Preparation method of solar cell, solar cell and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic modules, in particular to a preparation method of a solar cell, the solar cell and the photovoltaic module, and the preparation method of the solar cell comprises the steps: carrying out the two-sided texturing of a silicon substrate; boron diffusion is carried out on the silicon substrate, and boron diffusion layers and borosilicate glass layers are generated on the front face and the back face of the silicon substrate; the front surface of the silicon substrate is provided with a first contact area and a first non-contact area, and the borosilicate glass layer and the boron diffusion layer in the first non-contact area are removed by laser. When boron diffusion is carried out on the silicon substrate, wet oxygen and dry oxygen are introduced in the boron diffusion process, and the ratio of the wet oxygen to the dry oxygen is controlled, so that the density of the generated borosilicate glass layer can be controlled, the density of the prepared borosilicate glass layer is small, the energy density needed by laser when the borosilicate glass layer is removed can be reduced, and the quality of the borosilicate glass layer is improved. Therefore, thermal damage to a silicon substrate or other areas caused by laser during working is reduced, and the preparation quality of the solar cell and the economical efficiency in the preparation process can be improved.

Description

[0001] This application is a divisional application of the patent application filed on July 30, 2025, with application number 202511062050.7 and invention title "A method for preparing a solar cell and a solar cell and photovoltaic module". Technical Field

[0002] This application relates to the field of photovoltaic cell technology, specifically to a method for preparing a solar cell, as well as the solar cell and photovoltaic module. Background Technology

[0003] Photovoltaic cells can convert solar energy into electrical energy, offering advantages such as being pollution-free, not geographically limited, and inexhaustible, making them a major direction for developing new energy sources. Topcon cells, as a type of photovoltaic cell, significantly improve photoelectric conversion efficiency by employing a passivated contact structure composed of an ultrathin silicon oxide layer and a doped polycrystalline silicon layer. However, during the fabrication process of Topcon cells, lasers can easily cause thermal damage to the silicon substrate, affecting the fabrication quality. Summary of the Invention

[0004] This application provides a method for preparing a solar cell, as well as a solar cell and a photovoltaic module, to help solve the technical problem that laser molding can easily cause thermal damage in the prior art.

[0005] In a first aspect, embodiments of this application provide a method for preparing a solar cell, the method comprising: Double-sided texturing of the silicon substrate; Boron diffusion is performed on the silicon substrate to form a boron diffusion layer and a borosilicate glass layer on both the front and back sides of the silicon substrate. The front side of the silicon substrate has a first contact area and a first non-contact area, and the borosilicate glass layer and the boron diffusion layer in the first non-contact area are removed by laser. During the boron diffusion process on the silicon substrate, wet oxygen and dry oxygen are introduced, and the ratio ω of the wet oxygen to the dry oxygen satisfies 0% < ω ≤ 20%; the flow rate of the wet oxygen is 1000 sccm-2000 sccm, and the flow rate of the dry oxygen is 2000 sccm-20000 sccm.

[0006] In this embodiment, by introducing wet oxygen and dry oxygen during the borosilicate glass process, with the flow rate of wet oxygen being 1000 sccm-2000 sccm and the flow rate of dry oxygen being 2000 sccm-20000 sccm, the ratio of wet oxygen to dry oxygen can be controlled, thereby controlling the density of the generated borosilicate glass layer. The beneficial effect is that, compared with the borosilicate glass layers generated in related technologies, the borosilicate glass layer prepared by this method has a lower density, which facilitates laser removal. This reduces the energy density required for laser removal of the borosilicate glass layer, thereby reducing the thermal damage caused to the silicon substrate or other areas by the laser during operation, and thus improving the fabrication quality and economy of the solar cell.

[0007] In one specific embodiment, in the step of laser removal of the borosilicate glass layer and the boron diffusion layer in the first non-contact area, the energy density γ1 required for laser removal of the borosilicate glass layer and the boron diffusion layer is inversely proportional to the ratio ω of the wet oxygen to the dry oxygen.

