes a first silicon oxide layer and a first doped polysilicon layer sequentially arranged in a direction away from the silicon substrate, and the second electrode is connected to the doped polysilicon layer.

2. The laser boron doped selective emitter TOPCon cell according to claim 1, characterized in that: The first boron-doped layer is disposed in a local area of ​​the front surface of the silicon substrate.

3. The laser boron doped selective emitter TOPCon cell according to claim 1 or 2, characterized in that: The TOPCon cell further includes a back passivation film, which is disposed on a side of the back passivation contact structure away from the silicon substrate, and the second electrode passes through the back passivation film and is connected to the doped polysilicon layer.

4. The laser boron doped selective emitter TOPCon cell according to claim 3, characterized in that: The TOPCon cell further comprises at least one front passivation contact structure, wherein at least one front passivation contact structure is stacked on the first boron-doped layer; The front passivation contact structure comprises a second silicon oxide layer and a second doped polysilicon layer which are sequentially arranged in a direction from the silicon substrate to a direction away from the silicon substrate, and the first electrode is connected to the second doped polysilicon layer.

5. The laser boron doped selective emitter TOPCon cell according to claim 4, characterized in that: The front passivation contact structure and the back passivation contact structure have the same polarity.

6. The laser boron doped selective emitter TOPCon cell according to claim 3, characterized in that: The TOPCon cell further includes a front passivation film, which is disposed on the first boron-doped layer, and the first electrode is connected to the heavily doped region through the front passivation film.

7. The laser boron doped selective emitter TOPCon cell according to claim 6, characterized in that: The front passivation film and the back passivation film include at least one of silicon nitride, aluminum oxide, silicon oxynitride, and silicon oxide.

8. The laser boron doped selective emitter TOPCon cell according to claim 1, characterized in that: The front side of the silicon substrate and / or the back side of the silicon substrate is a polished surface or a velvet surface.

9. A photovoltaic module, characterized in that: Comprising the laser boron doped selective emitter TOPCon cell as claimed in any one of claims 1 to 8.

10. A laminated battery, characterized in that: The invention comprises a perovskite cell and a laser boron-doped selective emitter TOPCon cell as claimed in any one of claims 1 to 8.

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