Photovoltaic cell, module, and system

Abstract

The present disclosure is applicable to the technical field of photovoltaics, and provides a photovoltaic cell, a module, and a system. The photovoltaic cell comprises a first region and a second region that are arranged adjacent to each other, and the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%. In this way, there is a difference in contrast between the first region and the second region, thereby improving the distinguishability of the two regions.

Description

Photovoltaic cells, modules and systems

[0001] Cross-references to related applications

[0002] This disclosure claims priority to Chinese patent application No. 202510113342.2, filed on January 23, 2025, with the State Intellectual Property Office of China, entitled "A Photovoltaic Cell, Battery Module and Photovoltaic System," and to Chinese patent application No. 202511393927.0, filed on September 26, 2025, with the State Intellectual Property Office of China, both of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure pertains to the field of photovoltaic technology, and particularly relates to a photovoltaic cell, module, and system. Background Technology

[0004] In the manufacturing process of photovoltaic cells, photovoltaic cells are usually set with multiple areas, but these areas are generally similar in color. When it is necessary to distinguish a certain area of ​​a photovoltaic cell from other areas, it is not possible to distinguish them accurately because the overall color of the cell is similar. Therefore, it is necessary to increase the recognizability of the area to be identified in order to distinguish the area that needs to be identified. Summary of the Invention

[0005] This disclosure provides a photovoltaic cell designed to solve the problem of low identification accuracy of the area to be identified in the cell, making it impossible to accurately distinguish the area to be identified.

[0006] This disclosure is implemented as follows: a photovoltaic cell includes a first region and a second region, the first region and the second region are arranged adjacent to each other, and the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%.

[0007] In this embodiment, by setting a first region and a second region, the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%. The difference in reflectance can cause the first region and the second region to have different contrast, so that the first region and the second region can be accurately distinguished, thereby increasing the recognition accuracy of the two regions.

[0008] In some embodiments, on the back surface of the photovoltaic cell, a first region and a second region are arranged alternately along a first direction, the first region and the second region extend along a second direction, and the first direction and the second direction intersect.

[0009] At least one second region extends from a predetermined position along a first direction to an adjacent first region to form a marker point, wherein the first region and the second region have opposite polarities.

[0010] In this embodiment, by setting a first region and a second region, the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%, and an extension extends from the second region to the adjacent first region to form a marker point. Due to the difference in reflectance, the first region and the second region have different contrast, making the marker point formed by the extension point recognizable. This allows for rapid positioning and calibration of the device, greatly improving the recognition accuracy and efficiency of the machine vision system. It also avoids recognition difficulties caused by excessively small reflectance differences.

[0011] In some embodiments, the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is between 5% and 15%.

[0012] In this embodiment, the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is set to 5% to 15%. Increasing the absolute value of the difference in reflectance makes it easier to accurately distinguish between the first region and the second region, thereby enhancing the recognition of the two regions.

[0013] In some embodiments, for light in the 250–400 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 5%.

[0014] To avoid difficulty in identification due to small differences in reflectivity.

[0015] In some embodiments, for light in the 400–600 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 25%.

[0016] To avoid difficulty in identification due to small differences in reflectivity.

[0017] In some embodiments, for light in the 600–900 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.5% and less than 35%.

[0018] To avoid difficulty in identification due to small differences in reflectivity.

[0019] In some embodiments, for light in the 900–1200 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 2% and less than 15%.

[0020] To avoid difficulty in identification due to small differences in reflectivity.

[0021] In some embodiments, for light in the 1200–1400 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 10%.

[0022] To avoid difficulty in identification due to small differences in reflectivity.

[0023] In some embodiments, at a preset position, the second region extends into the adjacent first regions on both sides along a first direction to form a marker point.

[0024] At a preset position, the second region extends into the adjacent first region on both sides along the first direction, making the area of ​​the marker point larger and facilitating recognition by the machine vision system.

[0025] In some embodiments, the device further includes a silicon substrate; the first region includes a first tunneling oxide layer, a first doped layer, a first insulating layer, a second tunneling oxide layer, and a second doped layer sequentially stacked on the silicon substrate.

[0026] The second region includes a second tunneling oxide layer and a second doped layer sequentially stacked on a silicon substrate.

[0027] The different functional layers stacked in the first and second regions result in a difference in thickness between the two regions, which in turn leads to a difference in reflectivity. This makes it easier to accurately distinguish between the first and second regions and enhances the recognizability of the two regions.

[0028] In some embodiments, the first insulating layer is a silicon oxide layer containing a first dopant source.

[0029] Silicon oxide, as an insulating layer, has good insulating properties and chemical stability. Doping silicon oxide with a first dopant source is beneficial to improving the doping uniformity of the doped layer, thereby improving the electrical performance of photovoltaic cells.

[0030] In some embodiments, the first insulating layer is a silicon oxide layer containing a boron-doped source.

[0031] Boron doping can reduce surface recombination on silicon substrates, improve the open-circuit voltage and photoelectric conversion efficiency of cells, and optimize the electrical performance of photovoltaic cells.

[0032] In some embodiments, the first doped layer is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0033] Doped polycrystalline silicon layers, doped microcrystalline silicon layers, and doped amorphous silicon layers can effectively transport photogenerated carriers and improve the electrical performance of batteries.

[0034] In some embodiments, the first doped layer is one of a P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, or a P-type doped amorphous silicon layer.

[0035] Setting the first doped layer to any one of a P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, or a P-type doped amorphous silicon layer can significantly improve the performance and efficiency of the battery by forming a barrier effect, providing field passivation, improving metal electrode contact, achieving carrier transport selectivity, and extending minority carrier lifetime.

