Photovoltaic cell, cell assembly and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a photovoltaic cell, a cell assembly and a photovoltaic system, the photovoltaic cell comprises a first area and a second area, the first area and the second area are adjacently arranged, and the absolute value of the difference value of the reflectivity of the first area and the reflectivity of the second area is greater than 0.05%. Due to the fact that the contrast of the first area and the contrast of the second area are different due to the difference of the reflectivity, the first area and the second area can be accurately distinguished, and the identification degree of identification of the two areas is increased.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaic technology, and in particular relates to a photovoltaic cell, a cell assembly and a photovoltaic system. Background Art

[0002] In the manufacturing process of photovoltaic cells, photovoltaic cells are usually provided with multiple areas, but the multiple areas are generally of similar colors. When it is necessary to distinguish a certain area of ​​the photovoltaic cell from other areas, it is impossible to accurately distinguish them due to the similar colors of the entire battery. Therefore, it is necessary to increase the recognition of the area to be identified in order to distinguish the area to be identified. Summary of the invention

[0003] The present invention provides a photovoltaic cell, aiming to solve the problem that the recognition degree of the to-be-identified area of ​​the cell sheet is not high and the to-be-identified area cannot be accurately distinguished.

[0004] The present invention is implemented as follows: a photovoltaic cell includes a first region and a second region, wherein the first region and the second region are adjacently arranged, and 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%.

[0005] In this embodiment, by setting the first area and the second area, the absolute value of the difference between the reflectivity of the first area and the reflectivity of the second area is greater than 0.05%. The difference in reflectivity can cause the contrast of the first area and the second area to be different, so that the first area and the second area can be accurately distinguished, thereby increasing the recognition of the two areas.

[0006] Optionally, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is between 5% and 15%.

[0007] In this embodiment, the absolute value of the difference between the reflectivity of the first area and the reflectivity of the second area is set to 5%-15%. By increasing the absolute value of the difference in reflectivity, the first area and the second area can be more accurately distinguished, thereby enhancing the recognition of the two areas.

[0008] Optionally, for light in a wavelength band of 250-400 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05% and less than 5%.

[0009] Avoid small differences in reflectivity that make identification difficult.

[0010] Optionally, for light in the wavelength band of 400-600 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05% and less than 25%.

[0011] Avoid small differences in reflectivity that make identification difficult.

[0012] Optionally, for light in the wavelength range of 600-900 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.5% and less than 35%.

[0013] Avoid small differences in reflectivity that make identification difficult.

[0014] Optionally, for light in a wavelength band of 900-1200 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 2% and less than 15%.

[0015] Avoid small differences in reflectivity that make identification difficult.

[0016] Optionally, for light in a wavelength band of 1200-1400 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05% and less than 10%.

[0017] Optionally, the first area extends an extension portion toward the adjacent second area at a preset position to form a marking point.

[0018] In this embodiment, by setting the first area and the second area, the absolute value of the difference between the reflectivity of the first area and the reflectivity of the second area is greater than 0.05%, and an extension portion is extended from the first area to the adjacent second area to form a marking point. Due to the difference in reflectivity, the contrast of the first area and the second area is different, so that the marking point formed by the extension portion can be identified, and then the equipment is quickly located and calibrated through the marking point, thereby greatly improving the recognition accuracy and efficiency of the machine vision system.

[0019] Avoid small differences in reflectivity that make identification difficult.

[0020] Optionally, on the backlight surface of the photovoltaic cell, the first area and the second area are alternately arranged along a first direction, the first area and the second area extend along a second direction, and the first direction and the second direction intersect;

[0021] At least one of the first regions extends an extension portion toward an adjacent second region along the first direction at a preset position to form a marking point, and the first region and the second region have different polarities.

[0022] In this embodiment, a plurality of first regions and a plurality of second regions are alternately arranged on the backlight surface of the photovoltaic cell, and the electrodes are arranged on the backlight surface, which can minimize the blocking of light by the electrodes and improve the light absorption efficiency, thereby improving the overall photoelectric conversion efficiency of the cell.

[0023] Optionally, at the preset position, the first area extends an extension portion toward adjacent second areas on both sides along the first direction to form a marking point.

[0024] At the preset position, the first area extends an extension portion along the first direction toward the second areas adjacent to both sides, so that the area of ​​the marking point is larger, which is convenient for recognition by the machine vision system.

[0025] Optionally, it further includes a silicon substrate, and in the first region and the second region, includes a tunneling oxide layer, a first doping layer, and a first insulating layer sequentially stacked on the silicon substrate.

[0026] Optionally, the thickness of the first insulating layer in the first region and the first insulating layer in the second region are different.

