Solar cell, sliced cell, laminated cell, and photovoltaic module

Abstract

This invention provides a solar cell, a sliced ​​solar cell, a tandem solar cell, and a photovoltaic module. The solar cell provided by this invention includes a substrate and a passivation layer covering the substrate. The substrate has a first surface and a second surface disposed opposite to each other in the thickness direction. The first surface has alternately arranged grooved regions and textured regions. The second surface includes alternately arranged recessed regions and flat regions. The orthographic projection of the recessed regions onto the substrate falls within the orthographic projection range of the grooved regions onto the substrate. Each grooved region has a plurality of first light-trapping structures, the bottom edges of which are interconnected to form undulating hill-like protrusions. Each recessed region also has a plurality of second light-trapping structures, the average bottom diameter of the first light-trapping structures being greater than or equal to the average bottom diameter of the second light-trapping structures. The solar cell of this invention can improve the mechanical strength of the cell and increase its conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to a solar cell, a sliced ​​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, pre-cut grooves are designed for solar cells to facilitate their cutting. However, existing pre-cut grooves result in lower mechanical strength of the cells and are not conducive to improving conversion efficiency. Summary of the Invention

[0004] Based on this, the present invention provides a solar cell, a sliced ​​cell, a tandem cell, and a photovoltaic module to solve the technical problems of low mechanical strength of the cell and the inability to improve conversion efficiency in the prior art.

[0005] In a first aspect, embodiments of this application provide a solar cell, including a substrate and a passivation layer covering the substrate. The substrate has a first surface and a second surface disposed opposite to each other in the thickness direction. The first surface has alternating groove regions and textured regions, and the second surface includes alternating recessed regions and flat regions. The orthographic projection of the recessed region on the substrate falls within the orthographic projection range of the groove region on the substrate. The groove area has a plurality of first light-trapping structures, which are non-pyramid structures, and the bottom edges of the plurality of first light-trapping structures are connected to each other to form a continuous, undulating hill-like protrusion. The recessed area has a plurality of second light-trapping structures, the second light-trapping structures are non-pyramid structures, and the average bottom diameter of the first light-trapping structure is greater than or equal to the average bottom diameter of the second light-trapping structure.

[0006] Secondly, embodiments of this application provide a sliced ​​battery, including a stepped structure formed by cutting the groove region of the solar cell described above.

[0007] Thirdly, embodiments of this application provide a stacked battery, the stacked battery including a top battery, an intermediate connecting layer and a bottom battery, the intermediate connecting layer being connected between the top battery and the bottom battery; 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 a solar cell as described above.

[0008] Fourthly, embodiments of this application provide a photovoltaic module, comprising: A battery string is formed by connecting the solar cells described above; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

[0009] The solar cell of this application embodiment includes a substrate and a passivation layer covering the substrate. The substrate has a first surface and a second surface disposed opposite to each other in the thickness direction. The first surface has alternating groove regions and textured regions, and the second surface includes alternating recessed regions and flat regions. The orthographic projection of the recessed region onto the substrate falls within the orthographic projection range of the groove region onto the substrate. Each groove region has a plurality of first light-trapping structures, which are non-pyramid structures, and the bottom edges of the plurality of first light-trapping structures are interconnected to form undulating hill-like protrusions. Each recess region also has a plurality of second light-trapping structures, which are non-pyramid structures, and the average bottom diameter of the first light-trapping structures is greater than or equal to the average bottom diameter of the second light-trapping structures. Through the above method, the plurality of first light-trapping structures in the groove region can alter crack propagation. The path guides the cutting path, reducing mechanical stress during the cutting process and improving the mechanical strength of the battery cell. The orthographic projection of the recessed area onto the substrate falls within the orthographic projection range of the groove area onto the substrate. This allows the concentrated stress generated during the cutting process to be transformed into a more uniformly distributed stress field through the synergistic recessed structure on both sides, preventing accumulation at weak points and further reducing mechanical stress during the cutting process. The larger first light-trapping structure can more smoothly guide and redistribute stress, preventing excessive stress concentration at the sharp corners at the bottom of the groove, thereby reducing the risk of brittle battery materials cracking due to stress concentration. The geometry of the groove area can cause incident light to undergo multiple reflections and refractions within the groove, extending the optical path of light within the battery, increasing the probability of light absorption, and improving conversion efficiency. The recessed area on the second side can scatter and reflect light transmitted to the back of the battery, folding the light back into the battery body, further improving conversion efficiency. Attached Figure Description

[0010] Figure 1This is a schematic diagram of the first structure of a solar cell according to an embodiment of this application.