[0008] In one specific embodiment, the ratio of the energy density γ1 required for the laser to remove the borosilicate glass layer and the boron diffusion layer to the rated energy density γ of the laser satisfies 0.5 ≤ γ1 / γ < 1.

[0009] In one specific embodiment, the ratio of the laser speed V1 when removing the borosilicate glass layer and the boron diffusion layer to the laser's rated speed V satisfies 1 < V1 / V ≤ 2.

[0010] In one specific embodiment, in the step of removing the borosilicate glass layer and the boron diffusion layer in the first non-contact area by laser, the laser is a red nano laser or a green nano laser; the nanosecond pulse width of the laser is 20ns-200ns, the scan rate is 8000mm / s-50000mm / s, and the power is 30w-50w.

[0011] In one specific embodiment, in the step of performing boron diffusion on the silicon substrate to form a boron diffusion layer and a borosilicate glass layer on both the front and back sides of the silicon substrate, the thickness D1 of the borosilicate glass layer satisfies 40nm-80nm.

[0012] In one specific embodiment, in the step of boron diffusion on the silicon substrate to form a boron diffusion layer and a borosilicate glass layer on both the front and back sides of the silicon substrate, the oxygen flow rate is 2000 sccm-20000 sccm, the temperature is 850℃-1000℃, and the furnace tube pressure is 740 mBar-760 mBar.

[0013] In one specific embodiment, the silicon substrate has a first contact area and a first non-contact area on its front side. After the step of laser removal of the borosilicate glass layer and the boron diffusion layer in the first non-contact area, the method for fabricating the solar cell further includes: Remove the boron diffusion layer and the borosilicate glass layer from the back side of the silicon substrate; A tunneling oxide layer, a phosphorus diffusion layer, and a phosphorus silicate glass layer are sequentially formed on the front and back sides of the silicon substrate. The back side of the silicon substrate has a second contact area and a second non-contact area, and the tunneling oxide layer, the phosphorus diffusion layer and the phosphorosilicon glass layer in the second non-contact area are removed; Remove the phosphosilicate glass layer on the front side of the silicon substrate; The silicon substrate is then subjected to a secondary texturing process; Passivation layers are deposited on the front and back sides of the silicon substrate; Electrodes are fabricated in the first contact region and the second contact region.

[0014] In one specific embodiment, the method for fabricating the solar cell specifically includes the following steps in the secondary texturing process of the silicon substrate: The silicon substrate is texturized a second time to remove the phosphorus diffusion layer, the tunneling oxide layer on the front side of the silicon substrate and the phosphorosilicate glass layer on the back side of the silicon substrate, and to make the surface of the silicon substrate corresponding to the first non-contact area and the second non-contact area a textured surface.

[0015] Secondly, embodiments of this application provide a solar cell, which is prepared by the solar cell preparation method. Along the thickness direction of the solar cell, the solar cell includes a first electrode, a first passivation layer, a boron diffusion layer, a silicon substrate, a tunneling oxide layer, a phosphorus diffusion layer, a second passivation layer, and a second electrode stacked sequentially.

[0016] In this embodiment, the beneficial effects of the solar cell fabricated by the above method are as follows: The back side is provided with a tunneling oxide layer and a phosphorus diffusion layer to form a passivated contact structure, which can significantly reduce surface recombination loss, improve open-circuit voltage and fill factor, thereby improving the working efficiency of the solar cell. Simultaneously, the front side of the solar cell only has a boron diffusion layer. Compared to solar cells in related technologies with diffusion and tunneling layers on both sides, this simplifies the fabrication process and saves on fabrication costs while meeting usage requirements. Furthermore, the above method can reduce laser damage to the front side of the silicon substrate during solar cell fabrication, improving the fabrication quality of the solar cell.

[0017] In one specific embodiment, the surfaces of the silicon substrate corresponding to the first contact area, the first non-contact area, and the second non-contact area are textured; the surface of the silicon substrate corresponding to the second contact area is polished.

