A solar cell and its fabrication method, and a photovoltaic module

Abstract

This application provides a solar cell and its fabrication method, as well as a photovoltaic module. The solar cell includes: a cell body, the cell body including a conductive layer, a first region located in the center of the surface of the cell body, and a second region located at the edge of the cell body and surrounding the first region. The conductive layer is located in the first region, and the second region does not have a conductive layer and the surface energy of the second region is less than or equal to 0.05 J / m². 2 The grid lines are in contact with the conductive layer located in the first region. This application effectively overcomes the defects of traditional edge-binding processes using adhesive by adjusting the structure of the solar cell, thereby achieving a significant improvement in the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] This application relates to the technical field of solar cells, and more particularly to a solar cell and its preparation method, and a photovoltaic module. Background Technology

[0002] Copper interconnect technology is currently one of the important processes used to fabricate solar cell grid lines. This process requires edge banding of the cell body to be electroplated to suppress copper diffusion at the edges. However, the edge banding process has poor stability, which leads to the growth of small grid lines in areas where the edge banding adhesive is not covered, resulting in a decrease in the photoelectric conversion efficiency of the solar cell. Summary of the Invention

[0003] In order to overcome the defects of the traditional edge-binding process using edge-binding adhesive and improve the photoelectric conversion efficiency of solar cells, this application provides a solar cell and its preparation method, as well as a photovoltaic module.

[0004] In a first aspect, embodiments of this application provide a solar cell, the solar cell comprising: A battery body includes a conductive layer. The surface of the battery body has a first region located in the center and a second region located at the edge of the battery body and surrounding the first region. The conductive layer is located in the first region, and the second region does not have the conductive layer, and the surface energy of the second region is less than or equal to 0.05 J / m². 2 ; A gate line that contacts the conductive layer located in the first region.

[0005] As an optional implementation, in an embodiment of this application, the surface energy of the second region is 0.0295 J / m². 2 ~0.0375 J / m 2 .

[0006] As an optional implementation, in the embodiments of this application, the width of the second region is less than or equal to 300 μm.

[0007] As an optional implementation, in the embodiments of this application, the material of the conductive layer includes at least one of indium tin oxide and indium zinc oxide; And / or, The material of the grid line includes at least one of copper, nickel, and tin.

[0008] As an optional implementation, in the embodiments of this application, the contact angle of the second region surface is greater than or equal to 90°; And / or, the surface of the second region is concave compared to the surface of the first region.

[0009] As an optional implementation, in an embodiment of this application, the battery body includes: A silicon substrate having a first side and a second side disposed opposite to each other; A first passivation layer is disposed on the first surface of the silicon substrate; An N-type doped silicon layer disposed on the side of the first passivation layer opposite to the silicon substrate; A second passivation layer is disposed on the second side of the silicon substrate; A P-type doped silicon layer disposed on the side of the second passivation layer opposite to the silicon substrate; The conductive layer and the gate line are disposed on the side of the N-type doped silicon layer away from the silicon substrate, and / or the conductive layer and the gate line are disposed on the side of the P-type doped silicon layer away from the silicon substrate.

[0010] Secondly, embodiments of this application provide a method for preparing a solar cell. A method for fabricating a solar cell includes the following steps: A battery body is provided, the surface of which includes a conductive layer; A seed layer is prepared on the conductive layer, the seed layer having a mask region for printing a mask on the side opposite to the conductive layer and a non-mask region located at the edge of the seed layer and surrounding the mask region; A patterned mask is prepared in the mask region of the seed layer, exposing a portion of the seed layer surface in the mask region; Laser processing is performed to remove the seed layer in the non-masked area and the conductive layer located below the non-masked area, forming a first area in the battery body where the conductive layer is retained and a second area where the conductive layer is removed; Surface passivation treatment is applied to reduce the surface energy of the second region after laser treatment to less than or equal to 0.05 J / m². 2 ; Electroplating process, forming an electroplated sub-gate on the surface of the seed layer exposed in the mask region; Remove the patterned mask and the seed layer located below the patterned mask to obtain a gate line containing the seed layer and the electroplated sub-gate.

