Battery piece and photovoltaic module

Abstract

The invention provides a battery piece and a photovoltaic module, and relates to the technical field of photovoltaics. The battery piece comprises a substrate, and the substrate comprises a first surface and a second surface which are oppositely arranged, and a plurality of side surfaces which are connected with the first surface and the second surface; the plurality of side surfaces comprise a first cutting surface and a first non-cutting surface; the first non-cutting surface is provided with a first texture structure; a first passivation layer disposed on the first non-cutting surface, the first passivation layer including a silicon-containing compound; and a second passivation layer disposed on the first passivation layer and the first cutting surface, the second passivation layer including an inorganic material. According to the embodiment of the invention, the texture structure is arranged on the non-cutting surface, and different passivation layers are arranged on the non-cutting surface and the cutting surface, so that the difference between the passivation effect of the cutting surface and the passivation effect of the non-cutting surface is reduced, and the situation that the performance of a battery is attenuated too fast due to the poor passivation effect of one side is avoided; and thus, the use durability of the battery piece under the condition of relatively high photoelectric conversion efficiency is improved.

Description

[0001] This application claims priority to Chinese Patent Application No. 202510574050.9, filed with the Chinese Patent Office on April 30, 2025, entitled "Battery Cells and Photovoltaic Modules", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of photovoltaic technology, and in particular to a solar cell and a photovoltaic module. Background Technology

[0003] With the trend of energy transition, renewable energy is gradually becoming an important pillar of social development. Solar cells are devices that can directly convert solar energy into electrical energy. Because they utilize clean energy, they have received continuous attention and are developing rapidly. Therefore, we constantly pursue the ultimate in photoelectric conversion efficiency and durability of solar cells.

[0004] Currently, there is still a pressing need to balance or improve the photoelectric conversion efficiency and durability of solar cells. Summary of the Invention

[0005] This invention provides a solar cell and a photovoltaic module, aiming to solve the problem of how to balance or improve the photoelectric conversion efficiency and service life of the solar cell.

[0006] A first aspect of the present invention provides a battery cell, comprising: a battery cell comprising:

[0007] The substrate includes a first surface and a second surface disposed opposite to each other, and a plurality of side surfaces connecting the first surface and the second surface; the plurality of side surfaces include a first cut surface and a first non-cut surface; the first non-cut surface is provided with a first texture structure;

[0008] A first passivation layer is disposed on the first non-cut surface, and the first passivation layer includes a silicon-containing compound;

[0009] A second passivation layer is disposed on the first passivation layer and the first cutting surface, and the second passivation layer comprises an inorganic material.

[0010] In this embodiment, a first textured structure is provided on the first non-cut surface of the solar cell, and a first passivation layer and a second passivation layer are sequentially provided on the first non-cut surface with the first textured structure, and a second passivation layer is provided on the first cut surface of the solar cell. The first textured structure gives the non-cut surface of the solar cell a better light-trapping effect, improving the photoelectric conversion efficiency of the solar cell. For the first non-cut surface with the first textured structure, passivation protection is achieved in all directions by combining a passivation layer of inorganic material and a passivation layer containing silicon compound. This differentiated setting of passivation layers on the cut surface and the non-cut surface helps to reduce the difference in passivation effect between the cut surface and the non-cut surface, avoiding excessively rapid degradation of battery performance due to poor passivation effect on one side, thereby improving the service life of the solar cell under high photoelectric conversion efficiency.

[0011] In some embodiments, the first cut surface is provided with a second texture structure, and the ratio of the area of ​​the first texture structure to the area of ​​the first non-cut surface is greater than the ratio of the area of ​​the second texture structure to the area of ​​the first cut surface.

[0012] When the area ratio of the second texture structure on the cut surface is small (i.e., smaller than the area ratio of the first texture structure on the uncut surface), a passivation layer can still be applied, instead of the two passivation layers required on the uncut surface, thus minimizing the difference in passivation effect between the cut and uncut surfaces. This embodiment of the present application can improve the durability of the solar cell under conditions of higher photoelectric conversion efficiency.

[0013] In some embodiments, the first cut surface is provided with a second texture structure, and the surface undulation of the first non-cut surface is greater than that of the first cut surface.

[0014] The surface roughness of the first non-cut surface is greater than that of the first cut surface, and a first passivation layer and a second passivation layer are disposed on the first non-cut surface, while a second passivation layer is disposed on the first cut surface. In other words, when the surface roughness of the cut surface is smaller, only one passivation layer needs to be disposed, unlike the two passivation layers required for the non-cut surface, thus minimizing the difference in passivation effect between the cut and non-cut surfaces. This embodiment of the present application improves the durability of the solar cell under conditions of higher photoelectric conversion efficiency.

[0015] In some embodiments, the first texture structure includes a first sub-texture structure and a second sub-texture structure. The first sub-texture structure is a pyramid structure, and along a direction perpendicular to the first non-cut surface, the regions where the first sub-texture structure is located and the regions where the second sub-texture structure is located have a height difference.

[0016] The first non-cut surface, by setting a first sub-texture structure and a second sub-texture structure, and setting a height difference between the areas where the first sub-texture structure is located and the areas where the second sub-texture structure is located, provides more refractive surfaces for the sidewall formed by the height difference between the two areas. This allows incident light from the side or reflected / refracted light from inside the solar cell to be refracted or reflected more times on the non-cut surface, increasing the absorption and utilization rate of light by the solar cell, thereby further improving the photoelectric conversion efficiency of the cell.

[0017] In some embodiments, the first surface is the front side of the substrate, the second surface is the back side of the substrate, along a direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located is higher than the area where the second sub-texture area is located, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side, the first surface is provided with a first doped layer, and the area where the first sub-texture structure is located is provided with the first doped layer, the second surface is provided with a second doped layer, and the first doped layer and the second doped layer have different doping types.

[0018] The solution in this embodiment corresponds to a conventional TOPCon battery product (i.e., one with a pyramidal textured surface on the front). In the TOPCon battery, the area containing the first sub-texture structure is higher than the area containing the second sub-texture structure, and the first sub-texture structure is located on the side of the first uncut surface closer to the front. The front of the TOPCon battery has a first doped layer, and the back has a second doped layer; the doping types of the first and second doped layers are opposite. The area containing the first sub-texture structure on the first uncut surface also has a first doped layer. Because there is a height difference between the areas containing the first and second sub-texture structures, and the area containing the first sub-texture structure has a first doped layer while the area containing the second sub-texture structure does not have a second doped layer, leakage caused by the first and second doped layers overlapping on the side is prevented.

[0019] In some embodiments, the second surface is provided with a plurality of spaced local electrode contact regions, and adjacent local electrode contact regions are provided with spacer regions. The second doped layer is provided in the local electrode contact regions, and the spacer regions are provided with the second sub-texture structure, which is a pyramid structure.

[0020] The embodiments of this application are applied to solar cells that also have a light-trapping structure on the back, thereby further increasing the optical path and improving the photoelectric conversion efficiency of the solar cell.

[0021] In some embodiments, the first surface is the front side of the substrate, and the second surface is the back side of the substrate. Along a direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located is lower than the area where the second sub-texture area is located, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side. The second surface includes a first area and a second area arranged alternately. The first area is provided with a first doped layer, and the second area is provided with a second doped layer. The doping types of the first doped layer and the second doped layer are different.

[0022] The battery cell in this embodiment can be a back contact (BC) battery. In a BC battery, the area containing the first sub-texture structure is lower than the area containing the second sub-texture structure, and the first sub-texture structure is located on the side of the first non-cut surface closer to the front. The lower location of the first sub-texture structure area may be due to formation during the etching process; that is, the etching depth is the thickness from the front of the battery cell to the area containing the first texture structure. In this way, the area containing the second sub-texture structure is essentially unaffected by etching, thereby protecting the film layer on the back of the battery cell and improving the yield of BC battery cell production.

[0023] In some embodiments, the second sub-texture structure is a tower base structure.

[0024] The undulation of the area where the tower base structure is located is greater than that of the area where the second texture structure is located. This results in a larger overall undulation of the first non-cut surface compared to the first cut surface. This helps to narrow the gap between the passivation effects of the cut and non-cut surfaces, preventing excessively rapid performance degradation due to poor passivation on one side. Furthermore, the elevation difference between the areas containing the first and second sub-texture structures provides more refractive surfaces, allowing incident light from the sides or reflected / refracted light from inside the solar cell to undergo more refractions or reflections on the non-cut surfaces, increasing the solar cell's light absorption and utilization rate. Therefore, this embodiment improves the durability of the solar cell while maintaining high photoelectric conversion efficiency.

