Solar cell and preparation method thereof, photovoltaic module

Abstract

This application discloses a solar cell and its fabrication method, as well as a photovoltaic module. The solar cell includes a substrate; a doped silicon layer disposed on the substrate; a passivation layer and grid lines. The passivation layer is disposed on the side of the doped silicon layer facing away from the substrate and has a patterned open-film region. The grid lines are disposed in the patterned open-film region and form contact with the doped silicon layer. The patterned open-film region includes a first open-film sub-region and a second open-film sub-region. Along a first direction, the top of the first open-film sub-region facing away from the substrate has a first maximum opening width, W1, and the top of the second open-film sub-region facing away from the substrate has a second maximum opening width, W2, where W1 is greater than W2. The first direction is parallel to the width direction of the grid lines. This application can improve the stability of the grid lines, reduce damage to the passivation layer and the doped silicon layer, and improve the open-circuit voltage and 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] The grid lines of solar cells are primarily formed by printing silver paste. While silver paste offers good conductivity, its high cost and fluctuating price limit overall cell cost reduction and control. To lower grid line costs, electroplating with metals such as nickel can replace printed silver paste. However, before electroplating, the passivation layer on the cell surface needs to be locally patterned to allow the plated metal (e.g., nickel) to contact the semiconductor layer (e.g., a doped polycrystalline silicon layer). Currently, this approach struggles to effectively balance the stability of the gold-semiconductor contact with the passivation performance of the passivation layer, thus limiting improvements in open-circuit voltage and photoelectric conversion efficiency. Summary of the Invention

[0003] In order to improve the stability of the grid lines and reduce damage to the passivation layer and the doped silicon layer below it, so as to effectively improve the open-circuit voltage and photoelectric conversion efficiency of the solar cell, 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.

[0005] A solar cell, comprising: Base; A doped silicon layer is disposed on the substrate; A passivation layer and a gate line are provided, wherein the passivation layer is disposed on the side of the doped silicon layer away from the substrate, the passivation layer has a patterned open-film region, and the gate line is disposed in the patterned open-film region and forms contact with the doped silicon layer; The patterned opening region includes a first opening sub-region and a second opening sub-region; Along the first direction, the first open-film sub-region has a first maximum opening width away from the top of the substrate, the first maximum opening width being W1, and the second open-film sub-region has a second maximum opening width away from the top of the substrate, the second maximum opening width being W2, wherein W1 is greater than W2, and the first direction is a direction parallel to the width direction of the gate line.

[0006] As an optional implementation, in the embodiments of this application, the ratio of W2 to W1 is 30% to 80%.

[0007] As an optional implementation, in the embodiments of this application, W1 is 10 μm to 50 μm and W2 is 3 μm to 40 μm.

[0008] As an optional implementation, in the embodiments of this application, the patterned open-film region includes a plurality of first open-film sub-regions and a plurality of second open-film sub-regions, and the first open-film sub-regions and the second open-film sub-regions are alternately distributed along a second direction, which is a direction parallel to the length direction of the gate line.

[0009] And / or, The patterned opening region includes the first opening sub-region to the nth opening sub-region, where n is a positive integer greater than or equal to 3, and along the first direction, the nth opening sub-region has a maximum opening width of Wn away from the top of the substrate, and W1 to Wn gradually decrease.

[0010] As an optional implementation, in the embodiments of this application, when the graphic opening area includes the first opening sub-area to the nth opening sub-area, the first opening sub-area to the nth opening sub-area are arranged sequentially, or the first opening sub-area to the nth opening sub-area are arranged in a random order. And / or, The center line connecting adjacent first open membrane sub-regions partially coincides with or is parallel to the center line connecting adjacent second open membrane sub-regions.

[0011] As an optional implementation, in the embodiments of this application, the top outline shape of the first open membrane sub-region and the second open membrane sub-region away from the substrate is at least one of a circle, an ellipse, or a rectangle.

[0012] As an optional implementation, in an embodiment of this application, the passivation layer near the edge of the patterned open-film region is raised in a direction away from the substrate; The gate line extends into the gap region between the doped silicon layer and the raised passivation layer.

[0013] As an optional implementation, in the embodiments of this application, the passivation layer near the edge of the first open film sub-region has a first raised height, the first raised height being H1, and the passivation layer near the edge of the second open film sub-region has a second raised height, the second raised height being H2; H1 is greater than H2; and / or, H1 is 0.1 μm to 1 μm and H2 is 0.01 μm to 0.6 μm.

[0014] As an optional implementation, in the embodiments of this application, the contact surface between the gate line and the doped silicon layer away from the substrate is a surface-to-surface contact; And / or, The thickness of the doped silicon layer below the region where the gate line is located is the same as the thickness of the doped silicon layer below the region where the gate line is not located. And / or, The doped silicon layer does not contain any metal crystals.

[0015] As an optional implementation, in the embodiments of this application, the substrate has a light-receiving surface and a back-lighting surface; the doped silicon layer, the gate line, and the passivation layer having the patterned open-film region are disposed on the light-receiving surface and / or the back-lighting surface of the substrate; the doped silicon layer includes a first doped silicon sublayer and / or a second doped silicon sublayer, the first doped silicon sublayer is disposed on the light-receiving surface of the substrate, the second doped silicon sublayer is disposed on the back-lighting surface of the substrate, and a dielectric layer is further disposed between the second doped silicon sublayer and the substrate, wherein the first doped silicon sublayer and the second doped silicon sublayer have opposite conductivity types; And / or, The material of the grid lines includes at least one of nickel, copper, or tin; And / or, The material of the passivation layer includes at least one of aluminum oxide, silicon nitride, silicon oxynitride, or silicon oxide. And / or, The substrate is a silicon substrate; And / or, The doped silicon layer includes at least one of a doped polycrystalline silicon layer, a doped amorphous silicon layer, or a doped microcrystalline silicon layer.

[0016] Secondly, embodiments of this application provide a method for preparing a solar cell.

[0017] A method for fabricating a solar cell includes the following steps: A substrate is provided in which a doped silicon layer and a passivation layer are sequentially stacked on the surface; The passivation layer is subjected to laser patterning opening processing to form a patterned opening region with a first opening sub-region and a second opening sub-region in the passivation layer; wherein, along a first direction, the first opening sub-region has a first maximum opening width W1 away from the top of the substrate, and the second opening sub-region has a second maximum opening width W2 away from the top of the substrate, and W1 is greater than W2, and the first direction is a direction parallel to the width direction of the gate line; An electroplating process is used to form gate lines in the patterned open-film region, the gate lines being in contact with the doped silicon layer.

