Solar cell and photovoltaic module
The solar cell design with a doped region and passivation contact structure addresses efficiency issues by reducing optical losses and charge carrier recombination, improving overall performance.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2026-04-09
AI Technical Summary
The efficiency of existing solar cells is unsatisfactory due to optical losses and recombination of charge carriers at the surface and within the bulk of the silicon substrate.
A solar cell design with a doped region on the front surface and a passivation contact structure on the rear surface, featuring specific ratios and overlaps of doped areas, along with electrodes connected to these regions, to reduce optical losses and improve contact performance.
Enhances the efficiency of the solar cell by minimizing charge carrier recombination and reducing electrical losses, thereby increasing the photoelectric conversion efficiency.
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Abstract
Description
TECHNICAL AREA
[0001] Various embodiments of the present disclosure relate to the technical field of photovoltaics and in particular to a solar cell and a method for its manufacture as well as a photovoltaic module. BACKGROUND
[0002] With the gradual depletion of fossil fuels, solar cells are increasingly being used as a new alternative energy source. A solar cell is a device that converts solar energy into electrical energy. Solar cells generate charge carriers based on the photovoltaic effect, and electrodes are then used to extract these charge carriers, thus enabling the efficient use of electrical energy.
[0003] Currently, solar cells mainly include IBC (Interdigitated Back Contact) cells, TOPCon (Tunnel Oxide Passivation Contact) cells, PERC (Passivation Emitter and Rear Cell) cells, and heterojunction cells. By using different film layer configurations and functional constraints, optical losses can be reduced and the recombination of the photogenerated charge carrier at the surface and within the bulk of the silicon substrate can be suppressed, thereby improving the photoelectric conversion efficiency of solar cells.
[0004] However, the efficiency of existing solar cells is still unsatisfactory. SUMMARY
[0005] The embodiments of the present disclosure provide a solar cell, a method for manufacturing the same and a photovoltaic module.
[0006] According to some embodiments of the present disclosure, one aspect of the embodiments of the present disclosure provides a solar cell. The solar cell includes a substrate with a front surface and a rear surface facing each other. The front surface includes first metal regions and first non-metal regions. The rear surface includes second metal regions and second non-metal regions.The solar cell further includes: a doped region formed in the front surface of the substrate, wherein the doped region includes first subdoped regions formed in the front surface at positions corresponding to the metal regions; first electrodes arranged above the substrate corresponding to the metal regions and electrically connected to the first subdoped regions; a passivation contact structure arranged on a section of the rear surface that at least partially corresponds to the metal regions; and second electrodes arranged above the passivation contact structure corresponding to the metal regions and electrically connected to the passivation contact structure.
[0007] In some embodiments, the doped region further includes second subdoped regions formed in the front surface, corresponding to a first section of the non-metallic regions, and each of the second subdoped region connects two adjacent first subdoped regions.
[0008] In some embodiments, the doped region further includes third subdoped regions formed in the front surface in a second section adjacent to the non-metallic regions. The direction of extension of the third subdoped region is the same as that of the first subdoped regions. Each of the third subdoped regions is formed between adjacent first subdoped regions and is electrically connected to the second subdoped regions.
[0009] In some embodiments, along an arrangement direction of the first electrodes, there is a ratio of a total width of orthographic projections of the first subdoped areas and the third subdoped areas on the front surface to a width of the front surface in the range of 3% to 40%, and / or along the extension direction of the first electrodes, there is a ratio of a total width of orthographic projections of the second subdoped areas above the front surface to a length of the front surface in the range of 2% to 20%.
[0010] In some embodiments, an orthographic projection of the passivation contact structure on the rear surface overlaps with an orthographic projection of the doped area on the rear surface; or the orthographic projection of the passivation contact structure on the rear surface partially overlaps with the orthographic projection of the doped area on the rear surface and an overlap area is greater than or equal to 0.4 times the area of the doped area.
[0011] In some embodiments, a distance between the front surface of the substrate, which includes the doped region, and the rear surface is a first distance, a distance between the front surface of the substrate, which does not include the doped region, and the rear surface is a second distance, and the first distance is greater than the second distance.
[0012] According to some embodiments of the present disclosure, a further aspect of the embodiments of the present disclosure also provides a method for manufacturing a solar cell that includes metal areas and non-metal areas.The process includes: providing a substrate with a front surface and a back surface facing each other; forming a doped region in the front surface of the substrate, the doped region including first subdoped regions formed in the front surface at positions corresponding to the metal regions; forming first electrodes over the substrate corresponding to the metal regions and electrically connected to the first subdoped region; forming a passivation contact structure on the back surface of the metal regions; and forming second electrodes over the passivation contact structure corresponding to the metal regions and electrically connected to the passivation contact structure.
[0013] In some embodiments, the doped region further includes second subdoped regions, the front surface includes first machining regions and first non-machining regions, and the manufacturing process for forming the doped region includes: performing a doping treatment on the front surface of the substrate to convert a partial thickness of the substrate into a doped layer; removing the doped layer in the first machining region and retaining the doped layer located in the first non-machining regions as the doped region, wherein the doped region located in the metal regions serves as the first subdoped regions and a portion of the doped region located in the non-metal regions serves as the second subdoped regions.