[0036] In some embodiments, the first tunneling oxide layer and the second tunneling oxide layer are one or more of the following: oxide layer, nitride layer, oxynitride layer, carbide layer, and amorphous silicon layer.

[0037] The first and second tunneling oxide layers are designed to include oxide layers, such as titanium dioxide (TiO2), zinc oxide (ZnO), and silicon dioxide (SiO2). Titanium dioxide (TiO2) layer has high reflectivity (approximately 2.4%), serving as an anti-reflective layer to improve light absorption. Zinc oxide (ZnO) layer is a transparent conductive material that can simultaneously improve light transmittance and conductivity. Simultaneously, zinc oxide has low reflectivity (approximately 2.0%), reducing light reflection. Silicon dioxide (SiO2) layer has stable insulating properties, preventing charge leakage; its fabrication process is mature and easily achieved through mature processes such as thermal oxidation. Alumina (Al2O3) layer has a high breakdown voltage, enabling stable operation under high voltage. Furthermore, alumina possesses excellent insulating properties, further improving device reliability.

[0038] In some embodiments, the photovoltaic cell further includes a second insulating layer that covers the outermost layer of the first region and the second region.

[0039] The second insulating layer provides protection for the internal structure of the photovoltaic cell.

[0040] In some embodiments, the thickness of the second insulating layer in the first region and the second region is different.

[0041] The second insulating layer can usually be deposited using chemical vapor deposition (CVD). The thickness of the second insulating layer in each region can be easily controlled and adjusted, which is convenient for production and manufacturing. Furthermore, by setting different thicknesses of the second insulating layer in the first and second regions, the reflectivity of the first and second regions can be changed, resulting in different contrast between the first and second regions. This makes it easier to accurately distinguish between the first and second regions and enhances the recognizability of the two regions.

[0042] In some embodiments, the second insulating layer is a silicon oxide layer containing a second dopant source.

[0043] Silicon oxide has good insulating properties and chemical stability as an insulating layer. Doping silicon oxide with a second dopant source is beneficial to improving the electrical performance of photovoltaic cells.

[0044] In some embodiments, the second insulating layer is a silicon oxide layer containing a phosphorus doped source.

[0045] Phosphorus doping enhances charge trapping ability, improves charge transport performance of photovoltaic cells, improves optical contrast and recognition accuracy of markers, and enhances overall performance of photovoltaic cells.

[0046] In some embodiments, the second doped layer is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0047] Doped polycrystalline silicon layers, doped microcrystalline silicon layers, and doped amorphous silicon layers can effectively transport photogenerated carriers and improve the electrical performance of batteries.

[0048] In some embodiments, the second doped layer is one of an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer, or an N-type doped amorphous silicon layer.

[0049] Setting the second doped layer as any one of an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer, or an N-type doped amorphous silicon layer can significantly improve the performance and efficiency of the battery by forming a barrier effect, providing field passivation, improving metal electrode contact, achieving carrier transport selectivity, and extending minority carrier lifetime.

[0050] In some embodiments, the thickness of the first doped layer is 50–300 nm.

[0051] When the thickness of the first doped layer is 50–300 nm, the contrast difference between the first and second regions is large, and the markers can be more accurately identified by the equipment.

[0052] In some embodiments, the thickness of the first insulating layer is 5–100 nm.

[0053] When the thickness of the first insulating layer is 5–100 nm, the contrast difference between the first and second regions is large, and the marking points can be more accurately identified by the equipment.

[0054] In some embodiments, the marker point is at least one of a circle, square, trapezoid, rhombus, sector, and triangle, to facilitate device identification.

[0055] In some embodiments, the number of markers is at least four.

[0056] Setting the number of markers to at least four helps to accurately position the battery cells, ensuring that each battery cell is the same size and avoiding process errors caused by inaccurate battery cell positioning, which would affect production efficiency and battery performance.

[0057] Optionally, the marking points are set at the edge of the photovoltaic cell grid structure, and are evenly distributed along the four corners of the photovoltaic cell or evenly distributed along the edge of the photovoltaic cell.

[0058] This can prevent the marking points from affecting the light absorption and electrical performance of the battery, while ensuring that the grid structure can be accurately positioned during the battery manufacturing process.

[0059] This disclosure also provides a battery assembly including the aforementioned photovoltaic cell.

[0060] This disclosure also provides a photovoltaic system including the aforementioned battery module. Attached Figure Description

[0061] Figure 1 is a top view schematic diagram of a photovoltaic cell structure provided in this disclosure;

[0062] Figure 2 is a top view schematic diagram of another photovoltaic cell structure provided in this disclosure;

[0063] Figure 3 is a schematic diagram of a cross-sectional structure of a photovoltaic cell provided in this disclosure;

[0064] Figure 4 is a schematic diagram of another photovoltaic cell cross-sectional structure provided in this disclosure.

[0065] Explanation of reference numerals in the attached figures: 100, photovoltaic cell; 110, first region; 120, second region; 121, extension; 101, silicon substrate; 102, first tunneling oxide layer; 103, first doped layer; 104, first insulating layer; 105, second doped layer; 106, second insulating layer; 107, second tunneling oxide layer. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this disclosure and are not intended to limit this disclosure.

[0067] In the description of this disclosure, it should be understood that the terms “length”, “width”, “upper”, “lower”, “left”, “right”, “horizontal”, “top”, “bottom”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0069] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0070] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0071] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this disclosure. Furthermore, at least one of the following may be repeated in different examples: reference numerals and reference letters. This repetition is for simplification and clarity and does not in itself indicate a relationship between at least one of the various embodiments and arrangements discussed. In addition, various specific examples of processes and materials are provided in this disclosure; however, those skilled in the art will recognize at least one of the following: the application of other processes and the use of other materials.