[0018] As an optional implementation, in the embodiments of this application, the laser used for the laser patterning film opening process includes a first laser and a second laser. The spot size of the first laser is L1, and the spot size of the second laser is L2. The L1 is larger than the L2. The area processed by the first laser corresponds to the formation of the first film opening sub-region, and the area processed by the second laser corresponds to the formation of the second film opening sub-region. The ratio of L2 to L1 is 30% to 80%; and / or, L1 is 10 μm to 50 μm and L2 is 3 μm to 40 μm.

[0019] As an optional implementation, in the embodiments of this application, the energy of the first laser is greater than the energy of the second laser; The energy density of the second laser is 30% to 80% of the energy density of the first laser, and the energy density of the first laser is 100 mJ / cm². 2 Up to 600 mJ / cm 2 The energy density of the second laser is 30 mJ / cm². 2 Up to 480 mJ / cm 2 The ratio of the average power of the second laser to the average power of the first laser is 60% to 70%.

[0020] As an optional implementation method, in the embodiments of this application, The relationship between the first spot area of ​​the first laser and the second spot area of ​​the second laser is tangential, intersecting, or disjoint, wherein: When the first light spot area is separated from the second light spot area, the gap between the first light spot area and the second light spot area is 10 μm to 100 μm. When the first light spot action area intersects with the second light spot action area, the maximum width of the overlapping area between the first light spot action area and the second light spot action area is greater than 0 μm and less than or equal to 20 μm; When the first light spot action area is tangent to the second light spot action area, the gap distance between the first light spot action area and the second light spot action area is 0 μm; And / or, After the laser patterning film-opening process, a cleaning process is performed to remove the remaining passivation layer in the patterned film-opening area, followed by the electroplating process.

[0021] As an optional implementation, in the embodiments of this application, in the step of forming the patterned open film area, the first laser is first used to perform intermittent opening film to form a plurality of spaced first open film sub-regions, and then the second laser is applied to the spaced area between adjacent first open film sub-regions to form the second open film sub-region, resulting in a structure in which the first open film sub-regions and the second open film sub-regions are arranged alternately. or, First, the second laser is used to perform intermittent film opening to form several intermittently arranged second film opening sub-regions. Then, the first laser is applied to the interval region between adjacent second film opening sub-regions to form the first film opening sub-region, resulting in a structure in which the first film opening sub-region and the second film opening sub-region are arranged alternately.

[0022] As an optional implementation, in the embodiments of this application, the laser used in the laser patterning film opening process includes a first laser to an nth laser, where n is a positive integer greater than or equal to 3, the spot size of the nth laser is Ln, and L1 is greater than Ln; In the step of forming the patterned open film region, the first laser to the nth laser are used sequentially to perform intermittent opening film, resulting in a structure with the first open film sub-region to the nth open film sub-region arranged periodically.

[0023] As an optional implementation, in the embodiments of this application, the laser used in the laser patterning film opening process has a wavelength of green light or ultraviolet light, a pulse width of nanosecond, picosecond or femtosecond, an average power of 0.1 W to 50 W, a laser frequency of 500 KHz to 5000 KHz, a laser speed of 30 m / s to 90 m / s, and a laser spot shape of circular, elliptical or square.

[0024] Thirdly, embodiments of this application provide a photovoltaic module.

[0025] 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.

[0026] Compared with the prior art, the beneficial effects of this application are as follows: This application designs a first and second open-film sub-region with varying widths to significantly reduce damage to the cell structure caused by the patterning process while ensuring grid line contact stability, thereby synergistically improving the open-circuit voltage and photoelectric conversion efficiency of the solar cell. Specifically, the first open-film sub-region with a larger maximum opening width provides a reliable contact interface for the grid lines, ensuring grid line adhesion and stability; the second open-film sub-region with a smaller maximum opening width effectively suppresses damage to the passivation layer and doped silicon layer caused by the patterned open-film region, reducing carrier recombination losses. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a schematic diagram of the structure of the solar cell disclosed in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the first type of graphical opening region disclosed in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the second type of patterned film-opening region disclosed in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the third type of patterned film-opening region disclosed in the embodiments of this application; Figure 5 This is a SEM (scanning electron microscope) image of the edge lifting morphology of the passivation layer near the first open film sub-region disclosed in the embodiments of this application; Figure 6 This is a SEM image of the edge lifting morphology of the passivation layer near the second open film sub-region disclosed in the embodiments of this application; Figure 7 This is a schematic diagram of the structure in which the first light spot action area and the second light spot action area disclosed in the embodiments of this application are in a tangent (a), intersecting (b), and disjoint (c) relationship, respectively; Figure 8 This is a schematic diagram of the steps disclosed in the embodiments of this application to illustrate the preparation sequence of the first open membrane sub-region and the second open membrane sub-region; Figure 9 This is a schematic diagram illustrating the steps of preparing the first open membrane region and the second open membrane region as disclosed in the embodiments of this application.

[0029] Icons: 1. Substrate; 2. Doped silicon layer; 21. First doped silicon sublayer; 22. Second doped silicon sublayer; 3. Passivation layer; 3a. Patterned open-film region; 3a1. First open-film sub-region; 3a2. Second open-film sub-region; 3a3. Third open-film sub-region; 31. Light-receiving surface passivation layer; 32. Backlight-receiving surface passivation layer; 33. Gap region; 4. Gate line; 41. First gate line; 42. Second gate line; 5. Dielectric layer; 61. First light spot area; 62. Second light spot area. Detailed Implementation

[0030] 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.

[0031] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0032] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0033] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0034] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0035] In solar cells, the patterned open-form regions in the passivation layer are typically designed as elongated strips with uniform linewidth. Based on this shape design, using a laser spot of a specific size for laser patterning is essential for forming these regions. However, when the linewidth of the patterned open-form region is set large, the structural damage caused by the laser patterning process also increases, leading to exacerbated structural damage to the solar cell caused by the patterned open-form region. If the linewidth of the patterned open-form region is reduced to decrease structural damage, it becomes difficult to achieve a sufficient open-form area to ensure stable grid line contact, making it challenging to simultaneously reduce solar cell structural damage and maintain grid line contact stability.

[0036] Therefore, how to reduce the damage caused by setting patterned film opening areas while ensuring stable grid line contact has become an urgent problem to be solved.