[0018] Thirdly, embodiments of this application also provide a photovoltaic module, which includes the aforementioned solar cell. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the solar cell provided in this application in a specific embodiment; Figure 2 This is a schematic diagram of the structure corresponding to step S11 in the method for fabricating the solar cell provided in this application; Figure 3 This is a schematic diagram of the structure corresponding to step S12 in the method for preparing the solar cell provided in this application; Figure 4 This is a schematic diagram of the structure corresponding to step S13 in the method for preparing the solar cell provided in this application; Figure 5 This is a schematic diagram of the structure corresponding to step S14 in the method for preparing the solar cell provided in this application; Figure 6 This is a schematic diagram of the structure corresponding to step S14 in the method for preparing the solar cell provided in this application; Figure 7 This is a schematic diagram of the structure corresponding to step S15 in the method for fabricating the solar cell provided in this application; Figure 8 This is a schematic diagram of the structure corresponding to step S16 in the method for preparing the solar cell provided in this application; Figure 9 This is a schematic diagram of the structure corresponding to step S17 in the method for fabricating the solar cell provided in this application; Figure 10 This is a schematic diagram of the structure corresponding to step S18 in the method for preparing the solar cell provided in this application; Figure 11 This is a schematic diagram of the structure corresponding to step S19 in the method for fabricating the solar cell provided in this application; Figure label: 1-Solar cell; 11-Silicon substrate; 111-Boron diffusion layer; 112-Borosilicate glass layer; 113-First contact region; 114-First non-contact region; 115-Tunneling oxide layer; 116-Phosphorus diffusion layer; 117-Phosphosilicate glass layer; 118-Second contact region; 119-Second non-contact region; 12 - First passivation layer; 13 - Second passivation layer; 14 - First electrode; 15 - Second electrode. Detailed Implementation

[0021] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0022] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0023] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] Photovoltaic cells convert solar energy into electrical energy, offering advantages such as being pollution-free, geographically unrestricted, and inexhaustible, making them a major direction for developing new energy sources. Topcon cells, a type of photovoltaic cell, significantly improve photoelectric conversion efficiency through a passivated contact structure composed of an ultra-thin silicon oxide layer and a doped polycrystalline silicon layer. By optimizing the structure of the front and back sides of the Topcon cell, it can not only receive sunlight from the front but also utilize reflected light, thereby improving the overall photoelectric conversion efficiency. Topcon cell fabrication requires laser molding. To ensure the effectiveness of laser molding, the laser energy density needs to be increased, but this can easily cause thermal damage to the silicon substrate of the cell, affecting the fabrication quality.

[0026] To solve the above technical problems, such as Figures 1 to 4As shown, this application provides a method for fabricating a solar cell 1, which may include, but is not limited to, the following steps: S11: Double-sided texturing of silicon substrate 11; S12: Boron diffusion is performed on silicon substrate 11 to form a boron diffusion layer 111 and a borosilicate glass layer 112 on both the front and back sides of silicon substrate 11. S13: The front side of the silicon substrate 11 has a first contact area 113 and a first non-contact area 114. The borosilicate glass layer 112 and the boron diffusion layer 111 of the first non-contact area 114 are removed by laser. In the process of boron diffusion on silicon substrate 11, step S12 may further include: S121: Moist oxygen and dry oxygen are introduced, ensuring that the ratio ω of moist oxygen to dry oxygen satisfies 0% < ω ≤ 20%, and the density ρ1 of the borosilicate glass layer 112 satisfies 1.32 g / cm³. 3 <ρ1≤2.65g / cm 3 .

[0027] In this embodiment, by introducing wet oxygen and dry oxygen during the borosilicate glass diffusion process and controlling the ratio of wet oxygen to dry oxygen, the density of the generated borosilicate glass layer 112 can be controlled so that the density ρ1 of the borosilicate glass layer 112 satisfies 1.32 g / cm³. 3 <ρ1≤2.65g / cm 3 Compared with the borosilicate glass layer produced in related technologies, the borosilicate glass layer 112 prepared by this method has a lower density, which facilitates laser removal. This reduces the energy density required for laser removal of the borosilicate glass layer 112, thereby reducing thermal damage to the silicon substrate 11 or other areas caused by the laser during operation. This improves the fabrication quality of the solar cell 1 and the economic efficiency of the fabrication process.