[0027] The first insulating layer can usually be deposited by chemical vapor deposition technology CVD (Chemical Vapor Deposition), and the thickness of the first insulating layer in each area can be easily controlled and adjusted, which is convenient for production and manufacturing. In addition, by setting the thickness of the first insulating layer in the first area and the second area to be different, the reflectivity of the first area and the second area can be different by changing the thickness of the first insulating layer, resulting in different contrast between the first area and the second area, which is more conducive to accurately distinguishing the first area and the second area, thereby enhancing the recognition of the two areas.

[0028] Optionally, the first insulating layer is a silicon oxide layer containing a first doping source.

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

[0030] Optionally, the first insulating layer is a silicon oxide layer containing a phosphorus doping source.

[0031] The doping of phosphorus enhances the charge capture capability and improves the charge transfer performance of photovoltaic cells, which is beneficial to improving the optical contrast and recognition accuracy of the marking points and also enhances the overall performance of photovoltaic cells.

[0032] Optionally, the first doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0033] Doping a polycrystalline silicon layer, a microcrystalline silicon layer or an amorphous silicon layer can effectively transmit photogenerated carriers and improve the electrical performance of the battery.

[0034] Optionally, the first doped layer is an N-type doped polysilicon layer, an N-type doped microcrystalline silicon layer, or an N-type doped amorphous silicon layer.

[0035] Setting the first doped layer as an N-type doped polycrystalline silicon layer or 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.

[0036] Optionally, the tunneling oxide layer is one or more of an oxide layer, a nitride layer, a nitride oxide layer, a carbide layer, and an amorphous silicon layer.

[0037] The titanium dioxide (TiO2) layer has a high reflectivity (about 2.4%) and can be used as an anti-reflection layer to increase the light absorption rate. The zinc oxide (ZnO) layer is a transparent conductive material that can simultaneously improve the light transmittance and conductivity. At the same time, zinc oxide has a low reflectivity (about 2.0%) and can reduce light reflection. The silicon dioxide (SiO2) layer has stable insulating properties, can prevent charge leakage, has a mature preparation process, and can be easily prepared through mature processes such as thermal oxidation. The aluminum oxide (Al2O3) layer has a high breakdown voltage and can work stably under high voltage. At the same time, aluminum oxide has excellent insulating properties, which can further improve the reliability of the device.

[0038] Optionally, the first region or the second region further includes a second doping layer and a second insulating layer sequentially stacked between the tunneling oxide layer and the first doping layer.

[0039] A second doping layer and a second insulating layer are arranged in any one of the first region and the second region. The thickness difference between the two regions is caused by the different functional layers stacked in the first region and the second region, so that the reflectivity of the two regions is different, which is conducive to accurately distinguishing the first region and the second region and enhancing the recognition of the two regions.

[0040] Optionally, the first region or the second region further includes a second doping layer and a second insulating layer sequentially stacked between the tunneling oxide layer and the first doping layer.

[0041] A second doping layer and a second insulating layer are arranged in any one of the first region and the second region. The thickness difference between the two regions is caused by the different functional layers stacked in the first region and the second region. The thickness difference between the first region and the second region can be enhanced due to the different thicknesses of the first insulating layer in the first region and the first insulating layer in the second region. This makes the reflectivity of the two regions different, which is more conducive to accurately distinguishing the first region and the second region and enhancing the recognition of the two regions.

[0042] Optionally, the second insulating layer is a silicon oxide layer containing a second doping source. As an insulating layer, silicon oxide has good insulating properties and chemical stability. Doping the second doping source in silicon oxide is beneficial to improving the electrical properties of the photovoltaic cell.

[0043] Optionally, the second insulating layer is a silicon oxide layer containing a boron doping source.

[0044] Boron doping can reduce the surface recombination of the silicon substrate, improve the open circuit voltage and photoelectric conversion efficiency of the battery, and optimize the electrical performance of the photovoltaic cell.

[0045] Optionally, the second doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0046] Doping a polycrystalline silicon layer, a microcrystalline silicon layer or an amorphous silicon layer can effectively transmit photogenerated carriers and improve the electrical performance of the battery.

[0047] Optionally, the second doped layer is a P-type doped polysilicon layer, a P-type doped microcrystalline silicon layer, or a P-type doped amorphous silicon layer.

[0048] Setting the second doped layer as a P-type doped polysilicon 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.

[0049] Optionally, the thickness of the second doping layer is 50-300 nm.

[0050] When the thickness of the second doping layer is 50-300 nm, the contrast difference between the first region and the second region is large, and the marking point can be more accurately recognized by the device.

[0051] Optionally, the second insulating layer has a thickness of 5-100 nm.

[0052] When the thickness of the second insulating layer is 5-100 nm, the contrast difference between the first region and the second region is large, and the marking point can be more accurately recognized by the device.

[0053] Optionally, the marking point is at least one of a circle, a square, a trapezoid, a diamond, a sector, and a triangle.

