Solar cell, stacked cell, and photovoltaic module

Abstract

This application relates to the field of solar cell technology, and in particular to a solar cell, a tandem cell, and a photovoltaic module. In this solar cell, multiple non-metallized regions are arrayed on the first surface. These non-metallized regions have a closed structure. Through the cooperation of the non-metallized and metallized regions, the metallized region is divided into multiple sub-regions by the multiple non-metallized regions, reducing the area of ​​a single metallized sub-region. Photogenerated carriers generated at any location within a metallized sub-region can quickly enter the collection region within that sub-region, greatly reducing the lateral transmission distance of photogenerated carriers to the collection region, lowering the recombination probability of carriers, and thus improving photoelectric conversion efficiency. The boundary groove has a scattering effect on light incident on the inner wall surface of the boundary groove, which can change the propagation path of light inside the solar cell, increasing the effective optical path within the solar cell, and improving the absorption of long-wavelength light to increase photocurrent.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a solar cell, a tandem cell, and a photovoltaic module. Background Technology

[0002] With the accelerated transition from traditional fossil fuels and the increasing demand for sustainable development, solar cells, as a clean and renewable energy technology, are increasingly becoming an important component of the energy system. A solar cell is essentially a semiconductor device that directly converts solar energy into electrical energy. Its working principle is based on the photovoltaic effect: when sunlight shines on the cell, photon energy excites electron-hole pairs (i.e., charge carriers) to be generated inside the semiconductor. These charge carriers then separate under the influence of a built-in electric field, forming a potential difference. By effectively extracting these charge carriers through the metal electrodes on the front and back of the cell, direct current can be generated for use in external circuits, thus achieving the efficient conversion and utilization of solar energy into electrical energy.

[0003] In related technologies, in order to improve the electrical performance of solar cells, the regions of solar cells connected to the electrodes and those not connected to the electrodes are designed differently. However, the problem of high recombination rate still exists, which is not conducive to improving conversion efficiency. Summary of the Invention

[0004] Based on this, this application provides a solar cell, a tandem cell, and a photovoltaic module to solve the technical problems in the prior art that are not conducive to improving conversion efficiency.

[0005] In a first aspect, embodiments of this application provide a solar cell, comprising: A substrate having a first surface and a second surface disposed opposite to each other along the thickness direction; the first surface and the second surface are a front surface and a rear surface, respectively. A texture structure is provided on the first surface of the substrate. The texture structure includes a metallized area and a plurality of non-metallized areas. The non-metallized areas are polygonal. The plurality of non-metallized areas are arranged in an array on the first surface. The metallized areas surround the non-metallized areas. The metallized areas have a first pyramid texture structure. The non-metallized areas have a second pyramid texture structure. A boundary groove is provided between the non-metallized area and the metallized area. The boundary groove is in the shape of a polygonal ring and is arranged around the boundary between the metallized area and the non-metallized area. At the boundary between the non-metallized area and the metallized area, the first pyramid texture structure near the side of the second pyramid texture structure forms the first sidewall of the boundary groove, and the second pyramid texture structure near the side of the first pyramid texture structure forms the second sidewall of the boundary groove. The first sidewall and the second sidewall intersect in a V-shape. The boundary groove includes multiple boundary groove segments, each of which extends meanderingly in its extension direction.

[0006] Secondly, embodiments of this application provide a stacked battery, comprising: Top cell, which can be a perovskite cell, cadmium telluride solar cell, copper indium gallium selenide solar cell, or gallium arsenide solar cell; Intermediate connecting layer; and The bottom battery is the aforementioned solar cell; The top battery, the intermediate connecting layer, and the bottom battery are stacked and connected.

[0007] Thirdly, embodiments of this application provide a photovoltaic module, including the aforementioned solar cell or the aforementioned tandem cell.

[0008] In the solar cell of this application embodiment, multiple non-metallized regions are arrayed on the first surface. The non-metallized regions have a closed structure. Through the cooperation of the non-metallized and metallized regions, the metallized region is divided into multiple sub-regions by the multiple non-metallized regions, reducing the area of ​​a single metallized sub-region. Photogenerated carriers generated at any position in a metallized sub-region can quickly enter the collection region within that sub-region, greatly reducing the transmission distance of photogenerated carriers to the collection region laterally, reducing the recombination probability of carriers, and thus improving photoelectric conversion efficiency. The boundary groove has a scattering effect on light incident on the inner wall surface of the boundary groove, which can change the propagation path of light inside the solar cell, increase the effective optical path of light inside the solar cell, and improve the absorption of long-wavelength light to increase photocurrent. The meandering extension of the boundary groove further increases the contact area between the non-metallized and metallized regions, effectively coordinating the deformation between different texture regions, and further alleviating the stress concentration problem caused by local stiffness differences. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of a solar cell according to an embodiment of this application.

[0010] Figure 2 for Figure 1 The diagram shows a partial structural schematic of a solar cell.

[0011] Figure 3 This is a scanning electron microscope image of a solar cell according to an embodiment of this application.

[0012] Figure 4 This is another scanning electron microscope image of a solar cell according to an embodiment of this application.

[0013] Figure 5 This is another scanning electron microscope image of a solar cell according to an embodiment of this application.

[0014] Figure 6 This is a schematic diagram of the structure of the first protrusion and the second protrusion in the solar cell of this application embodiment, wherein (a) is a cone-like protrusion, (b) is a dune-like protrusion, (c) is a pyramid-like protrusion, (d) is a spherical protrusion, (e) is a pyramid, and (f) is a perspective structure of the first pyramid covered with a first passivation layer.

[0015] Figure 7 This is a schematic diagram of the structure at the junction of the first textured region and the second textured region in a solar cell according to an embodiment of this application.

[0016] Figure 8 This is another structural schematic diagram of a solar cell according to an embodiment of this application.

[0017] Figure 9 This is another structural schematic diagram of a solar cell according to an embodiment of this application.

[0018] Figure 10 This is a schematic diagram of a first distribution structure of the first textured region and the second textured region in a solar cell according to an embodiment of this application.

[0019] Figure 11 This is a schematic diagram of a second distribution structure of the first textured region and the second textured region in a solar cell according to an embodiment of this application.

[0020] Figure 12 This is another scanning electron microscope image of a solar cell according to an embodiment of this application.

[0021] Figure 13 This is a schematic diagram of the structure of a solar cell according to an embodiment of this application.

[0022] Figure 14 This is a schematic diagram of the structure of the battery string in the photovoltaic module according to an embodiment of this application.

[0023] Figure 15 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of this application.

[0024] Figure 16 This is a schematic diagram of the structure of the solar cell in Comparative Example 2.

[0025] Reference numerals: 100-Solar cell; 11-Substrate; 11a-First surface; 11b-Second surface; 12-First passivation layer; 13-Metalized region; 131-Emitter; 1321-First pyramid; 1322-Functional film layer; 14-Non-metallized region; 14a-Non-metallized region unit; I-Boundary; 15-Boundary groove; 15c - Boundary groove section; 15d - Extension section; 151 - First sidewall; 152 - Second sidewall; K1 - First top; K2 - Second top; 153 - Middle bottom; 1511 - First side; 1521 - Second side; 154 - Opening; 1512 - First side ridge; 1522 - Second side ridge; 1523 - Third side ridge; 150 - Quasi-prismatic structure; 16 - First line groove; 17 - First anti-reflection layer; 181 - First electrode; 182 - Second electrode; 191 - Tunneling oxide layer; 192 - Doped polycrystalline silicon layer; 193 - Back passivation layer; 194 - Second anti-reflection layer; 200 - Photovoltaic module; 201 - Battery string; 202 - Encapsulation film; 203 - Cover plate; 20 - Solder strip. Detailed Implementation

[0026] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0027] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0029] like Figures 1 to 12 As shown, this is a solar cell 100 provided in an embodiment of this application.

[0030] like Figure 1 and Figure 11As shown, the solar cell 100 of this application embodiment includes a substrate 11. The substrate 11 has a first surface 11a and a second surface 11b disposed opposite to each other along its thickness direction. The first surface 11a of the substrate 11 has a texture structure, which includes a metallized region 13 and a plurality of non-metallized regions 14. The non-metallized regions 14 are polygonal. Exemplarily, the non-metallized regions 14 are quadrilateral. More specifically, the non-metallized regions 14 may be rectangular. The plurality of non-metallized regions 14 are arranged in an array on the first surface 11a. The metallized regions 13 surround the non-metallized regions 14. The metallized regions 13 have a first pyramid texture structure, and the non-metallized regions 14 have a second pyramid texture structure. Exemplarily, the first pyramid texture structure may include a plurality of first pyramids, and the second pyramid texture structure may include a plurality of second pyramids.