[0011] As an optional implementation, in the embodiments of this application, the laser processing includes: The energy density of the laser is 0.5 J / cm². 2 ~2 J / cm 2; and / or, the laser includes at least one of picosecond laser, femtosecond laser, or nanosecond laser, with a pulse width of 8 ps to 12 ps, a repetition frequency of 400 kHz to 600 kHz, and a power density of 8 J / cm². 2 ~20 J / cm 2 The scanning speed is 8 m / s to 10 m / s, and the focal diameter is 14 μm to 16 μm.

[0012] As an optional implementation, in the embodiments of this application, the surface passivation treatment includes: passing in passivation gas and nitrogen at a temperature of 80°C to 280°C for 8 min to 25 min, wherein the passivation gas includes hydrogen or argon, and the partial pressure of the passivation gas is 0.45 atm to 0.55 atm; Alternatively, the surface of the second region after laser treatment may be modified by fluorination, silanization, or fluorosilanization.

[0013] Thirdly, embodiments of this application provide a photovoltaic module.

[0014] A photovoltaic module includes a solar cell as described in the first aspect, or a solar cell prepared by the method described in the second aspect.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: This application sets a surface energy of 0.05 J / m at the edge of the battery body. 2 The second region effectively reduces the adsorption capacity of the surface of the second region for the metal material used to form the grid lines. Therefore, the metal material is more easily deposited in the central first region to form the grid lines, but difficult to deposit in the edge second region. Based on this, this application can achieve effective insulation of the front and back sides of the battery body at the battery edge by suppressing the adsorption capacity of the surface of the second region for the metal material without introducing edge-sealing adhesive. This effectively solves the problem of open-circuit voltage decay caused by unstable edge-sealing adhesive or poor coverage during grid line fabrication, significantly improving the photoelectric conversion efficiency of the solar cell. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying 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.

[0017] Figure 1 This is a schematic diagram of the structure of the solar cell disclosed in the embodiments of this application; Figure 2This application discloses the structure of the battery body provided in the step of preparing a solar cell. Figure 3 This application discloses the structure of the seed layer after preparation in the process of preparing a solar cell. Figure 4 This application discloses the structure after patterned mask fabrication in the process of fabricating a solar cell. Figure 5 This is the structure after laser treatment in the process of preparing a solar cell, as disclosed in the embodiments of this application; Figure 6 This is the structure after electroplating treatment in the process of preparing a solar cell, as disclosed in the embodiments of this application; Figure 7 This application discloses the structure after removing the patterned mask and the seed layer located below the patterned mask during the fabrication of a solar cell. Figure 8 This is the structure after a protective layer is deposited during the fabrication of a solar cell, as disclosed in the embodiments of this application.

[0018] Icons: 1. Battery body; 1a. First region; 1b. Second region; 11. Conductive layer; 12. Silicon substrate; 121. First surface; 122. Second surface; 13. First passivation layer; 14. N-type doped silicon layer; 15. Second passivation layer; 16. P-type doped silicon layer; 2. Gate line; 21. Seed layer; 21a. Masked region; 21b. Non-masked region; 22. Electroplated sub-gate; 23. Protective layer; 3. Patterned mask. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] When fabricating grid lines on the cell body using copper interconnect technology, to prevent metals (such as copper) from diffusing to the sides of the cell body during electroplating and causing short circuits due to grid lines connecting on both sides of the cell body, it is usually necessary to insulate the edges of the cell body with an edge-sealing adhesive before electroplating. Commonly used edge-sealing adhesive materials include acrylic resin. However, traditional edge-sealing methods have many drawbacks.

[0021] First, the stability of the edge-sealing adhesive structure is poor. For example, the viscosity of acrylic resin and other edge-sealing adhesives increases significantly over time during circulation within the machine, leading to large variations in the flowability of the acrylic resin and consequently, deviations in the stability of the edge-sealing width. Second, the coating stability of the edge-sealing process is poor, easily resulting in the growth of small parasitic copper nodules of the same height as the normal grid lines in areas not covered by the edge-sealing adhesive. In other words, small areas of grid lines are prone to grow on the edges of the cell body where the edge-sealing adhesive is not applied. These problems can easily cause a decrease in the open-circuit voltage (Voc) of the solar cell, severely restricting further improvements in the photoelectric conversion efficiency of the solar cell.