[0054] Facilitates device identification.

[0055] Optionally, the number of identification points is at least four.

[0056] Setting the number of identification points to at least four is conducive to accurately positioning the battery cells to ensure that the size of each battery cell is consistent, avoiding process errors caused by inaccurate positioning of the battery cells, which affects production efficiency and battery performance.

[0057] Optionally, the identification points are arranged on at least one main grid on the backlight surface of the photovoltaic cell and are evenly distributed along the at least one main grid.

[0058] Setting identification points on the main grid can better locate the position of the battery cell and facilitate recognition by the machine vision system.

[0059] Optionally, the identification points are arranged at the edge of the photovoltaic cell grid line structure and are evenly distributed along the four corners of the photovoltaic cell or evenly distributed along the edge of the photovoltaic cell.

[0060] This can prevent the marking points from affecting the light absorption and electrical performance of the battery, while ensuring that the grid line structure can be accurately positioned during the battery process.

[0061] Optionally, one of the first region and the second region is a P region and the other is an N region, or both of the first region and the second region are P regions or both are N regions.

[0062] Optionally, the absolute value of the difference between the thickness of the first insulating layer in the first region and the thickness of the first insulating layer in the second region is 5-45 nm, which can enable the first region and the second region to be accurately distinguished and enhance the recognition of the two regions.

[0063] The present invention also provides a battery assembly, comprising the above-mentioned photovoltaic cell.

[0064] The present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram of a photovoltaic cell structure viewed from above provided by the present invention;

[0066] Figure 2 It is a schematic diagram of a top view structure of another photovoltaic cell provided by the present invention;

[0067] Figure 3 This is a schematic diagram of a cross-sectional structure of a photovoltaic cell provided by the present invention;

[0068] Figure 4 It is another schematic diagram of the cross-sectional structure of a photovoltaic cell provided by the present invention.

[0069] Description of reference numerals:

[0070] 100, photovoltaic cell; 110, first region; 111, extension portion; 120, second region; 101, silicon substrate; 102, tunneling oxide layer; 103, first doped layer; 104, first insulating layer; 105, second doped layer; 106, second insulating layer. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0072] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0074] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0076] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the examples of various specific processes and materials provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0077] The present invention sets a first area and a second area, and the absolute value of the difference between the reflectivity of the first area and the reflectivity of the second area is greater than 0.05%. The difference in reflectivity can lead to different contrasts between the first area and the second area, so that the first area and the second area can be accurately distinguished, thereby increasing the recognition of the two areas.

[0078] Embodiment 1

[0079] like Figure 1 As shown, 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 adjacently arranged, 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%.

[0080] In this embodiment, by setting the first area 110 and the second area 120, the absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the second area 120 is greater than 0.05%. The difference in reflectivity can cause the contrast of the first area 110 and the second area 120 to be different, so that the first area 110 and the second area 120 can be accurately distinguished, thereby increasing the recognition of the two areas.

[0081] In some embodiments, the absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the second area 120 is 5%-15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%. By setting the absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the second area 120 to 5%-15%, the absolute value of the difference in reflectivity is increased, so that the first area 110 and the second area 120 can be accurately distinguished, thereby enhancing the recognition of the two areas.

[0082] In some embodiments, the first region 110 extends an extension portion 111 toward the adjacent second region 120 at a preset position to form a marking point.

[0083] In some embodiments, when the first area 110 and the second area 120 are arranged alternately along the first direction, extensions 111 may be provided in a plurality of first areas 110 to form identification points, for example, adjacent first areas 110 may extend extensions 111 to adjacent second areas 120 at preset positions to form identification points. The accuracy of the identification point positioning may be improved by providing multiple groups of identification points. The above identification points may also assist in determining the contour and shape of the battery cell, and multiple groups of identification points may be provided when it is necessary to determine the contour and shape of the battery cell with the aid of identification points.

[0084] The identification point plays a vital role. The camera recognizes the identification point to achieve alignment with the photovoltaic cell, ensuring good positioning accuracy in the various process of the cell flow. Setting the identification point can not only improve positioning accuracy and reduce process errors, but also avoid misidentification and debris problems, and optimize production efficiency. By rationally designing the identification point, the manufacturing quality and production capacity of photovoltaic cells can be significantly improved.

[0085] The first region 110 and the second region 120 can be regions of the same polarity (such as P-type regions or N-type regions), or can be regions of different polarities (such as the first region 110 is an N-type region and the second region 120 is a P-type region, or the first region 110 is a P-type region and the second region is an N-type region), and no limitation is made here.