[0031] A boundary groove 15 is provided between the non-metallized region 14 and the metallized region 13. The boundary groove 15 is in the shape of a polygonal ring and is arranged around the boundary between the metallized region 13 and the non-metallized region 14. Specifically, the boundary groove 15 is arranged around the outer periphery of the non-metallized region 14. For example, if the non-metallized region 14 is rectangular, then the boundary groove 15 is arranged in a rectangular ring shape around the outer periphery of the non-metallized region 14. Please refer to... Figures 2 to 4 as well as Figure 7 As shown, at the boundary I between the non-metallized region 14 and the metallized region 13, the first pyramid texture structure near the side of the second pyramid texture structure forms the first sidewall 151 of the boundary groove 15, and the second pyramid texture structure near the side of the first pyramid texture structure forms the second sidewall 152 of the boundary groove 15. The boundary groove 15 includes a plurality of boundary groove segments 15c, each boundary groove segment 15c corresponding to a side of a polygon, and each boundary groove segment 15c extends meanderingly in its extending direction. For example, if the non-metallized region 14 is quadrilateral (e.g., rectangular), then the boundary groove 15 includes four boundary groove segments 15c. For example, please refer to [link to relevant documentation]. Figure 1 As shown, the solar cell 100 also includes a first passivation layer 12 disposed on the first surface 11a, the first passivation layer 12 covering the first pyramid texture structure of the metallized region 13 and the second pyramid texture structure of the non-metallized region 14.

[0032] The non-metallized region 14 is a closed region and is arranged in an array on the first surface 11a. The metallized region 13 is divided into multiple sub-regions by multiple non-metallized regions 14, which reduces the area of ​​a single metallized region 13 sub-region. Photogenerated carriers generated at any position in the metallized region 13 sub-region can quickly enter the collection region within that sub-region, greatly reducing the transmission distance of photogenerated carriers to the collection region laterally, reducing the recombination probability of carriers, and improving photoelectric conversion efficiency.

[0033] Without the junction groove 15, the first pyramidal texture structure of the metallized zone 13 and the second pyramidal texture structure of the non-metallized zone 14 would form a direct planar joint. In this case, the effective mechanical contact between the first pyramidal texture structure of the metallized zone 13 and the second pyramidal texture structure of the non-metallized zone 14 would be limited to line contact or a strip-like contact of limited width at the joint, with an area only equal to the projected area of ​​the joint. This limited contact form would result in low interface stress transfer efficiency. When external loads (such as tension, shear, or bending moment) are applied to the joint structure, due to the limited contact area, the load transfer path is restricted to a narrow contact range and cannot be diffused and dissipated through a wider material volume. This would cause significant stress concentration at the joint edge, i.e., at the interface where the material stiffness changes abruptly. The stress peak at the joint edge is very likely to exceed the bond strength (including tensile strength and shear strength) at the interface where the stiffness changes abruptly, thus causing cracking at the joint between the first pyramidal texture structure of the metallized zone 13 and the second pyramidal texture structure of the non-metallized zone 14. Furthermore, this simple planar splicing interface mainly relies on interfacial normal stress and shear stress to transfer loads. Since the bonding strength of the interface is usually much lower than the strength of the material itself, and this load transfer mode is singular, it is difficult to redistribute and reduce stress through multiaxial stress states or more complex mechanical paths.

[0034] Therefore, as a geometric transition design, this interface groove can effectively coordinate the deformation between different texture areas, reduce stress concentration caused by local stiffness differences, and thus optimize the overall strain distribution.

[0035] The boundary groove 15 can separate the metallized region 13 and the non-metallized region 14, which can reduce the probability of photogenerated carriers generated at any position below the metallized region 13 crossing the boundary groove 15 and entering the non-metallized region 14, thereby reducing the recombination probability of carriers and improving photoelectric conversion efficiency.

[0036] Furthermore, due to the presence of the junction groove 15, the functional film can be deposited better at the junction of the metallized region 13 and the non-metallized region 14, which improves the formation quality of the functional film at the junction of the metallized region 13 and the non-metallized region 14, thereby improving the passivation effect of the functional film on the substrate 11. At the same time, it also helps to reduce the contact resistance between the functional film and the subsequently deposited conductive material, thereby reducing transmission loss.

[0037] Each segment 15c of the boundary groove 15 extends meanderingly in its extension direction, further increasing the contact area between the first pyramid texture structure of the metallized area 13 and the second pyramid texture structure of the non-metallized area 14. This can effectively coordinate the deformation between different texture areas and further alleviate the stress concentration problem caused by local stiffness differences.

[0038] Furthermore, the distribution of the metallized region 13 and the non-metallized region 14 is more uniform, which can further improve the formation quality of the functional film layer (such as the passivation layer or the passivation layer and the anti-reflection layer) on the first surface of the substrate 11, so as to further improve the morphological consistency of the functional film layer on the first surface of the substrate 11, which is conducive to further improving the passivation effect of the functional film layer.

[0039] As one implementation method, please refer to Figure 10 As shown, multiple non-metallized regions 14 are divided into several non-metallized region units 14a. Each non-metallized region unit 14a includes several non-metallized regions 14 arranged in a uniformly spaced manner along a first direction. The several non-metallized region units are arranged in a uniformly spaced manner along a second direction. The first direction is perpendicular to the second direction, and the first direction and the second direction are parallel to the first surface, respectively.

[0040] In this embodiment, multiple non-metallized regions 14 are uniformly distributed in an array on the first surface 11a. In the first direction, the spacing between any two adjacent non-metallized regions 14 is equal; in the second direction, the spacing between any two adjacent non-metallized regions 14 is equal. The metallized region 13 is divided into multiple sub-regions by the multiple non-metallized regions 14, and the arrangement of the multiple metallized region 13 sub-regions is also more uniform. Photogenerated carriers generated at any position in the metallized region 13 sub-region can quickly enter the collection region within that sub-region, greatly reducing the transmission distance of photogenerated carriers to the collection region laterally, reducing the recombination probability of carriers, and thus improving the photoelectric conversion efficiency.

[0041] In one implementation, the doping concentration of the second pyramidal texture structure in the non-metallized region 14 is lower than the doping concentration of the first pyramidal texture structure in the metallized region 13. Exemplarily, the doping concentration is the doping concentration of a doping element with a doping type opposite to that of the substrate 11.

[0042] In this design, a strong PN junction electric field cannot be formed in and below the non-metallized region 14, which increases the passivation effect of the non-metallized region 14 and reduces the recombination probability of charge carriers in and below the non-metallized region 14, thus improving photoelectric conversion efficiency. The difference in doping concentration between the metallized region 13 and the non-metallized region 14 simultaneously achieves low contact resistance and low surface recombination. Specifically, the higher doping concentration of the metallized region 13 compared to the non-metallized region 14 relatively reduces the sheet resistance of the metallized region 13 and relatively increases the sheet resistance of the non-metallized region 14, further enhancing the carrier collection efficiency of the metallized region 13 and further enhancing the passivation effect of the non-metallized region 14.

[0043] The metallized region 13 has a first pyramid texture structure, which includes multiple first pyramids. The non-metallized region 14 has a second pyramid texture structure, which includes multiple second pyramids. The thickness of the metallized region 13 is the height of the first pyramid texture structure along the thickness direction of the base 11, and the thickness of the non-metallized region 14 is the height of the second pyramid texture structure along the thickness direction of the base 11.

[0044] In one implementation, there is no emitter below the non-metallized region 14. Specifically, the area below the non-metallized region 14 is the substrate 11 located below the non-metallized region 14 in the thickness direction of the substrate 11, such as... Figure 13 As shown at point A in the middle.

[0045] In this embodiment, there is no emitter below the non-metallized region 14, and a strong PN junction electric field cannot be formed below the non-metallized region 14. This can further increase the passivation effect of the non-metallized region 14, reduce the recombination probability of charge carriers in and below the non-metallized region 14, and help improve the photoelectric conversion efficiency.