[0072] This disclosure sets up a first region and a second region, where the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%. This difference in reflectance can cause the first region and the second region to have different contrast, making the first region and the second region able to be accurately distinguished and increasing the recognizability of the two regions.

[0073] Example 1

[0074] As shown in Figure 1, this embodiment provides a photovoltaic cell 100, including a first region 110 and a second region 120. The first region 110 and the second region 120 are arranged adjacent to each other, and the absolute value of the difference between the reflectivity of the first region 110 and the reflectivity of the second region 120 is greater than 0.05%.

[0075] In this embodiment, by setting a first region 110 and a second region 120, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.05%. The difference in reflectance can cause the first region 110 and the second region 120 to have different contrast, so that the first region 110 and the second region 120 can be accurately distinguished, thereby increasing the recognition accuracy of the two regions.

[0076] In some embodiments, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is between 5% and 15%, for example, one of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%. By setting the absolute value of the difference between the reflectance of the first region 110 and the second region 120 to 5% to 15%, increasing the absolute value of the reflectance difference makes it easier for the first region 110 and the second region 120 to be accurately distinguished, thereby enhancing the recognizability of the two regions.

[0077] As shown in Figure 1, in some embodiments, the second region 120 extends an extension 121 into the adjacent first region 110 at a preset position to form a marker point.

[0078] In some embodiments, when the first region 110 and the second region 120 are alternately arranged along a first direction, extensions 121 can be provided in multiple second regions 120 to form marker points. For example, extensions 121 can extend from adjacent second regions 120 to adjacent first regions 110 at preset positions to form marker points. By setting multiple sets of marker points, the accuracy of marker point positioning can be improved. The aforementioned marker points can also assist in determining the outline and shape of the battery cell. When it is necessary to determine the outline and shape of the battery cell using marker points, multiple sets of marker points can be set.

[0079] Marker points play a crucial role, using cameras to identify them and align them with photovoltaic cells, ensuring high positioning accuracy throughout the various processes. Setting marker points not only improves positioning accuracy and reduces process errors but also prevents misidentification and breakage, optimizing production efficiency. Through well-designed marker points, the manufacturing quality and production capacity of photovoltaic cells can be significantly improved.

[0080] The first region 110 and the second region 120 are regions of different polarities. For example, the first region 110 may be an N-type region and the second region 120 a P-type region, or vice versa. No specific limitation is made here. By setting the absolute value of the difference in reflectance between the first region 110 and the second region 120 to be greater than 0.05%, it is easier to identify the P-region and the N-region, increasing their difference.

[0081] The silicon substrate 101 has two main surfaces: a light-facing surface and a back-lighting surface. The light-facing surface directly faces the sunlight, while the back-lighting surface is the side facing away from the sunlight. The two surfaces are arranged opposite each other.

[0082] The first region 110 and the second region 120 are arranged adjacent to each other, that is, the first region 110 and the second region 120 are simultaneously arranged on the same side of the photovoltaic cell 100 (e.g., simultaneously arranged on the back surface of the photovoltaic cell 100). Specifically, the first region 110 and the second region 120 can be arranged side by side, or the first region 110 and the second region 120 can be in a wrap-around state (the first region 110 wraps around the second region 120 or the second region 120 wraps around the first region 110), which is not limited here. In a preset position, the second region 120 extends into the first region 110 with an extension portion 121, the extension portion 121 protruding beyond the original boundary of the second region 120, forming a marker point.

[0083] Select a suitable location on the surface of the photovoltaic cell 100 as the preset location for the marker point. This location should be an area that will not significantly affect the light energy absorption of the photovoltaic cell 100, while also facilitating recognition and detection by the machine vision system.

[0084] The first direction can be the lateral direction of the back contact battery, and the second direction can be the longitudinal direction of the back contact battery, with the two directions being perpendicular to each other. Of course, in other embodiments, the first and second directions can also be other directions, for example, they can be the diagonal directions of the silicon substrate 101, and there is no specific limitation here.

[0085] An extension 121 extends from the second region 120 at a preset position to the adjacent first region 110. The extension 121 protrudes from the original extension direction (second direction) of the second region 120, forming a unique shape. Specifically, the extension 121 can be one or more of the following: square, circular, trapezoidal, rhomboid, fan-shaped, triangular, etc. The extension 121 forms a visual mark through the difference in reflectivity, constituting an identification point. In the automated production and testing process of photovoltaic cells 100, it provides a reference point for photovoltaic cells 100. The identification point allows for rapid positioning and calibration of equipment. This mark formed by physical characteristics can greatly improve the recognition accuracy and efficiency of the machine vision system, thereby optimizing the entire manufacturing process.

[0086] When the marker is set in the first area 110 or the second area 120, the marker is not easy to identify because the battery cell is dark in color. This makes it impossible to accurately locate the marker on the battery cell and calibrate the position of the battery cell, which reduces the recognition accuracy and efficiency of the machine vision system. Therefore, the absolute value of the difference between the reflectance of the first area and the reflectance of the second area needs to be greater than 0.05% to create a contrast difference between the two areas, so as to facilitate the identification of the marker.

[0087] The absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 must be greater than 0.05%. That is, the reflectance of the first region 110 can be greater than that of the second region 120, or vice versa. The difference in reflectance between the two regions must be less than -0.05% or greater than 0.05%. Experiments have shown that when the absolute value of the difference in reflectance between the first region 110 and the second region 120 is less than 0.05%, the difference in contrast or color between the two regions is too small to be easily identified. Therefore, the absolute value of the difference in reflectance between the first region 110 and the second region 120 needs to be set to be greater than 0.05% to facilitate the identification of differences in contrast or color between the two regions.