[0025] In some embodiments, the second texture structure is at least one of a continuous or partially discontinuous linear structure, a groove structure, or a crack structure, wherein the linear structure extends in a direction perpendicular to the first surface to the second surface.

[0026] In some embodiments, the first non-cut surface is provided with the first texture structure on its entire surface, and the first cut surface is provided with the second texture structure on a portion thereof.

[0027] By increasing the optical path on both the first non-cut surface and the first cut surface, the photoelectric conversion efficiency of the solar cell is further improved. Furthermore, when the first texture structure accounts for 100% of the area on the first non-cut surface, and the area of ​​the second texture structure on the first cut surface is less than 100%, two passivation layers are applied to the non-cut surface, while only one passivation layer is applied to the first cut surface (without requiring two passivation layers as on the non-cut surface). This makes the passivation effect of the cut and non-cut surfaces relatively similar, thus improving the durability of the solar cell under higher photoelectric conversion efficiency conditions.

[0028] In some embodiments, the second passivation layer is further disposed on a first edge region of the first surface and / or the second surface adjacent to the first cutting surface; and / or

[0029] The second passivation layer is further disposed on the second edge region of the first surface and / or the second surface adjacent to the first non-cut surface; and / or

[0030] The second passivation layer is further disposed on a third edge region of a non-cut surface adjacent to the first cut surface; and / or

[0031] The second passivation layer is also disposed on the fourth edge region of the non-cut surface or the cut surface adjacent to the first non-cut surface.

[0032] The second passivation layer bypasses the edge, thus extending and wrapping around the edge region. This ensures that the edge region is fully passivated, reducing recombination sites and improving the photoelectric conversion efficiency of the solar cell. Furthermore, since the aforementioned edge region is prone to deformation problems such as edge chipping, the second passivation layer only covers this edge region. The uncovered areas can effectively release the stress on the edge region, reducing the probability of peeling, detachment, and edge chipping.

[0033] In some embodiments, the width of the second passivation layer disposed on the first edge region, the second edge region, the third edge region, or the fourth edge region is less than or equal to 6 mm.

[0034] The second passivation layer, with a width of less than or equal to 6 mm, can provide good passivation performance for the edge region. If the width of the second passivation layer on the edge region is greater than 6 mm, the coverage size of the edge region is too large, resulting in poor stress relief and making it easy for problems such as peeling, detachment, and edge chipping to occur in the edge region. Therefore, in this application, the width of the second passivation layer on the edge region is less than or equal to 6 mm, which not only provides good passivation quality but also reduces the probability of peeling, detachment, and edge chipping in the edge region.

[0035] In some embodiments, the sum of the thickness of the first passivation layer and the thickness of the second passivation layer is greater than or equal to 80 nm and less than or equal to 700 nm.

[0036] On the one hand, a passivation layer thickness greater than 80 nm on the side surface is sufficient to provide good passivation performance; on the other hand, a passivation layer thickness of 700 nm or less on the side surface avoids stress concentration or insufficient film density that might result from an excessively thick passivation layer. Therefore, in this embodiment, the sum of the thicknesses of the first and second passivation layers being less than or equal to 700 nm can increase the bonding strength between the passivation layer and the substrate, reducing the risk of interface peeling or defects. Furthermore, an excessively thick passivation layer on the side surface would increase production costs; this embodiment can improve production efficiency.

[0037] In some embodiments, the ratio of the thickness of the first passivation layer to the thickness of the second passivation layer is 0.5 to 3.

[0038] If the thickness of the first passivation layer is greater than the thickness of the second passivation layer, then the first passivation layer is thicker in the two passivation layers on the first non-cut surface, thus providing better field passivation. If the thickness of the first passivation layer is less than the thickness of the second passivation layer, then the second passivation layer is thicker in the two passivation layers on the first non-cut surface, thus providing better refraction and better light trapping. Therefore, different thickness ratios of the first and second passivation layers can accommodate more user needs.

[0039] In some embodiments, the first passivation layer includes a first sub-passivation layer and a second sub-passivation layer, the first sub-passivation layer including the silicon-containing compound, the second sub-passivation layer including a metal oxide, the second sub-passivation layer being disposed on the substrate surface and below the first sub-passivation layer, and the thickness of the second sub-passivation layer being 0.5 nm to 10 nm.

[0040] In this embodiment, when the textured structure or steps on the first non-cut surface affect the passivation effect, providing more passivation layers on the first non-cut surface can reduce the difference in passivation effect between the first non-cut surface and the first cut surface. A thinner second sub-passivation layer can reduce the probability of film bursting, further improving passivation performance and thus increasing photoelectric conversion efficiency. Simultaneously, the silicon compound layer can be used for hydrogen passivation, and metal oxides can be provided to provide field passivation or chemical passivation, resulting in a better passivation effect on the first non-cut surface, further reducing the difference in passivation effect between the first non-cut surface and the first cut surface, preventing excessively rapid degradation of battery performance due to poor passivation on one side, thereby improving the battery cell's lifespan.

[0041] In some embodiments, the inorganic material includes at least one of the following: metal oxide, silicon oxide, silicon nitride, intrinsic polycrystalline silicon, intrinsic amorphous silicon, silicon oxynitride, titanium oxide, and zinc oxide;

[0042] The silicon-containing compound includes at least one of silicon nitride, silicon oxynitride, and silicon oxide.

[0043] In some embodiments, the first cutting surface and the first non-cutting surface are disposed opposite to each other; or

[0044] The first cutting surface and the first non-cutting surface are arranged adjacent to each other.

[0045] It covers various relative positional relationships between the first cut surface and the first non-cut surface, and can be applied to almost all types of solar cells, making it widely applicable.

[0046] A second aspect of the present invention provides a photovoltaic module comprising a plurality of interconnected battery strings, wherein the battery strings are formed by sequentially connecting a plurality of any of the aforementioned battery cells.

[0047] The adjacent battery cells in the battery string are connected by conductive components;

[0048] The conductive element passes through the surface of the second passivation layer.

[0049] This application uses one or more of the solar cells described in the foregoing embodiments. Since the solar cells described in the foregoing embodiments can improve the durability of the solar cells under high photoelectric conversion efficiency, the durability of the module under high photoelectric conversion efficiency is also improved.

[0050] In some embodiments, the battery string includes N battery cells, wherein the battery string consists of alternating first and second battery cells among the N battery cells, and the N battery cells are arranged with negative spacing in sequence. The first battery cell includes three first uncut surfaces and one first cut surface, and the second battery cell includes two first cut surfaces and two first uncut surfaces.

[0051] In this embodiment, within a battery string, the first and second battery cells alternate sequentially with a negative spacing. The negative spacing can be understood as an overlapping area at the edges of the first and second battery cells. The conductive components have the same effect across both the first non-cut surface and the first cut surface; that is, this embodiment improves component consistency. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 A front view of a substrate according to an embodiment of the present invention is shown;

[0054] Figure 2 A top view of a single battery cell according to an embodiment of the present invention is shown;

[0055] Figure 3 A top view of a battery cell obtained by cutting a whole battery cell is shown in an embodiment of the present invention.

[0056] Figure 4 A front view structural diagram of a battery cell according to an embodiment of the present invention is shown;

[0057] Figure 5 A three-dimensional schematic diagram of a battery cell according to an embodiment of the present invention is shown;

[0058] Figure 6 A partial structural schematic diagram of the first uncut surface of the battery cell in an embodiment of the present invention is shown;

[0059] Figure 7 A partial three-dimensional structural schematic diagram of a battery cell according to an embodiment of the present invention is shown;

[0060] Figure 8 A partial top view of a battery string structure according to an embodiment of the present invention is shown.

[0061] Explanation of the attached drawing numbers:

[0062] 11-First surface, 12-Second surface, 13-First cut surface, 14-First non-cut surface, 141-First texture structure, 1411-First sub-texture structure, 1412-Second sub-texture structure, 131-Linear structure, 15-Non-cut surface, 21-First passivation layer, 22-Second passivation layer, 31-First battery cell, 32-Second battery cell. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] This invention provides a battery cell. The battery cell mentioned in this application may be a battery cell with electrodes on both sides, a back contact battery cell with electrodes only on the back side, a battery cell with a main grid, or a battery cell without a main grid, etc. The structure of the battery cell is not specifically limited.

[0065] The solar cell includes a substrate, which provides support for the various functional layers within the cell and functions as a light absorber, conductor, and current collector. The type of substrate is not limited here. For example, it can be a silicon substrate, and the doping type is also not limited; it can be N-type or P-type doped. The crystal type of the substrate is also not limited; for example, it can be single-crystal, microcrystalline, amorphous, or polycrystalline.