[0046] In one implementation, the substrate 11 is doped with a first conductivity type, and the non-metallized region 14 may not be doped with a second conductivity type. That is, the second pyramid microstructure in the second pyramid texture structure does not have a second conductivity type doping, and the first and second conductivity types are opposite. For example, the first conductivity type is N-type and the second conductivity type is P-type, or the first conductivity type is P-type and the second conductivity type is N-type. In this case, the non-metallized region 14 has no emitter, and there is no emitter below the non-metallized region 14. A PN junction electric field cannot be formed in the non-metallized region 14 and below it, which can increase the passivation effect of the non-metallized region 14, reduce the recombination probability of charge carriers in and below the non-metallized region 14, and help improve the photoelectric conversion efficiency.

[0047] In another implementation, the nonmetallization region 14 may have very shallow doping of the second conductivity type, that is, the second pyramidal texture structure may have very shallow doping of the second conductivity type, and the doping concentration of the second conductivity type element in the nonmetallization region 14 is less than or equal to 5E17. That is, the doping concentration of the second conductivity type element in the second pyramid microstructure is less than or equal to 5E17. At this point, the non-metallization region 14 cannot form a strong PN junction electric field, but it can effectively form field-effect passivation and suppress Auger recombination. Specifically, there are many defects in the metallization region 13 and the non-metallization region 14, which are prone to recombination. The main purpose of doping the non-metallization region 14 here is not to form a PN junction, but to form a fixed charge layer on the surface of the non-metallization region 14, and to form an electric field on the first surface of the substrate 11 to prevent photogenerated carriers (e.g., minority carriers) from reaching the surface of the substrate 11 and reduce the recombination probability.

[0048] In some embodiments, the second pyramidal texture structure may have very shallow doping of a second conductivity type, with the doping concentration of the second conductivity type element in the nonmetallization region 14 being less than or equal to 5E17. There is no doping of the second conductivity type element below the nonmetallization region 14, and there is no emitter below the nonmetallization region 14. At this time, a PN junction electric field cannot be formed below the nonmetallization region 14, and the nonmetallization region 14 can effectively form field-effect passivation and suppress Auger recombination.

[0049] In one implementation, the doping concentration of the second conductivity type element in the metallization region 13 can be 5E17. ~1E21 .

[0050] In this embodiment, the doping concentration of the second conductivity type element in the metallization region 13 is controlled within the above-mentioned range, which can reduce the contact resistance and improve the fill factor.

[0051] In one implementation, the metallized region 13 and the non-metallized region 14 have different heights.

[0052] Since the metallized region 13 and the non-metallized region 14 have different heights, the lateral diffusion of photogenerated carriers is suppressed before they are collected, and they are more likely to be rapidly extracted by the longitudinal electric field, thus reducing lateral recombination. For example, along the thickness direction of the substrate 11, the top height of the metallized region 13 and the top height of the non-metallized region 14 are different, or the top height of the metallized region 13 and the top height of the non-metallized region 14 are different, and the bottom height of the metallized region 13 and the bottom height of the non-metallized region 14 are also different.

[0053] As one implementation method, please refer to Figure 2 and Figure 4As shown, the boundary groove 15 includes a first sidewall 151, a second sidewall 152, a central bottom 153, and an opening 154. The central bottom 153 is the bottom of the boundary groove 15. The first sidewall 151 is the side of the metallized region 13 closest to the non-metallized region 14, and the second sidewall 152 is the side of the non-metallized region 14 closest to the metallized region 13. The central bottom 153 is located on the first surface 11a of the base 11 and is connected to the first sidewall 151 and the second sidewall 152. The opening 154 is defined by the end of the first sidewall 151 away from the central bottom 153 and the end of the second sidewall 152 away from the central bottom 153. The central bottom 153 and the opening 154 are opposite each other in the thickness direction of the base 11. The first sidewall 151, the second sidewall 152, the central bottom 153, and the opening 154 together form the boundary groove 15.

[0054] Furthermore, due to the presence of the boundary groove 15 between adjacent metallized regions 13 and non-metallized regions 14, when light is incident into the boundary groove 15, the inner wall of the boundary groove 15 has a scattering effect on the light, which can change the propagation path of the light inside the solar cell 100, increase the effective optical path of the light inside the solar cell 100, improve the absorption of long-wavelength light, and help increase the photocurrent. In other words, the groove-shaped boundary groove 15 has a certain light-trapping effect.

[0055] It is understood that the boundary groove 15 can be partially provided in the adjacent area of ​​the metallized area 13 and the non-metallized area 14. In addition to the first sidewall 151, the second sidewall 152, the middle bottom 153 and the opening 154, the boundary groove 15 further includes a third sidewall and a fourth sidewall that are arranged opposite to each other in its extension direction. The third sidewall is connected to the middle bottom 153, the first sidewall 151 and the second sidewall 152 respectively, and the fourth sidewall is connected to the middle bottom 153, the first sidewall 151 and the second sidewall 152 respectively. At this time, the opening 154 is defined by the end of the first sidewall 151 away from the middle bottom 153, the end of the second sidewall 152 away from the middle bottom 153, the end of the third sidewall away from the middle bottom 153 and the end of the fourth sidewall away from the middle bottom 153. That is, the first sidewall 151, the second sidewall 152, the third sidewall, the fourth sidewall, the middle bottom 153 and the opening 154 together form the boundary groove 15.

[0056] In this embodiment, the boundary trench 15 can be set in a part of the adjacent area of ​​the metallized region 13 and the non-metallized region 14, which can improve the flexibility of the boundary trench setting. The boundary trench 15 can be set at the stress concentration point, without having to be in a part of the adjacent area of ​​the metallized region 13 and the non-metallized region 14, thereby reducing the manufacturing difficulty of the solar cell.

[0057] In some implementations, please refer to Figure 12As shown, taking the boundary groove segment extending along the second direction in the boundary groove 15 as an example, the first sidewall 151 and the second sidewall 152 are arranged opposite to each other in the first direction. The boundary groove 15 (boundary groove segment) extends along the second direction, which is perpendicular to the first direction. The first and second directions are parallel to the first surface 11a, respectively. The boundary groove 15 meanders along the second direction on the first surface 11a. The width W1 of the boundary groove 15 in the first direction is less than or equal to 1000 μm.

[0058] like Figure 11 As shown, two of the boundary groove segments 15c in the boundary groove 15 extend along the second direction, while the other two boundary groove segments 15c can extend along the first direction. The boundary groove segments extending in other directions are... Figure 12 The structures shown are similar, and will not be described in detail here.

[0059] In some embodiments, the extension trajectory of the boundary groove segment 15c of the boundary groove 15 includes a broken line extension segment, wherein the included angle between two adjacent broken lines in the broken line extension segment is 90° to 108°.

[0060] In this embodiment, the zigzag extension section significantly increases the length of the force transmission path and uses its curved shape to guide the force flow around the stress concentration point, thereby reducing the stress peak and effectively preventing cracks from propagating in a straight line.

[0061] In some embodiments, the extension trajectory of the boundary groove segment 15c of the boundary groove 15 includes a curved extension segment, wherein the curvature of any curve in the curved extension segment is 0 to 0.001m. -1 .

[0062] In this embodiment, the curved extension section smoothly decomposes the unidirectional principal stress into multi-directional components through continuous curvature changes, achieving uniform stress distribution. The crack propagation path is forced to deflect continuously, resulting in greater energy consumption and effectively delaying crack propagation.

[0063] In some embodiments, the extension trajectory of the boundary groove segment 15c of the boundary groove 15 includes a polygonal extension segment and a curved extension segment, wherein the included angle between two adjacent polygonal lines in the polygonal extension segment is 90° to 108°, and the curvature of any curve in the curved extension segment is 0 to 0.001m. -1 .

[0064] In this embodiment, the force flow distribution is dominated by the broken line segment, and the stress transition is achieved by the curved segment. This can take into account both directional guidance and stress homogenization, which can not only effectively reduce the peak stress, but also obtain the smoothest stress distribution. Due to the relatively complex crack propagation path, it can consume crack energy to a large extent, which is beneficial to improving fatigue resistance.

[0065] As one implementation method, please refer to Figure 4 As shown, the sidewall of the junction groove 15 has a prismatic structure 150.

[0066] In this embodiment, the prismatic structure on the sidewall of the junction groove 15 can further enhance the optical light trapping effect of the junction groove 15, further enhance the scattering effect of light incident on the sidewall of the junction groove 15, change the propagation path of light inside the solar cell, increase the effective optical path of light inside the solar cell, and improve the absorption of long-wavelength light to increase the photocurrent.