[0022] To address the open-circuit voltage decay problem caused by unstable or poorly covered edge adhesive during grid line fabrication and to significantly improve the photoelectric conversion efficiency of solar cells, this application provides a solar cell, its fabrication method, and a photovoltaic module. The technical solution of this application will be further described below with reference to embodiments and accompanying drawings.

[0023] In a first aspect, embodiments of this application provide a solar cell.

[0024] Reference Figure 1 The solar cell includes: The battery body 1 includes a conductive layer 11. The surface of the battery body 1 has a first region 1a located in the center and a second region 1b located at the edge of the battery body 1 and surrounding the first region 1a. The conductive layer 11 is located in the first region 1a, and the second region 1b does not have the conductive layer 11, and the surface energy of the second region 1b is less than or equal to 0.05 J / m. 2 ; Gate line 2 is in contact with conductive layer 11 located in first region 1a.

[0025] This application addresses the issue of open-circuit voltage decay caused by unstable or poorly covered edge-sealing adhesive during the fabrication of the grid lines 2 by creating a second region 1b with a specific surface energy at the edge of the battery body 1, instead of the traditional edge-sealing process. This achieves insulation between the front and back sides of the battery body and effectively solves the problem of open-circuit voltage decay caused by unstable edge-sealing adhesive or poor coverage during the fabrication of the grid lines 2. Subsequently, the grid lines 2 fabricated on the battery body 1 can selectively grow above the conductive layer 11 located in the first region 1a, thereby significantly improving the photoelectric conversion efficiency of the solar cell.

[0026] Specifically, in this application, no conductive layer 11 is provided in the second region 1b of the battery body 1, and the surface energy of the second region 1b is set to 0.05 J / m. 2The low surface energy configuration results in a "super-copper-repellent state" in the second region 1b, significantly reducing the adsorption capacity of the surface of the second region 1b for the metal material used to form the grid lines. For example, the adsorption energy of copper ions can be reversed from -1.8 eV (attractive state) to +0.6 eV (repulsive state). This allows for effective suppression of metal deposition at the edge of the cell body 1 without the need for edge-sealing adhesive during the fabrication of the grid lines 2. It also facilitates metal deposition and growth on the first region 1a, thereby achieving front and back insulation of the cell body, reducing edge metal diffusion and edge leakage, and improving the open-circuit voltage and photoelectric conversion efficiency of the solar cell. For example, the surface energy of the second region 1b can be 0.05 J / m². 2 0.04J / m 2 0.03 J / m 2 0.02 J / m 2 wait.

[0027] Furthermore, the surface energy of the second region 1b is 0.0295 J / m². 2 ~0.0375 J / m 2 By setting the surface energy of the second region 1b to 0.0295 J / m² 2 ~0.0375 J / m 2 This can effectively suppress the diffusion of metal in the second region 1b during the electroplating process, forming a stable superhydrophobic copper state.

[0028] Reference Figure 1 In some embodiments, the width W of the second region 1b is less than or equal to 300 μm. In traditional edge-sealing processes, the width of the edge-sealing adhesive is typically set between 400 μm and 700 μm. Due to limitations in the flowability and process precision of the edge-sealing adhesive before curing, it is difficult to further reduce the edge width. This results in greater photogenerated carrier loss and higher edge leakage loss at the edge of the battery body 1.

[0029] This application uses a second region 1b with a specific surface energy to replace the edge-sealing adhesive, enabling the width W of the second region 1b to be less than or equal to 300 μm within a specific range, for example, up to 250±5 μm in a specific embodiment. This not only achieves a breakthrough reduction in the distance between the grid line 2 and the edge of the battery body, effectively preventing short circuits caused by the grid line 2 connecting the front and back sides of the battery body, but also reduces edge leakage losses, further improving the photoelectric conversion efficiency of the solar cell. For example, the width W of the second region 1b can be 100 μm, 150 μm, 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm, etc.

[0030] In some embodiments, the material of the conductive layer 11 includes at least one of indium tin oxide and indium zinc oxide. Indium tin oxide, indium zinc oxide, etc., have good light transmittance and conductivity, and can cooperate with the gate line 2 to better collect charge carriers.

[0031] In some embodiments, the material of the grid line 2 includes at least one of copper, nickel, and tin. These materials have better conductivity and are cheaper than conventionally used silver materials, making them a better material choice to replace silver grid lines 2, which helps to reduce production costs while ensuring the battery's electrical performance.