[0066] Reference Figure 1 The substrate includes a first surface 11 and a second surface 12 disposed opposite to each other, and a plurality of side surfaces connecting the first surface 11 and the second surface 12. During normal operation of the solar cell, the side of the substrate that primarily absorbs light is its light-facing side, while the back-light side is disposed opposite to the light-facing side. Of the first surface 11 and the second surface 12, one is the light-facing surface of the substrate, and the other is the back-light surface. The plurality of side surfaces connect the light-facing and back-light surfaces of the substrate. The number of side surfaces is related to the shape of the substrate. For example, Figure 1 In the case where the base is a cuboid, it has four sides.

[0067] Reference Figure 2 , Figure 2 The diagram shown is of the entire battery cell. Figure 2 In the diagram, A, B, C, and D all refer to the side of the entire battery cell. Figure 3 for Figure 2 The diagram shows a whole battery being cut into battery cells. Figure 2 The direction indicated by the dashed line can be the extension direction of the fine grid. The fine grid can be used to collect current. Typically, the entire battery cell is cut along the extension direction of the fine grid, resulting in multiple battery cells. The cutting can be symmetrical or asymmetrical; the battery cells provided in this application are applicable to both symmetrical and asymmetrical cutting. Cutting the entire battery cell N times, where N is a positive integer {1, 2, 3, 4, ...}, yields N+1 battery cells. For example, Figure 2 The entire battery cell was cut three times to obtain four battery cells. Specifically, the battery cells referred to in this application are those obtained by cutting the entire battery cell.

[0068] The substrate has multiple sides, including a first cut surface 13 and a first non-cut surface 14. A cut surface refers to the cross-section formed after the complete substrate is divided using laser or mechanical cutting processes during the process of cutting a whole battery cell into a battery sheet. The cut surface represents a new interface created after the battery is cut. A non-cut surface refers to the surface area that retains the original, complete structure during the process of cutting a whole battery cell into a battery sheet; in other words, it represents the interface that already exists in the battery cell itself, without significant cutting damage. For example, Figure 3In the solar cells obtained by cutting, E1, E2, F1, F2, G1, and G2 are schematic diagrams of the cut surfaces, while A, B1, B2, B3, B4, D1, D2, D3, D4, and C are schematic diagrams of the non-cut surfaces.

[0069] The first cutting surface 14 is any one of the multiple side cutting surfaces. Figure 1 In the diagram, the left side can be a schematic of the first non-cut surface, and the right side can be a schematic of the first cut surface 13. In this embodiment, by setting a first texture structure 141 on the first non-cut surface, that is, the first non-cut surface presents an uneven and concave-convex morphology, the incident light can undergo multiple reflections and refractions, increasing the optical path and improving the photoelectric conversion efficiency of the solar cell.

[0070] Figure 4 for Figure 1 A schematic diagram of a partial structure of the solar cell formed on the substrate shown. (Refer to...) Figure 4 The solar cell also includes a first passivation layer 21 disposed on the first non-cut surface. The first passivation layer 21 comprises a silicon-containing compound. The film formed by the silicon-containing compound has a hydrogen passivation effect, which can eliminate dangling bonds on the substrate side and has a good repair effect on cutting damage to the solar cell (e.g., lattice fracture caused by cutting), thereby improving the photoelectric conversion efficiency of the solar cell. Furthermore, the silicon-containing compound has excellent density, which can effectively prevent the diffusion and penetration of external substances into the solar cell, reduce the surface energy of the material to reduce the external corrosion rate, and keep the solar cell in a relatively stable state. In other words, it isolates external impurities and other substances from the sides of the solar cell, preventing the diffusion and adsorption of impurities, and reducing the recombination rate of photogenerated carriers at the sides, thus improving the photoelectric conversion efficiency of the solar cell.

[0071] Reference Figure 4 The solar cell also includes a second passivation layer 22 disposed on the first passivation layer 21 and the first cut surface 13. The second passivation layer 22 comprises an inorganic material. Inorganic materials generally exhibit higher passivation durability compared to organic materials. For example, the inorganic material can be at least one of the following: metal oxide, silicon oxide, silicon nitride, intrinsic polycrystalline silicon, intrinsic amorphous silicon, silicon oxynitride, titanium oxide (which may be titanium oxide nanowires, etc.), and zinc oxide.

[0072] The first non-cut surface, due to its textured structure, exhibits significant undulations, negatively impacting the passivation film deposition quality. Therefore, a robust passivation method is required for this textured surface. Combining inorganic materials with silicon-containing compounds can comprehensively enhance the passivation protection of the non-cut surface of the solar cell from multiple perspectives. For instance, the combination of metal oxides and silicon-containing compounds can provide comprehensive passivation protection for the non-cut surface through chemical passivation, field passivation, mechanical protection, and hydrogen passivation.

[0073] It is understandable that the outermost layer of the first cut surface and the first non-cut surface being the same second passivation layer can be achieved in the same passivation process, thereby saving process steps and improving the production efficiency of solar cells.

[0074] In this embodiment, a first textured structure is provided on the first non-cut surface of the solar cell, and a first passivation layer and a second passivation layer are sequentially provided on the first non-cut surface with the first textured structure, and a second passivation layer is provided on the first cut surface of the solar cell. The first textured structure gives the non-cut surface of the solar cell a better light-trapping effect, improving the photoelectric conversion efficiency of the solar cell. For the first non-cut surface with the first textured structure, passivation protection is achieved in all directions by combining a passivation layer of inorganic material and a passivation layer containing silicon compound. This differentiated setting of passivation layers on the cut surface and the non-cut surface helps to reduce the difference in passivation effect between the cut surface and the non-cut surface, avoiding excessively rapid degradation of battery performance due to poor passivation effect on one side, thereby improving the service life of the solar cell under high photoelectric conversion efficiency.

[0075] In some possible embodiments of this application, the metal oxide includes at least one of aluminum oxide, titanium oxide (which may be titanium oxide nanowires, etc.), and zinc oxide.

[0076] The passivation layer of the aforementioned metal oxide can be prepared by methods such as atomic layer deposition (ALD) based on self-limiting reaction, plasma-assisted atomic layer deposition (PE-ALD) based on plasma discharge, pyrolysis deposition, delocalized PECVD, molecular beam epitaxy, and aluminum deposition followed by oxidation. For example, atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PE-ALD) can be used to deposit an aluminum oxide passivation layer.

[0077] In some possible embodiments of this application, the silicon-containing compound includes at least one of silicon nitride, silicon oxynitride, and silicon oxide. Dense silicon oxide can block the diffusion and penetration of external substances into the solar cell, reduce interface defects, and achieve a passivation effect. The silicon oxide layer can also block charge carriers, enabling selective carrier passage. Moreover, the low defect state density at the silicon oxide-silicon substrate interface can effectively improve carrier lifetime. Silicon oxide can be prepared by thermal oxidation, PECVD, or room temperature wet oxidation, etc. Silicon nitride has excellent chemical stability and good insulation properties, making it a good insulating material with stronger interface protection. It can effectively prevent damage to the solar cell from external substances and also effectively block damage from external ions, delaying cell degradation and improving the adaptability of the solar cell in complex environments, effectively expanding the application range and scenarios of the solar cell. The preparation method of silicon nitride can also make it typically hydrogen-rich, with light hydrogen atoms saturated with dangling bonds and other recombination centers, effectively reducing carrier recombination. Furthermore, silicon nitride is effective in reducing reflection. By matching the silicon nitride film layer with its refractive index, it can reduce solar reflection and increase light absorption, thereby improving solar cell efficiency. Silicon nitride can be prepared using plasma-enhanced chemical vapor deposition (PECVD) and magnetron sputtering (PVD). PECVD can be further divided into direct PECVD and indirect PECVD. Silicon oxynitride combines the advantages of both silicon oxide and silicon nitride.

[0078] In some possible embodiments of this application, the first texture structure may include a pyramid structure, which can be an upright pyramid structure, an inverted pyramid structure, etc., and is not limited thereto. The pyramid structure can be formed in the same process as the pyramid structures on the first and second surfaces of the substrate, resulting in good process compatibility and good light-trapping effect. Alternatively, the pyramid structure can also be formed separately, and this application does not limit this.