[0011] Figure 2 This is a first scanning electron microscope image of a solar cell according to an embodiment of this application.

[0012] Figure 3 This is a second scanning electron microscope image of a solar cell according to an embodiment of this application.

[0013] Figure 4 This is a schematic diagram of the second structure of a solar cell according to an embodiment of this application.

[0014] Figure 5 This is a schematic diagram of the structure of a sliced ​​battery according to an embodiment of this application.

[0015] Figure 6 This is a schematic diagram of the structure of the battery string in the photovoltaic module according to an embodiment of this application.

[0016] Figure 7 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of this application. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] 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.

[0020] like Figures 1 to 4 As shown, this is a solar cell 100 provided in an embodiment of this application.

[0021] like Figure 1As shown, the solar cell 100 of this embodiment includes a substrate 11 and a passivation layer 12 covering the substrate 11. The substrate 11 has a first surface 13 and a second surface 14 disposed opposite to each other in the thickness direction. The first surface 13 is provided with alternating groove regions 15 and textured regions 16. The second surface includes alternating recessed regions 23 and flat regions 25. The orthographic projection of the recessed region 23 on the substrate 11 falls within the orthographic projection range of the groove region 15 on the substrate 11. The recessed region 15 has a plurality of first light-trapping structures 17, which are non-pyramid structures, and the bottom edges of the plurality of first light-trapping structures 17 are connected to each other to form undulating hill-like protrusions; the recessed region 23 has a plurality of second light-trapping structures 27, which are non-pyramid structures, and the average bottom diameter of the first light-trapping structures 17 is greater than or equal to the average bottom diameter of the second light-trapping structures 27.

[0022] The first light-trapping structure 17 on the bottom surface 19 of the groove region 15 can change the path of crack propagation, guide the cutting path, reduce mechanical stress during the cutting process, and improve the mechanical strength of the battery cell. The orthographic projection of the recessed region 23 on the substrate 11 falls within the orthographic projection range of the groove region 15 on the substrate 11. This can transform the concentrated stress generated during the cutting process into a more uniformly distributed stress field through the synergistic recessed structure on both sides, avoiding accumulation at weak points and further reducing mechanical stress during the cutting process. The larger first light-trapping structure 17 can guide and redistribute stress more smoothly, avoiding excessive stress concentration at the sharp corners at the bottom of the groove, thereby reducing the risk of brittle battery materials cracking due to stress concentration. The geometry of the groove region 15 can cause incident light to undergo multiple reflections and refractions within the groove, extending the optical path of light within the battery, increasing the probability of light absorption, and improving conversion efficiency. The recessed region 23 on the second surface 14 can scatter and reflect the light transmitted to the back of the battery, folding the light back into the battery body, further improving conversion efficiency.

[0023] In one embodiment, the groove region 15 includes a bottom surface 19 that is recessed inward relative to the velvet region and a slope 18 that extends obliquely from the velvet region and is connected to the bottom surface 19. The reflectivity of the bottom surface 19 of the groove region 15 is greater than or equal to the reflectivity of the bottom of the recessed region.

[0024] In this embodiment, the reflectivity of the bottom surface 19 of the groove region 15 is greater than or equal to the reflectivity of the bottom of the recessed region 23. The highly reflective bottom surface 19 reflects the long-wavelength light transmitted to the back side back into the battery for secondary absorption, thereby causing multiple internal reflections of light inside the battery, increasing the optical path and improving the utilization rate of light.

[0025] In one embodiment, the bottom surface 19 of the groove region 15 is doped with boron.

[0026] This application provides a pre-cut groove, i.e., a groove area 15, on the front side of the battery, and provides a polyfinger structure on the back side of the battery. The groove formed by removing the poly layer from the polyfinger corresponds to the pre-cut groove, and the groove formed by removing the poly layer is the recessed area 23.