[0028] The ratio ω of wet oxygen to dry oxygen can be 5%, 12%, 15%, 18%, 20%, etc., and the density ρ1 of the borosilicate glass layer 112 can be 1.34 g / cm³. 3 1.64 g / cm 3 2.00g / cm 3 2.34 g / cm 3 2.65g / cm 3 wait.

[0029] In other embodiments, the ratio of wet oxygen to dry oxygen ω and the density ρ1 of the borosilicate glass layer 112 can also be other values. In this application embodiment, the specific values ​​of ω and ρ1 are not limited, and can be adjusted adaptively according to the actual situation.

[0030] In one specific embodiment, such as Figure 1 , Figures 5 to 10As shown, after step S13, the method for preparing solar cell 1 may also include, but is not limited to, the following steps: S14: Remove the boron diffusion layer 111 and borosilicate glass layer 112 from the back side of the silicon substrate 11; S15: A tunneling oxide layer 115, a phosphorus diffusion layer 116, and a phosphorosilicate glass layer 117 are sequentially formed on the front and back sides of the silicon substrate 11. S16: The back side of the silicon substrate 11 has a second contact area 118 and a second non-contact area 119. The tunneling oxide layer 115, the phosphorus diffusion layer 116 and the phosphorosilicate glass layer 117 of the second non-contact area 119 are removed. S17: Remove the phosphosilicate glass layer 117 on the front side of the silicon substrate 11; S18: Perform secondary texturing on silicon substrate 11; S19: Deposit passivation layers on the front and back sides of the silicon substrate 11; S20: Electrodes are prepared in the first contact region 113 and the second contact region 118.

[0031] In this embodiment, through the above-described preparation steps S14-S20, a passivated contact structure composed of a tunneling oxide layer 115 and a phosphorus diffusion layer 116 can be formed on the back side of the silicon substrate 11 to improve the open-circuit voltage and fill factor of the solar cell 1, reduce surface recombination, and retain the ability to absorb reflected or scattered light. Simultaneously, through steps S11-S13, a boron diffusion layer 111 and a passivation layer are formed on the front side of the silicon substrate 11, which can efficiently absorb direct sunlight from the front side. In summary, by optimizing the front and back structures of the solar cell 1, the solar cell 1 can achieve a high bifaciality, thereby further improving the overall operating efficiency of the solar cell 1.

[0032] like Figure 1 As shown, this application embodiment also provides a solar cell 1 prepared by the above preparation method. Along the thickness direction of the solar cell 1, the solar cell 1 may include a first electrode 14, a first passivation layer 12, a boron diffusion layer 111, a silicon substrate 11, a tunneling oxide layer 115, a phosphorus diffusion layer 116, a second passivation layer 13, and a second electrode 15, which are stacked sequentially along the thickness direction.

[0033] In this embodiment, the solar cell 1 prepared by the above method has a tunneling oxide layer 115 and a phosphorus diffusion layer 116 on its back side to form a passivated contact structure, which can significantly reduce surface recombination loss, improve open-circuit voltage and fill factor, thereby improving the working efficiency of the solar cell 1. Meanwhile, the front side of the solar cell 1 only has a boron diffusion layer 111. Compared with solar cells in related technologies that have diffusion layers and tunneling layers on both sides, this simplifies the preparation process and saves on preparation costs while meeting usage requirements.

[0034] In addition, the above-mentioned preparation method can reduce the damage of laser to the front side of silicon substrate 11 during the preparation of solar cell 1, thereby improving the preparation quality of solar cell 1.

[0035] In this embodiment, the solar cell 1 has a first electrode 14 on its front side. The projection of the first electrode 14 along the thickness direction of the solar cell 1 is located in the first contact area 113, and the first non-contact area 114 is the area outside the first contact area 113. Meanwhile, the solar cell 1 has a second electrode 15 on its back side. The projection of the second electrode 15 along the thickness direction of the solar cell 1 is located in the second contact area 118, and the second non-contact area 119 is the area outside the second contact area 118.