[0037] This application provides a solar cell and its fabrication method, as well as a photovoltaic module, which effectively reduces damage caused by the patterned open-film area while ensuring the stability of the grid line contact. The technical solution of this application will be further described below with reference to embodiments and accompanying drawings.

[0038] In a first aspect, embodiments of this application provide a solar cell.

[0039] Reference Figure 1 A solar cell, comprising: Base 1; A doped silicon layer 2 is disposed on the substrate 1; Passivation layer 3 and gate line 4, the passivation layer 3 is disposed on the side of the doped silicon layer 2 away from the substrate 1, the passivation layer 3 has a patterned open film region 3a, and the gate line 4 is disposed in the patterned open film region 3a and forms contact with the doped silicon layer 2. Among them, such as Figure 2 As shown, the graphical open film region 3a includes a first open film sub-region 3a1 and a second open film sub-region 3a2; Along the first direction, the first open-film sub-region 3a1 has a first maximum opening width of W1 away from the top of the substrate 1, and the second open-film sub-region 3a2 has a second maximum opening width of W2 away from the top of the substrate 1. W1 is greater than W2. The first direction is a direction parallel to the width direction of the gate line 4 (the first direction is...). Figure 2 (The X direction is shown).

[0040] This application provides a solar cell with a special patterned design in the patterned open-film region 3a on the surface. Compared with a patterned open-film region 3a with uniform line width, this application sets the patterned open-film region 3a into a first open-film sub-region 3a1 and a second open-film sub-region 3a2 with different maximum opening widths. This effectively reduces structural damage caused by the patterned open-film region 3a and the resulting carrier recombination loss while ensuring the contact stability between the grid line 4 and the doped silicon layer 2. This synergistically improves the open-circuit voltage and photoelectric conversion efficiency of the solar cell.

[0041] Specifically, the first open-film sub-region 3a1 of this application, with its larger maximum opening width, provides sufficient contact for the gate line 4, ensuring stable contact between the gate line 4 and the doped silicon layer 2, thereby guaranteeing the adhesion of the gate line 4 and preventing a decrease in contact stability due to insufficient contact area. The second open-film sub-region 3a2, with its smaller maximum opening width, significantly reduces damage to the surrounding passivation layer 3 and the underlying doped silicon layer 2 during the laser patterning process, effectively suppressing the generation of defect recombination centers and improving minority carrier lifetime. In summary, this application achieves a comprehensive improvement in the open-circuit voltage and photoelectric conversion efficiency of solar cells by setting a patterned open-film region 3a with varying widths.

[0042] The first open-film sub-region 3a1 and the second open-film sub-region 3a2 can be configured to be interconnected, allowing the gate line 4 to form continuous contact with the doped silicon layer 2 through the interconnected patterned open-film region 3a. This provides a larger contact area between the gate line 4 and the doped silicon layer 2, which is beneficial for improving the stability and reliability of the gate line 4. Alternatively, the first open-film sub-region 3a1 and the second open-film sub-region 3a2 can be configured to be non-interconnected. In this case, the gate line 4 forms a more dispersed, scattered contact with the doped silicon layer 2 through the non-interconnected first open-film sub-region 3a1 and second open-film sub-region 3a2. It should be noted that even if the gate line 4 forms scattered contact with the doped silicon layer 2, the gate line 4 itself still maintains structural and electrical continuity, and this does not mean that the gate line 4 is in a broken gate or other abnormal state.

[0043] It should be noted that, as Figure 2As shown, the first maximum opening width W1 refers to the maximum distance between the two edges of the top opening contour of the first open membrane sub-region 3a1 along the first direction, and the second maximum opening width W2 refers to the maximum distance between the two edges of the top opening contour of the second open membrane sub-region 3a2 along the first direction. In actual measurement, errors are unavoidable in the measurement of the first maximum opening width W1 and the second maximum opening width W2. To reduce measurement errors, the first open membrane sub-region 3a1 and the second open membrane sub-region 3a2 can be tested 3-5 times respectively, and the arithmetic mean can be taken as the first maximum opening width W1 and the second maximum opening width W2.

[0044] In some embodiments, the ratio of W2 to W1 is 30% to 80%. By limiting the ratio of W2 to W1 to the above range, it is beneficial to better reduce structural damage caused by setting the patterned opening region 3a while ensuring contact reliability. For example, the ratio of W2 to W1 can be 30%, 40%, 50%, 60%, 70%, or 80%.

[0045] In some embodiments, W1 is 10 μm to 50 μm and W2 is 3 μm to 40 μm.

[0046] When W1 and W2 are within the aforementioned ranges, the overall structural damage caused by laser-induced film opening can be effectively controlled while ensuring sufficient contact area and stability for the gate line 4. Specifically, controlling W1 between 10 μm and 50 μm ensures the contact stability of the gate line 4 while avoiding excessively wide W1, which could lead to excessive damage to the passivation layer 3 and an increase in potential local defects. Controlling W2 between 3 μm and 40 μm provides a sufficient contact area and ensures stable implementation during production without easily causing defects such as virtual breaks in the gate line due to excessively low W2.

[0047] The patterned open-film region 3a of this application can be two sub-regions alternating or multiple sub-regions alternating. (Refer to...) Figure 2 In some embodiments, the patterned open-film region 3a includes a plurality of first open-film sub-regions 3a1 and a plurality of second open-film sub-regions 3a2, and the first open-film sub-regions 3a1 and second open-film sub-regions 3a2 are alternately distributed along a second direction, which is a direction parallel to the length direction of the gate line 4 (the second direction is...). Figure 2 Y direction shown).

[0048] By alternating the first open-film sub-region 3a1 and the second open-film sub-region 3a2 along the extension direction of the grid line 4, a periodic contact interface structure of wide-narrow-wide-narrow is formed. This alternating distribution ensures that the first open-film sub-region 3a1 (i.e., the wide region) for forming reliable contact and the second open-film sub-region 3a2 (i.e., the narrow region) for reducing structural damage are uniformly distributed along the length of the grid line 4. This allows the grid line 4, located in the narrow region, to receive effective support from the wide region, reducing potential uneven contact resistance or localized weak adhesion points caused by the continuous distribution of long-distance narrow regions.

[0049] In other embodiments, the patterned open-film region 3a includes a first open-film sub-region 3a1 to an nth open-film sub-region, where n is a positive integer greater than or equal to 3. Along a first direction, the nth open-film sub-region has a maximum opening width of Wn away from the top of the substrate 1, with W1 gradually decreasing towards Wn. By providing multiple open-film sub-regions, the contact stability of the patterned open-film region 3a can be improved while better reducing structural damage caused by its configuration.