[0014] In some embodiments, the front surface includes secondary machining areas and secondary non-machining areas, and the manufacturing process for forming the doped area includes performing a laser doping treatment on the secondary machining areas of the substrate to convert a section of areas of the substrate into the doped area.
[0015] According to some embodiments of the present disclosure, yet another aspect of the embodiments of the present disclosure further provides a photovoltaic module comprising: a cell string formed by connecting a plurality of solar cells according to one of the preceding embodiments or solar cells produced by the manufacturing process according to one of the preceding embodiments; a connecting element configured to electrically connect two adjacent solar cells; an encapsulation film configured to cover a surface of the cell string; a cover plate configured to cover a surface of the encapsulation film facing away from the cell string. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] One or more embodiments are described for illustrative purposes with reference to the accompanying drawings. These illustrative descriptions are not intended to limit the embodiments, and unless otherwise stated, the drawings are not drawn to scale. For a clearer explanation of the technical solutions of the embodiments of this disclosure or of conventional technology, the drawings required for the embodiments are briefly presented below. It is obvious that the drawings described below illustrate only some embodiments of this disclosure and that other drawings can also be obtained by a person skilled in the art without creative effort. Fig. 1 is a schematic structural diagram of a solar cell according to an embodiment of the present disclosure; Fig. 2 is a section view along a line A1-A2 in Fig. 1. Fig. Figure 3 is a schematic structural diagram of another solar cell according to an embodiment of the present disclosure; Fig. Figure 4 is a top view of a doped area in yet another solar cell according to an embodiment of the present disclosure. Fig. Figure 5 is a top view of a doped area in yet another solar cell according to embodiments of the present disclosure. Fig. 6 is another section view along a line A1-A2 in Fig. 1. Fig. Figures 7 to 15 are schematic structural diagrams of a solar cell, which correspond to the respective processes of a method for manufacturing a solar cell according to another embodiment of the present disclosure. Fig. Figure 16 is a schematic structural diagram of a tandem cell according to yet another embodiment of the present disclosure. Fig. Figure 17 is a schematic structure diagram of a photovoltaic module according to an embodiment of the present disclosure. Fig. 18 is a section structure diagram along a line M1-M2 in Fig. 17. DETAILED DESCRIPTION OF THE EXECUTION FORMS
[0017] Background technology has shown that the efficiency of current solar cells is unsatisfactory.
[0018] Embodiments of the present disclosure provide a solar cell, a method for manufacturing the same, and a photovoltaic module. By providing a doped region located within a metal region, optical losses in non-metal regions can be reduced, and the contact performance between the electrode and the doped region can be improved, thereby increasing the efficiency of the cell.
[0019] In the description of embodiments of this disclosure, the technical terms "first," "second," etc., are used only to distinguish different objects and should not be understood as indicating or implying any relative importance or implicitly indicating the number, specific order, or priority of the specified technical features. In the description of embodiments of this disclosure, the term "a plurality of" means two or more, unless expressly defined otherwise.
[0020] As mentioned herein, “elaboration” means that a particular feature, structure, or property described in connection with the embodiment may be included in at least one embodiment of the present disclosure. The appearance of this term in different places in the patent specification does not necessarily always refer to the same embodiment, nor do they represent mutually exclusive alternative or independent embodiments. It should be understood explicitly and implicitly by those skilled in the art that the embodiment described herein may be combined with other embodiments.
[0021] In the description of the embodiments of the present disclosure, the term "and / or" merely describes an associative relationship between associated objects and represents three possible relationships. For example, A and / or B can mean: the presence of A, the presence of both A and B, or the presence of B. Furthermore, the symbol " / " generally indicates an "or" relationship between the associated objects preceding and following it.
[0022] In the description of the embodiments of the present disclosure, the term “a plurality of” refers to two or more (including two). Similarly, “a plurality of groups” refers to two or more groups (including two groups), and “a plurality of parts” refers to two or more parts (including two parts).
[0023] In the description of the embodiments of this disclosure, the technical terms "central", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate positional or orientation relationships based on those shown in the drawings. They serve only to facilitate and simplify the description of the embodiments of this disclosure and should not be understood as indicating or implying that the devices or elements mentioned must have a particular orientation, be constructed in a particular orientation, or operate in a particular orientation. Therefore, they should not be interpreted as limiting the embodiments of this disclosure.
[0024] In the description of the embodiments of the present disclosure, unless expressly stated and defined otherwise, the technical terms "assembled," "connected," "coupled," "fastened," and the like should be understood in a broad sense. For example, they may refer to a fixed connection, a detachable connection, or an integral formation; they may refer to a mechanical or an electrical connection; they may refer to a direct connection and an indirect connection via an intermediate medium; they may also refer to communication between the interiors of two elements or an interaction relationship between two elements. For persons skilled in the art, the specific meanings of the aforementioned terms in the embodiments of the present invention can be understood according to the specific circumstances.