[0027] Pre-cutting and final cell separation operations (such as laser scribing or mechanical cutting) can damage the silicon lattice, generating numerous defect states. These defects become strong recombination centers for charge carriers, severely impairing cell performance. In this embodiment, the pre-cut groove corresponds to the groove formed during the removal of the poly layer in the polyfinger technique. During cell slicing, the cutting operation separates the cell into two pieces along the pre-cut groove, without damaging the poly layer retained on the back of the cell. This achieves the goal of reducing cutting losses through pre-cutting grooves and can be combined with another efficiency-enhancing technology to improve overall efficiency.

[0028] In this embodiment, the bottom surface 19 of the groove region 15 is doped with boron. During the high-temperature propagation process, boron atoms can repair some lattice defects, effectively passivating these damaged areas, significantly reducing the recombination rate at the cutting edge, and minimizing cutting losses. The groove region 15 may eventually become the physical boundary of the battery cell. The PN junction formed by the doped P+ region and the N-type substrate 11 is prone to bending at the edge due to defects and stress, leading to edge leakage current. By precisely controlling the boron doping of the bottom surface 19 of the groove region 15, the electric field distribution at the edge can be optimized, suppressing carrier tunneling and recombination in the edge region, improving the parallel resistance and open-circuit voltage of the battery, and thus enhancing conversion efficiency.

[0029] In one embodiment, the ratio of the average bottom diameter of the first light-trapping structure 17 to the average bottom diameter of the second light-trapping structure 23 is greater than 1 to 10.

[0030] In this embodiment, the ratio of the average bottom diameter of the first light-trapping structure 17 to the average bottom diameter of the second light-trapping structure 23 is greater than 2 to 8. This ensures that the areas of the optical functional region that generates charge carriers and the electrical contact region that collects charge carriers are optimally matched. This maximizes light absorption while minimizing the high recombination risk of charge carriers in the electrode contact region, thereby maximizing efficiency.

[0031] In one embodiment, the first light-trapping structure 17 is the first tower base, and the second light-trapping structure 27 is the second tower base.

[0032] In this embodiment, the first light-trapping structure 17 is the first tower base and the second light-trapping structure 27 is the second tower base. This can increase the effective surface area of ​​the first light-trapping structure 17 and the second light-trapping structure 27, thereby enhancing the light trapping effect and causing the light to be reflected and absorbed multiple times in the groove, thus increasing the short-circuit current.

[0033] As one implementation method, such as Figure 1 As shown, the bottom surface of the groove region 15 has a plurality of first light-trapping structures 17; at least two first light-trapping structures 17 have overlapping projections on the first surface 13, or, two adjacent first light-trapping structures 17 have at least one shared edge, or, the projections of any two first light-trapping structures 17 on the first surface 13 do not overlap.

[0034] In this embodiment, the bottom surface 19 of the groove region 15 has a plurality of first light-trapping structures 17. At least two of the first light-trapping structures 17 have overlapping projections on the first surface 13, or two adjacent first light-trapping structures 17 have at least one common edge, so that light will be reflected and scattered more times in the overlapping area or the common edge, greatly increasing the propagation path of light in the silicon wafer and significantly reducing the surface reflectivity, which is especially beneficial for absorbing incident light at different angles. If the projections of any two first light-trapping structures 17 on the first surface 13 do not overlap, the lateral transport path of the charge carriers can be clearly defined, avoiding detours or congestion in complex networks, so as to ensure that the generated charge carriers can be utilized as much as possible.

[0035] In this embodiment, the bottom surface 19 of the groove region 15 further includes wrinkles, which, in conjunction with the first light-trapping structure 17, cause light to undergo more reflections and scatterings within the groove, greatly extending the optical path and effectively reducing surface reflectivity. The stepped structure provides a clear lateral electric field guiding path, promoting the directional movement of photogenerated carriers towards the electrode. The increased surface area, covered by a high-quality passivation layer 12, effectively reduces the surface recombination rate. Smooth transition structures such as gentle hill structures, zigzag structures, or curved structures avoid sharp edges, allowing for more uniform and better coverage deposition of the subsequently deposited passivation layer 12, reducing local defects. The wrinkles, acting as precise stress buffers, can disperse and absorb thermal and mechanical stresses generated during battery fabrication and subsequent use.