[0050] Furthermore, when the patterned open-film region 3a includes the first open-film sub-region 3a1 to the nth open-film sub-region, the first open-film sub-region 3a1 to the nth open-film sub-region are arranged sequentially, or randomly arranged among the first open-film sub-region 3a1 to the nth open-film sub-region. By arranging the patterned open-film regions 3a sequentially in descending order of width, it is beneficial to form a patterned open-film region 3a with better contact stability.

[0051] It should be noted that the terms "first" to "n" in this application do not necessarily refer to a strict spatial order, but can be defined based on factors such as the sequence of laser ablation or the size of the opening width. For example, in a patterned ablation region 3a of a continuous ablation process, there can be multiple ablation sub-regions prepared sequentially after laser ablation. Figure 3 As shown, these open-membrane subregions can be arranged spatially in the order of first open-membrane subregion 3a1, second open-membrane subregion 3a2, third open-membrane subregion 3a3, etc., or in the order of... Figure 4 The first open membrane subregion 3a1, the third open membrane subregion 3a3, the second open membrane subregion 3a2, etc., are arranged in sequence.

[0052] In some embodiments, the center line connecting adjacent first open membrane sub-regions 3a1 partially coincides with or is parallel to the center line connecting adjacent second open membrane sub-regions 3a2, such as... Figure 2 As shown, the center line A1A2 of the first open membrane sub-region 3a1 and the center line B1B2 of the second open membrane sub-region 3a2 partially overlap.

[0053] This helps to ensure that the extension direction of the entire patterned open film region 3a is highly consistent, thereby reducing errors or process fluctuations caused by frequent changes in the direction of the open film sub-regions in the patterned open film region 3a. This significantly improves the processing accuracy and repeatability of the patterned open film region 3a and the gate line 4, which is conducive to ensuring the stable realization of the designed contact stability and structural damage reduction performance.

[0054] In some embodiments, the top contour shape of the first open membrane sub-region 3a1 and the second open membrane sub-region 3a2 away from the substrate 1 is at least one of a circle, an ellipse or a rectangle.

[0055] The planar geometry of the openings in the first open-film sub-region 3a1 and the second open-film sub-region 3a2 can be designed in various ways. Circular, elliptical, or rectangular unit laser patterning processes offer flexible spot matching options. For example, when fabricating an open-film sub-region with a circular top contour, a circular spot laser can be used; when fabricating an open-film sub-region with a rectangular top contour, a rectangular spot laser can be used. By selecting laser spot shapes of different shapes, the diversity of shape design for the patterned open-film region 3a can be increased.

[0056] In some embodiments, reference is made to Figure 5 or Figure 6 The passivation layer 3 is raised at the edge of the patterned open film region 3a in a direction away from the substrate 1. The gate line 4 extends into the gap region 33 between the doped silicon layer 2 and the raised passivation layer 3.

[0057] During the fabrication of the patterned open-film region 3a, the thermal stress or thermal expansion and contraction caused by laser processing can easily cause the passivation layer 3 to lift off the edge of the patterned open-film region 3a in a direction away from the substrate 1. When the gate line 4 is set in the patterned open-film region 3a, it will penetrate into the gap region 33 formed by this lifting, thereby forming an interlocking structure with a certain anchoring effect between the gate line 4 and the passivation layer 3. This significantly enhances the adhesion and anti-peeling ability of the gate line 4 and improves the stability of the gate line 4.

[0058] In some embodiments, the passivation layer 3 has a first raised height near the edge of the first open-film sub-region 3a1, and the morphology of the raised edge of the passivation layer 3 near the edge of the first open-film sub-region 3a1 is as follows: Figure 5 As shown, the first raised height is H1, and the passivation layer 3 near the edge of the second open film sub-region 3a2 has a second raised height. The morphology of the raised edge of the passivation layer 3 near the edge of the second open film sub-region 3a2 is as follows. Figure 6 As shown, the height of the second upward tilt is H2; H1 is greater than H2, for example, such as Figure 5 The H1 labeled in the middle is 580.7 nm, such as Figure 5The H2 marked in the figure is 134.0 nm.

[0059] In this application, because the first open-film sub-region 3a1 has a larger width, the energy effect or thermal accumulation effect during laser irradiation is often more significant. Compared with the narrower second open-film sub-region 3a2, it is more likely to induce greater thermal stress and produce a higher passivation layer 3 warpage. The higher warpage height near the first open-film sub-region 3a1 can provide a deeper anchoring gap for the gate line 4, thereby enhancing the interlocking stability between the gate line 4 and the passivation layer 3. The lower warpage height near the second open-film sub-region 3a2 is beneficial to improving the adhesion between the passivation layer 3 and the doped silicon layer 2, so as to better maintain the integrity of the passivation layer 3.

[0060] It should be noted that, as Figure 5 and Figure 6 As shown in the figure, the first and second lift heights are measured in the following manner: the first lift height is the distance from the surface of the doped silicon layer 2 to the bottom of the passivation layer 3 that lifts up near the edge of the first open film sub-region 3a1; the second lift height is the distance from the surface of the doped silicon layer 2 to the bottom of the passivation layer 3 that lifts up near the edge of the second open film sub-region 3a2.

[0061] Furthermore, H1 is 0.1 μm to 1 μm, and H2 is 0.01 μm to 0.6 μm.

[0062] By setting H1 and H2 within a specific range, the advantages brought by the edge lifting of the passivation layer 3 can be fully utilized: it can provide effective adhesion enhancement and avoid large-area instability of the passivation layer 3 due to excessive lifting, thereby further improving the passivation effect and electrical contact performance of the solar cell.

[0063] Refer to the return Figure 1 In some embodiments, the contact surface between the gate line 4 and the doped silicon layer 2 away from the substrate 1 is a surface-to-surface contact.

[0064] In this application, the gate line 4 forms a surface-to-surface contact with the surface of the doped silicon layer 2 away from the substrate 1, meaning that the gate line 4 does not penetrate or extend into the interior of the doped silicon layer 2 due to laser ablation or alloying reactions. This helps to maintain the integrity of the doped silicon layer 2 and avoids introducing additional defects into the doped silicon layer 2.