[0088] Reflectivity refers to the proportion of light reflected after it strikes an object's surface, usually expressed as a percentage. Different materials and surface treatment processes significantly affect reflectivity. Different reflectivities in different areas result in different reflected light intensities, causing variations in contrast between these areas. Contrast refers to the degree of difference in brightness or color between different areas in an image; the greater the difference in reflectivity between two areas, the greater the contrast, and the more pronounced the difference between the two areas.

[0089] When testing reflectance, natural light (sunlight) or artificial light (such as a tungsten filament lamp) can be used as the light source, incident perpendicularly to the direction of the sample stage where the photovoltaic cell 100 under test is placed, or incident at an angle of 0 to 90 degrees, such as 20 degrees, 30 degrees, or 40 degrees. The reflectance at different wavelengths can be tested to obtain the detection results. Alternatively, a dedicated reflectance measuring instrument can be used for measurement; this disclosure does not limit the scope of the test.

[0090] The difference in reflectivity between the first region 110 and the second region 120 necessitates the existence of a high-reflectivity region and a first low-reflectivity region. Between the first region 110 and the second region 120, the region with relatively higher reflectivity is the high-reflectivity region, and the region with relatively lower reflectivity is the low-reflectivity region. The high-reflectivity region reflects more light to the device's visual recognition system, while the low-reflectivity region reflects less light. The difference in the intensity of the reflected light collected by the device's visual recognition system from the first region 110 and the second region 120 facilitates the device's identification and positioning of these two regions.

[0091] In this embodiment, by setting a first region 110 and a second region 120, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.05%, and an extension 121 extends from the second region 120 to the adjacent first region 110 to form a marker point. Due to the difference in reflectance, the contrast between the first region 110 and the second region 120 is different, so the marker point formed by the extension 121 can be identified. In this way, the equipment can be quickly located and calibrated through the marker point, which greatly improves the recognition accuracy and efficiency of the machine vision system.

[0092] In some embodiments, for light in the 250–400 nm wavelength band, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.05% and less than 5%. Specifically, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 can be one of 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, and 5%, or other values ​​within the range of 0.05% to 5%, which are not limited here.

[0093] The 250-400nm band mainly covers ultraviolet (UV) light, including UVA (320-400nm) and UVB (280-320nm).

[0094] The absolute value of the reflectance difference is greater than 0.05%. This lower limit ensures that, under ultraviolet conditions, the reflectance difference between the first region 110 and the second region 120 remains significant enough to be recognized by a machine vision system. Even under very weak lighting conditions, a 0.05% reflectance difference provides sufficient contrast.

[0095] The absolute value of the difference in reflectance is less than 5%. This upper limit ensures that the difference in reflectance is not too large, thus avoiding excessive reflection or absorption under certain extreme lighting conditions, which could make it difficult to identify the marker points. At the same time, a smaller difference in reflectance can reduce the thickness of the film layer, thereby reducing the manufacturing cost of the photovoltaic cell 100.

[0096] In some embodiments, for light in the 400–600 nm wavelength band, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.05% and less than 25%. Specifically, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 can be one of 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, and 25%, or other values ​​within the range of 0.05% to 25%, which are not limited here.

[0097] The 400-600nm band includes visible light in the blue (470-490nm), green (530-580nm), and part of the yellow (580-600nm) range.

[0098] The absolute value of the difference in reflectance is greater than 0.05%. This lower limit ensures that, under low-light conditions, the difference in reflectance between the first region 110 and the second region 120 remains significant enough to be recognized by the machine vision system. If the difference in reflectance is less than 0.05%, the contrast difference between the first region 110 and the second region 120 is too small, making the two regions difficult to distinguish.

[0099] The upper limit of the absolute value of the difference in reflectance being less than 25% ensures that the difference in reflectance will not be too large, avoiding excessive reflection under certain extreme lighting conditions, which could exceed the machine's detection limit and affect the response of the recognition system.

[0100] In some embodiments, for light in the 600–900 nm wavelength band, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.5% and less than 35%. Specifically, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 can be one of 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, and 35%, or other values ​​within the range of 0.05% to 35%, which are not limited here.

[0101] The 600–900 nm wavelength range includes red light (620–750 nm) and near-infrared light (750–900 nm). This is to avoid situations where the reflectivity difference is too small under light within this wavelength range, making identification difficult.

[0102] In some embodiments, for light in the 900–1200 nm wavelength range, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 2% and less than 15%. Specifically, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 can be one of 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, and 25%, or other values ​​within the range of 0.05% to 25%, which are not limited here. The 900–1200 nm wavelength range is near-infrared light. This avoids situations where the reflectance difference is too small under light in this wavelength range, making identification difficult.

[0103] In some embodiments, for light in the 1200–1400 nm wavelength range, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 is greater than 0.05% and less than 10%. Specifically, the absolute value of the difference between the reflectance of the first region 110 and the reflectance of the second region 120 can be one of 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, or other values ​​within the range of 0.05% to 10%, which are not limited here. This avoids situations where the reflectance difference is too small to be easily identifiable under light in this wavelength range.

[0104] Example 2

[0105] As shown in Figure 1, in one embodiment, on the back surface of the photovoltaic cell 100, the second region 120 and the first region 110 are arranged alternately along the first direction, and the second region 120 and the first region 110 extend along the second direction, with the first direction and the second direction intersecting.