[0067] Those skilled in the art will understand that if the metallized and non-metallized areas also include other protruding structures besides pyramids, the sidewalls of the junction groove 15 may also have pleated structures, multi-curved surface structures, or irregular protruding structures. The pleated structures, multi-curved surface structures, or irregular protruding structures on the sidewalls of the junction groove 15 can further enhance the optical light-trapping effect of the junction groove 15.

[0068] In some implementations, please refer to [the relevant documentation]. Figure 3 As shown, the boundary groove 15 includes a first sidewall 151 and a second sidewall 152. The metallized region 13 has a first pyramid, and the first pyramid located at the boundary is arranged on the side near the non-metallized region 14 to form the first sidewall 151 of the boundary groove 15. The non-metallized region 14 has a second pyramid, and the second pyramid located at the boundary is arranged on the side near the metallized region 13 to form the second sidewall 152 of the boundary groove 15.

[0069] Specifically, multiple first pyramids are arranged along the extension direction of the boundary groove 15 at the junction, and the sides of these multiple first pyramids near the non-metallized region 14 are continuously connected to form a first sidewall 151; multiple second pyramids are arranged along the extension direction of the boundary groove 15 at the junction, and the sides of these multiple second pyramids near the metallized region 13 are continuously connected to form a second sidewall 152; the boundary groove 15 is naturally formed by the natural enclosure of the side of the first pyramid texture structure near the non-metallized region 14 and the side of the second pyramid texture structure near the metallized region 13, that is, the boundary groove 15 is a micro-groove formed by the natural enclosure of the sides of the micro-structural units of the metallized region 13 and the non-metallized region 14, which can effectively block the lateral diffusion of photogenerated carriers, improve the collection efficiency of carriers, and reduce the recombination probability of carriers.

[0070] In related technologies, macroscopic grooves formed by laser ablation can exist on the substrate surface. The size (e.g., depth or width) of the macroscopic grooves formed by laser ablation is much larger than that of microscopic grooves. Macroscopic grooves generally extend from the texture structure to a deeper depth below. For example, macroscopic grooves can be used to accommodate at least part of the structure of an electrode. The boundary groove 15, as a microscopic groove, is fundamentally different from the macroscopic grooves in related technologies. This microscopic groove is naturally formed by the sides of the microstructural units of the metallized region 13 and the non-metallized region 14, forming a naturally smooth transition structure. The microscopic groove does not extend in the thickness direction to the substrate below the texture structure (first pyramid texture structure or second pyramid texture structure), and the formation of the microscopic groove does not cause any damage to the substrate surface.

[0071] Those skilled in the art will understand that the bottom of the junction groove 15, i.e., the middle bottom 153 of the junction groove 15, is undulating in the thickness direction of the substrate 11, and the bottoms of the junction groove 15 may not be at the same height. The undulating bottom can reduce the reflectivity of light, further increasing the light-trapping effect of the junction groove, thereby improving the conversion efficiency. For example, in the thickness direction of the substrate 11, the distance between the bottom of the junction groove 15 and the first surface 11a can be 0.5 μm to 10 μm.

[0072] Those skilled in the art will understand that in other embodiments, if the metallized area and the non-metallized area also include other protruding structures besides the pyramid, for example, the metallized area includes a first protrusion and the non-metallized area includes a second protrusion, specifically, multiple first protrusions at the junction are arranged along the extending direction of the junction groove 15, and these multiple first protrusions are continuously connected near the side of the non-metallized area 14 to jointly form a first sidewall 151; multiple second protrusions at the junction are arranged along the extending direction of the junction groove 15, and these multiple second protrusions are continuously connected near the side of the metallized area 13 to jointly form a second sidewall 152; please refer to Figure 6 As shown, the first protrusion includes at least one of a conical protrusion, a dune protrusion, a pyramidal protrusion, a spherical protrusion, or a pyramid. The side of the first protrusion near the non-metallized area 14 includes at least one of a convex curved surface, a concave curved surface, an inclined tower surface, a partially spherical surface, or a triangular tower surface.

[0073] The second protrusion includes at least one of a conical protrusion, a dune protrusion, a pyramidal protrusion, a spherical protrusion, or a pyramid, and the side of the second protrusion near the metallized area includes at least one of a convex curved surface, a concave curved surface, an inclined tower surface, a partially spherical surface, or a triangular tower surface.

[0074] In this embodiment, the texture structure in the metallized region 13 and the texture structure in the non-metallized region 14 are highly consistent. During the deposition of the passivation layer in the functional film, when the passivation layer deposition gas flows to the top of the first surface of the substrate 11, the gas flow rate can be more uniformly distributed. The passivation layer can undulate with the surface undulations of the metallized region 13 and the non-metallized region 14, thereby improving the formation quality of the passivation layer on the first surface of the substrate 11 and thus improving the passivation effect of the substrate 11.

[0075] In some embodiments, the first sidewall 151 and the second sidewall 152 intersect in a V-shape. Exemplarily, the junction groove 15 is perpendicular to its extending direction (e.g., Figure 3 The cross-section shown (in the second direction) is V-shaped.

[0076] In some embodiments, the junction groove 15 is perpendicular to its extending direction (e.g., Figure 3 The cross-section of the groove 15 (shown in the second direction) is V-shaped, U-shaped, asymmetrical V-shaped, or asymmetrical U-shaped. Specifically, the bottom of the first sidewall 151 and the bottom of the second sidewall 152 of the V-shaped or asymmetrical V-shaped junction groove 15 are directly connected, and the middle bottom 153 is formed by the intersection of the first sidewall 151 and the second sidewall 152.

[0077] In this embodiment, the V-shaped or asymmetrical V-shaped junction groove 15 can further enhance the light trapping effect, especially for oblique light with a large angle.

[0078] In some embodiments, the cross-section of the junction groove 15 perpendicular to its extension direction is U-shaped or asymmetrical U-shaped.

[0079] In this embodiment, the U-shaped or asymmetrical U-shaped junction groove 15 makes it easier to achieve continuous, uniform, and pore-free coverage of the subsequently deposited passivation layer and antireflection film.

[0080] In some embodiments, on a cross section of the junction groove 15 perpendicular to its extension direction, the included angle between the first sidewall 151 and the second sidewall 152 is greater than or equal to 30° and less than 180°.

[0081] In this embodiment, the first sidewall 151 and the second sidewall 152 each have a certain inclination angle, which can effectively scatter and reflect light. For example, long-wavelength light from the non-metallized region 14 can be guided to the metallized region 13, enhancing the light-trapping effect. Controlling the included angle between the first sidewall 151 and the second sidewall 152 within the above-mentioned range, avoiding an excessively large or small angle, can effectively disperse stress, prevent stress concentration, and improve crack resistance; the inclined sidewalls provide multiple reflection opportunities, enhancing light absorption.

[0082] As one possible implementation method, please refer to [link / reference]. Figure 2 As shown, along the thickness direction of the base 11, the depth of the junction groove 15 is greater than the average recess depth between two adjacent first pyramids or the average recess depth between two adjacent second pyramids. For details, please refer to... Figure 2 As shown, along the thickness direction of the base 11, the depth of the depression between two adjacent first pyramids is H1, the depth of the depression between two adjacent second pyramids is H2, and the depth of the junction groove 15 is H3.

[0083] For example, such as Figure 2 As shown, the depth H3 of the interface groove 15 is 0.5μm to 8μm; for example, as... Figure 2 As shown, on the cross-section of the corresponding boundary groove segment perpendicular to its extension direction, the width H4 of the boundary groove 15 is 0.1μm to 5μm. Specifically, on the cross-section of the corresponding boundary groove segment perpendicular to its extension direction, the first sidewall 151 has a first top K1 and the second sidewall 152 has a second top K2. The width H4 of the boundary groove 15 is the distance between the projection of the first top K1 along the thickness direction onto the first surface 11a and the projection of the second top K2 along the thickness direction onto the first surface 11a.

[0084] Please see Figure 8 and Figure 9 As shown, the heights of the metallized region 13 and the non-metallized region 14 are different along the thickness direction of the substrate 11. For example, the top height of the metallized region 13 and the top height of the non-metallized region 14 are different along the thickness direction of the substrate 11, or the top height of the metallized region 13 and the top height of the non-metallized region 14 are different, and the bottom height of the metallized region 13 and the bottom height of the non-metallized region 14 are different.