[0065] From the perspective of the thickness variation of the doped silicon layer 2 below the region where gate line 4 is located and below the region where gate line 4 is not located, the thickness of the doped silicon layer 2 below the region where gate line 4 is located is the same as the thickness of the doped silicon layer 2 below the region where gate line 4 is not located. It can be seen that in this application, the thickness of the doped silicon layer 2 below the region where gate line 4 is located and below the region where gate line 4 is not located is basically the same, which also indicates that gate line 4 has not ablated and destroyed the internal structure of the doped silicon layer 2.

[0066] Furthermore, the doped silicon layer 2 does not contain metal crystals. The material of the gate line 4 typically contains metallic elements, such as copper and nickel. In this application, the metallic elements of the gate line 4 do not form a metallic crystal structure in the doped silicon layer 2, indicating that no ablation or alloying reaction occurred during the formation of the gate line 4, further demonstrating that the gate line 4 did not ablate or destroy the internal structure of the doped silicon layer 2.

[0067] In this application, the passivation layer 3 with the patterned open-film region 3a can be applied to the light-receiving surface or the back-lighting surface of the battery, or it can be applied to both sides of the battery. When applied to different solar cells such as passivated contact solar cells or back contact solar cells, the patterned open-film region 3a of this application can be adapted to different passivation layer 3 characteristic requirements by adjusting the W1 parameters of the first open-film sub-region 3a1 and the W2 parameters of the second open-film sub-region 3a2. This optimizes the balance between structural damage and reliability caused by the patterned open-film region 3a setting while ensuring excellent passivation performance of the solar cell.

[0068] Reference Figure 1 In some embodiments, the substrate 1 has a light-receiving surface and a back-lighting surface; a doped silicon layer 2, a gate line 4, and a passivation layer 3 with a patterned open-film region 3a are disposed on the light-receiving surface and / or the back-lighting surface of the substrate 1; the doped silicon layer 2 includes a first doped silicon sublayer 21 and / or a second doped silicon sublayer 22, the first doped silicon sublayer 21 is disposed on the light-receiving surface of the substrate 1, the second doped silicon sublayer 22 is disposed on the back-lighting surface of the substrate 1, and a dielectric layer 5 is further disposed between the second doped silicon sublayer 22 and the substrate 1, and the first doped silicon sublayer 21 and the second doped silicon sublayer 22 have opposite conductivity types.

[0069] In this application, the first doped silicon sublayer 21 and the second doped silicon sublayer 22 have opposite conductivity types, meaning that when one of the first doped silicon sublayer 21 and the second doped silicon sublayer 22 is an N-type doped silicon sublayer, the other is a P-type doped silicon sublayer. Further, the doped silicon sublayer includes at least one of a doped polycrystalline silicon layer, a doped amorphous silicon layer, or a doped microcrystalline silicon layer. For example, the first doped silicon sublayer 21 is a P-type doped silicon sublayer, specifically a P-type boron doped layer, and the second doped silicon sublayer 22 is an N-type doped silicon sublayer, specifically an N-type phosphorus doped polycrystalline silicon layer.

[0070] Furthermore, the material of the dielectric layer 5 may include at least one of various dielectric materials, such as silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Specifically, the dielectric layer 5 may be composed of a silicon oxide layer containing silicon oxide. This is because the silicon oxide layer has excellent passivation properties, which can minimize the recombination loss of minority carriers on the semiconductor substrate surface.

[0071] Furthermore, the material of the gate line 4 includes at least one of nickel, copper, or tin. Also, the gate line 4 formed on the light-receiving side is the first gate line 41, and the gate line 4 formed on the backlight side is the second gate line 42.

[0072] Furthermore, the passivation layer 3 is made of at least one of aluminum oxide, silicon nitride, silicon oxynitride, or silicon oxide; these materials have better passivation effects and can perform better passivation performance in solar cells. The passivation layer 3 disposed on the light-receiving side is the light-receiving passivation layer 31, and the passivation layer 3 disposed on the back-lighting side is the back-lighting passivation layer 32. For example, the light-receiving passivation layer 31 can be a light-receiving aluminum oxide layer and a light-receiving silicon nitride layer stacked sequentially, wherein the light-receiving aluminum oxide layer is located on the side closer to the substrate 1, and the light-receiving silicon nitride layer is located on the side of the light-receiving aluminum oxide layer away from the substrate 1; the back-lighting passivation layer 32 can be a back-lighting aluminum oxide layer and a back-lighting silicon nitride layer stacked sequentially, wherein the back-lighting aluminum oxide layer is located on the side closer to the substrate 1, and the back-lighting silicon nitride layer is located on the side of the back-lighting aluminum oxide layer away from the substrate 1.

[0073] Furthermore, substrate 1 is a silicon substrate, which can be an N-type silicon wafer or a P-type silicon wafer.

[0074] Secondly, embodiments of this application provide a method for preparing a solar cell.

[0075] A method for fabricating a solar cell includes the following steps: A substrate 1 is provided in which a doped silicon layer 2 and a passivation layer 3 are sequentially stacked on the surface; The passivation layer 3 is subjected to laser patterning opening process to form a patterned opening region 3a with a first opening sub-region 3a1 and a second opening sub-region 3a2 in the passivation layer 3; wherein, along the first direction, the first opening sub-region 3a1 has a first maximum opening width away from the top of the substrate 1, the first maximum opening width is W1, the second opening sub-region 3a2 has a second maximum opening width away from the top of the substrate 1, the second maximum opening width is W2, W1 is greater than W2, and the first direction is a direction parallel to the width direction of the gate line 4; Electroplating process is used to form gate lines 4 in the patterned open film region 3a, and the gate lines 4 are in contact with the doped silicon layer 2.

[0076] This application employs a laser patterning film-opening process to fabricate a first open-film sub-region 3a1 and a second open-film sub-region 3a2 with differentiated maximum opening widths on the passivation layer 3, laying the foundation for subsequent electroplating to form high-quality gate lines 4. After forming the patterned open-film region 3a, electroplating is performed, causing the electroplated metal to grow on the doped silicon layer 2 along the height direction of the patterned open-film region 3a, thereby forming the gate line 4 disposed in the patterned open-film region 3a and extending towards the side away from the doped silicon layer 2. The shape of the gate line 4 disposed in the patterned open-film region 3a is consistent with the shape of the patterned open-film region 3a, which is beneficial for the gate line 4 to obtain better adhesion, and the laser patterning film-opening process reduces structural damage to the passivation layer 3 and the underlying doped silicon layer 2 and other film layers.