[0106] At least one second region 120 extends an extension 121 from a first direction at a preset position to an adjacent first region 110 to form a marker point, wherein the second region 120 and the first region 110 have opposite polarities.

[0107] Specifically, on the back surface of the photovoltaic cell 100, several second regions 120 and several first regions 110 are arranged alternately. Different polarity doped layers are disposed within the second regions 120 and the first regions 110, causing the second regions 120 and the first regions 110 to exhibit different polarities. Specifically, the second region 120 can be a P-type region and the first region 110 an N-type region, or vice versa. The second regions 120 and the first regions 110 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of charge carriers.

[0108] In this embodiment, several second regions 120 and several first regions 110 are alternately arranged on the back surface of the photovoltaic cell 100, and the electrodes are disposed on the back surface. This can minimize the shading of light by the electrodes and improve the light absorption efficiency. This improves the overall photoelectric conversion efficiency of the cell.

[0109] Example 3

[0110] As shown in Figure 2, in some embodiments, at a preset position, the second region 120 extends into extensions 121 along a first direction to the adjacent first regions 110 on both sides to form a marker point.

[0111] At a preset position, the second region 120 extends into the adjacent first regions 110 on both sides along the first direction, resulting in a larger area of ​​the marker point and facilitating recognition by the machine vision system. The extensions 121 extending from the second region 120 into the adjacent first regions 110 on both sides can be symmetrical or other asymmetrical arrangements, which are not limited here.

[0112] Specifically, the second region 120 extends rectangular extensions 121 to the adjacent first regions 110 on both sides. The two extensions 121 are symmetrically arranged, and the two extensions 121 and the second region 120 connecting the two extensions 121 together form a square marker.

[0113] Example 4

[0114] As shown in FIG3, in some embodiments, the photovoltaic cell 100 further includes a silicon substrate 101, and in the first region 110, a first tunneling oxide layer 102, a first doped layer 103, a first insulating layer 104, a second tunneling oxide layer 107, and a second doped layer 105 are sequentially stacked on the silicon substrate 101.

[0115] The second region 120 includes a second tunneling oxide layer 107 and a second doped layer 105 sequentially stacked on a silicon substrate 101.

[0116] The polarity of the second doped layer 105 is different from that of the first doped layer 103. Specifically, the first doped layer 103 can be a P-type doped layer and the second doped layer 105 can be an N-type doped layer, or the first doped layer 103 can be an N-type doped layer and the second doped layer 105 can be a P-type doped layer. The first and second polar doped layers form regions with different electrical characteristics, that is, the second region 120 and the first region 110 have different polarities, which supports the formation of the PN junction and the separation of charge carriers.

[0117] The number of functional layers stacked in the first region 110 and the number of functional layers stacked in the second region 120 are different. Light is reflected between the functional layers, resulting in different reflectivities between the first region 110 and the second region 120. This leads to differences in brightness or color between the first region 110 and the second region 120, making it easier to accurately distinguish between the two regions, enhancing the recognizability of the two regions, and making them easier to identify.

[0118] In some embodiments, the thickness of the first insulating layer 104 in the second region 120 and the first region 110 is different.

[0119] Two distinct regions, a second region 120 and a first region 110, are arranged alternately on the backlight surface of the silicon substrate 101. Specifically, a plurality of second regions 120 and a plurality of first regions 110 are arranged alternately along a first direction, and both second regions 120 and first regions 110 extend along a second direction, which intersects the first direction. The second regions 120 and first regions 110 can be arranged alternately along the lateral direction of the silicon substrate 101 and both extend along the longitudinal direction; that is, the first direction can be the lateral direction of the back contact battery, and the second direction can be the longitudinal direction of the back contact battery, and the two are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, they can be the diagonal directions of the silicon substrate 101, and no specific limitation is made here. The second regions 120 and the first regions 110 do not overlap and are arranged adjacent to each other.

[0120] The first tunneling oxide layer 102 typically contacts the silicon substrate 101 on one side and the adjacent doped layer on the other. The first tunneling oxide layer 102 is typically composed of silicon dioxide (SiO2) and is very thin, usually between 1-2 nm. Tunneling occurs in the first tunneling oxide layer 102, allowing electrons to be transported from the silicon substrate 101 to the adjacent doped layer. Although very thin, the first tunneling oxide layer 102 provides additional insulating properties, preventing unwanted charge leakage between different areas.

[0121] The first doped layer 103 forms a highly conductive region for electrode connection or additional charge transport. The first doped layer 103 can be doped polycrystalline silicon, doped microcrystalline silicon, or doped amorphous silicon, or other types of doped layers, which are not limited here.

[0122] Within the second region 120 and the first region 110, the first doped layer 103 can be in direct contact with the first tunneling oxide layer 102, or it can be indirect contact with the first tunneling oxide layer 102 through other functional layers (i.e., other functional layers are also provided between the first tunneling oxide layer 102 and the first doped layer 103). The second doped layer 105 can be in direct contact with the second tunneling oxide layer 107, or it can be indirect contact with the second tunneling oxide layer 107 through other functional layers (i.e., other functional layers are also provided between the second tunneling oxide layer 107 and the second doped layer 105). This is not limited here.

[0123] The thickness and material of the second tunneling oxide layer 107 disposed in the second region 120 and the first tunneling oxide layer 102 disposed in the first region 110 can be the same, or at least one of the thickness and material of the second tunneling oxide layer 107 disposed in the second region 120 and the first tunneling oxide layer 102 disposed in the first region 110 can be different. Specifically, the material and thickness of the second tunneling oxide layer 107 and the first tunneling oxide layer 102 in the second region 120 and the first region 110 are related to the doped layers disposed in the corresponding regions, and are not limited here.