[0036] In one embodiment, the bottom of the first light-trapping structure 17 is polygonal or irregular in shape.

[0037] In this embodiment, the bottom of the first light-trapping structure 17 is polygonal in shape, which can provide a clear and designable reflective surface to achieve precise guidance of the light path, especially optimizing the capture of large-angle incident light. The bottom of the first light-trapping structure 17 is irregular in shape, forming an extremely complex diffuse reflection network to achieve the ultimate wide-spectrum and wide-angle light-trapping effect.

[0038] In one implementation, the height of the ramp 18 in the thickness direction of the substrate 11 is 0.2~10μm. This allows the ramp 18 to work synergistically with the groove region 15 and the textured structure, causing multiple reflections of light on the surface of the ramp 18, increasing the propagation path of light inside the cell. Precisely controlling the height of the ramp 18 helps to form an effective built-in electric field in the ramp 18 region, promoting the separation and collection of photogenerated carriers while suppressing their recombination on the surface. A suitable ramp 18 height provides stable mechanical support for the pre-cut groove, helping to disperse and absorb the mechanical and thermal stresses generated during cutting, welding, and use, improving the mechanical strength of the cell, and reducing the risk of microcracks and fragmentation.

[0039] In one embodiment, the ratio of the projected area of ​​the ramp 18 on the first surface 13 to the projected area of ​​the bottom surface 19 of the groove region 15 on the first surface 13 is 0.1% to 10%.

[0040] In this embodiment, the ratio of the projected area of ​​the ramp 18 on the first surface 13 to the projected area of ​​the bottom surface 19 of the groove region 15 on the first surface 13 is 1% to 3%, which can accurately allocate the directly illuminated surface and the secondary reflection surface, maximizing the light trapping effect.

[0041] In one embodiment, the outward tilt angle of the ramp 18 is 80° to 160°.

[0042] In this embodiment, the outward tilt angle of the ramp 18 is 85°~145°. The tilt angle works in conjunction with the groove area 15 and the textured surface to cause multiple reflections of light on the surface of the ramp 18, greatly increasing the propagation path of light inside the battery and reducing direct reflection loss, thereby improving light absorption efficiency and current output.

[0043] In one embodiment, the distance between the top and bottom of the slope 18 is 0.2~10μm.

[0044] In this embodiment, the distance between the top and bottom of the slope 18 is 4~6μm, which provides space for multiple reflections of light within the groove, increases the propagation path of light inside the battery, and thus improves light absorption efficiency. The appropriate length of the slope 18 can more effectively disperse and absorb the mechanical and thermal stress generated during battery preparation, cutting and subsequent use, suppress the initiation and propagation of microcracks, and improve the mechanical strength of the battery cell.

[0045] As one implementation method, such as Figure 3 As shown, the slope 18 includes several prism-like structures that extend between the top and bottom of the slope 18.

[0046] In this embodiment, the prism-like structure 22 provides more reflection and scattering surfaces for light. The light undergoes multiple reflections between the sides of adjacent prisms, which greatly increases the propagation path of light inside the battery, reduces direct reflection loss, and thus improves light absorption efficiency.

[0047] In one implementation, the plurality of prism structures 22 are distributed at equal intervals or at unequal intervals.

[0048] In this embodiment, the equidistant distribution of several types of prism structures 22 provides an ideal substrate for the subsequent deposition of the passivation layer 12 and the functional film layer 172, ensuring uniform film layer 172 thickness and achieving optimal surface passivation effect, thereby reducing carrier recombination. Simultaneously, the regular spacing makes process parameters such as etching and cleaning easier to optimize and control, significantly improving production yield and consistency. The unequal spacing of the several types of prism structures 22 allows the battery to maintain high conversion efficiency under illumination at different incident angles.

[0049] In one embodiment, the boundary line between the bottom surface 19 of the groove region 15 and the ramp 18 is perpendicular to the length direction of the prism-like structure 22.

[0050] In this embodiment, the boundary line between the bottom surface 19 of the groove region 15 and the ramp 18 is perpendicular to the length direction of the prism-like structure 22, so that the edges of the prism-like structure 22 can more effectively guide the light to be reflected as expected in the groove, avoid the light from being scattered to the ineffective area, increase the propagation path of light inside the battery, and thus improve the light absorption efficiency.