[0025] In the accompanying drawings of the embodiments in the present disclosure, layers and regions are exaggerated for clarity and description. When a component (e.g., a layer, a film, a region, or a substrate) is described as being "on" or "over" another component, it may be located directly on top of the other component or have an intermediate component between the two components described above. Conversely, "directly on" or "formed / arranged on the surface" does not mean an intermediate component. Furthermore, "approximately formed on" means that the component is not formed on the entire surface (or the front surface) of the other component, or is not formed on the partial edge of the entire surface.
[0026] When, in the description of the embodiments of this disclosure, a component “includes” another component, this does not, unless otherwise specified, exclude the presence of other components, and other components may likewise be included. Furthermore, when a component such as a layer, a film, a region, or a plate is described as being “on” another component, it may be “directly on” the other component (i.e., on the surface of the other component without any other component in between), or another component may be present in between. Moreover, when a layer, a film, a region, a plate, or the like is “directly on” another component, or when such a component is “on” the surface of another component, this means that no other component is present in between.
[0027] The terminology used in the description of the various embodiments of this disclosure is intended to describe only certain embodiments and is not intended to be restrictive. As used in the description of the various embodiments and the appended claims, the term "the part" is intended to include the plural form unless the context clearly indicates otherwise. The components include, for example, layers, films, areas, or plates.
[0028] The embodiments of the present disclosure are described in detail with reference to the accompanying drawings. However, it should be understood by those skilled in the art that many technical details in the embodiments of the present disclosure are proposed to facilitate a better understanding of the disclosure. Nevertheless, the technical solutions claimed in the present disclosure can also be realized without these technical details and with various modifications and variants based on the following embodiments.
[0029] Fig. Figure 1 is a schematic structural diagram of a solar cell according to some embodiments of the present disclosure. Fig. 2 is a section view along a line A1-A2 in Fig. 1.
[0030] With reference to Fig. 1 and Fig. 2. According to some embodiments of the present disclosure, a solar cell is provided which includes a front surface 10 and a rear surface 20 facing each other. The front surface 10 and the rear surface 20 have metal regions 11 and non-metal regions 12, wherein the metal regions 11 in the front surface 10 and the metal regions 11 in the rear surface 20 may not exactly coincide. The solar cell further includes a doped region 120 formed in the front surface 10 of the substrate 100. The doped region includes first subdoped regions 121 formed in a section of the front surface 10 of the substrate 100 corresponding to the metal regions 11.The solar cell further includes first electrodes 106, which are arranged over the first subdoped regions 121 and electrically connected to them; a passivation contact structure, which is arranged on a section of the rear surface 20 corresponding to the metal regions 11; and second electrodes 116, which are arranged over the passivation contact structure and electrically connected to it. Thus, the doped region 120 is formed in the front surface 10 of the solar cell, with a section located on the metal regions 11 and a portion of the non-metal regions 12. The first subdoped regions 121, located in the metal regions 11, form a highly doped region with low resistance, thereby reducing metal recombination at the first electrodes 106 and the contact resistance between the first electrodes 106 and the first subdoped regions 121.In the other part of the non-metallic regions 12, no doped regions 120 are provided, which means that no heavily doped regions are formed, thereby reducing the charge carrier recombination rate in the non-metallic regions 12 on the front surface 10.
[0031] Furthermore, the passivation contact structure formed on the rear surface 20, corresponding to the metal areas 11, can ensure the passivation performance of the areas in which the metal areas 11 are arranged and the highly doped concentration of the areas that are touched by the second electrodes 116.
[0032] With reference to Fig. 2 In some embodiments, the material of the substrate 100 can be an elemental semiconductor material. In particular, the elemental semiconductor material consists of a single element, for example, silicon or germanium. The elemental semiconductor material can be in a monocrystalline state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state with both monocrystalline and amorphous properties, referred to as the microcrystalline state). For example, the silicon can be at least one selected from monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.
[0033] In some embodiments, the substrate 100 material can also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, and copper indium selenide. The substrate 100 can also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.
[0034] In some embodiments, the substrate 100 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant, which can be any element of group V, such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate 100 is doped with a P-type dopant, which can be any element of group III, such as boron (B), aluminum (Al), gallium (Ga), or indium (In).
[0035] In some embodiments, the substrate 100 has a front surface 10 and a rear surface 20 facing each other. The solar cell is a single-sided cell in which the front surface 10 can serve as a light-receiving surface for receiving incident light, and the rear surface 20 serves as a backlighting surface. The rear surface can also receive incident light, but its efficiency in receiving incident light is lower than that of the light-receiving surface.
[0036] In some embodiments, the metal regions 11 refer to areas corresponding to orthographic projections of the first electrodes 106 above the substrate 100, and the non-metal regions 12 refer to areas outside the orthographic projections of the first electrodes 106 above the substrate 100. To ensure that the foil layer contacted by the first electrodes 106 has a high doping concentration, or that all areas contacted by the first electrodes 106 are heavily doped sections of the doped region 120, the area of the metal regions 11 is generally adjusted to be greater than or equal to the area of the orthographic projections of the first electrodes 106 above the substrate 100.