[0032] In some embodiments, the contact angle of the surface of the second region 1b is greater than or equal to 90°. When the contact angle of the surface of the second region 1b is greater than or equal to 90°, it indicates that the surface of the second region 1b has extremely strong hydrophobicity, making it difficult for the electroplating solution to wet and for metal ions therein to adhere to the surface of the second region 1b, thereby further reducing the possibility of metal deposition on the edge of the battery body 1 during the electroplating process. Exemplarily, the contact angle of the surface of the second region 1b can be 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, etc.

[0033] Reference Figure 1 In some embodiments, the surface of the second region 1b is recessed compared to the surface of the first region 1a. Further, the height of the recess in the second region 1b compared to the surface of the first region 1a can be the thickness of the conductive layer 11. This ensures that the conductive layer 11 is sufficiently removed, forming a non-conductive or nearly non-conductive surface of the second region 1b, which helps to block conductive pathways and further prevents the deposition of metal ions from the electroplating solution on the surface of the second region 1b.

[0034] Reference Figure 1 In some embodiments, the battery body 1 includes: A silicon substrate 12 has a first surface 121 and a second surface 122 disposed opposite to the first surface 121; A first passivation layer 13 is disposed on the first surface 121 of the silicon substrate 12; An N-type doped silicon layer 14 is disposed on the side of the first passivation layer 13 away from the silicon substrate 12; A second passivation layer 15 is disposed on the second surface 122 of the silicon substrate 12; A P-type doped silicon layer 16 is disposed on the side of the second passivation layer 15 away from the silicon substrate 12; The conductive layer 11 and the gate line 2 are disposed on the side of the N-type doped silicon layer 14 away from the silicon substrate 12, and / or the conductive layer 11 and the gate line 2 are disposed on the side of the P-type doped silicon layer 16 away from the silicon substrate 12.

[0035] The first region 1a and the second region 1b of this application can be disposed on the side of the N-type doped silicon layer 14 facing away from the silicon substrate 12, or on the side of the P-type doped silicon layer 16 facing away from the silicon substrate 12, or simultaneously on both sides. This facilitates the formation of a supercopper-repellent surface at the edges of both the N-type doped silicon layer 14 and the P-type doped silicon layer 16 facing away from the silicon substrate 12. During the fabrication of the gate line 2 disposed on the first surface 121 or the second surface 122, selective metal deposition can be achieved during electroplating, effectively suppressing the possibility of metal deposition at the edges of the cell body 1 during electroplating, thereby improving the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0036] Furthermore, the silicon substrate 12 can be a silicon wafer; the first passivation layer 13 can be a first hydrogenated silicon layer, specifically a first hydrogenated amorphous silicon layer; the doping atoms in the N-type doped silicon layer 14 can be phosphorus atoms, arsenic atoms, etc., and the N-type doped silicon layer 14 can specifically be a phosphorus-doped amorphous silicon layer, a phosphorus-doped microcrystalline silicon layer, a phosphorus-doped polycrystalline silicon layer, an arsenic-doped amorphous silicon layer, an arsenic-doped microcrystalline silicon layer, or an arsenic-doped polycrystalline silicon layer; the second passivation layer 15 can be a second hydrogenated silicon layer, specifically a second hydrogenated amorphous silicon layer; the doping atoms in the P-type doped silicon layer 16 can be boron atoms, gallium atoms, etc., and the P-type doped silicon layer 16 can specifically be a boron-doped amorphous silicon layer, a boron-doped microcrystalline silicon layer, a boron-doped polycrystalline silicon layer, a gallium-doped amorphous silicon layer, a gallium-doped microcrystalline silicon layer, or a gallium-doped polycrystalline silicon layer, etc.

[0037] Secondly, this application provides a method for fabricating a solar cell. The following describes the fabrication of grid lines 2 on one side of the cell body 1. Figures 2-8 The method for preparing the gate line 2 in this application is further explained.