[0036] In one specific embodiment, such as Figures 2 to 4 As shown, in step S121 above, the energy density γ1 required for laser removal of the borosilicate glass layer 112 and the boron diffusion layer 111 is inversely proportional to the ratio ω of wet oxygen to dry oxygen.

[0037] In this embodiment, the energy density required for laser removal of the borosilicate glass layer 112 and the boron diffusion layer 111 can satisfy the following formula with respect to the ratio ω of wet oxygen to dry oxygen: Wherein, ρ1 is the density of the borosilicate glass layer 112 prepared by the method of this application, ρ is the density of the borosilicate glass layer in the related art, and γ is the rated energy density of the laser. The above formulas (1) and (2) are derived from experimental data. From formulas (1) and (2), it can be concluded that γ1 and ω satisfy the following formula: Combining formulas (1), (2) and (3), it can be concluded that when the ratio of wet oxygen to dry oxygen increases, the density of the prepared borosilicate glass layer 112 decreases, thereby reducing the energy density required for the laser to remove the borosilicate glass layer 112 and the boron diffusion layer 111, and thus reducing the thermal damage caused by the laser to the silicon substrate 11.

[0038] Since the density of the borosilicate glass layer 112 is higher than that of the boron diffusion layer 111, the laser can sequentially remove the borosilicate glass layer 112 and the boron diffusion layer 111.

[0039] In one specific embodiment, such as Figure 3 As shown, step S121 above may further include: S1211: When boronizing the silicon substrate 11, the flow rate of wet oxygen is 1000 sccm-2000 sccm, and the flow rate of dry oxygen is 2000 sccm-20000 sccm.

[0040] In this embodiment, the flow rate of the introduced wet oxygen can be 1000 sccm-2000 sccm, for example, 1000 sccm, 1500 sccm, 2000 sccm, etc., and the flow rate of the introduced dry oxygen can be 2000 sccm-20000 sccm, for example, 2000 sccm, 10000 sccm, 20000 sccm, etc., so that the ratio of the introduced wet oxygen to dry oxygen can satisfy 0% < ω ≤ 20%. On the basis of satisfying the borosilicate glass process, the density of the generated borosilicate glass layer 112 is reduced, thereby reducing the energy density required for laser removal of the borosilicate glass layer 112, thereby reducing the thermal damage caused by the laser to the silicon substrate 11.

[0041] In other embodiments, the flow rates of dry oxygen and wet oxygen can also be other values. In this application embodiment, the flow rate values ​​of dry oxygen and wet oxygen are not specifically limited, and can be adjusted adaptively according to the actual situation.

[0042] In the above embodiments, such as Figures 2 to 4 As shown, the ratio of the energy density γ1 required for laser removal of the borosilicate glass layer 112 and the boron diffusion layer 111 to the rated energy density γ of the laser satisfies 0.5 ≤ γ1 / γ < 1.

[0043] In this embodiment, by controlling the ratio of wet oxygen to dry oxygen during boron diffusion, the density of the generated borosilicate glass layer 112 can be controlled. The lower the density, the lower the energy density required for laser irradiation. When the density ρ1 of the borosilicate glass layer 112 satisfies 1.32 g / cm³, the density of the borosilicate glass layer 112 is determined to be 1.32 g / cm³. 3 <ρ1≤2.65g / cm 3 As can be seen from the above formula (3), the ratio of the energy density required by the laser to the rated density of the laser can satisfy 0.5≤γ1 / γ<1, for example, it can be 0.5, 0.7, 0.9, etc., so that the laser can meet the mold opening requirements while significantly reducing the energy density required by the laser.