[0037] In some embodiments, the doping element in the doped region 120 differs from the doping element in the substrate 100. The substrate 100 may be doped with one N-type doping element and one P-type doping element, and the doped region 120 may be doped with another N-type doping element and one P-type doping element.
[0038] In some embodiments, with reference to Fig. 1. The width of the first subdoped regions 121 along the arrangement direction X thereof is in a range of 20 µm to 500 µm. This width range ensures that the regions directly facing the first electrodes 106 are completely covered by the first subdoped regions 121. And since the regions where the PN junction is formed, i.e., the regions that generate electrons or holes, are relatively large, this contributes to higher cell efficiency. This width range also helps to minimize the number of recombination centers formed by heavy doping on the surface of the substrate 100, thereby reducing the charge carrier recombination rate at the substrate surface.
[0039] In some embodiments, the width of the first subdoped regions 121 along the arrangement direction X can be 20 µm, 53 µm, 88 µm, 120 µm, 210 µm, 380 µm or 500 µm.
[0040] With reference to Fig. 3 The doped region further includes second subdoped regions 122 formed in the front surface 10 of the substrate 100, corresponding to a first section of the non-metal regions 12. Each of the second subdoped regions 122 connects two adjacent first subdoped regions 121, thereby enabling electrical transport between the two adjacent first subdoped regions 121 and reducing lateral transport resistance. Furthermore, the presence of the second subdoped regions 122 provides lateral transport capability between the electrodes. To ensure strong lateral transport capability, the distance between two adjacent first electrodes 106 can be increased, thereby reducing the total number of first electrodes 106 across the front surface 10 and consequently reducing the shading area.
[0041] In some embodiments, one section of the doped region 120 formed in the metal regions 11 functions as an emitter, while another section of the doped region 120 formed in the non-metal regions 12 functions as a transport layer. The transport layers improve the lateral transport capability between adjacent emitters, thereby improving cell efficiency. In particular, the first subdoped regions 121 formed in the metal regions 11 serve as the emitters, and the second subdoped regions 122 formed in the non-metal regions 12 serve as the transport layers.
[0042] In some embodiments, the doped area 120 includes, with reference to Fig. 4, furthermore, third subdoped regions 123 formed in the front surface 10 of the substrate 100, corresponding to a second section of the non-metal regions 12. The third subdoped regions 123 extend in the same direction as the first subdoped regions 121 and are spaced apart from the first subdoped regions 121 and electrically connected to the second subdoped regions 122. The third subdoped regions 123 act as emitters, thereby increasing the areas for electron and hole conversion and improving cell efficiency.
[0043] In some embodiments, the number of third-subdoped regions 123 between adjacent first-subdoped regions 121 ranges from 0 to 10. This number of third-subdoped regions 123 increases the area available for electron-hole conversion. For the substrate 100 in the non-metal regions 12, the areas not covered by the doped region 120 can reduce the surface recombination rate of the substrate 100, thereby minimizing losses in the substrate 100 itself and improving cell efficiency.
[0044] In some embodiments, the number of third subdoped regions 123 between adjacent first subdoped regions 121 can be 2, 5, 7 or 9.
[0045] In some embodiments, the width of the third subdoped region 123 along the arrangement direction of the first subdoped regions 121 is defined as a first width, and the width of the first subdoped region 121 along the arrangement direction thereof is defined as a second width, the first width being less than or equal to the second width. With this configuration, the third subdoped regions 123 can be designed with smaller dimensions, which not only reduces the area through which two adjacent regions are transferred to the third subdoped regions 123, but also avoids the problem of an increased surface recombination rate of the substrate 100 caused by an excessive number of third subdoped regions 123.
[0046] In some embodiments, the distance between each of the first subdoped regions 121 and a corresponding third subdoped region 123, or the distance between adjacent third subdoped regions 123, can be in a range of 100 µm to 1000 µm. The distance can be 120 µm, 203 µm, 420 µm, 560 µm, 710 µm, 860 µm, or 980 µm.
[0047] In some embodiments, along the arrangement direction of the first electrodes 106, the ratio of the total width of the orthographic projections of the first subdoped areas 121 and the third subdoped areas 123 on the front surface 10 to the width of the front surface 10 can be in a range of 3% to 40%. This ensures that the area of the doped area 120 is relatively large, providing a larger conversion area for photogenerated charge carriers, thus resulting in a higher open-circuit voltage and increased cell efficiency. Meanwhile, the series resistance between the first electrodes 106 and the doped area 120 is relatively low, leading to lower electrical losses in the cell.
[0048] In some embodiments, the ratio of the total width of the orthographic projections of the first subdoped areas 121 and the third subdoped areas 123 on the front surface 10 to the width of the front surface 10 can be 3%, 8%, 12%, 18%, 26%, 33%, 35% or 39%.
[0049] In some embodiments, further referring to Fig. 1. The width of the second subdoped region 122 along the extension direction of the first electrodes 106 lies in a range of 50 µm to 600 µm. The width of the second subdoped region 122 along the extension direction Y of the first electrodes 106 can be 53 µm, 88 µm, 120 µm, 210 µm, 380 µm, 500 µm, or 600 µm.