[0038] A method for fabricating a solar cell includes the following steps: Provide such as Figure 2 The battery body 1 shown includes a conductive layer 11; A seed layer 21 is prepared on the conductive layer 11 to obtain the following... Figure 3 The structure shown includes a mask region 21a for printing a mask on the side of the seed layer 21 away from the conductive layer 11, and a non-mask region 21b located at the edge of the seed layer 21 and surrounding the mask region 21a. A patterned mask 3 is prepared in the mask region 21a of the seed layer 21, exposing a portion of the surface of the seed layer 21 in the mask region 21a, resulting in... Figure 4 The structure shown; Laser processing is performed to remove the seed layer 21 of the unmasked region 21b and the conductive layer 11 located below the unmasked region 21b. This forms a first region 1a (corresponding to the masked region 21a) retaining the conductive layer 11 and a second region 1b (corresponding to the unmasked region 21b) without the conductive layer 11 in the battery body 1, resulting in the following: Figure 5 The structure shown; Surface passivation treatment ensures that the surface energy of the second region 1b after laser treatment is less than or equal to 0.05 J / m. 2 ; Electroplating process is performed to form an electroplated sub-gate 22 on the surface of the seed layer 21 exposed in the mask region 21a, resulting in... Figure 6 The structure shown; Remove the patterned mask 3 and the seed layer 21 located below the patterned mask 3 to obtain the gate line 2 containing the seed layer 21 and the electroplated sub-gate 22, resulting in the following: Figure 7 The structure shown.

[0039] It should be noted that in this application, the mask region 21a is the region located in the middle of the seed layer 21. The subsequently fabricated patterned mask 3 and grid lines 2 are both formed on this mask region 21a, which corresponds to the first region 1a in the battery body 1 where the conductive layer 11 is ultimately retained. The non-mask region 21b is the region located at the edge of the seed layer 21, surrounding the mask region 21a. This non-mask region 21b is not used to fabricate the patterned mask 3 or grid lines 2, but rather serves as an edge region to be removed, corresponding to the second region 1b in the battery body 1 where the conductive layer 11 is ultimately removed to form an insulating edge. The patterned mask 3 is a mask structure formed on the surface of the mask region 21a. The patterned mask 3 has several cutouts to expose parts of the seed layer 21 of the mask region 21a, which are used to define the growth position and shape of the metal grid lines 2 during the electroplating process.

[0040] This application utilizes laser processing to specifically remove the seed layer 21 and the underlying conductive layer 11 of the unmasked region 21b. Simultaneously, it induces dangling bond proliferation in the laser-processed region, resulting in a high-density dangling bond formation in the second region 1b. This high-density dangling bond density lowers the surface energy and passivation barrier of the edge of the second region 1b, allowing subsequent surface passivation reactions to preferentially act on the surface of the second region 1b, further reducing its surface energy and forming a "super-copper-repellent state" where metal adhesion is difficult. Meanwhile, the seed layer 21 of the masked region 21a is not laser-processed, thus maintaining a relatively high surface energy and passivation barrier, which is unfavorable for surface passivation. Therefore, after the surface passivation reaction, the seed layer 21 surface retains high electroplating activity, facilitating the deposition of metal ions on the seed layer 21 surface and the formation of the electroplated sub-gate 22 during subsequent electroplating processes. By combining the above steps, metal can grow on the surface of the exposed seed layer 21 in a specific area without using an edge-sealing process, while avoiding the purpose of electroplating and depositing metal on the edge of the battery body 1.

[0041] In some embodiments, during laser processing: the laser energy density is 0.5 J / cm². 2 ~2 J / cm 2 ; and / or, the laser includes at least one of picosecond lasers, femtosecond lasers, or nanosecond lasers, with a pulse width of 8 ps to 12 ps, a repetition rate of 400 kHz to 600 kHz, and a power density of 8 J / cm². 2 ~20 J / cm 2 The scanning speed is 8 m / s to 10 m / s, and the focal diameter is 14 μm to 16 μm.

[0042] The laser energy density was controlled at 0.5 J / cm². 2 ~2 J / cm 2 Within this range, the precision of removing the seed layer 21 and conductive layer 11 of the non-masked region 21b can be improved, preventing over-melting due to excessive energy or incomplete removal due to insufficient energy. Furthermore, by employing picosecond, femtosecond, or nanosecond lasers, and in conjunction with specific pulse widths, repetition frequencies, power densities, scanning speeds, and focal diameters, the surface roughness of the second region 1b after laser treatment can be effectively controlled. This allows for precise control of the composite interface formed between the surface of the second region 1b and the air, ensuring the stability and uniformity of the surface energy of the second region 1b.