[0085] In this embodiment, due to the height difference between the metallized and non-metallized regions, the lateral diffusion of photogenerated carriers is suppressed before they are collected, and they tend to be rapidly extracted by the longitudinal electric field, thus reducing lateral recombination.

[0086] For example, in the thickness direction of the substrate 11, the thickness of the metallized region 13 is 0.5 μm to 10 μm, and the thickness of the non-metallized region 14 is 0.5 μm to 10 μm.

[0087] In some embodiments, the height of the first pyramid is greater than the height of the second pyramid in the thickness direction of the base 11. Specifically, in the thickness direction of the base 11, the bottom of the metallized region 13 and the bottom of the non-metallized region 14 may be at the same height, and the height difference between the metallized region 13 and the non-metallized region 14 is due to the difference in height between the first pyramid and the second pyramid.

[0088] In this embodiment, photons incident on the lower second pyramid are more easily guided to the adjacent higher first pyramid after being scattered or reflected by its surface and the sidewalls of the junction slot, thus improving the effective utilization rate of photons.

[0089] In some implementations, please refer to Figure 9 As shown, in the thickness direction of the substrate 11, the bottom of the metallized region 13 is higher than the bottom of the non-metallized region 14.

[0090] In this embodiment, because the bottom of the non-metallized region 14 is lower, it is constructed as a recessed region surrounded by the raised metallized region 13. Light incident or reflected into the non-metallized region 14, as it extends upwards or laterally, is highly likely to be reflected or scattered by the first sidewall 151 formed by the first pyramid. This increases the chance of the light contacting the metallized region 13 before escaping, enhancing the light-trapping effect of the non-metallized region 14, especially effectively capturing large-angle incident light and long-wavelength light, significantly improving the short-circuit current. On the other hand, the lower bottom of the non-metallized region 14 effectively blocks the lateral diffusion path of photogenerated carriers from the metallized region 13 to the non-metallized region 14. Photogenerated carriers are physically held within the higher metallized region 13 and can only be efficiently collected by the vertical PN junction electric field, greatly reducing surface recombination. In this embodiment, please refer to... Figure 7 As shown, the first pyramid at the junction has at least one first side 1511 near the non-metallized area 14, and the second pyramid at the junction has at least one second side 1521 near the metallized area 13. The first sidewall 151 of the junction groove 15 is formed by the first sidewall 1511 of the first pyramid at the junction in sequence, and the second sidewall 152 of the junction groove 15 is formed by the second sidewall 1521 of the second pyramid at the junction in sequence.

[0091] In some implementations, please refer to Figure 6 As shown in (f), a first pyramid and a functional membrane layer covering the first pyramid form a first composite protrusion, and a second pyramid and a functional membrane layer covering the second pyramid form a second composite protrusion. Exemplarily, the first composite protrusion includes at least one of a conical protrusion, a dune-like protrusion, a pyramid-like protrusion, or a spherical protrusion, and the second composite protrusion includes at least one of a conical protrusion, a dune-like protrusion, a pyramid-like protrusion, or a spherical protrusion. For example, please refer to [link to example]. Figure 6 As shown in (f), the first composite protrusion includes a first pyramid 1321 and a functional membrane layer 1322 covering the outside of the first pyramid 1321. The coverage of the functional membrane layer 1322 makes the first composite protrusion more rounded than the first pyramid 1321.

[0092] In some embodiments, the height of the first pyramid is 0.5–10 μm, and the height of the second pyramid is 0.5–10 μm. Further, the height of the first pyramid is 0.5–5 μm, and the height of the second pyramid is 0.5–5 μm.

[0093] In this embodiment, controlling the height dimensions of the first pyramid and the second pyramid within the aforementioned ranges helps to balance the light-trapping effect of the metallized and non-metallized regions, making it easier for light to be guided to the metallized region. Furthermore, controlling the height dimensions of the first pyramid and the second pyramid within the aforementioned ranges improves the dimensional uniformity of the texture structure in different regions on the first surface of the substrate 11. This improves the formation quality of the passivation layer on the first surface of the substrate 11, enhances the morphological consistency of the passivation layer on the first surface of the substrate 11, and ultimately improves the passivation effect of the passivation layer.

[0094] In some embodiments, the apex of the first pyramid is higher than the apex of the second pyramid in the thickness direction of the substrate 11. Specifically, in the thickness direction of the substrate 11, the bottom of the metallized region 13 and the bottom of the non-metallized region 14 may be at the same height, and the height difference between the metallized region 13 and the non-metallized region 14 is due to the difference in height between the first pyramid and the second pyramid. For example, the height difference between the apex of the first pyramid and the apex of the second pyramid is 0.1 nm to 10 μm.

[0095] In this embodiment, the non-metallized region and the metallized region are not only separated by a meandering boundary groove on the plane, but also form a clear height difference in the vertical direction. The boundary groove and its sidewalls are naturally spliced ​​together by the sides of two pyramids of different heights. The boundary groove also serves as a light guiding structure and a photogenerated carrier boundary groove.

[0096] In some implementations, please refer to Figure 7 As shown, the side length of the first side edge 1512 of the first pyramid near the non-metallized zone 14 is greater than the side length of the second side edge 1522 of the second pyramid near the metallized zone 13.

[0097] In this embodiment, the first sidewall 151 of the junction groove 15 has a relatively wider slope than the second sidewall 152, which can efficiently reflect light scattered from the non-metallized region or emitted from itself back to the depth of the metallized region or reflect it to the non-metallized region at a smaller angle, thereby increasing the optical path.

[0098] In some embodiments, the side length of the first lateral edge of the first pyramid near the non-metallized region 14 is 1.64 μm to 3.44 μm.

[0099] In some implementations, such as Figure 7As shown, the first side edge 1512 of the first pyramid near the non-metallized zone 14 is parallel to the third side edge 1523 of the second pyramid facing away from the metallized zone 13.

[0100] In this embodiment, the side edges of the first and second pyramids facing the same side are parallel. The relatively orderly arrangement allows light to be reflected multiple times and in a coordinated manner in the metallized area, non-metallized area and the junction groove, rather than being scattered randomly. This improves the efficiency of guiding light from the non-metallized area to the metallized area, reduces photon escape, and achieves a high light trapping efficiency.

[0101] In some implementations, such as Figure 10 As shown, the ratio of the length L1 of the metallized region 13 along the first direction to the length L2 of the non-metallized region 14 along the first direction is 0.3 to 3. Exemplarily, the first direction can be parallel to the extension direction of the main gate line, and the second direction can be perpendicular to the extension direction of the main gate line.

[0102] In this embodiment, by controlling the ratio of the lengths of the metallized region 13 and the non-metallized region 14 along the first direction within the above-mentioned range, the area of ​​the metallized region 13 and the non-metallized region can be precisely controlled, which is beneficial to balancing the area ratio of different functional regions on the surface of the solar cell.

[0103] In related technologies, if the metallized region 13 and the non-metallized region 14 are disposed on at least one side connecting the first surface 11a and the second surface 11b, the contribution of the multi-textured region arrangement on the side to the overall light absorption is limited because the side is not directly exposed to light. Furthermore, since the side is not a major carrier generation and collection area, the effect of multi-textured zoning on optimizing photoelectric conversion efficiency is limited. Achieving uniform and controllable texture processing on steep sides would increase the difficulty of the process and even lead to defects. Therefore, disposing the metallized region 13 and the non-metallized region 14 on the side cannot reduce the recombination rate, optimize the light trapping effect, or improve the stress effect.

[0104] For example, during the fabrication of the solar cell 100, the first surface 11a of the substrate 11 can be texturized to form a metallization region 13 on the first surface 11a of the substrate 11; the first surface 11a of the substrate 11 can be doped to form an initial emitter layer, and the positions of each non-metallization region 14 on the first surface 11a of the substrate 11 are the initial non-metallization regions; then, each initial non-metallization region on the first surface 11a of the substrate 11 is irradiated with a laser, and then each initial non-metallization region after laser irradiation is subjected to alkaline etching, the initial emitter layer on the initial non-metallization region is destroyed, and a recessed structure is formed in the initial non-metallization region through laser irradiation and alkaline etching, and at least a portion of the thickness of the initial emitter layer of the initial non-metallization region is removed; subsequently, the initial non-metallization region is texturized to form the non-metallization region 14. The thickness of the initial emitter layer in the initial non-metallized region damaged by laser irradiation varies, which leads to different doping concentrations of the second conductivity type element in the non-metallized region. The greater the thickness of the initial emitter layer in the initial non-metallized region, the lower the doping concentration of the second conductivity type element in the non-metallized region. If the initial emitter layer in the initial non-metallized region is completely destroyed, then the non-metallized region has no emitter.