[0050] In some embodiments, along the extension direction of the first electrodes 106, the ratio of the total width of the orthographic projection of the second subdoped areas 122 on the front surface 10 to the length of the front surface 10 can be in a range of 2% to 20%. The ratio of the total width of the orthographic projections of the second subdoped areas 122 on the front surface 10 to the length of the front surface 10 can be 3%, 5%, 6%, 8%, 12%, 15%, 18%, or 20%.
[0051] With reference to Fig. The doped region 120 further includes fourth subdoped regions 124. The fourth subdoped regions 124 are formed in the front surface 10 of the substrate 100, which corresponds to a third section of the non-metallic regions 12. The direction of extension of the fourth subdoped regions 124 is the same as the direction of extension of the second subdoped regions 122, and the fourth subdoped regions 124 are spaced apart from the second subdoped regions 122. The fourth subdoped regions 124 are electrically connected to the first subdoped regions 121 and the third subdoped regions 123.
[0052] In some embodiments, along the extension direction Y of the first electrodes 106, the width of the fourth subdoped region 124 is less than or equal to the width of the second subdoped region 122.
[0053] In some embodiments, the distance between each of the second subdoped regions 122 and a corresponding fourth subdoped region 124, or the distance between adjacent fourth subdoped regions 124, can be in a range of 200 µm to 1 cm. The distances can be 203 µm, 420 µm, 560 µm, 710 µm, 860 µm, 1300 µm, or 6800 µm.
[0054] In some embodiments, further referring to Fig. 2, when the orthographic projections of the passivation contact structure on the rear surface 20 overlap with the orthographic projection of the doped area 120 on the rear surface 20, there are no lateral transport areas for electrons and holes within the substrate 100, thereby shortening the transport path and improving the efficiency of electron collection.
[0055] In some embodiments, with reference to Fig. 6. The orthographic projections of the passivation contact structure on the rear surface 20 partially overlap with the orthographic projections of the doped area 120 on the rear surface 20, and the overlap area is greater than or equal to 0.4 times the area of the doped area 120. This overlapping area ensures a shorter lateral transport path for charge carriers on the front surface 10, allowing the charge carriers to be collected more quickly from the second electrodes 116 via the rear surface 20. Furthermore, the mutual offset between the doped area 120 and the passivation contact structure allows for the processing of different areas of the substrate 100, thus avoiding safety issues caused by excessive mechanical operations in a single area that could lead to local thinning of the substrate 100.Meanwhile, the non-overlapping electrode collection areas can also collect charge carriers from different regions of the electrodes, thereby improving the efficiency of charge carrier collection. To illustrate the partial overlap between the orthographic projections of the passivation contact structure and the orthographic projections of the doped region 120 on the rear surface 20, they are shown offset by a first distance L.
[0056] With reference to Fig. Figure 2 includes the passivation contact structure comprising a dielectric tunnel layer 131 and a doped conductive layer 132. The dielectric tunnel layer 131 is arranged on the rear surface 20 of the substrate 100, and the doped conductive layer 132 is arranged on the surface of the dielectric tunnel layer 131. The doped conductive layer 132 can be doped with elements of the same conductivity type as the substrate 100. The material of the dielectric tunnel layer 131 can include at least one selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and magnesium fluoride. The material of the doped conductive layer 132 can include at least one selected from the group consisting of monocrystalline silicon, amorphous silicon, polycrystalline silicon, and silicon carbide.
[0057] In some embodiments, the doped conductive layer can induce band bending at the surface of the substrate 100, while the dielectric tunneling layer 131 causes an asymmetric offset in the energy bands at the substrate surface. This results in a lower energy barrier for majority carriers compared to minority carriers. Therefore, majority carriers can readily undergo quantum tunneling through the dielectric tunneling layer 131, while minority carriers are largely blocked, enabling selective charge carrier transport.
[0058] Furthermore, the dielectric tunnel layer 131 provides chemical passivation. In particular, interfacial defects exist at the interface between the substrate 100 and the dielectric tunnel layer 131, leading to a high interfacial density of states on the rear surface 20 of the substrate 100. An increase in the interfacial density of states promotes the recombination of photogenerated charge carriers, which increases the fill factor, short-circuit current, and open-circuit voltage of the solar cell, thus improving the photovoltaic conversion efficiency of the solar cell. The presence of the dielectric tunnel layer 131 on the rear surface 20 of the substrate 100 facilitates the chemical passivation of the substrate surface by saturating free bonds, reducing the defect density of states of the substrate 100, and decreasing recombination centers, thereby lowering the charge carrier recombination rate.
[0059] In some embodiments, the thickness of the dielectric tunneling layer 131 is in the range of 0.5 nm to 5 nm. The thickness of the dielectric tunneling layer 131 can be in the range of 0.5 nm to 1.3 nm, 1.3 nm to 2.6 nm, 2.6 nm to 4.1 nm, or 4.1 nm to 5 nm. If the dielectric tunneling layer 131 has a thickness within one of the aforementioned ranges, it is relatively thin, so that majority carriers can more easily undergo quantum tunneling through the dielectric tunneling layer 131, while minority carriers are more difficult to tunnel through the dielectric tunneling layer 131, thereby achieving selective transport of charge carriers.