[0079] In some possible embodiments of this application, reference is made to Figure 5The first cut surface 13 is provided with a second textured structure. Due to the presence of the second textured structure, the surface of the first cut surface 13 also has a certain unevenness, which allows incident light to undergo multiple reflections and refractions, increasing the optical path and further improving the photoelectric conversion efficiency of the solar cell. Furthermore, the area of ​​the first textured structure 141 relative to the area of ​​the first non-cut surface 14 is greater than the area of ​​the second textured structure relative to the area of ​​the first cut surface 13. A first passivation layer 21 and a second passivation layer 22 are provided on the first non-cut surface 14, and a second passivation layer 22 is provided on the first cut surface 13. In other words, even when the area ratio of the second textured structure on the cut surface is small (i.e., smaller than the area ratio of the first textured structure on the non-cut surface), one passivation layer can still be provided, instead of two passivation layers as on the non-cut surface, making the passivation effect of the cut surface and the non-cut surface not significantly different. Thus, this embodiment of the application can improve the durability of the solar cell under conditions of higher photoelectric conversion efficiency.

[0080] It is understandable that the ratio of the area of ​​the first texture structure 141 to the area of ​​the first non-cut surface 14 can be: for any one of the first non-cut surfaces in the battery cell, when the first texture structure 141 is illuminated by light perpendicular to the first non-cut surface, the ratio of the area of ​​the region where the first texture structure 141 is located on the first non-cut surface to the area of ​​the first non-cut surface. Correspondingly, the ratio of the area of ​​the region where the second texture structure is located to the area of ​​the first cut surface 13 is determined in a similar way to the ratio of the area of ​​the first texture structure 141 to the area of ​​the first non-cut surface, and will not be described again here to avoid repetition.

[0081] It is understandable that, since the first non-cut surface is non-planar, the direction perpendicular to the first non-cut surface can refer to the direction perpendicular to the base plane of the first non-cut surface.

[0082] In some possible implementations of this application, the first non-cut surface 14 is entirely provided with a first texture structure 141, and the first cut surface 13 is partially provided with a second texture structure. This increases the optical path on both the first non-cut surface and the first cut surface, thereby further improving the photoelectric conversion efficiency of the solar cell. Furthermore, when the first texture structure accounts for 100% of the area on the first non-cut surface, and the area of ​​the second texture structure on the first cut surface is less than 100%, two passivation layers are provided on the non-cut surface, while the first cut surface can still have one passivation layer (without needing two passivation layers like the non-cut surface). This makes the passivation effect of the cut surface and the non-cut surface not significantly different, thus improving the durability of the solar cell under higher photoelectric conversion efficiency conditions in this embodiment.

[0083] It is understandable that the second texture structure is set on the first cutting surface 13, specifically meaning that the second texture structure does not completely cover the first cutting surface 13.

[0084] It is also understandable that when the first non-cut surface is provided with the first texture structure 141, the area of ​​the first texture structure 141 accounts for 100% or close to 100% of the area of ​​the first non-cut surface.

[0085] It is also understood that the area of ​​the first texture structure relative to the area of ​​the first non-cut surface can be 80%, 70%, 60%, or 50%, or other values, or in other words, the area of ​​the first texture structure relative to the area of ​​the first non-cut surface can be greater than or equal to 50%. Correspondingly, the area of ​​the second texture structure relative to the area of ​​the first cut surface can be 40%, 30%, 20%, 10%, or other values, or in other words, the area of ​​the second texture structure relative to the area of ​​the first cut surface can be less than 50%. This application does not impose any limitations on this.

[0086] In some possible embodiments of this application, the first cut surface 13 is provided with a second texture structure, and the surface undulation of the first non-cut surface 14 is greater than that of the first cut surface 13. Due to the presence of the second texture structure, the surface of the first cut surface 13 also has a certain unevenness, which allows incident light to undergo multiple reflections and refractions, increasing the optical path and improving the photoelectric conversion efficiency of the solar cell. Furthermore, the surface undulation of the first non-cut surface is greater than that of the first cut surface, and a first passivation layer and a second passivation layer are provided on the first non-cut surface, while a second passivation layer is provided on the first cut surface. That is, when the surface undulation of the cut surface is small, one passivation layer can still be provided, instead of two passivation layers as on the non-cut surface, making the passivation effect of the cut surface and the non-cut surface not significantly different. Thus, the embodiments of this application improve the durability of the solar cell under higher photoelectric conversion efficiency.

[0087] In some possible embodiments of this application, the second texture structure is a continuous or partially discontinuous linear structure 131 (see reference). Figure 5 At least one of the following: (as shown), groove structure, or crack structure. Wherein, the linear structure 131 extends along a direction perpendicular to the first surface to the second surface, i.e. Figure 5 The direction of the center and the top and bottom is the direction from the first surface to the second surface.

[0088] It is understandable that the direction from the first surface to the second surface specifically refers to the thickness direction of the substrate, meaning the linear structure extends along the thickness direction perpendicular to the substrate. The extension of the linear structure 131 along the thickness direction perpendicular to the substrate can be understood as follows: the overall orientation of the linear structure 131 is along the thickness direction perpendicular to the substrate, but local areas of the linear structure are allowed to bend or fold in other directions. For example, refer to... Figure 5 The linear structure 131 is a partially discontinuous linear structure.

[0089] In some possible embodiments of this application, the width of the linear structure 131 is 10 μm to 140 μm, and the length is 5 μm to 210 μm. The direction of the length of the linear structure 131 is parallel to its extension direction, and the direction of the width of the linear structure 131 is perpendicular to its extension direction. If the width of the linear structure is greater than 140 μm and the length is greater than 210 μm, the size of the linear structure is large, and the passivation damage caused by the linear structure is greater, resulting in a poor passivation effect of the first cut surface 13. If the width of the linear structure is less than 10 μm and the length is less than 5 μm, the size of the linear structure is small, and the light-trapping effect caused by the linear structure is poor. Therefore, in this application, the width of the linear structure is 10 μm to 140 μm and the length is 5 μm to 210 μm, which is the result of optimizing and balancing the passivation effect and the light-trapping effect of the first cut surface 13.

[0090] For example, the width of the linear structure can be 10μm, 20μm, 50μm, 65μm, 75μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, or 140μm, and the length can be 5μm, 10μm, 20μm, 40μm, 50μm, 60μm, 80μm, 90μm, 100μm, 105μm, 110μm, 120μm, 150μm, 160μm, 180μm, 190μm, 200μm, or 210μm.

[0091] In some possible embodiments of this application, the surface roughness of the region with the second texture structure on the first cutting surface is less than or equal to 2 μm, achieving a good balance between light trapping and passivation effects. For example, the surface roughness of the region with the second texture structure on the first cutting surface can be 2 μm, 1.8 μm, 1.6 μm, 1.5 μm, 1.2 μm, 1 μm, 0.9 μm, 0.8 μm, or 0.5 μm.

[0092] In some possible embodiments of this application, the depth of the trench structure is less than the depth of the crack structure, and the surface of the crack structure is smoother than the surface of the trench structure. A second passivation layer covers both the trench structure and the crack structure. Typically, the trench structure is densely distributed and complex. When the substrate is silicon, the trench structure sometimes also contains non-monocrystalline silicon components, resulting in a complex surface morphology and composition with a high density of surface recombination centers. Therefore, the thickness of the second passivation layer is greater than the depth of the trench structure. In this case, the second passivation layer can completely fill the trench structure to maximize passivation repair and improve the conversion efficiency of the solar cell. Furthermore, since crack structures are mostly formed by natural fracture under stress, their surfaces are relatively smooth. Setting the thickness of the second passivation layer to be less than the depth of the crack structure is sufficient to perform limited passivation of this area. Simultaneously, the second passivation layer formed on the first cut surface has an undulating pattern, which can improve the light-trapping effect of the first cut surface and increase the concentration of photogenerated carriers on the cut surface, thereby improving the light utilization rate of the solar cell's cut surface and further improving the photoelectric conversion efficiency of the solar cell.

[0093] In this application, surface undulation can refer to the degree of change or complexity of surface morphology. A large surface undulation indicates a greater degree of change or complexity of surface morphology. Understandably, the undulation of the area where the first texture structure is set on the first non-cut surface is greater than the undulation of the area where the second texture structure is set on the first cut surface 13. In one case, the number of protrusions and / or depressions in the area where the first texture structure is set on the first non-cut surface may be greater than the number of protrusions and / or depressions in the area where the second texture structure is set on the first cut surface 13. In another case, the degree of protrusions and / or depressions in the area where the first texture structure is set on the first non-cut surface may be greater than the degree of protrusions and / or depressions in the area where the second texture structure is set on the first cut surface 13. In yet another case, the arrangement of protrusions and / or depressions in the area where the first texture structure is set on the first non-cut surface may be more disordered than the arrangement of protrusions and / or depressions in the area where the second texture structure is set on the first cut surface 13. In yet another case, the height of the protrusions and / or the depth of the depressions in the area where the first texture structure is set on the first non-cut surface may be greater than the height of the protrusions and / or the depth of the depressions in the area where the second texture structure is set on the first cut surface 13. The shape of the area where the first texture structure is set on the first non-cut surface is more complex, or in other words, the area where the first texture structure is set on the first non-cut surface has a relatively greater degree of undulation.