[0105] In some embodiments, the ratio of the area of ​​the non-metallized region 14 to the area of ​​the metallized region 13 is 0.2 to 5.

[0106] In this embodiment, by controlling the ratio of the area of ​​the non-metallized region 14 to the area of ​​the metallized region 13 within the above-mentioned range, the area of ​​the metallized region 13 and the non-metallized region can be precisely controlled, which is beneficial to balancing the area ratio of different functional regions on the surface of the solar cell.

[0107] In some embodiments, the metallization region 13 includes an electrode contact region and a non-electrode contact region.

[0108] In this embodiment, the electrode contact area is the area where the electrode is located. The electrode contact area subsequently comes into contact with and is covered by the electrode, while the non-electrode contact area is not covered by the electrode.

[0109] In some implementations, the area ratio of the electrode contact area to the metallized area is greater than or equal to 30%.

[0110] In this embodiment, by controlling the area ratio of the electrode contact region within the above-mentioned range, the problem of a sharp increase in contact resistance and semiconductor lateral transport resistance below the electrode caused by the current being concentrated in a few channels due to the electrode contact area being too small can be avoided. This is beneficial for balancing the fill factor and overall efficiency of the solar cell.

[0111] Specifically, the non-metallization region has no second conductivity type doping or has very shallow second conductivity type doping, and the lateral and longitudinal electric field gradients formed by the local PN junction are more reasonable. This can quickly "pull" the charge carriers generated in the non-electrode contact region of the metallization region 13 to the electrode contact region of the metallization region 13, reduce the recombination of charge carriers during the transport process, and further improve the stability of the fill factor (FF) and open circuit voltage (Voc).

[0112] In some implementations, the density of the first pyramid differs from the density of the second pyramid. For example, the density of the first pyramid is 360,000 pyramids / mm². 2 Up to 500,000 pieces / mm 2 The density of the second pyramid is 300,000 / mm². 2 Up to 350,000 pieces / mm 2 .

[0113] In this embodiment, the densities of the first pyramid and the second pyramid are different. Specifically, the number of first pyramids per unit area in the metallized region is a first quantity, and the number of second pyramids per unit area in the non-metallized region is a second quantity. This difference in density between the first and second pyramids results in different roughnesses in the metallized region 13 and the non-metallized region 14. This allows the metallized region 13 and the non-metallized region 14 to have different light-trapping effects, thus balancing the light-trapping effect of the first surface of the substrate 11 with the quality of the functional film layer. For example, the density of the first pyramid is greater than that of the second pyramid, and the roughness of the metallized region 13 is less than that of the non-metallized region 14. The metallized region 13 can provide a smoother substrate for the passivation layer (such as alumina or silicon nitride), ensuring its uniform and continuous coverage and achieving excellent surface passivation. The non-metallized region 14 can extend the light propagation path within the battery through stronger light scattering, increasing the probability of photogenerated carrier generation and thus significantly improving the short-circuit current of the battery.

[0114] In some implementations, the boundary groove 15 extends discontinuously along its extension trajectory.

[0115] Specifically, such as Figure 11 As shown, the extension trajectory of the interface groove 15 can conform to the outer contour of the non-metallized region 14. (See also...) Figure 12 As shown, the boundary groove segment 15c of the boundary groove 15 may be discontinuous in at least a partial region. The extension trajectory of the boundary groove segment 15c of the boundary groove 15 is broken at the discontinuity T. Specifically, the boundary groove segment 15c may include at least two extension segments 15d, and two adjacent extension segments 15d are separated by a discontinuity T, for example, Figure 12The two spaced extension segments 15d shown are separated by a discontinuity T. In the discontinuous area of ​​the junction groove 15, there is no clear boundary between the metallized area 13 and the non-metallized area 14; in this way, the manufacturing difficulty of the non-metallized area can be reduced.

[0116] In some implementations, such as Figure 12 As shown, the metallized region 13 has at least one first line groove 16.

[0117] In this embodiment, the light-trapping effect of the metallized region 13 can be further enhanced by setting the first line groove.

[0118] In some implementations, such as Figure 12 As shown, the non-metallized region 14 has at least one first line groove 16.

[0119] In this embodiment, the light-trapping effect of the non-metallized region 14 can be further enhanced by the provision of the first line groove. For example, the first line groove 16 can extend in a meandering manner, and the extension contour of the first line groove 16 can be approximately straight.

[0120] In some embodiments, the extension direction of the first line groove 16 is not parallel to the extension direction of any boundary groove segment of the boundary groove 15.

[0121] Specifically, such as Figure 12 As shown, the first line groove 16 on the metallized region 13 is not parallel to the boundary groove segment 15c, and the first line groove 16 on the non-metallized region 14 is not parallel to the boundary groove segment 15c. Exemplarily, the extending directions of the different first line grooves 16 can be approximately the same, for example... Figure 12 In the metallized region 13, the extension directions of different first line grooves 16 can be approximately the same, and the extension directions of different first line grooves 16 in the non-metallized region 14 can be approximately the same. The extension directions of the first line grooves 16 in the metallized region 13 and the extension directions of the first line grooves 16 in the non-metallized region 14 can be approximately the same.

[0122] In some embodiments, the depth of the first line groove 16 is less than the depth of the junction groove 15. The top width of the first line groove 16 is less than the top width of the junction groove 15.

[0123] In this embodiment, the function of the first line groove 16 is to enhance the light trapping effect, and the first line groove 16 does not separate the metallized area 13 or the non-metallized area 14.

[0124] In some embodiments, the first surface 11a and the second surface 11b are the front surface and the rear surface, respectively.

[0125] Specifically, the first surface 11a is the front surface, an emitter is provided below the metallized region 13, and there is no emitter below the non-metallized region 14. The metallized region 13 and the non-metallized region 14 each have a certain light trapping effect. The emitter region below the metallized region 13 can form photogenerated carriers through the photoelectric effect.

[0126] In some implementations, the emitterless region below the non-metallized region 14 is a PN junctionless region.

[0127] In this embodiment, carrier recombination is minimized in the non-metallized region through the absence of a PN junction and effective surface passivation.

[0128] In some implementations, the emitterless region below the non-metallized region 14 has a residual PN junction.

[0129] In this embodiment, a residual PN junction may be present below the non-metallized region 14. This residual PN junction cannot generate a photoelectric effect, which can reduce the manufacturing difficulty of the non-metallized region 14.

[0130] In some embodiments, the solar cell 100 may be a PERC cell (Passivated Emitter RearCell), an IBC cell (Interdigitated Back Contact), a TOPCon cell (Tunnel Oxide Passivated Contact), or a HIT / HJT cell (Heterojunction Technology).

[0131] For example, taking a TOPCon cell as an example, the structure of the solar cell 100 will be described in detail. Please refer to [link to relevant documentation]. Figure 13 As shown, the direction from the first surface 11a to the second surface 11b is defined as the third direction. The solar cell 100 includes a substrate 11, a first passivation layer 12 and a first antireflection layer 17 sequentially stacked on the first surface 11a along the direction away from the third direction, and a first electrode 181. The first electrode 181 is correspondingly disposed in the metallization region 13. The first electrode 181 sequentially passes through the first surface 11a, the first passivation layer 12 and the first antireflection layer 17 along the direction away from the third direction. The solar cell 100 also includes a tunneling oxide layer 191, a doped polycrystalline silicon layer 192, a back passivation layer 193 and a second antireflection layer 194 sequentially stacked on the second surface 11b along the third direction, and a second electrode 182. The second electrode 182 is disposed in the direction corresponding to the metallization region 13 along the third direction and sequentially passes through the doped polycrystalline silicon layer 192, the back passivation layer 193 and the second antireflection layer 194.

[0132] The first surface 11a of the substrate 11 is a positive surface. The first surface 11a of the substrate 11 includes a metallized region 13 and a non-metallized region 14. The emitter 131 is located below the metallized region 13, and there may be no emitter below the non-metallized region 14. A first passivation layer 12 covers the metallized region 13 and the non-metallized region 14. A first antireflection layer 17 covers the first passivation layer 12. A first electrode 181 is disposed in the region where the metallized region 13 is located. The first electrode 181 extends through the first antireflection layer 17 and the first passivation layer 12 in the thickness direction of the substrate 11 to the emitter 131 below the metallized region 13. The first electrode 181 is connected to the emitter 131.