[0060] In some embodiments, the doped conductive layer 132 provides a field passivation effect. In particular, an electric field directed towards the interior of the substrate 100 is generated on the surface of the substrate 100, causing minority carriers to escape from the interface. This reduces the minority carrier concentration and decreases the charge carrier recombination rate at the interface of the substrate 100. As a result, the open-circuit voltage, short-circuit current, and fill factor of the solar cell are increased, thereby improving the photoelectric conversion efficiency of the solar cell.
[0061] In some embodiments, the substrate 100 is doped with N-type elements, and the doped conductive layer 132 is also doped with N-type elements. The N-doped element promotes uniform grain formation and a single-crystal structure in the doped conductive layer 132. Additionally, the N-doped conductive layer 132 is characterized by smaller particle sizes, a higher density of grain boundaries, and improved uniformity.
[0062] In some embodiments, the rear surface 20 has a first textured structure in the metal regions 11, while the rear surface 20 has a second textured structure 114 in the non-metal regions 12, the roughness of the first textured structure being less than that of the second textured structure 114. The second textured structure 114 includes a plurality of second projection structures 104, which may be pyramidal structures or platform projection structures.
[0063] In some embodiments, the front surface 10 has a textured structure 111 that includes a plurality of first projection structures 101. The first projection structures can be pyramid structures or platform projection structures.
[0064] In some embodiments, the front surface 10 has a third textured structure in the metal areas 11, while the front surface 10 has a fourth textured structure in the non-metal areas 12, wherein the roughness of the fourth textured structure is greater than or equal to that of the third textured structure.
[0065] It should be noted that each of the aforementioned first, second, third, or fourth textured structures, as well as the general textured structure, can function as a light-trapping structure. The inclined surfaces of these light-trapping structures improve the internal reflection of incident light, thereby enhancing the absorption and utilization of incident light by substrate 100 and consequently increasing the efficiency of the solar cell.
[0066] In some embodiments, the distance between the surface of the substrate 100 including the doped region 120 and the rear surface 20 is defined as a first distance, while the distance between the surface of the substrate 100 excluding the doped region 120 and the rear surface 20 is defined as a second distance, the first distance being greater than the second distance.
[0067] In some embodiments, which are based on Fig. 3. Referring to the solar cell, the solar cell further includes main electrodes 107. The extension direction of the main electrodes 107 intersects with the first electrodes 106, and the orthographic projections of the main electrodes 107 on the front surface 10 are located within the second subdoped regions 122.
[0068] In some embodiments, the solar cell further includes a first passivation layer 105, which covers the surface of the doped region 120 away from the substrate, and the surface of the substrate 100, which does not include the doped region 120.
[0069] In some embodiments, the first passivation layer 105 may have a single-layer or multi-layer structure and may be made of one or more materials selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxynitride, titanium oxide, hafnium oxide and aluminum oxide.
[0070] In some embodiments, the solar cell further includes a second passivation layer 115, which covers the surface of the doped conductive layer 132 and the rear surface 20 of the substrate 100 that is not covered by the passivation contact structure. The second passivation layer 115 can have a single-layer or multi-layer structure and can be made of one or more materials selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxynitride, titanium oxide, hafnium oxide, and aluminum oxide.
[0071] In some embodiments, the first electrodes 106 can be formed by sintering burn-through pastes. The method for forming the first electrodes 106 includes: printing a metal paste onto a section of the first passivation layer 105 using a screen printing process. The metal pastes can include at least one of silver, aluminum, copper, tin, gold, lead, or nickel. Subsequently, a sintering process is carried out on the metal paste. Since the metal pastes contain highly corrosive components such as glass frit, these corrosive components etch through the first passivation layer 105 during the sintering process, allowing the metal pastes to penetrate the first passivation layer 105 and come into electrical contact with the first subdoped regions 121.
[0072] In some embodiments, the first electrodes 106 can be formed by sintering LECO pastes (laser-enhanced contact optimization pastes), wherein part of the LECO pastes corrode the first passivation layer 105 and come into contact with the first subdoped areas 121 or connect electrically with the first subdoped areas 121 through crystals.
[0073] In some embodiments, the second electrodes 116 can be formed by sintering burn-through pastes. The method for forming the second electrodes 116 involves printing a metal paste onto a section of the second passivation layer 115 using a screen printing process. The metal pastes can include at least one of silver, aluminum, copper, tin, gold, lead, or nickel. Subsequently, a sintering process is performed on the metal pastes. Since the metal pastes contain highly corrosive components such as glass frit, these corrosive components etch through the second passivation layer 115 during the sintering process, allowing the metal pastes to penetrate the second passivation layer 115 and come into contact with the doped conductive layer 132.