[0051] In one embodiment, the ratio of the length of the prism-like structure 22 to the distance between the top and bottom of the slope 18 is 0.6 to 3.6.

[0052] In this embodiment, the ratio of the length of the prism-like structure 22 to the distance between the top and bottom of the slope 18 is 1.0 to 2.5. This ensures that the prism-like structure 22 can fully cover the important light-reflecting surface of the slope 18. When light shines on the slope 18, the prism-like structures 22, which are distributed at equal or unequal intervals, can effectively scatter and reflect the light multiple times, greatly increasing the propagation path of light inside the battery, reducing direct reflection loss, and thus improving light absorption efficiency.

[0053] In one embodiment, the velvet area 16 includes multiple pyramid-like structures.

[0054] In this embodiment, such as Figure 1 As shown, the textured area 16 includes multiple pyramid-like structures 24, which cause light to be reflected multiple times between the pyramid slopes, greatly increasing the propagation path of light in the silicon wafer, reducing reflection loss, and improving short-circuit current.

[0055] 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).

[0056] 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 6 As shown, the solar cell 100 includes a substrate 11, a passivation layer 12 disposed on a first surface 13 of the substrate 11, a first antireflection layer 21 disposed on the passivation layer 12, a first electrode 181 disposed on the first surface 13 of the substrate 11, a tunneling oxide layer 191 disposed on a second surface 14 of the substrate 11, a doped polycrystalline silicon layer 192 disposed on the tunneling oxide layer 191, a back passivation layer 193 disposed on the doped polycrystalline silicon layer 192, a second antireflection layer 194 disposed on the back passivation layer 193, and a second electrode 182 disposed on the second surface 14 of the substrate 11.

[0057] The first surface 13 of the substrate 11 is a positive surface. The first surface 13 of the substrate 11 includes a textured region 16. Below the textured region 16 is an emitter 131. A passivation layer 12 covers the textured region 16. A first antireflection layer 21 covers the passivation layer 12. A first electrode 181 is disposed in the region where the textured region 16 is located. The first electrode 181 extends through the first antireflection layer 21 and the passivation layer 12 in the thickness direction of the substrate 11 to the emitter 131 below the textured region 16. The first electrode 181 is connected to the emitter 131.

[0058] The second surface 14 of the substrate 11 is the back surface, on which a tunneling oxide layer 191, a doped polysilicon layer 192, a back passivation layer 193 and a second antireflection layer 194 are deposited sequentially. The second electrode 182 is disposed in the region corresponding to the textured region 16. The second electrode 182 extends through the second antireflection layer 194 and the back passivation layer 193 to the doped polysilicon layer 192. The second electrode 182 is connected to the doped polysilicon layer 192.

[0059] 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 VA 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 IIIA elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0060] In some embodiments, the solar cell can be a single-sided cell, with the front surface (first surface 13) serving as the light-receiving surface for receiving incident light and the back surface (second surface 14) serving as the backlight surface.

[0061] In some embodiments, the front surface of the solar cell is a pre-cut groove, i.e., a recessed region 15; the back surface of the solar cell is a polyfinger structure. The polycrystalline silicon structure (poly structure) in the non-grid area of ​​the back surface of the solar cell is directly removed by laser, leaving only a poly layer in the grid area. That is, a recessed region 23 is formed in the non-grid area of ​​the back surface of the solar cell, containing only a silicon substrate; the grid area includes a tunneling oxide layer 191, a doped polycrystalline silicon layer 192, and a metal electrode. Furthermore, the recessed region 15 on the front surface of the solar cell corresponds to the recessed region 23 on the back surface of the solar cell.

[0062] In some embodiments, the solar cell can be a bifacial cell, meaning that both the first surface 13 and the second surface 14 of the substrate 11 can serve as light-receiving surfaces and can be used to receive incident light. The back surface (second surface 14) can also receive incident light, but its efficiency in receiving incident light is weaker than that of the light-receiving surface (first surface 13).

[0063] In some embodiments, the emitter 131 may be formed by doping the original substrate. The emitter 131 is made of the same base material as the substrate 11. Specifically, a portion of the original substrate corresponding to the textured region 16 may be doped. The doped portion of the original substrate serves as the emitter 131, and the remaining portion of the 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 may be formed by P-type doping of a portion of the N-type silicon substrate.