[0043] In some embodiments, the surface passivation treatment includes: introducing a passivating gas and nitrogen at a temperature of 80°C to 280°C for 8 min to 25 min, wherein the passivating gas includes hydrogen or argon, and the partial pressure of the passivating gas is 0.45 atm to 0.55 atm. By heat-treating with a passivating gas and nitrogen at a temperature of 80°C to 280°C, the laser-induced dangling bonds can be converted into stable chemical bonds (such as Si-H bonds), thereby achieving a significant reduction in surface energy. This ensures the passivation effect of the second region 1b surface, forming a low surface energy superhydrophobic copper surface, while also reducing the impact of the surface passivation treatment on the seed layer 21 exposed in the mask region 21a, maintaining high electroplating activity in the seed layer 21, and ensuring the adhesion and conductivity of the metal during subsequent electroplating.

[0044] Furthermore, the surface of the second region 1b after laser treatment is modified by fluorination, silanization, or fluorosilanization. By performing chemical modification treatments such as fluorination, silanization, or fluorosilanization on the surface of the second region 1b after laser treatment, the surface energy of the second region 1b can also be effectively reduced.

[0045] Furthermore, after removing the patterned mask 3 and the seed layer 21 located below the patterned mask 3, light injection and the deposition of the protective layer 23 can be performed. After the protective layer 23 is prepared, the following is obtained: Figure 8 The structure shown is such that light injection can form stable Si-H bonds by using infrared light passivation, saturating defects inside the cell body 1. A protective layer 23 can be formed on the surfaces of the copper seed layer 21 and the electroplated sub-gate 22 by electroplating. The material of the protective layer 23 can be metallic tin, etc. By setting the protective layer 23, the possibility of air oxidation of the copper seed layer 21 and the electroplated sub-gate 22 can be reduced.

[0046] Thirdly, embodiments of this application provide a photovoltaic module.

[0047] A photovoltaic module includes a solar cell as mentioned in the first aspect, or a solar cell prepared by the preparation method mentioned in the second aspect.

[0048] The technical solution of this application will be further described below with reference to more specific embodiments.