[0133] The second surface 11b of the substrate 11 is the back surface. In the thickness direction of the substrate 11, along the direction from the first surface 11a to the second surface 11b, a tunneling oxide layer 191, a doped polysilicon layer 192, a back passivation layer 193, and a second antireflection layer 194 are sequentially deposited on the second surface 11b. The second electrode 182 is disposed in the region corresponding to the metallization region 13. In the thickness direction of the substrate 11, the second electrode 182 extends through the second antireflection layer 194 and the back passivation layer 193 to the doped polysilicon layer 192 along the direction from the second surface 11b to the first surface 11a. The second electrode 182 is connected to the doped polysilicon layer 192.

[0134] In some embodiments, the substrate 11 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0135] In some embodiments, the solar cell can be a single-sided cell, with the front surface (first surface 11a) serving as the light-receiving surface for receiving incident light and the back surface (second surface 11b) serving as the back-lighting surface.

[0136] In some embodiments, the solar cell can be a bifacial cell, meaning that both the first surface 11a and the second surface 11b of the substrate 11 can serve as light-receiving surfaces and can be used to receive incident light. The back surface (second surface 11b) can also receive incident light, but its efficiency in receiving incident light is somewhat lower than that of the light-receiving surface (first surface 11a).

[0137] In some embodiments, the emitter 131 may be formed by doping the original substrate 11. The emitter 131 and the substrate 11 are made of the same base material. Specifically, a portion of the original substrate corresponding to the metallization region 13 may be doped. The doped original substrate serves as the emitter 131, and the undoped original substrate serves as the substrate 11. Furthermore, the doping element type in the emitter 131 is different from the doping element type in the substrate 11. For example, if the substrate 11 is an N-type silicon substrate, the emitter 131 is formed by P-type doping of a portion of the N-type silicon substrate.

[0138] In some embodiments, the first passivation layer 12 can be a single-layer structure or a stacked structure, and the material used to prepare the first passivation layer 12 can be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0139] In some embodiments, the material used to prepare the first antireflection layer 17 may be one or more of silicon nitride or silicon oxynitride.

[0140] In some embodiments, the tunneling oxide layer 191 may be a silicon dioxide layer.

[0141] In some embodiments, the doping type of the doped polysilicon layer 192 is the same as the doping type of the substrate 11. For example, if the substrate 11 is doped with an N-type dopant, then the doped polysilicon layer 192 is doped with an N-type dopant. The tunneling oxide layer 191 and the doped polysilicon layer 192 together form a passivation contact structure.

[0142] In some embodiments, the back passivation layer 193 can be a single-layer structure or a stacked structure, and the material used to prepare the back passivation layer 193 can be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0143] In some embodiments, the material used to prepare the second antireflection layer 194 can be one or more of silicon nitride or silicon oxynitride.

[0144] In some embodiments, the first electrode 181 and the second electrode 182 have opposite polarities.

[0145] One embodiment of this application provides a stacked battery, which includes a top battery, an intermediate connecting layer and a bottom battery, wherein the intermediate connecting layer is connected between the top battery and the bottom battery.

[0146] The top cell is one of a perovskite cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or a gallium arsenide solar cell, and the bottom cell is the aforementioned solar cell 100.

[0147] In some implementations, the interlayer can be a transparent material with a high refractive index. To reduce light reflection and absorption at the interlayer interface and achieve good conductivity to minimize the impact of series resistance on device performance, the interlayer typically needs to have high light transmittance. For example, the interlayer can be a transparent conductive metal oxide thin film (ITO).

[0148] One embodiment of this application provides a photovoltaic module 200. Please refer to [link / reference]. Figure 14 and Figure 15 As shown, it includes a battery string 201, an encapsulating film 202, and a cover plate 203. Please refer to [the provided text]. Figure 14 As shown, the battery string 201 is formed by connecting multiple solar cells 100 as described above, or the battery string 201 is formed by connecting multiple stacked cells as described above; the encapsulating film 202 is used to cover the surface of the battery string 201; the cover plate 203 is used to cover the surface of the encapsulating film 202 away from the surface of the battery string 201.

[0149] In some embodiments, multiple solar cells 100 can be electrically connected to each other by solder strips 20, which are connected to each pair of adjacent solar cells 100. The solder strips 20 are connected to the front surface of the first solar cell 100 and the back surface of the second solar cell 100, respectively.

[0150] In some embodiments, the solar cells 100 may be spaced apart, and during string bonding, the solder strip 20 extends from the front surface of the first solar cell 100 to the gap, passes through the gap, and extends to the back surface of the second solar cell 100.

[0151] In some embodiments, no gap is provided between the solar cells 100, that is, two adjacent solar cells 100 overlap each other.

[0152] In some embodiments, the encapsulating film 202 includes a first encapsulating film and a second encapsulating film. The first encapsulating film covers one of the front or back sides of the solar cell 100, and the second encapsulating film covers the other of the front or back sides of the solar cell 100. Specifically, at least one of the first or second encapsulating film can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film.

[0153] Example 1 The structure of the solar cell in this embodiment 1 is as follows: Figure 11 and Figure 13As shown, the method for fabricating the solar cell in Example 1 includes the following steps: Step 1-1: Provide a texturized N-type silicon wafer. The front surface of the N-type silicon wafer has a first pyramid with an average size of 2μm to 5μm, an average height of 1.2μm to 2.8μm, and a density of 300,000 pyramids / mm². 2 Up to 500,000 pieces / mm 2 .

[0154] Steps 1-2 involve boron diffusion doping of the N-type silicon wafer to form an initial doped layer on the positive surface. The sheet resistance of the positive surface after boron diffusion doping is... .

[0155] Steps 1-3 involve using a laser to perform laser-induced film removal on the non-metallized region of the boron-diffused N-type silicon wafer's positive surface. This process removes at least a portion of the initial doped layer from the non-metallized region, yielding a first intermediate solar cell. The laser used is a picosecond ultraviolet laser (wavelength 266nm to 355nm, spot diameter 60μm to 500μm, frequency 600kHz, scanning speed 50m / s to 60m / s, single-pulse energy 1J / s). Up to 10J / ).

[0156] Steps 1-4 involve alkaline etching of the first solar cell intermediate with an alkaline etching solution to remove at least a portion of the initial doped layer thickness in the non-metallized regions, followed by secondary texturing of the non-laser-etched regions to form a second textured surface in the non-metallized regions, resulting in the second solar cell intermediate. The alkaline etching solution comprises an alkaline solution and an alkaline polishing additive; the alkaline solution is either NaOH or KOH solution. The second textured surface includes second pyramids with an average size of 2 μm to 5 μm, an average height of 1.2 μm to 2.8 μm, and a density of 300,000 pyramids / mm². 2 Up to 500,000 pieces / mm 2 .

[0157] Steps 1-5 involve oxidizing the second solar cell intermediate to oxidize the initial doped layer of at least a portion of the thickness of the metallized region on the front surface to form a first oxide layer and to form a second oxide layer of at least a portion of the thickness of the non-metallized region. The first oxide layer is borosilicate glass with a thickness of 60 nm to 150 nm, and the second oxide layer is also borosilicate glass with a thickness of 60 nm to 120 nm. Simultaneously, a third oxide layer is formed on the back surface, also made of borosilicate glass with a thickness of 60 nm to 150 nm. During the oxidation process of the second solar cell intermediate, the PN junction of the metallized region is advanced. After oxidation, the depth of the PN junction in the metallized region is 0.3 μm to 1.5 μm, and the surface concentration of boron in the metallized region is 4E17. Up to 9E18 .

[0158] Steps 1-6: Use hydrogen fluoride (HF) to remove the borosilicate glass from the back surface of the second cell intermediate. Then, polish the back surface of the second cell intermediate to expose a clean, flat, and parasitic-free N-type single-crystal silicon surface. The size of the tower base after back surface etching is 6μm to 18μm.