[0094] In some possible embodiments of this application, the first texture structure includes a first sub-texture structure and a second sub-texture structure. The first sub-texture structure is a pyramid structure. Along the direction perpendicular to the first non-cut surface, the regions where the first and second sub-texture structures are located have different heights, or in other words, a height difference exists. By setting the first and second sub-texture structures on the first non-cut surface, and by creating a height difference between the regions where the first and second sub-texture structures are located, the sidewalls formed by the height difference between the two regions provide more refractive surfaces. This allows incident light from the sides or reflected / refracted light from inside the solar cell to undergo more refractions or reflections on the non-cut surface, increasing the absorption and utilization rate of light by the solar cell, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0095] In some possible implementations, the aforementioned first surface is the front side of the substrate, and the aforementioned second surface is the back side of the substrate. Along a direction perpendicular to the first non-cut surface, the region containing the first sub-texture structure is higher than the region containing the second sub-texture structure, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side. The first surface is provided with a first doped layer, and the first non-cut surface is also provided with the first doped layer. The first doped layer is disposed on the region containing the first sub-texture structure and below the first passivation layer. The second surface is provided with a second doped layer, and the first and second doped layers have different doping types.

[0096] The battery cells in this application embodiment can be bifacial cells, such as, but not limited to, TOPCon cells, heterojunction cells (HIT cells), and bifacial hybrid cells. For ease of description, the following description uses TOPCon cells as an example.

[0097] This embodiment corresponds to a conventional TOPCon battery product (i.e., one with a pyramidal textured surface on the front). In a TOPCon battery, the area containing the first sub-texture structure is higher than the area containing the second sub-texture structure, and the first sub-texture structure is located on the side of the first uncut surface closer to the front. The front of the TOPCon battery has a first doped layer, and the back has a second doped layer, with opposite doping types. The area containing the first sub-texture structure on the first uncut surface also has a first doped layer. In this TOPCon battery structure, because there is a height difference between the areas containing the first and second sub-texture structures, it indicates that after removing the portion of the first doped layer located on the back and the side of the uncut surface closer to the back, no first or second doped layer remains on the portion of the first uncut surface of the silicon substrate closer to the back, thus preventing a short circuit between the first and second doped layers on the first uncut surface.

[0098] In some possible implementations, the second surface is provided with multiple spaced-apart local electrode contact regions, and adjacent local electrode contact regions are separated by interval regions, which are provided with a textured structure (e.g., a pyramid structure). A second doped layer is disposed in the local electrode contact regions. The electrode contact regions can be polyfinger structures (polycrystalline silicon comb-finger structures). In other words, the embodiments of this application are applied to solar cells with light-trapping structures also provided on the back side, thereby further increasing the light-trapping area of ​​the solar cell and improving the photoelectric conversion efficiency of the cell.

[0099] For example, in a polyfinger-TOPCon battery, a first doped layer covers the entire first surface, and a second doped layer is disposed in the local electrode contact region of the second surface, thereby reducing recombination and parasitic absorption on the second surface while achieving passivation.

[0100] In some possible implementations, the texture structure set in the spacer region is a second sub-texture structure, which is a pyramid structure. That is, the texture structure in the spacer region has the same structural type as the second sub-texture structure in the first uncut surface. Because there is a height difference between the regions containing the first and second sub-texture structures, short circuits between the first and second doped layers on the uncut surface are prevented. Furthermore, the pyramid structure on the surface of the uncut surface of the silicon substrate corresponding to the region containing the second sub-texture structure further increases the light-trapping area of ​​the first uncut surface of the solar cell, improving the photoelectric conversion efficiency of the cell. At the same time, the process is simpler and the cost is lower.

[0101] It is understandable that by preparing the second sub-texture structure in the first non-cut surface while preparing the texture structure in the spacer region of the polyfinger, the photoelectric conversion efficiency can be improved while saving process steps.

[0102] It is understood that, in this embodiment, the second sub-texture structure can be a tower-based structure. In this case, the morphology distribution of the first non-cut surface can be as follows: Figure 6 As shown, the first sub-texture structure 1411 is a pyramid structure, and the second sub-texture structure 1412 is a base structure. Furthermore, the area containing the first sub-texture structure 1411 is higher than the area containing the second sub-texture structure 1412 (not shown in the figure). For example, for a bifacial battery, the pyramid structure can be provided only on the front side. In this case, the pyramid structure is provided on the side of the corresponding first non-cut surface closer to the front, while the base structure is on the side closer to the back. The surface of the base structure can be polygonal, and the shape of the polygonal plane includes at least one of rhombus, square, trapezoid, approximate rhombus, approximate square, and approximate trapezoid.

[0103] It is understandable that the interface between the region containing the first sub-texture structure and the region containing the second sub-texture structure can be a wavy interface. Or, the first sub-texture structure is similar to an island structure existing on the first non-cut surface.

[0104] It is also understood that one or more first sub-texture structure regions may exist on the side of the first non-cut surface near the front. Correspondingly, one or more second sub-texture structure regions may exist on the side of the first non-cut surface near the back. That is to say, the second sub-texture structure region in the first non-cut surface can extend to the side near the front, and the first sub-texture structure region in the first non-cut surface can also extend to the side near the back.

[0105] In some possible implementations, the height difference between the region containing the second sub-texture structure and the region containing the first sub-texture structure can be between 0.5 μm and 10 μm (preferably between 2 μm and 6 μm). For example, the height difference between the region containing the second sub-texture structure and the region containing the first sub-texture structure can be 0.5 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, or 10 μm.

[0106] In some other possible implementations, the first surface is the front side of the battery cell, and the second surface is the back side of the battery cell. Along the direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located is lower than the area where the second sub-texture area is located, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side. The second surface includes a first area and a second area, and the first area and the second area are alternately provided with a gap area. The first area is provided with a first doped layer, and the second area is provided with a second doped layer. The doping types of the first doped layer and the second doped layer are different.

[0107] The solar cell in this embodiment can be a back contact (BC) cell. A back contact cell is a cell where both the positive and negative electrodes are located on the back side. Examples include, but are not limited to, TBC cells (solar cells where both conductive regions are passivated contact structures), HBC cells (heterojunction back contact cells), and hybrid back contact cells (solar cells where one conductive region is a passivated contact structure and the other conductive region is a heterojunction passivated structure). In a BC cell, the area containing the first sub-texture structure is lower than the area containing the second sub-texture structure, and the first sub-texture structure is located on the side of the first non-cut surface closer to the front side. This structural arrangement ensures that when removing the film layers (e.g., doped layers or passivation layers) on the front and non-cut surfaces, the etching on the back side of the solar cell is reduced, protecting the doped layer on the back side and ensuring the integrity of the doped layer on the back side of the solar cell, especially near the non-cut surface.

[0108] It is understandable that in BC cells, when a doped layer is formed on the back side, the resulting BSG and / or PSG protect the sides, causing the area on the first uncut surface closer to the back side to be higher than the area on the front side.

[0109] In some possible implementations, the second sub-texture structure is a tower-based structure. The undulation of the area containing the tower-based structure is greater than that of the area containing the second texture structure. This results in a larger overall undulation of the first non-cut surface compared to the first cut surface. By placing a first passivation layer and a second passivation layer on the first non-cut surface, and a second passivation layer on the first cut surface, the difference in passivation effects between the cut and non-cut surfaces is reduced, preventing excessively rapid performance degradation due to poor passivation on one side. Furthermore, the elevation difference between the areas containing the first and second sub-texture structures provides more refractive surfaces, allowing incident light from the sides or reflected / refracted light from inside the solar cell to undergo more refractions or reflections on the non-cut surfaces, increasing the solar cell's light absorption and utilization rate. Therefore, this embodiment improves the durability of the solar cell while maintaining high photoelectric conversion efficiency.

[0110] In some possible implementations, the first non-cut surface includes two types of pyramid structures (i.e., the second sub-texture structure is also a pyramid structure). The second sub-texture structure increases the optical path of the first non-cut surface to the pyramid structure, thereby further improving the photoelectric conversion efficiency of the non-cut surface of the solar cell. The first and second sub-texture structures can be on the same plane, or in other words, the height difference between them is small. This results in a greater degree of undulation in the first non-cut surface (i.e., the pyramid structure of the first and second sub-texture structures), exceeding the undulation of the first cut surface. This helps to narrow the gap between the passivation effect of the cut surface and the non-cut surface, preventing excessively rapid performance degradation due to poor passivation on one side, and thus improving the durability of the solar cell under high photoelectric conversion efficiency.