[0049] Example 1 This application provides a solar cell, the preparation method of which includes the following steps: A battery body is provided, comprising an N-type monocrystalline silicon wafer having a first surface and a second surface disposed opposite to the first surface; a first hydrogenated amorphous silicon layer and an N-type phosphorus-doped amorphous silicon layer are disposed on the first surface of the N-type monocrystalline silicon wafer, and a second hydrogenated amorphous silicon layer and a P-type boron-doped amorphous silicon layer are disposed on the second surface of the silicon substrate; indium tin oxide conductive layers are respectively fabricated on the side of the N-type phosphorus-doped amorphous silicon layer facing away from the N-type monocrystalline silicon wafer and on the side of the P-type boron-doped amorphous silicon layer facing away from the N-type monocrystalline silicon wafer; The steps for fabricating grid lines on the battery body include: A copper seed layer is prepared on an indium tin oxide conductive layer by magnetron sputtering. The side of the copper seed layer opposite to the indium tin oxide conductive layer includes a mask region for printing a mask and a non-mask region located at the edge of the copper seed layer and surrounding the mask region. A photosensitive adhesive layer is coated in the mask area of ​​the copper seed layer, and the photosensitive adhesive layer is 250±2μm away from the edge. That is, an uncoated area with a width of 250±2 μm is reserved at the edge of the battery. The photosensitive adhesive layer in the non-gate area is exposed using a light source with a wavelength greater than 400 nm, so that the exposed photosensitive adhesive layer undergoes a cross-linking reaction and is not easily corroded by a weak alkaline solution. The photosensitive emulsion layer is rinsed with a sodium carbonate solution with a mass fraction of 1% to 2% to clean the unexposed photosensitive emulsion layer, exposing part of the seed layer surface in the mask area to form a patterned mask. Laser processing is performed, with a laser energy density of 1 J / cm². 2 Furthermore, the laser is a picosecond laser with a pulse width of 10 ps, ​​a repetition rate of 500 kHz, and a power density of 12 J / cm². 2 The scanning speed is 9 m / s and the focal diameter is 15 μm. Through this laser processing, the copper seed layer in the unmasked area and the indium tin oxide conductive layer located below the unmasked area are removed, forming a first area with the indium tin oxide conductive layer retained and a second area with the indium tin oxide conductive layer removed in the battery body. After surface passivation treatment, the product enters the buffer heating chamber at 22°C and waits for 2 minutes. Then, it enters the first heating chamber and is heated to 180°C in 4 minutes, held for 2 minutes, and then enters the second heating chamber and is heated to 280°C in 3 minutes. A mixture of N2 and H2 gas (N2 volume percentage 95% and H2 volume percentage 5%) is introduced and held for 4 minutes. At 280°C, the dangling bonds generated by laser treatment are converted into stable Si-H bonds. The product then enters the first cooling chamber and is cooled to 180°C in 3 minutes, held for 3 minutes. Next, it is cooled to 22°C in the second cooling chamber in 3 minutes. After cooling, it is sent to the cooling buffer chamber for a final 2-minute hold. By combining these heating and cooling processes, stress can be effectively reduced. Electroplating process causes copper ions in the electroplating solution to migrate to the surface of the copper seed layer exposed in the mask area under the action of an electric field, forming an electroplated sub-gate; The patterned mask is removed using a sodium hydroxide solution with a mass fraction of 3% to 4%, and the copper seed layer below the patterned mask is etched using a sulfuric acid solution with a mass fraction of 5% to 7% until the indium tin oxide conductive layer below the copper seed layer is exposed. Light injection, using infrared light passivation to form stable Si-H bonds, saturates defects inside the battery body; A protective layer is plated, followed by electroplating to deposit metallic tin on the surface of the electroplated sub-gate as a protective layer, forming a gate line that includes a copper seed layer, an electroplated sub-gate, and a protective layer; the protective layer can protect the gate line and improve its oxidation resistance. Among them, the gate line formed on the side of the indium tin oxide conductive layer away from the P-type boron-doped amorphous silicon layer is the first gate line, and the gate line formed on the side of the indium tin oxide conductive layer away from the N-type phosphorus-doped amorphous silicon layer is the second gate line.

[0050] Comparative Example 1 This application provides a comparative example of a solar cell, which differs from Example 1 in that: after forming a patterned mask, acrylic adhesive is used for edge wrapping instead of laser processing and surface passivation, followed by electroplating; otherwise, it remains the same as Example 1.

[0051] Experiment 1 Suspended bond density test According to GB / T 19500-2025 "General Rules for X-ray Photoelectron Spectroscopy Analysis of Surface Chemical Analysis", X-ray photoelectron spectroscopy (XPS) was used to test the dangling bond density of the second region before and after the surface passivation treatment in Example 1. The test results are shown in Table 1.

[0052] Experiment 2 Surface energy testing The surface energy of the second region before and after the surface passivation treatment in Example 1 was tested using a surface energy analyzer. The test results are shown in Table 1.

[0053] Experiment 3 Contact angle test According to GB / T 30447-2013 "Method for measuring contact angle of nanofilm", a contact angle measuring instrument was used to test the contact angle of water droplets in the second region before and after surface passivation treatment in Example 1. The test results are shown in Table 1.

[0054] Table 1

[0055] As can be seen from Table 1, before and after the surface passivation treatment, the dangling bond density and surface energy of the second region can be reduced. The adsorption energy of copper ions on the surface of the second region can be reversed from -1.8 eV to +0.6 eV repulsive state, and the contact angle is increased. This indicates that during the electroplating process, the electroplating solution is difficult to wet the second region and make the copper metal ions in it adhere to the surface of the second region, thereby forming a "super-copper-repellent state" on the surface of the second region.

[0056] Experiment 4 Electrical performance testing The performance of solar cells was tested using an IV tester under standard test conditions: AM1.5, 1000 W / m. 2 The test environment temperature was 25℃. Before the test, the simulated sunlight intensity was calibrated using a standard silicon solar cell. The open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE) of the corresponding solar cells were recorded.

[0057] The test results of the solar cells in Example 1 and Comparative Example 1 are shown in Table 2.