[0159] Steps 1-7: A tunneling oxide layer and a polycrystalline silicon layer are sequentially formed on the back surface of the second solar cell intermediate. The polycrystalline silicon layer is then phosphorus-doped to obtain a phosphorus-doped polycrystalline silicon layer (Poly). The thickness of the tunneling oxide layer is 1.2 nm to 2.2 nm, the thickness of the phosphorus-doped polycrystalline silicon layer (Poly) is 60 nm to 180 nm, and the phosphorus doping surface concentration is 1E20. up to 9E20 During this process, a portion of the phosphorus-doped polycrystalline silicon layer forms a fourth oxide layer, which is a phosphorus-silicon glass with a thickness ranging from 16 nm to 40 nm.

[0160] Steps 1-8: Use acid to remove the first and second oxide layers on the front surface, then use alkaline etching to remove the polycrystalline silicon layer plated around the front surface, and then use acid to remove the fourth oxide layer on the back surface and the remaining oxide layer on the front surface.

[0161] Steps 1-9 involve passivating the second battery cell intermediate to form passivation layers on the front and back surfaces, and then forming an anti-reflection layer covering the passivation layers to obtain the battery cell.

[0162] Steps 1-10: Print and sinter the first electrode on the front surface of the solar cell to form a first electrode, and print and sinter the second electrode on the back surface of the solar cell to form a second electrode, thus obtaining a solar cell.

[0163] The solar cell prepared in Example 1 has a metallized region and a non-metallized region with the following characteristics: Figures 2 to 4 The shown interface trench has a metallized region to non-metallized region area ratio of 0.8, and the boron doping concentration of the non-metallized region is 4E17. .

[0164] Example 2 The structure of the solar cell in Example 2 is basically the same as that in Example 1, except that the boron doping concentration in the non-metallization region of the solar cell in Example 2 is 2E17. .

[0165] Example 3 The structure of the solar cell in Example 3 is basically the same as that in Example 1, except that the boron doping concentration in the non-metallized region of the solar cell in Example 3 is 1E17. .

[0166] Example 4 The structure of the solar cell in Example 4 is basically the same as that in Example 1, except that the non-metallized region of the solar cell in Example 4 has no emitter, that is, the boron doping concentration in the non-metallized region is below the detection limit.

[0167] Accordingly, in steps 1-5 of Example 4, the second battery cell intermediate is oxidized to form a first oxide layer at least a portion of the thickness of the initial doped layer in the metallized region of the front surface, and a second oxide layer at least a portion of the thickness in the non-metallized region. The first oxide layer is borosilicate glass with a thickness of 60 nm to 150 nm, and the second oxide layer is a silicon oxide layer with a thickness of 60 nm to 120 nm. Simultaneously, a third oxide layer is formed on the back surface. The third oxide layer is borosilicate glass with a thickness of 60 nm to 150 nm. During the oxidation process of the second battery cell intermediate, the PN junction in the metallized region is advanced. After oxidation, the depth of the PN junction in the metallized region is 0.3 μm to 1.5 μm, and the surface concentration of boron in the metallized region is 4E17. Up to 9E18 .

[0168] Example 5 The structure of the solar cell in Example 5 is basically the same as that in Example 1, except that the area ratio of the metallized region to the non-metallized region in the solar cell of Example 5 is 0.2.

[0169] Example 6 The structure of the solar cell in Example 6 is basically the same as that in Example 1, except that the area ratio of the metallized region to the non-metallized region in the solar cell of Example 6 is 0.5.

[0170] Example 7 The structure of the solar cell in Example 7 is basically the same as that in Example 1, except that the area ratio of the metallized region to the non-metallized region in the solar cell of Example 7 is 1.

[0171] Example 8 The structure of the solar cell in Example 8 is basically the same as that in Example 1, except that the area ratio of the metallized region to the non-metallized region in the solar cell of Example 8 is 2.5.

[0172] Example 9 The structure of the solar cell in Example 9 is basically the same as that in Example 1, except that the area ratio of the metallized region to the non-metallized region in the solar cell of Example 9 is 5.

[0173] Example 10 The structure of the solar cell in Example 10 is basically the same as that in Example 1, except that the density of the first pyramid in the solar cell of Example 10 is 360,000 / mm². 2 Up to 500,000 pieces / mm 2 The density of the second pyramid is 300,000 / mm². 2 Up to 350,000 pieces / mm 2 .

[0174] Comparative Example 1 The structure of the solar cell in Comparative Example 1 is basically the same as that in Example 1, except that the solar cell in Comparative Example 1 does not have a junction groove, and there is no clear boundary between the metallized region and the non-metallized region in Comparative Example 1.

[0175] Comparative Example 2 The structure of the solar cell in Comparative Example 2 is basically the same as that in Example 1, except that: the solar cell in Comparative Example 2 does not have a junction groove, and the metallized region and non-metallized region of Comparative Example 2 have a junction groove. Figure 16 The diagram shows a sloping structure with a pyramid on it.

[0176] Performance testing The solar cells of Examples 1 to 9 and Comparative Examples 1 to 2 were subjected to performance comparison tests. The test conditions were as follows: using a pulsed solar simulator, under an ambient temperature of 25°C, AM1.5 atmospheric mass, and a solar irradiance of 1000 W / m², the electrical performance parameters of the cells, including photoelectric conversion efficiency (Eta), fill factor (FF), open-circuit voltage (Voc), and short-circuit current (Isc), were measured. The results are shown in Table 1. Table 1. Performance Test Comparison Table of Examples and Comparative Examples The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0177] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0178] The above embodiments merely illustrate preferred implementations of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A solar cell, characterized in that, include: A substrate having a first surface and a second surface disposed opposite to each other along the thickness direction; the first surface and the second surface are a front surface and a rear surface, respectively. A texture structure is provided on the first surface of the substrate. The texture structure includes a metallized area and a plurality of non-metallized areas. The non-metallized areas are polygonal. The plurality of non-metallized areas are arranged in an array on the first surface. The metallized areas surround the non-metallized areas. The metallized areas have a first pyramid texture structure. The non-metallized areas have a second pyramid texture structure. A boundary groove is provided between the non-metallized area and the metallized area. The boundary groove is in the shape of a polygonal ring and is arranged around the boundary between the metallized area and the non-metallized area. At the boundary between the non-metallized area and the metallized area, the first pyramid texture structure near the side of the second pyramid texture structure forms the first sidewall of the boundary groove, and the second pyramid texture structure near the side of the first pyramid texture structure forms the second sidewall of the boundary groove. The first sidewall and the second sidewall intersect in a V-shape. The boundary groove includes multiple boundary groove segments, each of which extends meanderingly in its extension direction.

2. The solar cell as described in claim 1, characterized in that, Multiple non-metallized regions are divided into several non-metallized region units. Each non-metallized region unit includes several non-metallized regions arranged in a uniformly spaced manner along a first direction. The several non-metallized region units are arranged in a uniformly spaced manner along a second direction. The first direction is perpendicular to the second direction, and the first direction and the second direction are parallel to the first surface, respectively.

3. The solar cell as described in claim 2, characterized in that, The ratio of the length of the metallized region along the first direction to the length of the non-metallized region along the first direction is 0.3 to 3.

4. The solar cell as described in claim 2, characterized in that, The ratio of the area of ​​the non-metallized region to the area of ​​the metallized region is 0.2 to 5.

5. The solar cell as described in claim 1, characterized in that, The metallized region includes the electrode contact region and the non-electrode contact region.

6. The solar cell as described in claim 5, characterized in that, The area ratio of the electrode contact area to the metallized area is greater than or equal to 30%.

7. The solar cell according to claim 1, characterized in that, The boundary groove includes multiple boundary groove segments. In the cross section of each boundary groove segment perpendicular to its extension direction, the included angle between the first sidewall and the second sidewall is greater than or equal to 30° and less than 180°.

8. The solar cell as claimed in claim 1, characterized in that, The boundary trench section includes at least two extension sections, with adjacent extension sections spaced apart.

9. The solar cell according to claim 1, characterized in that, The first pyramid texture structure includes multiple first pyramids, and the second pyramid texture structure includes multiple second pyramids, wherein the density of the first pyramids is greater than the density of the second pyramids.

10. A stacked battery, characterized in that, include: Top cell, which can be a perovskite cell, cadmium telluride solar cell, copper indium gallium selenide solar cell, or gallium arsenide solar cell; Intermediate connection layer; and The base cell is the solar cell according to any one of claims 1 to 9; The top battery, the intermediate connecting layer, and the bottom battery are stacked and connected.

11. A photovoltaic module, characterized in that, Includes the solar cell according to any one of claims 1 to 9, or the tandem cell according to claim 10.

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