[0074] In some embodiments, the second electrodes 116 can be formed by sintering LECO pastes, wherein a section of the LECO pastes corrodes the second passivation layer 115 and comes into contact with the doped conductive layer 132 or forms an electrical connection with the doped conductive layer 132 by means of crystals.
[0075] In the solar cell provided in the preceding embodiments, the doped region 120 is formed in the front surface 10 of the solar cell, and the doped region 120 is located in the metal regions 11 and a portion of the non-metal regions 12 of the solar cell. The first subdoped regions 121, located in the metal regions 11, can form a highly doped region with low resistance, thereby reducing the metal recombination of the first electrodes 106 and the contact resistance between the first electrodes 106 and the first subdoped regions 121. For the other portion of the non-metal regions 12, no doped region 120 is provided; that is, no highly doped regions are formed, thereby reducing the charge carrier recombination rate of the front surface 10 in the non-metal regions 12.
[0076] Furthermore, the passivation contact structure formed on the rear surface 20 in the metal areas 11 can ensure the passivation performance of the areas in which the metal areas 11 are located and the highly doped concentration of the areas contacted by the second electrodes 116.
[0077] Therefore, in some embodiments of the present disclosure, a further aspect of the embodiments of the present disclosure also provides a method for manufacturing a solar cell in order to provide the solar cell described in the embodiments above. The same or corresponding technical features as those in the embodiments above are not described in detail here. As an example, a method for manufacturing the solar cell described in Fig. The solar cell shown in the 3 images was used.
[0078] With reference to Fig. 7 and Fig. 8 includes the solar cell metal regions 11 and non-metal regions 12. The manufacturing process includes: providing a substrate that includes a front surface and a rear surface facing each other. In particular, a starting substrate 117 is provided. Referring to Fig. 9. One side of the initial substrate 117 is subjected to a texturing treatment, such that one side of the initial substrate 117 has a textured structure 111. The textured structure 111 includes a plurality of first projection structures 101.
[0079] In some embodiments, the texturing treatment includes chemical etching. For example, a mixed solution of potassium hydroxide and hydrogen peroxide can be used to purify the starting substrate 117. In particular, the ratio of the concentrations of potassium hydroxide and hydrogen peroxide solution can be controlled to form a textured structure with a desired morphology. In some embodiments, the textured structure can also be formed by laser etching, mechanical processes, or plasma etching. In the case of laser etching, the morphology of the textured structure can be controlled by adjusting the laser process parameters.
[0080] With reference to Fig. 10 and Fig. 11 A doped region 120 is formed on the surface of the substrate 100. The doped region 120 includes first subdoped regions 121 on the front surface of the substrate 100, which correspond to the metal regions 11.
[0081] In some embodiments, the doped region further includes second subdoped regions 122 formed in the front surface of the substrate 100, corresponding to a first section of the non-metallic regions 12, and a respective second subdoped region connecting two adjacent first subdoped regions 121.
[0082] In some embodiments, referring to Fig. 7, the front surface 10, first machining areas 21 and first non-machining areas 22. A method for forming the doped area 120 includes: with reference to Fig. 10. Performing a doping treatment on the front surface 10 of the starting substrate 117 such that a section of the thickness of the starting substrate 117 is converted into a doped layer; referring to Fig. 11, Removal of the doped layer in the first machining area, while the doped layer is retained as doped area 120 in the first non-machining areas, the doped area 120 serving as the first subdoped areas 121 in the metal areas 11 and the doped area 120 serving as the second subdoped areas 122 in the first section of the non-metal areas 12.
[0083] In some embodiments, the front surface 10 includes secondary processing areas and secondary non-processing areas. One method for forming the doped area 120 includes: performing a laser doping treatment on the secondary processing areas of the substrate 100, such that a section of the substrate 100 is converted into the doped area 120.
[0084] In some embodiments, the parameters of the laser doping treatment include: a laser frequency of 400 kHz to 1200 kHz; a laser spot size of 60 µm to 200 µm; a laser energy of 1 W to 20 W; a laser scan speed of 3000 m / s to 50000 m / s; and a laser overlap ratio of 50% to 90%.
[0085] With reference to Fig. 12-14 a passivation contact structure is formed on the rear surface 20 in the metal areas 11.
[0086] In some embodiments, which are based on Fig. With reference to 12, a dielectric film 102 is formed on the rear surface, and a doped conductive film 103 is formed on the surface of the dielectric film 102. Fig. 13 The dielectric foil and the doped conductive foil are removed in the non-metallic regions 12, the remaining dielectric foil serving as a dielectric tunnel layer and the remaining doped conductive foil serving as a doped conductive layer. With reference to Fig. 14 The starting substrate 117 is etched in the non-metallic areas 12 to form a second textured structure on the rear surface of the starting substrate 117, with the remaining starting substrate 117 serving as substrate 100.
[0087] In some embodiments, the removal of the dielectric layer and the doped conductive layer in the non-metal regions 12 and the formation of the second textured structure on the surface of the starting substrate 117 in the non-metal regions 12 can be achieved in a single operation.