[0064] In some embodiments, the passivation layer 12 can be a single-layer structure or a stacked structure, and the material used to prepare the 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.

[0065] In some embodiments, the material used to prepare the first antireflection layer 21 may be one or more of silicon nitride or silicon oxynitride.

[0066] In some embodiments, the tunneling oxide layer 191 may be a silicon dioxide layer.

[0067] 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.

[0068] 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.

[0069] In some embodiments, the material used to prepare the second antireflection layer 194 can be one or more of silicon nitride or silicon oxynitride.

[0070] In some embodiments, the first electrode 181 and the second electrode 182 have opposite polarities.

[0071] One embodiment of this application provides a sliced ​​battery, such as Figure 5As shown, it includes a stepped structure formed by cutting the groove region 15 of the solar cell described in any of the above embodiments.

[0072] 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.

[0073] 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.

[0074] 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 generally needs to have high light transmittance. Exemplarily, the interlayer can be a transparent conductive metal oxide (TCO) thin film.

[0075] One embodiment of this application provides a photovoltaic module 200. Please refer to [link / reference]. Figure 6 and Figure 7 As shown, it includes a battery string 201, an encapsulating film 202, and a cover plate 203. Please refer to [the provided text]. Figure 7 As shown, the battery string 201 is formed by connecting multiple solar cells 100 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 facing away from the surface of the battery string 201.

[0076] In some embodiments, multiple solar cells 100 can be electrically connected to each other by solder ribbon 20, which is connected to each pair of adjacent solar cells 100. The solder ribbon 20 is connected to the front surface of the first solar cell 100 and the back surface of the second solar cell 100, respectively.

[0077] 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.

[0078] In some embodiments, no gap is provided between the solar cells 100, that is, two adjacent solar cells 100 overlap each other.

[0079] 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.

[0080] 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.

[0081] 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, The substrate includes a substrate and a passivation layer covering the substrate. The substrate has a first surface and a second surface disposed opposite to each other in the thickness direction. The first surface has alternating groove regions and textured regions. The second surface includes alternating recessed regions and flat regions. The orthographic projection of the recessed region on the substrate falls within the orthographic projection range of the groove region on the substrate. The groove area has a plurality of first light-trapping structures, which are non-pyramid structures, and the bottom edges of the plurality of first light-trapping structures are connected to each other to form a continuous, undulating hill-like protrusion. The recessed area has a plurality of second light-trapping structures, the second light-trapping structures are non-pyramid structures, and the average bottom diameter of the first light-trapping structure is greater than or equal to the average bottom diameter of the second light-trapping structure.

2. The solar cell according to claim 1, characterized in that, The grooved region includes a bottom surface that is recessed inward relative to the velvet region and a slope that extends obliquely from the velvet region and connects to the bottom surface. The reflectivity of the bottom surface of the grooved region is greater than or equal to the reflectivity of the bottom of the recessed region.

3. The solar cell according to claim 1, characterized in that, The ratio of the average bottom diameter of the first light-trapping structure to the average bottom diameter of the second light-trapping structure is greater than 1 to 10.

4. The solar cell according to claim 1, characterized in that, The first light-trapping structure is a first recessed structure, and the second light-trapping structure is a second recessed structure.

5. The solar cell according to claim 4, characterized in that, The first light-trapping structure is the first tower base, and the second recessed structure is the second tower base.

6. The solar cell according to claim 2, characterized in that, The slope includes several prismatic structures that extend between the top and bottom of the slope.

7. The solar cell according to any one of claims 1, characterized in that, The velvet surface area includes multiple pyramid-like structures.

8. A sliced ​​battery, characterized in that, This includes a stepped structure formed by cutting the groove region of the solar cell described in any one of claims 1-7.

9. A stacked battery, characterized in that, The stacked battery includes a top battery, an intermediate connecting layer, and a bottom battery, wherein the intermediate connecting layer connects the top battery and the bottom battery. 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 a solar cell as described in any one of claims 1 to 7.

10. A photovoltaic module, characterized in that, include: A battery string, comprising a plurality of solar cells connected together as described in any one of claims 1 to 7; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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