[0058] Table 2

[0059] As can be seen from the comparison of the data of Example 1 and Comparative Example 1 in Table 1, the open-circuit voltage, fill factor, and photoelectric conversion efficiency of Example 1 are all improved compared with those of Comparative Example 1. This proves that by controlling the surface energy of the second region, a "super-copper-repellent state" can be formed on the surface of the second region, which can effectively block the deposition of copper in the second region during electroplating, thereby further reducing edge metal diffusion and edge leakage, and achieving further improvement in the electrical performance of the solar cell.

[0060] The technical solutions disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core inventive points of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solar cell, characterized in that, include: A battery body includes a conductive layer. The surface of the battery body has a first region located in the center and a second region located at the edge of the battery body and surrounding the first region. The conductive layer is located in the first region, and the second region does not have the conductive layer, and the surface energy of the second region is less than or equal to 0.05 J / m. 2 ; A gate line that contacts the conductive layer located in the first region.

2. The solar cell according to claim 1, characterized in that, The surface energy of the second region is 0.0295 J / m². 2 ~0.0375 J / m 2 .

3. The solar cell according to claim 1, characterized in that, The width of the second region is less than or equal to 300 μm.

4. The solar cell according to claim 1, characterized in that, The material of the conductive layer includes at least one of indium tin oxide and indium zinc oxide; And / or, The material of the grid line includes at least one of copper, nickel, and tin.

5. The solar cell according to claim 1, characterized in that, The contact angle of the surface of the second region is greater than or equal to 90°; And / or, the surface of the second region is concave compared to the surface of the first region.

6. The solar cell according to any one of claims 1-5, characterized in that, The battery body includes: A silicon substrate having a first side and a second side disposed opposite to each other; A first passivation layer is disposed on the first surface of the silicon substrate; An N-type doped silicon layer disposed on the side of the first passivation layer opposite to the silicon substrate; A second passivation layer is disposed on the second side of the silicon substrate; A P-type doped silicon layer disposed on the side of the second passivation layer opposite to the silicon substrate; The conductive layer and the gate line are disposed on the side of the N-type doped silicon layer away from the silicon substrate, and / or the conductive layer and the gate line are disposed on the side of the P-type doped silicon layer away from the silicon substrate.

7. A method for fabricating a solar cell, characterized in that, Includes the following steps: A battery body is provided, the battery body including a conductive layer; A seed layer is prepared on the conductive layer, the seed layer having a mask region for printing a mask on the side opposite to the conductive layer and a non-mask region located at the edge of the seed layer and surrounding the mask region; A patterned mask is prepared in the mask region of the seed layer, exposing a portion of the surface of the seed layer in the mask region; Laser processing is performed to remove the seed layer in the non-masked area and the conductive layer located below the non-masked area, forming a first area in the battery body where the conductive layer is retained and a second area where the conductive layer is removed; Surface passivation treatment is applied to reduce the surface energy of the second region after laser treatment to less than or equal to 0.05 J / m². 2 ; Electroplating process, forming an electroplated sub-gate on the surface of the seed layer exposed in the mask region; Remove the patterned mask and the seed layer located below the patterned mask to obtain a gate line containing the seed layer and the electroplated sub-gate.

8. The method for preparing a solar cell according to claim 7, characterized in that, In the laser processing: The energy density of the laser is 0.5 J / cm². 2 ~2 J / cm 2 ; and / or, the laser includes at least one of picosecond laser, femtosecond laser, or nanosecond laser, with a pulse width of 8 ps to 12 ps, a repetition frequency of 400 kHz to 600 kHz, and a power density of 8 J / cm². 2 ~20 J / cm 2 The scanning speed is 8 m / s to 10 m / s, and the focal diameter is 14 μm to 16 μm.

9. The method for preparing a solar cell according to claim 7, characterized in that, The surface passivation treatment includes: introducing passivating gas and nitrogen at a temperature of 80℃~280℃ for 8 min~25 min, wherein the passivating gas includes hydrogen or argon, and the partial pressure of the passivating gas is 0.45 atm~0.55 atm; Alternatively, the surface of the second region after laser treatment may be modified by fluorination, silanization, or fluorosilanization.

10. A photovoltaic module, characterized in that, Includes the solar cell as described in any one of claims 1-6, or the solar cell prepared by the method described in any one of claims 7-9.

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