[0124] The first insulating layer 104 provides good insulation properties, preventing charge leakage between different regions. The thickness of the first insulating layer 104 in the second region 120 and the first region 110 is different. Reflectivity is an optical property of a material. When the thickness of the material changes, it affects the propagation path and phase of light in the material, resulting in different optical behaviors, and its reflectivity will also be affected to a certain extent.

[0125] The first insulating layer 104 can typically be deposited using chemical vapor deposition (CVD). The thickness of the first insulating layer 104 in each region can be easily controlled and adjusted, facilitating production and manufacturing. Furthermore, by setting different thicknesses of the first insulating layer 104 in the second region 120 and the first region 110, the reflectivity of the second region 120 and the first region 110 can be changed, resulting in different contrast between the second region 120 and the first region 110. This facilitates the identification of the first region and the second region and improves their recognizability.

[0126] In some embodiments, the first insulating layer 104 is a silicon oxide layer containing a first dopant source.

[0127] Silicon oxide, as an insulating layer, possesses excellent insulating properties and chemical stability. Doping silicon oxide with a first dopant source helps improve the doping uniformity of the doped layer, thereby enhancing the electrical performance of the photovoltaic cell 100. Specifically, the first dopant source can be a boron dopant source, resulting in a borosilicate glass (BSG) layer, or a phosphorus dopant source, resulting in a phosphorus-silicon phosphate (PSG) layer. The choice is not limited here but depends on the actual performance requirements of the photovoltaic cell 100. Since both boron-doped and phosphorus-doped silicon oxide layers are formed during the diffusion process, the silicon wafer doping diffusion process can be optimized, achieving uniform diffusion of the dopant, improving diffusion efficiency, reducing contamination, and enhancing the device's performance and reliability.

[0128] In some embodiments, the first insulating layer 104 is a silicon oxide layer containing a boron dopant source. In this case, the first doped layer 103 is a boron-doped layer, meaning the first region 110 is a P-type region. Specifically, the first insulating layer 104 is a boron-doped silicon oxide layer. Boron doping can reduce surface recombination on the silicon substrate 101, improve the open-circuit voltage and photoelectric conversion efficiency of the cell, optimize the electrical performance of the photovoltaic cell 100, and simultaneously improve the optical contrast and recognition accuracy of the marker points, thus enhancing the overall performance of the photovoltaic cell 100.

[0129] In some embodiments, the first doped layer 103 is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0130] Doping with any one of the following silicon doping layers—polycrystalline silicon, microcrystalline silicon, or amorphous silicon—can significantly improve battery performance and efficiency by creating a barrier effect, providing field passivation, improving metal electrode contact, achieving carrier transport selectivity, and extending minority carrier lifetime. Furthermore, the doping concentration and thickness of any one of these layers can be precisely controlled through various processes, offering high process flexibility.

[0131] In some embodiments, the first doped layer 103 is one of a P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, and a P-type doped amorphous silicon layer. Specifically, the doping source of the first doped layer 103 is boron, and the first doped layer 103 is one of a boron doped polycrystalline silicon layer, a boron doped microcrystalline silicon layer, and a boron doped amorphous silicon layer. Setting the first doped layer as any one of a P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, and a P-type doped amorphous silicon layer can significantly improve the performance and efficiency of the battery by forming a potential barrier effect, providing field passivation, improving metal electrode contact, achieving carrier transport selectivity, and extending minority carrier lifetime.

[0132] In some embodiments, the first tunneling oxide layer 102 and the second tunneling oxide layer 107 are one or more of the following: oxide layer, nitride layer, oxynitride layer, carbide layer, and amorphous silicon layer. For example, the first tunneling oxide layer 102 and the second tunneling oxide layer 107 can be composed of one or more of the following: titanium dioxide layer, zinc oxide layer, silicon oxide layer, aluminum oxide layer, silicon nitride, and silicon oxynitride. The first tunneling oxide layer 102 and the second tunneling oxide layer 107 can have the same structure or material, or they can have different structures or materials, which is not limited here.

[0133] The advantages of using one or more layers of titanium dioxide, zinc oxide, silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride to form the first tunneling oxide layer 102 and the second tunneling oxide layer 107 are as follows: The titanium dioxide (TiO2) layer has a high refractive index (approximately 2.4%), which can serve as an anti-reflective layer and improve light absorption. The zinc oxide (ZnO) layer is a transparent conductive material that can simultaneously improve light transmittance and conductivity. Simultaneously, zinc oxide has a low refractive index (approximately 2.0%), which can reduce light reflection. The silicon dioxide (SiO2) layer has stable insulating properties, preventing charge leakage; its fabrication process is mature and easily prepared using mature processes such as thermal oxidation. The aluminum oxide (Al2O3) layer has a high breakdown voltage, enabling stable operation under high voltage. Furthermore, aluminum oxide has excellent insulating properties, which can further improve the reliability of the device.

[0134] Specifically, the first tunneling oxide layer 102 and the second tunneling oxide layer 107 can be a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, or a combination of a titanium dioxide layer and a zinc oxide layer, or a combination of a zinc oxide layer, a silicon oxide layer, and an aluminum oxide layer. It can also be any combination of at least two of the following: a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, and a silicon oxynitride layer. No limitation is imposed here.

[0135] As shown in Figure 4, in some embodiments, a second insulating layer 106 is also provided on the outermost layer of the first region 110 and the second region 120.