[0077] This application uses electroplating to form the grid lines 4. Therefore, this application can use metals such as copper or nickel to replace silver, a precious metal, thereby reducing the amount of silver used and lowering costs.

[0078] In some embodiments, the laser used for laser patterning film opening processing includes a first laser and a second laser. The spot size of the first laser is L1, and the spot size of the second laser is L2. L1 is larger than L2. The area processed by the first laser corresponds to the formation of a first film opening sub-region 3a1, and the area processed by the second laser corresponds to the formation of a second film opening sub-region 3a2. The ratio of L2 to L1 is 30% to 80%.

[0079] This application employs two lasers with different spot sizes, a first laser and a second laser, and applies the first laser and the second laser to different regions, enabling the etching of a first open-film sub-region 3a1 and a second open-film sub-region 3a2 in the passivation layer 3. Furthermore, limiting the ratio of L2 to L1 within the aforementioned range helps to better reduce structural damage caused by setting the patterned open-film region 3a while ensuring contact reliability.

[0080] Furthermore, L1 is 10 μm to 50 μm, and L2 is 3 μm to 40 μm. By limiting the ratio of L2 to L1 within a specific range, a first open-film sub-region 3a1 and a second open-film sub-region 3a2 with a specific width ratio can be formed. With L1 in the first open-film sub-region 3a1 within the aforementioned range, sufficient electroplated contact substrate 1 can be provided for the gate line 4, thereby improving the contact stability of the gate line 4. Simultaneously, with L2 in the second open-film sub-region 3a2 within the aforementioned range, structural damage caused by laser patterning open-film processing can be effectively reduced.

[0081] In some embodiments, the energy of the first laser is greater than the energy of the second laser; wherein the ratio of the energy density of the second laser to the energy density of the first laser is 30% to 80%, and the energy density of the first laser is 100 mJ / cm². 2 Up to 600 mJ / cm 2The energy density of the second laser is 30 mJ / cm². 2 Up to 480 mJ / cm 2 The ratio of the average power of the second laser to the average power of the first laser is 60% to 70%.

[0082] In this application, the first laser uses a high laser energy, which can effectively improve the degree of passivation layer 3 opening, while the second laser uses a lower laser energy, which can reduce energy damage caused by laser opening and avoid secondary damage to the passivation layer 3 warping structure caused by the first laser opening during the use of the second laser. Furthermore, by combining the first and second lasers with the above-mentioned specific laser energy densities, complete opening of the patterned opening region 3a can be achieved, while reducing laser damage caused by laser patterning opening.

[0083] Reference Figure 7 In some embodiments, the relationship between the first spot area 61 of the first laser and the second spot area 62 of the second laser is tangent, intersecting, or separate.

[0084] The areas affected by a single first laser beam and the areas affected by a single second laser beam can be as follows: Figure 7 (a) shows the tangency, Figure 7 The intersection shown in (b), or... Figure 7 (c) shows the phase separation state. After laser patterning, combined with cleaning, the passivation layer 3 material that may remain at the bottom of the patterned open film region 3a or between the areas affected by the first and second laser beams can be removed, thereby forming the patterned open film region 3a and ensuring the continuity of the gate line 4.

[0085] Furthermore, when the first light spot's effective area is separated from the second light spot's effective area, the gap between the first light spot's effective area and the second light spot's effective area is 10 μm to 100 μm; When the first light spot's effective area intersects with the second light spot's effective area, the width of the overlapping area between the first light spot's effective area and the second light spot's effective area is greater than 0 μm and less than or equal to 20 μm; When the first light spot's effective area is tangent to the second light spot's effective area, the gap distance between the first light spot's effective area and the second light spot's effective area is 0 μm.

[0086] It should be noted that, in this application, the width of the overlapping area between the first and second light spot areas refers to the distance between the line segment connecting the centers of the two light spot areas (c1c2) and the overlapping portion when the two light spot areas intersect. Figure 7In the intersection example shown in (b), the width of the overlapping region is denoted as d1. The gap distance between the first and second light spot action areas is the shortest distance between their contours, as shown in the example. Figure 7 In the example of the phase separation state shown in (c), the gap distance is denoted as d2.

[0087] In some embodiments, after the laser patterning and film-opening process, a cleaning process is performed to remove the remaining passivation layer 3 in the patterned film-opening region 3a, followed by electroplating. After the laser patterning and film-opening process, the passivation layer 3 may still contain loosely structured passivation layer 3 material. The cleaning process can remove the residual passivation layer 3 material in the patterned film-opening region 3a, providing a good growth surface for the electroplated gate lines 4, thus facilitating the high-quality deposition of the gate lines 4.

[0088] In some embodiments, in the step of forming the patterned open-film region 3a, a first laser is first used to perform intermittent opening to form, as shown in the figure. Figure 8 (a) shows several spaced first open-film sub-regions 3a1, and then a second laser is applied to the spaced regions between adjacent first open-film sub-regions 3a1 to form a structure as shown in the diagram. Figure 8 (b) shows the second open membrane subregion 3a2, resulting in a structure in which the first open membrane subregion 3a1 and the second open membrane subregion 3a2 are arranged alternately; or, First, a second laser is used to perform intermittent film opening to form a film like... Figure 9 (a) shows several spaced second open-film sub-regions 3a2, and then the first laser is applied to the spaced regions between adjacent second open-film sub-regions 3a2, so as... Figure 9 (b) shows the formation of the first open membrane sub-region 3a1, resulting in a structure in which the first open membrane sub-region 3a1 and the second open membrane sub-region 3a2 are arranged alternately.

[0089] The distributed film-opening method of this application can significantly reduce the heat accumulation damage caused by laser patterning film-opening processing. If continuous laser scanning is used to scan alternating wide and narrow areas, energy superposition or thermal management difficulties can easily occur at the width change points. Step-by-step processing allows time and space for heat dissipation after the first laser treatment before the second laser treatment, avoiding local overheating that may occur with continuous processing. Secondly, this application also simplifies process control. The laser used in each step only needs to focus on achieving a maximum opening width, and the setting and stability of laser parameters (such as energy and power) are easier to ensure, improving the stability and repeatability of the process.

[0090] In some embodiments, the laser used for laser patterning film opening processing includes a first laser to an nth laser, where n is a positive integer greater than or equal to 3, and the spot size of the nth laser is Ln, where L1 is greater than Ln; In the step of forming the patterned open film region 3a, the first laser to the nth laser are used sequentially to perform intermittent opening film, resulting in a structure with the first open film sub-region 3a1 to the nth open film sub-region arranged periodically.