[0044] In the above embodiments, such as Figures 2 to 4 As shown, by adjusting the density of the borosilicate glass layer 112 to reduce the laser energy density, the laser speed during the removal of the borosilicate glass layer 112 and the boron diffusion layer 111 can be increased. Specifically, the increase in laser speed V1 can satisfy the following formula: Wherein, V is the rated speed of the laser. The above formula (4) can be derived from the general formula for calculating laser energy density (the general formula for calculating laser energy density is γ=P / VS, where P is the laser power and S is the spot area. When the values ​​of P and S are fixed, the laser energy density is inversely proportional to the speed). As can be seen from formula (4), when the ratio of the rated energy density of the laser to the energy density required by the laser in this embodiment satisfies 0.5-1, the laser speed V1 in this embodiment can be up to twice the rated laser speed V, thereby increasing the laser mold opening speed to further improve the fabrication efficiency of solar cells.

[0045] In one specific embodiment, such as Figures 2 to 4 As shown, in the step of removing the borosilicate glass layer 112 and the boron diffusion layer 111 of the first non-contact area 114 by laser, the laser can be a red nano laser or a green nano laser.

[0046] In this embodiment, a red nanolaser or a green nanolaser is selected because it has lower penetration power. When removing the borosilicate glass layer 112 and the boron diffusion layer 111 in the first non-contact area 114, it can reduce the thermal damage to the silicon substrate 11, thereby improving the fabrication quality of the subsequent solar cells. At the same time, red and green nanolasers also have the advantages of high precision, ease of use, and low maintenance costs, which can reduce the difficulty and cost of solar cell fabrication.

[0047] Furthermore, the nanosecond pulse width of the laser can be 20ns-200ns, such as 20ns, 100ns, 200ns, etc. The scan rate can be 8000mm / s-50000mm / s, such as 8000mm / s, 25000mm / s, 50000mm / s, etc., and the power can be 30W-50W, such as 30W, 40W, 50W, etc. By controlling the parameters of the red or green nanolaser, and in conjunction with the low-density borosilicate glass layer 112, non-destructive molding of the silicon substrate 11 can be achieved during the fabrication of solar cells, thereby improving the fabrication quality of the patterned structure on the front side of the solar cell, and thus improving the open-circuit voltage, fill factor, and conversion efficiency of the solar cell.

[0048] In other embodiments, the nanosecond pulse width, scan rate, and power of the laser can also be other values. In the embodiments of this application, the nanosecond pulse width, scan rate, and power of the laser are not specifically limited and can be adaptively adjusted according to the actual situation.

[0049] In one specific embodiment, such as Figure 3 As shown, in step S12, the thickness D1 of the generated borosilicate glass layer 112 can meet the requirement of 40nm-80nm.

[0050] In this embodiment, the thickness of the borosilicate glass layer 112 can be 40nm-80nm, for example, the thickness of the borosilicate glass layer 112 can be 40nm, 50nm, 60nm, 70nm, 80nm, etc. Compared with the thicker borosilicate glass layers in related technologies, by limiting the thickness of the generated borosilicate glass layer 112 in this embodiment, the energy density required for laser removal of the borosilicate glass layer 112 can be further reduced, thereby further reducing the thermal damage caused by the laser to the silicon substrate 11 and improving the fabrication quality of the solar cell.

[0051] In other embodiments, the thickness of the borosilicate glass layer 112 may also be other values. In this embodiment, the specific thickness of the borosilicate glass layer 112 is not limited and can be adjusted adaptively according to the actual situation.

[0052] In the above embodiments, such as Figure 3 As shown, when generating the boron diffusion layer 111 and the borosilicate glass layer 112, the oxygen flow rate can be 2000 sccm-20000 sccm, the temperature can be 850℃-1000℃, and the furnace tube pressure can be 740 mBar-760 mBar.

[0053] In this embodiment, the generation of the boron diffusion layer 111 and the borosilicate glass layer 112 may include steps such as heating, isothermal control, oxidation, and cooling. In the above steps, the oxygen flow rate is controlled to be 2000 sccm-20000 sccm, the temperature is 850℃-1000℃, and the furnace tube pressure is 740 mBar-760 mBar. This limits the thickness of the generated borosilicate glass layer 112, thereby reducing the energy density required for subsequent laser removal of the borosilicate glass layer 112 and the boron diffusion layer 111, and thus reducing the thermal damage caused by the laser to the silicon substrate 11.