[0136] The second insulating layer 106 is laid on the outermost layer, covering the outermost contours of the first region 110 and the second region 120, including the exposed side surfaces of each functional layer. This protects the internal structure of the battery from the influence of external environmental factors. Special patterns can also be formed on the second insulating layer 106, allowing for further etching of the battery according to these patterns.

[0137] In some embodiments, the absolute value of the thickness difference between the first insulating layer 104 thickness in the second region 120 and the first insulating layer 104 thickness in the first region 110 is 5-45 nm, for example, set to one of 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, or 45 nm. This can enhance the distinguishability of the two regions, enabling the second region 120 and the first region 110 to be accurately differentiated.

[0138] In some embodiments, the second insulating layer 106 is a silicon oxide layer containing a second dopant source.

[0139] Silicon oxide, as an insulating layer, possesses excellent insulating properties and chemical stability. Doping silicon oxide with a second dopant source is beneficial for improving the electrical performance of the photovoltaic cell 100. Specifically, the second dopant source can be a phosphorus dopant source, resulting in a phosphorus-silicon oxide layer (PSG layer), or a boron dopant source, resulting in a borosilicate glass layer (BSG layer). No specific limitation is made here; the choice is made based on the actual performance requirements of the photovoltaic cell 100.

[0140] In some embodiments, the second insulating layer 106 is a silicon oxide layer containing a phosphorus doping source. That is, the second insulating layer 106 is a phosphorus-doped silicon oxide layer. The phosphorus-doped silicon oxide improves the doping uniformity of the underlying doped layer, which is beneficial to improving the charge transport performance of the photovoltaic cell 100. At the same time, it is also beneficial to improve the optical contrast and recognition accuracy of the marker points, thereby improving the manufacturing precision of the photovoltaic cell 100.

[0141] In some embodiments, the second doped layer 105 is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0142] Doped polycrystalline silicon layers, doped microcrystalline silicon layers, and doped amorphous silicon layers can provide a potential barrier effect, effectively transporting photogenerated carriers and improving the electrical performance of the battery. Furthermore, the doping concentration and thickness of any of these layers can be precisely controlled through various processes, offering high process flexibility.

[0143] In some embodiments, the second doped layer 105 is one of an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer, and an N-type doped amorphous silicon layer. Specifically, the doping source of the second doped layer 105 is phosphorus, and the second doped layer 105 is one of a phosphorus doped polycrystalline silicon layer, a phosphorus doped microcrystalline silicon layer, and a phosphorus doped amorphous silicon layer. Setting the second doped layer as any one of an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer, and an N-type doped amorphous silicon layer can significantly improve the performance and efficiency of the battery by forming a potential barrier effect, providing field passivation, improving metal electrode contact, achieving carrier transport selectivity, and extending minority carrier lifetime.

[0144] In some embodiments, the thickness of the first doped layer 103 is 50–300 nm. Laboratory verification shows that when the thickness of the first doped layer 103 is 50–300 nm, the contrast difference between the second region 120 and the first region 110 is large, which is more conducive to identifying the first region and the second region. For example, it can be set to one of 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0145] In some embodiments, the thickness of the first insulating layer 104 is 5–100 nm. Laboratory verification shows that when the thickness of the first insulating layer 104 is 5–100 nm, the contrast difference between the second region 120 and the first region 110 is large, which is more conducive to identifying the first region and the second region. For example, it can be set to one of 5 nm, 6 nm, 7 nm, 80 nm, 90 nm, 100 nm, etc.

[0146] Example 5

[0147] In some embodiments, the number of markers is at least four.

[0148] The fabrication of photovoltaic cells 100 involves multiple processes, including cleaning, diffusion, patterning, and metallization. The purpose of these processes is to perform specific treatments on different areas of the cell. Failure to accurately position these areas can lead to significant process errors and cell failure. The purpose of the marker points is to precisely position the cells. A large silicon wafer (including the silicon substrate 101 and the functional layers deposited on it) is used with the aid of a camera recognition system and automated equipment to place the cells in the correct process location. Setting the number of marker points to at least four facilitates precise cell positioning, ensuring that specific areas of each cell undergo specific processing, and preventing process errors caused by inaccurate cell positioning that could affect production efficiency and cell performance.

[0149] In some embodiments, the number of markers can be set to five, six, seven, eight, etc. When precise positioning of markers on the battery cell is required, the number of markers can be increased to improve positioning accuracy.

[0150] Specifically, the marking points are set on both sides of the solar cell along the extension direction of the solar cell, and the distance between any marking point and the end point of the solar cell is different.

[0151] Example 6

[0152] In some embodiments, the marking points can be set on the edge of the grid line structure of the photovoltaic cell 100, and evenly distributed along the four corners of the photovoltaic cell 100 or evenly distributed along the edge of the photovoltaic cell 100. When the photovoltaic cell 100 is a gridless structure, multiple fine grids are arranged in sequence. In this case, the marking points can be set on the edge of the fine grid line structure of the photovoltaic cell 100 and evenly distributed along the four corners or the edge, or set on the silicon wafer directly below the solder ribbon and evenly distributed along the extension direction of the solder ribbon.

[0153] The grid lines are disposed on the silicon wafer (including the silicon substrate 101 and the functional layers deposited on the silicon substrate 101) and are used to collect and transport photogenerated carriers. The markers are placed at the edges of the grid line structure to avoid the markers affecting the light absorption and electrical performance of the cell, while ensuring that the grid line structure can be accurately positioned during the cell manufacturing process.

[0154] Example 7

[0155] This embodiment provides a battery module, including the photovoltaic cell 100 in the above embodiment.