[0091] By employing multiple laser processing steps, the opening width of the patterned film-opening region 3a can be more precisely controlled. Using three or more laser spot sizes, a patterned film-opening region 3a with a stepped decrease in width can be constructed. This helps to improve the control of the damage caused by the laser patterning film-opening process and keep the overall process damage level lower.

[0092] In some embodiments, the laser used for laser patterning film opening processing has a wavelength of green light or ultraviolet light, a pulse width of nanosecond, picosecond, or femtosecond, an average power of 0.1 W to 50 W, a laser frequency of 500 kHz to 5000 kHz, a laser speed of 30 m / s to 90 m / s, and a laser spot shape of circular, elliptical, or square.

[0093] This application finds that when the relevant parameters of the laser are set within the above range, the requirements for ensuring the quality of patterned film opening and production efficiency can be better balanced, thereby achieving further improvement in production efficiency and solar cell quality.

[0094] Thirdly, embodiments of this application provide a photovoltaic module.

[0095] 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.

[0096] The technical solution of this application will be further described below with reference to more specific embodiments.

[0097] Example 1 This application provides a solar cell, the preparation method of which includes the following steps: An N-type monocrystalline silicon wafer is provided. The light-receiving surface of the N-type monocrystalline silicon wafer is sequentially provided with a P-type boron doped layer with a thickness of 900 nm and a light-receiving passivation layer with a thickness of 100 nm. The light-receiving passivation layer is a stack of a light-receiving alumina layer and a light-receiving silicon nitride layer sequentially disposed on the P-type boron doped layer. The thickness of the light-receiving alumina layer is 4 nm and the thickness of the light-receiving silicon nitride layer is 96 nm. The back-lighting surface is sequentially provided with a silicon oxide dielectric layer with a thickness of 1 nm, an N-type phosphorus doped polycrystalline silicon layer with a thickness of 900 nm and a back-lighting passivation layer with a thickness of 90 nm. The back-lighting passivation layer is a stack of a back-lighting alumina layer and a back-lighting silicon nitride layer sequentially disposed on the side of the N-type phosphorus doped polycrystalline silicon layer away from the N-type monocrystalline silicon wafer. The thickness of the back-lighting alumina layer is 4 nm and the thickness of the back-lighting silicon nitride layer is 86 nm. Laser patterning and opening processes are performed on the passivation layers of the light-receiving and back-light-receiving surfaces respectively to form patterned opening regions with a first opening sub-region and a second opening sub-region on the light-receiving and back-light-receiving surfaces, respectively. The specific preparation steps are as follows: A first laser is used for intermittent membrane opening, forming several spaced-apart first membrane opening sub-regions. The first laser is a green picosecond laser with a spot size of 30 μm and a laser energy density of 400 mJ / cm². 2 The average power is 5.7 W, the laser frequency is 2000 KHz, and the laser speed is 80 m / s; A second open-membrane sub-region is formed by applying a second laser to the spacer region between adjacent first open-membrane sub-regions. This second open-membrane sub-region is connected to the first open-membrane sub-region. The second laser is a green picosecond laser with a spot size of 15 μm and a laser energy density of 200 mJ / cm². 2 The average power is 3 W, the laser frequency is 2000 KHz, and the laser speed is 80 m / s. Along the first direction, the first maximum opening width W1 of the first open-film sub-region away from the top of the substrate is 30 μm, and the second maximum opening width W2 of the second open-film sub-region away from the top of the substrate is 15 μm. The first direction is the direction parallel to the width direction of the grid line. Cleaning process to remove loose passivation layer material remaining in the patterned open film area; Electroplating process is used to form gate lines in the patterned open film area. The gate lines are in contact with the doped silicon layer. The gate line formed on the light-receiving side is the first gate line with a thickness of 2 μm, and the gate line formed on the back-light side is the second gate line with a thickness of 2 μm.

[0098] Comparative Example 1 This application provides a comparative example of a solar cell, which differs from Example 1 in that the widths of the first maximum opening width W1 and the second maximum opening width W2 are both 30 μm, while the rest remains the same as in Example 1.

[0099] experiment Solar cell 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 (pFF), and photoelectric conversion efficiency (PCE) of the corresponding solar cells were recorded.

[0100] The solar cells of Example 1 and Comparative Example 1 were subjected to the above performance tests, and the difference between the test results of Example 1 and Comparative Example 1 is shown in Table 1.

[0101] Table 1

[0102] The data comparison in Table 1 shows that the open-circuit voltage, short-circuit current, and fill factor of the solar cell in Example 1 are all improved to a certain extent compared with those in Comparative Example 1. This proves that by using a patterned open-film region with a combination of wide and narrow sections, compared with the patterned open-film region with a more uniform width used in Comparative Example 1, laser damage can be better reduced, thereby reducing carrier recombination and further improving the performance of the solar cell.

[0103] 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: Base; A doped silicon layer is disposed on the substrate; A passivation layer and a gate line are provided, wherein the passivation layer is disposed on the side of the doped silicon layer away from the substrate, the passivation layer has a patterned open-film region, and the gate line is disposed in the patterned open-film region and forms contact with the doped silicon layer; The patterned opening region includes a first opening sub-region and a second opening sub-region; Along the first direction, the first open-film sub-region has a first maximum opening width away from the top of the substrate, the first maximum opening width being W1, and the second open-film sub-region has a second maximum opening width away from the top of the substrate, the second maximum opening width being W2, wherein W1 is greater than W2, and the first direction is a direction parallel to the width direction of the gate line.

2. The solar cell according to claim 1, characterized in that, The ratio of W2 to W1 is 30% to 80%.

3. The solar cell according to claim 2, characterized in that, The W1 is 10 μm to 50 μm, and the W2 is 3 μm to 40 μm.

4. The solar cell according to claim 1, characterized in that, The patterned opening region includes a plurality of first opening sub-regions and a plurality of second opening sub-regions, and the first opening sub-regions and the second opening sub-regions are alternately distributed along a second direction, which is a direction parallel to the length direction of the gate line; And / or, The patterned opening region includes the first opening sub-region to the nth opening sub-region, where n is a positive integer greater than or equal to 3, and along the first direction, the nth opening sub-region has a maximum opening width of Wn away from the top of the substrate, and W1 to Wn gradually decrease.