[0054] The oxygen flow rate can be 2000 sccm, 7000 sccm, 12000 sccm, 16000 sccm, 20000 sccm, etc., the temperature can be 850℃, 900℃, 920℃, 960℃, 1000℃, etc., and the furnace tube pressure can be 740 mBar, 745 mBar, 750 mBar, 755 mBar, 760 mBar, etc. In other embodiments, the oxygen flow rate, temperature, and furnace tube pressure can also be other values. The specific values ​​of these three parameters are not limited in the embodiments of this application and can be adjusted adaptively according to specific circumstances.

[0055] In one specific embodiment, such as Figure 9 and Figure 10 As shown, step S18 above may further include: S181: Perform secondary texturing on the silicon substrate 11 to remove the phosphorus diffusion layer 116, tunneling oxide layer 115 on the front side of the silicon substrate 11 and the phosphorosilicate glass layer 117 on the back side of the silicon substrate 11, and make the surfaces of the silicon substrate 11 corresponding to the first non-contact area 114 and the second non-contact area 119 textured.

[0056] In this embodiment, by performing secondary texturing on the silicon substrate 11, part of the target structural layer can be removed, and the surfaces of the silicon substrate 11 corresponding to the first non-contact area 114 and the second non-contact area 119 can be texturized, thereby increasing the effective surface area of ​​the first non-contact area 114 and the second non-contact area 119, thus improving the light absorption effect and further improving the working efficiency of the solar cell.

[0057] In one specific embodiment, such as Figure 1 As shown, the surfaces of the silicon substrate 11 corresponding to the first contact area 113, the first non-contact area 114, and the second non-contact area 119 can be textured, and the surface of the silicon substrate 11 corresponding to the second contact area 118 can be polished.

[0058] In this embodiment, the surface of the silicon substrate 11 corresponding to the first contact region 113 is textured, which can increase the effective surface area of ​​the first contact region 113, optimize carrier transport, and improve the fill factor. Furthermore, the surface of the silicon substrate 11 corresponding to the first non-contact region 114 and the second non-contact region 119 is textured, which can increase the effective surface area of ​​the first non-contact region 114 and the second non-contact region 119, thereby improving the light absorption effect of the first non-contact region 114 and the second non-contact region 119. Simultaneously, the surface of the silicon substrate 11 corresponding to the second contact region 118 is polished, which can make the tunneling oxide layer 115 and the phosphorus diffusion layer 116 deposited on the second contact region 118 more uniform, improving the passivation effect.

[0059] This application also provides a photovoltaic module, which can be composed of the solar cell 1, photovoltaic glass, encapsulant film, backsheet, and frame described in the above embodiments. By using the solar cell 1 fabrication method described in the above embodiments, the overall performance of the photovoltaic module can be guaranteed by improving the fabrication quality of the solar cell 1.

[0060] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a solar cell, characterized in that, The method for preparing the solar cell (1) includes: The silicon substrate (11) is textured on both sides; Boron diffusion is performed on the silicon substrate (11) to form a boron diffusion layer (111) and a borosilicate glass layer (112) on both the front and back sides of the silicon substrate (11). The front side of the silicon substrate (11) has a first contact area (113) and a first non-contact area (114), and the borosilicate glass layer (112) and the boron diffusion layer (111) of the first non-contact area (114) are removed by laser. During the boron diffusion process on the silicon substrate (11), wet oxygen and dry oxygen are introduced, and the ratio ω of the wet oxygen to the dry oxygen satisfies 0% < ω ≤ 20%; the flow rate of the wet oxygen is 1000 sccm-2000 sccm, and the flow rate of the dry oxygen is 2000 sccm-20000 sccm.

2. The method for preparing a solar cell according to claim 1, characterized in that, In the step of laser removal of the borosilicate glass layer (112) and the boron diffusion layer (111) in the first non-contact area (114), the energy density γ1 required for laser removal of the borosilicate glass layer (112) and the boron diffusion layer (111) is inversely proportional to the ratio ω of the wet oxygen to the dry oxygen.