[0088] With reference to Fig. In step 15, a first passivation layer 105 and a second passivation layer 115 are formed. The first passivation layer 105 covers the surface of the doped region 120 and the surface of the substrate 100, excluding the doped region 120. The second passivation layer 115 covers the surface of the doped conductive layer 132 and the rear surface of the substrate 100 that is not covered by the passivation contact structure.
[0089] With reference to Fig. 2. First electrodes 106 are formed above the substrate 100, corresponding to the metal regions 11 and electrically connected to the first subdoped regions 121. Second electrodes 116 are formed above the passivation contact structure, corresponding to the metal regions 11, which are electrically connected to the passivation contact structure.
[0090] Accordingly, in some embodiments of the present disclosure and with reference to Fig. 16 Another aspect of the embodiments of the present disclosure is a tandem cell comprising: a lower cell, which is the solar cell according to one of the preceding embodiments or a solar cell produced by the manufacturing processes according to one of the preceding embodiments; and an upper cell, which is arranged on one side of the lower cell remote from the first and second electrodes of the substrate. Fig. Figure 18 is a schematic cross-sectional structure diagram of a tandem cell according to yet another embodiment of the present disclosure.
[0091] In some embodiments, the tandem cell includes first grid lines 186 with a first polarity and second grid lines with a second polarity. The first grid lines 186 are in electrical contact with the upper cell 180, and the second grid lines are in electrical contact with the lower cell 150. The second grid lines are the first electrodes 106 of the lower cell.
[0092] In some embodiments, an interface layer 181 is arranged between the upper cell and the lower cell, and the interface layer 181 also covers the passivation contact structure.
[0093] It should be noted that the tandem cell in the embodiments of the present disclosure illustrates only two solar cell layers. Depending on the actual requirements, a person skilled in the art can arrange three solar cell layers or multilayer tandem solar cells with more than three layers.
[0094] In some embodiments, the upper cell 180 can be a perovskite solar cell comprising: a first transport layer 182, a perovskite absorber layer 183, a second transport layer 184, a transparent conductive layer 185, and an antireflection layer (not shown), stacked sequentially. The first transport layer faces the lower cell.
[0095] In some embodiments, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be either the other electron transport layer or the hole transport layer.
[0096] Accordingly, in some embodiments of the present disclosure, a further aspect of the embodiments of the present disclosure provides a photovoltaic module. The module includes the solar cell provided in the preceding embodiments, and since the technical features are identical or correspond to those in the preceding embodiments, they will not be explained in detail here.
[0097] With reference to Fig. 17 and Fig.18 The photovoltaic module includes: at least one cell string formed by electrically connecting a plurality of solar cells according to one of the preceding embodiments, solar cells manufactured by the manufacturing process according to one of the preceding embodiments, or tandem cells as described in the preceding embodiments; a connecting element 218 for electrically connecting two adjacent solar cells 20; at least one encapsulation film 21 covering the surface of the at least one cell string; and at least one cover plate 22 covering the surface of the at least one encapsulation film 21 facing away from the at least one cell string.
[0098] In particular, in some embodiments, the plurality of solar cells can be electrically connected via the connecting element 218, which is welded to the busbars on the solar cells. The busbars include a main electrode 107, which is electrically connected to the first electrodes 106, and a main electrode, which is electrically connected to the second electrodes 116.
[0099] In some embodiments, there is no gap between the solar cells, meaning the solar cells overlap.
[0100] In some embodiments, the connecting element 218 is welded to the solar cells with the fingers 208. The fingers enclose the first electrodes 106 and the second electrodes 116.
[0101] In some embodiments, the at least one encapsulation film 21 includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front or rear surfaces of the solar cell, and the second encapsulation layer covers the other of the front or rear surfaces of the solar cell. In particular, at least one of the first and second encapsulation layers can be an organic encapsulation film, such as a polyvinyl butyral film (PVB film), an ethylene vinyl acetate copolymer film (EVA film), a polyolefin elastomer (POE) film, or a polyethylene terephthalate (PET) film.
[0102] It should be noted that before the lamination process, a boundary exists between the first and second encapsulation layers. However, after the lamination process, the concepts of the first and second encapsulation layers no longer apply when forming the photovoltaic module, as the first and second encapsulation layers have fused together to form an integral encapsulation film 21.
[0103] In some embodiments, the cover plate 22 can be a glass cover plate, a plastic cover plate, or other cover plates with a light-transmitting function. In particular, the surface of the cover plate 22 facing the encapsulation film 21 can be a textured surface to increase the utilization of the incident light. The cover plate 22 includes a first cover plate and a second cover plate, wherein the first cover plate corresponds to the first encapsulation layer and the second cover plate corresponds to the second encapsulation layer; or the first cover plate corresponds to one side of the solar cell and the second cover plate corresponds to the other side of the solar cell.
[0104] Those skilled in the art should understand that the embodiments described above are specific implementations of the present disclosure. In practical applications, various changes to form and details can be made without deviating from the scope of protection and the spirit of the present disclosure. Any person skilled in the art can make various changes and modifications without deviating from the spirit and scope of protection of the present disclosure. The scope of protection of the present disclosure is therefore defined by the claims.