[0111] It is understandable that in BC cells, the pyramid structure in the gap region on the back side can be the same as the pyramid structure near the back side on the uncut side. In other words, the pyramid structure can be fabricated simultaneously with the textured structure in the gap region on the back side, thereby improving photoelectric conversion efficiency while saving on process steps.

[0112] It is understood that the surface of the tower base structure in the embodiments of this application can be polygonal in shape, and the shape of the polygonal plane includes at least one of rhombus, square, trapezoid, approximate rhombus, approximate square, and approximate trapezoid.

[0113] It is understandable that the first and second sub-texture structures, both being pyramid structures, can have different one-dimensional dimensions. For example, the first sub-texture structure can be fabricated simultaneously with the pyramid-structured textured surface on the front side of the solar cell, while the second sub-texture structure can be fabricated simultaneously with the pyramid-structured textured surface in the spaced areas on the back side of the solar cell. This avoids the need to fabricate the first and second sub-texture structures separately, thus saving on process costs.

[0114] Figure 7 In the diagram, the first cut surface 13, indicated by the dashed line, is completely covered by the second passivation layer 22. In some possible embodiments of this application, reference is made to... Figure 7 The second passivation layer 22 is also disposed on the first edge region of the first surface 11 adjacent to the first cutting surface 13. That is, the second passivation layer 22 bypasses the edge. Therefore, the second passivation layer 22 extends and wraps around the first edge region, which can ensure that the first edge region is fully passivated, reduce recombination sites, and improve the photoelectric conversion efficiency of the solar cell. In addition, the first edge region is prone to deformation problems such as edge chipping. The second passivation layer 22 only covers the first edge region. The uncovered areas can effectively release the stress on the first edge region, which can reduce the probability of peeling, detachment, and edge chipping in the first edge region.

[0115] In some possible embodiments of this application, the second passivation layer 22 is also disposed on the first edge region of the second surface 12 adjacent to the first cutting surface 13, which can also ensure that the first edge region is sufficiently passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the battery cell, and reduce the probability of peeling, falling off, or chipping of the first edge region.

[0116] In some possible embodiments of this application, the second passivation layer 22 is also disposed on the second edge region of the first surface 11 adjacent to the first non-cut surface, which can also ensure that the second edge region is sufficiently passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the battery cell, and reduce the probability of peeling, falling off, or chipping of the second edge region.

[0117] In some possible embodiments of this application, the second passivation layer 22 is also disposed on the second edge region of the second surface 12 adjacent to the first non-cut surface, which can also ensure that the second edge region is sufficiently passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the cell, and reduce the probability of peeling, falling off, or chipping of the second edge region.

[0118] It is understandable that the first passivation layer under the second passivation layer on the first non-cut surface can also be designed with an edge-wrapping structure as described above for the second passivation layer. This application does not limit this, and it will not be elaborated here for the sake of convenience.

[0119] In some possible embodiments of this application, reference is made to Figure 7 The second passivation layer 22 is also disposed on the third edge region of the non-cut surface 15 adjacent to the first cut surface 13, which can also ensure that the third edge region is fully passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the cell, and reduce the probability of peeling, falling off, or chipping of the first edge region.

[0120] In some possible embodiments of this application, the second passivation layer 22 is also disposed on the fourth edge region of the non-cut surface adjacent to the first non-cut surface, which can also ensure that the fourth edge region is sufficiently passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the solar cell, and reduce the probability of peeling, detachment, and edge breakage in the fourth edge region.

[0121] In some possible embodiments of this application, the second passivation layer 22 is also disposed on the fourth edge region of the cut surface adjacent to the first non-cut surface. Similarly, it can ensure that the fourth edge region is sufficiently passivated, reduce recombination sites, improve the photoelectric conversion efficiency of the battery cell, and reduce the probability of peeling, detachment, and edge breakage in the fourth edge region.

[0122] In some possible embodiments of this application, there is no specific limitation on whether a passivation layer is provided on the non-cutting surfaces other than the first non-cutting surface and on the cutting surfaces other than the first cutting surface. For example, a passivation layer may not be provided or may be provided on the non-cutting surfaces other than the first non-cutting surface, while a passivation layer may be provided on the cutting surfaces other than the first cutting surface.

[0123] In some possible embodiments of this application, reference is made to Figure 7 The second passivation layer 22 is disposed on the aforementioned first edge region with a width d1 less than the distance from the edge to the location of the gate line (or PAD point), which can avoid poor component soldering. The value of d1 can be different on the front and back sides, and this application does not limit this. For example, d1 is less than 6.56 mm on the front side and less than 8.58 mm on the back side.

[0124] In some possible embodiments of this application, d1 is less than or equal to 6 mm. Specifically, a width d1 of the second passivation layer 22 disposed on the aforementioned first edge region that is less than or equal to 6 mm is sufficient to provide good passivation performance for the first edge region. If the width d1 of the second passivation layer 22 disposed on the aforementioned first edge region is greater than 6 mm, the coverage area of ​​the first edge region is too large, resulting in poor stress relief for the first edge region. This can easily lead to problems such as peeling, detachment, and edge chipping in the first edge region, and may also cause poor component welding. Therefore, in this application, a width d1 of the second passivation layer 22 disposed on the aforementioned first edge region that is less than or equal to 6 mm not only provides good passivation quality but also reduces the probability of peeling, detachment, and edge chipping in the first edge region.

[0125] For example, the width d1 of the second passivation layer 22 disposed on the aforementioned first edge region can be 6mm, 5mm, 4.8mm, 4.5mm, 4.2mm, 4mm, 3.9mm, 3.8mm, 3.7mm, 3.6mm, 3.5mm, 3.2mm, 3mm, 2.8mm, 2.5mm, 2mm, 1.8mm, 1.5mm, 1mm, or 0.8mm.

[0126] It should be noted that the direction of the width d1 is perpendicular to the boundary line between the first cutting surface 13 and its adjacent first surface and / or second surface. When the shape of the second passivation layer 22 in the aforementioned first edge region is curved, the width d1 of the second passivation layer 22 in the aforementioned first edge region can be the width of the second passivation layer 22 at a corner position in the first edge region; or, the width d1 of the second passivation layer 22 in the aforementioned first edge region can be the average of the widths of the second passivation layer 22 at multiple corner positions in the first edge region; or, the width d1 of the second passivation layer 22 in the aforementioned first edge region can be the average of the maximum and minimum widths of the second passivation layer 22 in the first edge region; the width d1 of the second passivation layer 22 in the aforementioned first edge region can be the average of the width, maximum width, and minimum width of the second passivation layer 22 at at least one corner position in the first edge region. Specific methods for determining the width d1 of the second passivation layer 22 in the aforementioned first edge region include, but are not limited to, the methods described above.

[0127] In some possible embodiments of this application, the width of the second passivation layer 22 disposed on the aforementioned second edge region is less than or equal to 6 mm. This not only results in good passivation quality, but also reduces the probability of peeling, detachment, or edge chipping in the second edge region.

[0128] In some possible embodiments of this application, reference is made to Figure 7 The width d2 of the second passivation layer 22 disposed on the aforementioned third edge region is less than or equal to 6mm. Similarly, not only is the passivation quality good, but the probability of peeling, falling off, or chipping in the third edge region is also small.

[0129] For example, the width d2 of the second passivation layer 22 disposed on the aforementioned third edge region can be 6mm, 5mm, 4.7mm, 4.5mm, 4.3mm, 4mm, 3.95mm, 3.8mm, 3.7mm, 3.6mm, 3.5mm, 3.2mm, 3mm, 2.8mm, 2.5mm, 2mm, 1.8mm, 1.5mm, 1mm, or 0.5mm.

[0130] In some possible embodiments of this application, the width of the second passivation layer 22 disposed on the aforementioned fourth edge region is less than or equal to 6 mm. This not only results in good passivation quality, but also reduces the probability of peeling, detachment, or edge chipping in the second edge region.

[0131] In some possible embodiments of this application, reference is made to Figure 7 The shape of the edge of the second passivation layer 22 disposed on the aforementioned first edge region includes an arc shape, which can effectively reduce and release the stress on the first edge region and reduce the probability of peeling, falling off, or chipping of the first edge region.

[0132] In some possible embodiments of this application, the shape of the edge of the second passivation layer 22 disposed on the aforementioned second edge region includes an arc shape, which can effectively reduce and release the stress on the second edge region and reduce the probability of peeling, detachment, or edge chipping in the second edge region.