[0156] The battery module may include multiple photovoltaic cells 100. The multiple photovoltaic cells 100 in the battery module can be connected in series to form a battery string. The battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current output. For example, the connection between the individual cells can be achieved by welding the welding strips, or the connection between the individual battery strings can be achieved by using bus bars.

[0157] The battery module may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulant film (not shown in the figures). The encapsulant film can be filled between the front and photovoltaic glass, the back and backsheet of the photovoltaic cell 100, and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulant film can be EVA film or POE film. The specific choice can be made according to the actual situation and is not limited here.

[0158] Photovoltaic glass can be applied to the encapsulating film on the front side of the photovoltaic cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%. It can protect the photovoltaic cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the photovoltaic cell 100 together, providing sealing, insulation, waterproofing, and moisture protection for the photovoltaic cell 100.

[0159] The backsheet can be attached to the adhesive film on the back of the photovoltaic cell 100. The backsheet provides protection and support for the photovoltaic cell 100, and has reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice is determined based on the specific circumstances and is not limited here. The backsheet, photovoltaic cell 100, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0160] The beneficial effects of the battery module in this embodiment are equivalent to those of the photovoltaic cell 100 described above, and will not be repeated here.

[0161] Example 8

[0162] This embodiment provides a photovoltaic system, including the battery module described in the above embodiment.

[0163] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted, rooftop, and floating power plants, as well as in equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation network as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. A photovoltaic array can be a combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0164] The beneficial effects of the photovoltaic system in this embodiment are equivalent to the beneficial effects of the battery module described above, and will not be repeated here.

[0165] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A photovoltaic cell, comprising a first region and a second region, wherein the first region and the second region are arranged adjacent to each other, and the absolute value of the difference between the reflectance of the first region and the reflectance of the second region is greater than 0.05%.

2. The photovoltaic cell as described in claim 1, wherein, On the back surface of the photovoltaic cell, the first region and the second region are arranged alternately along a first direction, the first region and the second region extend along a second direction, and the first direction and the second direction intersect. At least one of the second regions extends from the first region to the adjacent first region at a preset position to form a marker point, wherein the first region and the second region have opposite polarities.

3. The photovoltaic cell as described in claim 1 or 2, wherein, The absolute value of the difference between the reflectance of the first region and the reflectance of the second region is between 5% and 15%.

4. The photovoltaic cell as described in claim 1 or 2, wherein, For light in the 250–400 nm wavelength range, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 5%.

5. The photovoltaic cell as described in claim 1 or 2, wherein, For light in the 400–600 nm wavelength range, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 25%.

6. The photovoltaic cell as described in claim 1 or 2, wherein, For light in the 600–900 nm wavelength range, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.5% and less than 35%.

7. The photovoltaic cell as described in claim 1 or 2, wherein, For light in the 900–1200 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 2% and less than 15%.

8. The photovoltaic cell as described in claim 1 or 2, wherein, For light in the 1200–1400 nm wavelength band, the absolute value of the difference between the reflectivity of the first region and the reflectivity of the second region is greater than 0.05% and less than 10%.

9. The photovoltaic cell as described in claim 2, wherein, At the preset position, the second region extends the extension portion to the two adjacent first regions along the first direction to form a marker point.

10. The photovoltaic cell as described in claim 1 or 2, wherein, It also includes silicon substrates; The first region includes a first tunneling oxide layer, a first doped layer, a first insulating layer, a second tunneling oxide layer, and a second doped layer sequentially stacked on the silicon substrate; The second region includes the second tunneling oxide layer and the second doped layer sequentially stacked on the silicon substrate.

11. The photovoltaic cell as described in claim 10, wherein, The first insulating layer is a silicon oxide layer containing a first dopant source.

12. The photovoltaic cell as described in claim 11, wherein, The first insulating layer is a silicon oxide layer containing a boron-doped source.

13. The photovoltaic cell as described in claim 10, wherein, The first doped layer is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

14. The photovoltaic cell as described in claim 13, wherein, The first doped layer is one of a P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, or a P-type doped amorphous silicon layer.

15. The photovoltaic cell as described in claim 10, wherein, The first tunneling oxide layer and the second tunneling oxide layer are composed of one or more of the following: oxide layer, nitride layer, oxynitride layer, carbide layer, and amorphous silicon layer.

16. The photovoltaic cell as described in claim 10, wherein, It also includes a second insulating layer, which covers the outermost layer of the first region and the second region.

17. The photovoltaic cell as described in claim 16, wherein, The second insulating layer is a silicon oxide layer containing a second doping source.

18. The photovoltaic cell as described in claim 17, wherein, The second insulating layer is a silicon oxide layer containing a phosphorus dopant source.

19. The photovoltaic cell as described in claim 10, wherein, The second doped layer is one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

20. The photovoltaic cell as described in claim 19, wherein, The second doped layer is one of an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer, or an N-type doped amorphous silicon layer.

21. The photovoltaic cell as described in claim 10, wherein, The thickness of the first doped layer is 50–300 nm.

22. The photovoltaic cell as described in claim 10, wherein, The thickness of the first insulating layer is 5–100 nm.

23. The photovoltaic cell as described in claim 2, wherein, The marker point is at least one of the following: circle, square, trapezoid, rhombus, sector, and triangle.

24. The photovoltaic cell as described in claim 2, wherein, The number of the markers is at least four.

25. The photovoltaic cell as described in claim 24, wherein, The marking points are set on the edge of the photovoltaic cell grid structure and are evenly distributed along the four corners of the photovoltaic cell or evenly distributed along the edge of the photovoltaic cell.

26. A battery module comprising the photovoltaic cell according to any one of claims 1 to 25.

27. A photovoltaic system comprising the battery module of claim 26.

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