5. The solar cell according to claim 4, characterized in that, When the graphic opening area includes the first opening sub-area to the nth opening sub-area, the first opening sub-area to the nth opening sub-area are arranged sequentially, or the first opening sub-area to the nth opening sub-area are arranged in a random order. And / or, The center line connecting adjacent first open membrane sub-regions partially coincides with or is parallel to the center line connecting adjacent second open membrane sub-regions.

6. The solar cell according to claim 1, characterized in that, The top outline shape of the first open membrane sub-region and the second open membrane sub-region away from the substrate is at least one of a circle, an ellipse or a rectangle.

7. The solar cell according to claim 1, characterized in that, The passivation layer near the edge of the patterned open film area is raised in a direction away from the substrate; The gate line extends into the gap region between the doped silicon layer and the raised passivation layer.

8. The solar cell according to claim 7, characterized in that, The passivation layer has a first raised height (H1) near the edge of the first open film sub-region, and a second raised height (H2) near the edge of the second open film sub-region. H1 is greater than H2; and / or, H1 is 0.1 μm to 1 μm and H2 is 0.01 μm to 0.6 μm.

9. The solar cell according to claim 1, characterized in that, The contact surface between the gate line and the doped silicon layer away from the substrate is a surface-to-surface contact; And / or, The thickness of the doped silicon layer below the region where the gate line is located is the same as the thickness of the doped silicon layer below the region where the gate line is not located. And / or, The doped silicon layer does not contain any metal crystals.

10. The solar cell according to any one of claims 1-9, characterized in that, The substrate has a light-receiving surface and a back-lighting surface; the doped silicon layer, the gate line, and the passivation layer having the patterned open-film region are disposed on the light-receiving surface and / or the back-lighting surface of the substrate; the doped silicon layer includes a first doped silicon sublayer and / or a second doped silicon sublayer, the first doped silicon sublayer is disposed on the light-receiving surface of the substrate, the second doped silicon sublayer is disposed on the back-lighting surface of the substrate, and a dielectric layer is further disposed between the second doped silicon sublayer and the substrate, wherein the first doped silicon sublayer and the second doped silicon sublayer have opposite conductivity types; And / or, The material of the grid lines includes at least one of nickel, copper, or tin; And / or, The material of the passivation layer includes at least one of aluminum oxide, silicon nitride, silicon oxynitride, or silicon oxide. And / or, The substrate is a silicon substrate; And / or, The doped silicon layer includes at least one of a doped polycrystalline silicon layer, a doped amorphous silicon layer, or a doped microcrystalline silicon layer.

11. A method for preparing a solar cell, characterized in that, Includes the following steps: A substrate is provided in which a doped silicon layer and a passivation layer are sequentially stacked on the surface; The passivation layer is subjected to laser patterning opening process to form a patterned opening region with a first opening sub-region and a second opening sub-region in the passivation layer; wherein, along a first direction, the first opening sub-region has a first maximum opening width W1 on the top away from the substrate, and the second opening sub-region has a second maximum opening width W2 on the top away from the substrate, wherein W1 is greater than W2; Electroplating process is used to form gate lines in the patterned open film region, the gate lines being in contact with the doped silicon layer; The first direction is a direction parallel to the width direction of the gate line.

12. The method for preparing a solar cell according to claim 11, characterized in that, The laser used in the laser patterning film opening process includes a first laser and a second laser. The spot size of the first laser is L1, and the spot size of the second laser is L2. L1 is larger than L2. The area processed by the first laser corresponds to the formation of the first film opening sub-region, and the area processed by the second laser corresponds to the formation of the second film opening sub-region. The ratio of L2 to L1 is 30% to 80%; and / or, L1 is 10 μm to 50 μm and L2 is 3 μm to 40 μm.

13. The method for preparing a solar cell according to claim 12, characterized in that, The energy of the first laser is greater than the energy of the second laser; The energy density of the second laser is 30% to 80% of the energy density of the first laser, and the energy density of the first laser is 100 mJ / cm². 2 Up to 600 mJ / cm 2 The energy density of the second laser is 30 mJ / cm². 2 Up to 480 mJ / cm 2 The ratio of the average power of the second laser to the average power of the first laser is 60% to 70%.

14. The method for preparing a solar cell according to claim 12, characterized in that, The relationship between the first spot area of ​​the first laser and the second spot area of ​​the second laser is tangential, intersecting, or disjoint, wherein: When the first light spot area is separated from the second light spot area, the gap between the first light spot area and the second light spot area is 10 μm to 100 μm. When the first light spot action area intersects with the second light spot action area, the maximum width of the overlapping area between the first light spot action area and the second light spot action area is greater than 0 μm and less than or equal to 20 μm; When the first light spot action area is tangent to the second light spot action area, the gap distance between the first light spot action area and the second light spot action area is 0 μm; And / or, After the laser patterning film-opening process, a cleaning process is performed to remove the remaining passivation layer in the patterned film-opening area, followed by the electroplating process.

15. The method for preparing a solar cell according to claim 12, characterized in that, In the step of forming the patterned open film area, the first laser is first used to perform intermittent opening film to form a number of spaced first open film sub-regions, and then the second laser is applied to the spaced area between adjacent first open film sub-regions to form second open film sub-regions, resulting in a structure in which the first open film sub-regions and the second open film sub-regions are arranged alternately. or, First, the second laser is used to perform intermittent film opening to form several intermittently arranged second film opening sub-regions. Then, the first laser is applied to the interval region between adjacent second film opening sub-regions to form the first film opening sub-region, resulting in a structure in which the first film opening sub-region and the second film opening sub-region are arranged alternately.

16. The method for preparing a solar cell according to claim 12, characterized in that, The laser used in the laser patterning film opening process includes a first laser to an nth laser, where n is a positive integer greater than or equal to 3, the spot size of the nth laser is Ln, and L1 is greater than Ln; In the step of forming the patterned open film region, the first laser to the nth laser are used sequentially to perform intermittent opening film, resulting in a structure with the first open film sub-region to the nth open film sub-region arranged periodically.

17. The method for preparing a solar cell according to claim 11, characterized in that, The laser used in the laser patterning film-opening process has a wavelength of either green or ultraviolet light, a pulse width of either nanosecond, picosecond, or femtosecond, an average power of 0.1 W to 50 W, a laser frequency of 500 kHz to 5000 kHz, a laser speed of 30 m / s to 90 m / s, and a laser spot shape of circular, elliptical, or square.

18. A photovoltaic module, characterized in that, This includes solar cells as described in any one of claims 1-10 or solar cells prepared by any one of claims 11-17.

Images