[0133] In some possible embodiments of this application, reference is made to Figure 7 The shape of the edge of the second passivation layer 22 disposed on the aforementioned third edge region includes an arc shape, which can effectively reduce and release the stress on the third edge region and reduce the probability of peeling, falling off, or chipping of the third edge region.

[0134] In some possible embodiments of this application, the shape of the edge of the second passivation layer 22 disposed on the aforementioned fourth edge region includes an arc shape, which can effectively reduce and release the stress on the fourth edge region and reduce the probability of peeling, detachment, and edge chipping in the fourth edge region.

[0135] In some possible embodiments of this application, the sum of the thickness of the first passivation layer 21 and the thickness of the second passivation layer 22 is less than or equal to 700 nm and greater than or equal to 80 nm. Specifically, on the one hand, a passivation layer thickness greater than 80 nm on the side surface is sufficient to provide good passivation performance; on the other hand, a passivation layer thickness of less than or equal to 700 nm on the side surface avoids excessively thick passivation layers. Therefore, in the embodiments of this application, the sum of the thicknesses of the first and second passivation layers being less than or equal to 700 nm can increase the bonding strength between the passivation layer and the substrate, reducing the risk of interface peeling or defects. Furthermore, excessively thick passivation layers on the side surface increase production costs, while the embodiments of this application can improve production efficiency.

[0136] For example, the sum of the thickness of the first passivation layer 21 and the thickness of the second passivation layer 22 can be 80nm, 100nm, 120nm, 150nm, 180nm, 200nm, 250nm, 280nm, 300nm, 320nm, 350nm, 380nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, or 700nm.

[0137] In some possible implementations, the ratio of the thickness of the first passivation layer to the thickness of the second passivation layer is 0.5 to 3.

[0138] If the thickness of the first passivation layer is greater than the thickness of the second passivation layer, the first passivation layer is thicker on the first non-cut surface, thus providing better field passivation. If the thickness of the first passivation layer is less than the thickness of the second passivation layer, the second passivation layer is thicker on the first non-cut surface, allowing for more passivation layers with different refractive indices to be incorporated, resulting in a smoother refractive index transition on the first non-cut surface and better light trapping. Therefore, different thickness ratios of the first and second passivation layers can accommodate a wider range of user needs.

[0139] For example, the ratio of the thickness of the first passivation layer to the thickness of the second passivation layer can be 0.5, 0.6, 0.8, 0.9, 1, 1.2, 1.5, 1.8, 1.9, 2, 2.2, 2.3, 2.5, 2.6, 2.8, or 3.

[0140] In some possible embodiments of this application, the thickness of the first passivation layer 21 can be from 25nm to 550nm. A thickness less than 25nm results in poor passivation performance, while a thickness greater than 550nm does not further improve passivation performance and increases processing time. For example, the thickness of the first passivation layer 21 can be 25nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 150nm, 180nm, 200nm, 230nm, 250nm, 280nm, 300nm, 320nm, 350nm, 380nm, 400nm, 450nm, 500nm, or 500nm.

[0141] In some possible embodiments of this application, the first passivation layer 21 may be a single-layer structure or a multi-layer structure. The multi-layer structure may be distinguished by the different elements contained therein. In the case of containing the same elements, it may be distinguished by the different mass percentages of the elements.

[0142] In some possible embodiments of this application, the thickness of the second passivation layer 22 can be from 25 nm to 150 nm. If the thickness of the second passivation layer is less than 25 nm, the thinner film will not effectively repair the first passivation layer, resulting in poor passivation performance. If the thickness of the second passivation layer is greater than 150 nm, the thicker film will not further improve the passivation effect, and excessive thickness will increase processing time. For example, the thickness of the second passivation layer 22 can be 25 nm, 30 nm, 40 nm, 45 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, or 150 nm. In some possible embodiments of this application, the refractive index of the first passivation layer 21 is from 1.4 to 5, which can reduce solar reflection, increase light absorption, and thus further improve the efficiency of the solar cell. Furthermore, the first passivation layer 21 of silicon-containing compounds within the above refractive index range is easy to prepare.

[0143] In some possible implementations, the refractive index of the first passivation layer 21 is 1.5 to 3.5.

[0144] For example, the first passivation layer 21 is a silicon oxide layer with a refractive index of about 1.50. Alternatively, the refractive index of the first passivation layer 21 can be 1.4, 1.5, 1.6, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.5, 2.6, 2.8, 3, 3.2, 3.5, 4, 4.5, or 5.

[0145] In some possible embodiments of this application, the refractive index of the second passivation layer 22 is 1.4 to 5, which can reduce sunlight reflection, increase light absorption, and thus further improve the efficiency of the solar cell. Moreover, the second passivation layer 22 of the metal oxide in the above refractive index range is easy to prepare.

[0146] In some possible implementations, the refractive index of the second passivation layer 22 is 1.5 to 3.8.

[0147] For example, the first passivation layer 22 is an aluminum oxide layer with a refractive index of about 1.64. As another example, the refractive index of the second passivation layer 22 can be 1.4, 1.5, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.5, 2.6, 2.8, 3, 3.2, 3.5, 3.6, 3.8, 4, 4.5, or 5.

[0148] It is understandable that the refractive index of the second passivation layer can be the overall refractive index including the underlying structure.

[0149] In some possible embodiments of this application, the second passivation layer 22 may contain one or more layers. When including at least two layers, the mass ratio of oxygen differs from the mass ratio of the metal elements. Throughout the preparation of the second passivation layer 22, it is not necessary to ensure that the process parameters are completely consistent, resulting in a wide process window. When the second passivation layer 22 contains at least two layers, the number of layers can be less than or equal to 40. More layers result in better passivation quality, but more than 40 layers lead to excessive layers and low production efficiency. A number of layers of 40 or less in the second passivation layer is sufficient to provide good passivation quality. Different layers in the second passivation layer can be distinguished by different metal elements, or, if the metal elements are the same, by different mass ratios of metal elements and oxygen elements. The specific method of distinction is not limited.

[0150] In some possible embodiments of this application, the first passivation layer includes a first sub-passivation layer and a second sub-passivation layer. The first sub-passivation layer includes a silicon-containing compound, and the second sub-passivation layer includes a metal oxide. The second sub-passivation layer is disposed on the surface of the substrate and below the first sub-passivation layer, or in other words, the first sub-passivation layer is disposed between the first non-cut surface of the substrate and the second sub-passivation layer. The thickness of the second sub-passivation layer is 0.5 nm to 10 nm.

[0151] In this embodiment, when a textured structure or step is set on the first non-cut surface, affecting the passivation effect, more passivation layers can be set on the first non-cut surface to reduce the difference in passivation effect between the first non-cut surface and the first cut surface. For example, in this embodiment, the first passivation layer further includes a metal oxide layer (i.e., a second sub-passivation layer). The thickness of the second sub-passivation layer is 0.5 nm to 10 nm, such as 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 6 nm, 7 nm, 8 nm, 8.5 nm, 9 nm, and 10 nm. A second sub-passivation layer of this thickness can reduce the probability of film bursting, further improve passivation performance, and thus improve photoelectric conversion efficiency. Furthermore, the small thickness of the second sub-passivation layer (i.e., 0.5 nm to 10 nm) avoids the second sub-passivation layer blocking the first sub-passivation layer, allowing the first sub-passivation layer to still provide hydrogen passivation for the silicon substrate. In this way, the silicon-containing compound layer can be used for hydrogen passivation, and the metal oxide provides field passivation or chemical passivation, thereby making the passivation effect of the first non-cut surface better overall. This further reduces the difference in passivation effect between the first non-cut surface and the first cut surface, and avoids the battery performance from degrading too quickly due to poor passivation effect on one side, thereby improving the service life of the battery cell.

[0152] In some other possible embodiments of this application, the thickness ratio of the second passivation layer to the second sub-passivation layer is 5 to 50.

[0153] In this embodiment, the inner second sub-passivation layer is thinner, while the outer second passivation layer is thicker, thus further enhancing the field passivation effect. The second passivation layer and the second sub-passivation layer can be the same material in a metal oxide. For example, both the second passivation layer and the second sub-passivation layer are aluminum oxide. The outer aluminum oxide layer further enhances the passivation effect, and combined with the second passivation layer, the passivation effect on the first non-cut surface is better, further reducing the difference in passivation effect between the first non-cut surface and the first cut surface. This prevents the battery performance from degrading too quickly due to poor passivation on one side, thereby improving the battery cell's lifespan.

[0154] In some possible embodiments of this application, the second passivation layer may be a single layer or multiple layers, and this application does not limit this.