3. The method for preparing a solar cell according to claim 2, characterized in that, The ratio of the energy density γ1 required for the laser to remove the borosilicate glass layer (112) and the boron diffusion layer (111) to the rated energy density γ of the laser satisfies 0.5 ≤ γ1 / γ < 1.

4. The method for preparing a solar cell according to claim 3, characterized in that, The ratio of the speed V1 of the laser removing the borosilicate glass layer (112) and the boron diffusion layer (111) to the rated speed V of the laser satisfies 1 < V1 / V ≤ 2.

5. The method for preparing a solar cell according to claim 3, characterized in that, In the step of removing the borosilicate glass layer (112) and the boron diffusion layer (111) of the first non-contact area (114) by laser, the laser is a red nano laser or a green nano laser; The laser has a nanosecond pulse width of 20ns-200ns, a scan rate of 8000mm / s-50000mm / s, and a power of 30w-50w.

6. The method for preparing a solar cell according to claim 1, characterized in that, In the step of performing boron diffusion on the silicon substrate (11) to form a boron diffusion layer (111) and a borosilicate glass layer (112) on both the front and back sides of the silicon substrate (11), the thickness D1 of the borosilicate glass layer (112) satisfies 40nm-80nm.

7. The method for preparing a solar cell according to claim 6, characterized in that, In the step of boron diffusion on the silicon substrate (11) to form a boron diffusion layer (111) and a borosilicate glass layer (112) on both the front and back sides of the silicon substrate (11), the oxygen flow rate is 2000 sccm-20000 sccm, the temperature is 850℃-1000℃, and the furnace tube pressure is 740 mBar-760 mBar.

8. The method for preparing a solar cell according to any one of claims 1-7, characterized in that, After the step of removing the borosilicate glass layer (112) and the boron diffusion layer (111) from the first non-contact area (114) by laser from the front side of the silicon substrate (11), the method for fabricating the solar cell (1) further includes: Remove the boron diffusion layer (111) and the borosilicate glass layer (112) on the back side of the silicon substrate (11). A tunneling oxide layer (115), a phosphorus diffusion layer (116), and a phosphorus silicate glass layer (117) are sequentially formed on the front and back sides of the silicon substrate (11). The back side of the silicon substrate (11) has a second contact area (118) and a second non-contact area (119), and the tunneling oxide layer (115), the phosphorus diffusion layer (116) and the phosphorosilicate glass layer (117) are removed from the second non-contact area (119). Remove the phosphosilicate glass layer (117) on the front side of the silicon substrate (11). The silicon substrate (11) is subjected to secondary texturing; Passivation layers are deposited on the front and back sides of the silicon substrate (11); Electrodes are prepared in the first contact region (113) and the second contact region (118).

9. The method for preparing a solar cell according to claim 8, characterized in that, In the step of performing secondary texturing on the silicon substrate (11), the method for preparing the solar cell (1) specifically includes: The silicon substrate (11) is texturized a second time to remove the phosphorus diffusion layer (116), the tunneling oxide layer (115) on the front side of the silicon substrate (11) and the phosphorosilicate glass layer (117) on the back side of the silicon substrate (11), and to make the surface of the silicon substrate (11) corresponding to the first non-contact area (114) and the second non-contact area (119) a textured surface.

10. A solar cell, characterized in that, The solar cell (1) is prepared by the method of preparing the solar cell (1) according to any one of claims 1-9. Along the thickness direction of the solar cell (1), the solar cell (1) includes a first electrode (14), a first passivation layer (12), a boron diffusion layer (111), a silicon substrate (11), a tunneling oxide layer (115), a phosphorus diffusion layer (116), a second passivation layer (13), and a second electrode (15) stacked sequentially.

11. The solar cell according to claim 10, characterized in that, The surfaces of the silicon substrate (11) corresponding to the first contact area (113), the first non-contact area (114), and the second non-contact area (119) are textured; The surface of the silicon substrate (11) corresponding to the second contact area (118) is a polished surface.

12. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell (1) as described in any one of claims 10-11.

Images