[0155] In some possible embodiments of this application, the first cut surface 13 and the first non-cut surface are arranged parallel or opposite to each other; or the first cut surface 13 and the first non-cut surface are arranged adjacent to each other, covering various relative positional relationships between the first cut surface 13 and the first non-cut surface, which can be applied to almost all battery cells and has a wide range of applications. The foregoing embodiments may have the first cut surface 13 and the first non-cut surface arranged opposite to each other, but this application is not limited to this.

[0156] For example, Figure 1 In this case, the first cutting surface 13 and the first non-cutting surface are positioned opposite each other. For example, Figure 3 If side surface A has a first texture structure, then side surface A is the first non-cut surface. If side surface E1 is the first cut surface, then... Figure 3 In the leftmost cell, the first non-cut surface is positioned opposite or parallel to the first cut surface. If side A is the first non-cut surface and E1 is the first cut surface, then the first non-cut surface is positioned opposite or parallel to the first cut surface. If B2 is the first non-cut surface and F1 is the first cut surface, then the first non-cut surface is positioned adjacent to the first cut surface.

[0157] It is also understood that a single battery cell may include the three first non-cut surfaces and one first cut surface (as shown in the embodiments of this application). Figure 3 The first battery cell on the left in the image). Or a battery cell includes two first uncut surfaces and two first cut surfaces (e.g., ...). Figure 3 (The two battery cells in the middle).

[0158] This application also provides a photovoltaic module, including multiple electrically connected cell strings, each cell string being formed by sequentially connecting multiple of the aforementioned cells. Adjacent cells within a cell string are connected by a conductive element. Specifically, in the cell string, the conductive element electrically connects the positive electrode of one adjacent cell to the negative electrode of the other. This conductive element can be a solder ribbon, conductive interconnect, etc. The conductive element passes through the surface of the second passivation layer of the cell. Thus, this application embodiment uses one or more of the cells described in the aforementioned embodiments. Because the cells described in the aforementioned embodiments can improve the durability of the module while maintaining high photoelectric conversion efficiency, the durability of the module's lifespan while maintaining high photoelectric conversion efficiency is also improved.

[0159] In some possible embodiments of this application, the battery string includes N battery cells, and the battery string consists of alternating first and second battery cells among the N battery cells. The first battery cell includes three first uncut surfaces and one first cut surface, and the second battery cell includes two first cut surfaces and two first uncut surfaces. The N battery cells are arranged with negative spacing in sequence.

[0160] In this embodiment of the application, in a battery string, the first and second battery cells alternate sequentially, and are arranged with a negative spacing. For example, Figure 8 The first battery cell 31 and the second battery cell 32 are included. The negative spacing setting can be understood as an overlapping area at the edges of the first and second battery cells. The conductive component has the same effect as the first non-cut surface and the first cut surface; that is, the embodiments of this application can improve the consistency of the component.

[0161] It should be noted that in a battery string, the connection position of the first and second battery cells is the cut edge or the edge parallel to the cut edge.

[0162] It is understandable that negative spacing settings can also be called "edge overlay settings", where negative spacing can be 0.1mm to 0.8mm, for example, negative spacing of 0.1, 0.3, 0.5, 0.7, 0.8.

[0163] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0164] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A battery cell, characterized in that, include: The substrate includes a first surface and a second surface disposed opposite to each other, and a plurality of side surfaces connecting the first surface and the second surface; the plurality of side surfaces include a first cut surface and a first non-cut surface; the first non-cut surface is provided with a first texture structure; A first passivation layer is disposed on the first non-cut surface, and the first passivation layer includes a silicon-containing compound; A second passivation layer is disposed on the first passivation layer and the first cutting surface, and the second passivation layer comprises an inorganic material.

2. The battery cell according to claim 1, characterized in that, The first cut surface is provided with a second texture structure, and the ratio of the area of ​​the first texture structure to the area of ​​the first non-cut surface is greater than the ratio of the area of ​​the second texture structure to the area of ​​the first cut surface.

3. The battery cell according to claim 1, characterized in that, The first cut surface is provided with a second texture structure, and the surface undulation of the first non-cut surface is greater than that of the first cut surface.

4. The battery cell according to claim 1, characterized in that, The first texture structure includes a first sub-texture structure and a second sub-texture structure. The first sub-texture structure is a pyramid structure. Along the direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located and the area where the second sub-texture structure is located have a height difference.

5. The battery cell according to claim 4, characterized in that, The first surface is the front side of the substrate, and the second surface is the back side of the substrate. Along the direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located is higher than the area where the second sub-texture area is located, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side. The first surface is provided with a first doped layer, and the area where the first sub-texture structure is located is provided with the first doped layer. The second surface is provided with a second doped layer, and the first doped layer and the second doped layer have different doping types.

6. The battery cell according to claim 5, characterized in that, The second surface is provided with a plurality of spaced local electrode contact areas, and adjacent local electrode contact areas are provided with spacer areas. The second doped layer is provided in the local electrode contact areas, and the spacer areas are provided with the second sub-texture structure, which is a pyramid structure.

7. The battery cell according to claim 4, characterized in that, The first surface is the front side of the substrate, and the second surface is the back side of the substrate. Along the direction perpendicular to the first non-cut surface, the area where the first sub-texture structure is located is lower than the area where the second sub-texture area is located, and the first sub-texture structure is disposed on the side of the first non-cut surface closer to the front side. The second surface includes a first area and a second area arranged alternately. The first area is provided with a first doped layer, and the second area is provided with a second doped layer. The doping types of the first doped layer and the second doped layer are different.

8. The battery cell according to claim 7, characterized in that, The second sub-texture structure is a tower-based structure.

9. The battery cell according to claim 2 or 3, characterized in that, The second texture structure is at least one of a continuous or partially discontinuous linear structure, a groove structure, or a crack structure, wherein the linear structure extends in a direction perpendicular to the first surface to the second surface.

10. The battery cell according to claim 2, characterized in that, The first non-cut surface is provided with the first texture structure on its entire surface, and the first cut surface is provided with the second texture structure on a portion thereof.

11. The battery cell according to claim 1, characterized in that, The second passivation layer is further disposed on the first edge region of the first surface and / or the second surface adjacent to the first cutting surface; and / or The second passivation layer is further disposed on the second edge region of the first surface and / or the second surface adjacent to the first non-cut surface; and / or The second passivation layer is further disposed on a third edge region of a non-cut surface adjacent to the first cut surface; and / or The second passivation layer is also disposed on the fourth edge region of the non-cut surface or the cut surface adjacent to the first non-cut surface.

12. The battery cell according to claim 11, characterized in that, The width of the second passivation layer disposed on the first edge region, the second edge region, the third edge region, or the fourth edge region is less than or equal to 6 mm.

13. The battery cell according to claim 1, characterized in that, The sum of the thickness of the first passivation layer and the thickness of the second passivation layer is greater than or equal to 80 nm and less than or equal to 700 nm.

14. The battery cell according to claim 13, characterized in that, The ratio of the thickness of the first passivation layer to the thickness of the second passivation layer is 0.5 to 3.

15. The battery cell according to claim 1, characterized in that, The first passivation layer includes a first sub-passivation layer and a second sub-passivation layer. The first sub-passivation layer includes the silicon-containing compound, and the second sub-passivation layer includes a metal oxide. The second sub-passivation layer is disposed on the surface of the substrate and below the first sub-passivation layer. The thickness of the second sub-passivation layer is 0.5 nm to 10 nm.

16. The battery cell according to claim 1, characterized in that, The inorganic material includes at least one of the following: metal oxide, silicon oxide, silicon nitride, intrinsic polycrystalline silicon, intrinsic amorphous silicon, silicon oxynitride, titanium oxide, and zinc oxide; The silicon-containing compound includes at least one of silicon nitride, silicon oxynitride, and silicon oxide.

17. The battery cell according to claim 1, characterized in that, The first cutting surface and the first non-cutting surface are arranged opposite to each other; or The first cutting surface and the first non-cutting surface are arranged adjacent to each other.

18. A photovoltaic module, characterized in that, It includes multiple battery strings that are electrically connected to each other, wherein the battery strings are formed by connecting multiple battery cells as described in any one of claims 1 to 17 in series. The adjacent battery cells in the battery string are connected by conductive components; The conductive element passes through the surface of the second passivation layer.

19. The photovoltaic module according to claim 18, characterized in that, The battery string includes N battery cells, and the battery string consists of alternating first and second battery cells among the N battery cells, with the N battery cells arranged in a negative spacing order. The first battery cell includes three first uncut surfaces and one first cut surface, and the second battery cell includes two first cut surfaces and two first uncut surfaces.

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