[0086] When the first region 110 and the second region 120 are set to regions of the same polarity, by setting the absolute value of the difference in reflectivity between the first region 110 and the second region 120 to be greater than 0.05%, the contrast difference between regions of the same polarity can be easily determined, and the region to be identified can be easily located. When the first region 110 and the second region 120 are set to regions of different polarities, by setting the absolute value of the difference in reflectivity between the first region 110 and the second region 120 to be greater than 0.05%, the P region and the N region can be easily identified, and the difference between the two can be increased.

[0087] The silicon substrate 101 has two main surfaces, a light-facing surface and a backlight surface. The light-facing surface directly faces the sunlight, while the backlight surface is the other side facing away from the sunlight. The two surfaces are arranged opposite to each other.

[0088] The first area 110 and the second area 120 are arranged adjacent to each other, that is, the first area 110 and the second area 120 can be arranged on the same surface of the photovoltaic cell 100 (such as being arranged on the backlight surface of the photovoltaic cell 100 or on the light-facing surface of the photovoltaic cell 100). Specifically, the first area 110 and the second area 120 can be arranged side by side, or the first area 110 and the second area 120 can be in a wrapping state (the first area 110 wraps the second area 120 or the second area 120 wraps the first area 110), which is not limited here. At the preset position, the first area 110 extends an extension portion 111 to the second area 120, and the extension portion 111 protrudes from the original boundary of the first area 110 to form an identification point.

[0089] A suitable position is selected on the surface of the photovoltaic cell 100 as the preset position of the identification point. This position should be an area that does not significantly affect the light energy absorption of the photovoltaic cell 100, and is convenient for the machine vision system to identify and detect.

[0090] Generally, when the photovoltaic cell 100 is a back contact cell, the back contact cell can be a busbar cell or a busbar-free cell. When the back contact cell is a busbar cell, a plurality of busbars are generally provided for collecting current on the fine grids, and a plurality of identification points are generally provided on the busbars, and the plurality of identification points are sequentially arranged along the second direction. When the back contact cell is a busbar-free cell, a plurality of fine grids are sequentially arranged along the first direction, and the identification points can be set at the edge of the back contact cell fine grid line structure and evenly distributed along the four corners or evenly distributed along the edge.

[0091] The first direction may be the lateral direction of the back contact battery, and the second direction may be the longitudinal direction of the back contact battery, and the two directions are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, the two directions may be diagonal directions of the silicon substrate 101, respectively, and are not specifically limited here. The first region 110 and the second region 120 do not overlap each other, and the first region 110 and the second region 120 are arranged adjacent to each other.

[0092] At the preset position, the first area 110 extends an extension portion 111 toward the adjacent second area 120. The extension portion 111 protrudes from the original extension direction (second direction) of the first area 110 to form a specific shape. Specifically, the extension portion 111 may be one or more of a square, a circle, a trapezoid, a rhombus, a sector, a triangle, etc. The extension portion 111 forms a visual mark through a reflectivity difference to form an identification point. In the process of automated production and testing of the photovoltaic cell 100, a reference point is provided for the photovoltaic cell 100. The equipment can be quickly located and calibrated through the identification point. 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.

[0093] Since the color of the battery cell is darker, when the identification point is set, if there is no obvious color difference or other difference between the P area and the N area, the identification point set on the P area or the N area cannot be identified, resulting in the inability to accurately locate the identification point on the battery cell and calibrate the position of the battery cell, thereby reducing the recognition accuracy and efficiency of the machine vision system. Therefore, the absolute value of the difference between the reflectivity of the first area and the reflectivity of the second area needs to be greater than 0.05% to create a contrast difference between the two areas to facilitate the identification of the identification point.

[0094] The absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the second area 120 is greater than 0.05%, that is, the reflectivity of the first area 110 may be greater than that of the second area 120, or the reflectivity of the second area 120 may be greater than that of the first area 110, and the difference between the reflectivity of the two areas is less than -0.05%, or greater than 0.05%. Through experimental verification, when the absolute value of the difference between the reflectivity of the first area 110 and the second area 120 is less than 0.05%, the difference in contrast or color between the two areas is too small and difficult to be identified, so the absolute value of the difference in reflectivity of the first area 110 and the second area 120 needs to be set to be greater than 0.05% to facilitate identification of the difference in contrast or color between the two areas.

[0095] Reflectivity refers to the proportion of light that is reflected after it hits the surface of an object, usually expressed as a percentage. Different materials and surface treatment processes will significantly affect reflectivity. Different reflectivity in different areas will result in different reflected light intensities, which will cause different contrasts between different 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 obvious the difference between the two areas.

[0096] When testing the reflectivity, natural light (sunlight) or light (such as a tungsten filament lamp) can be used as a light source, and the light can be incident vertically in a direction perpendicular to the direction of the sample stand on which the photovoltaic cell 100 to be tested is placed, or at an angle of 0 to 90 degrees, such as 20 degrees, 30 degrees, 40 degrees, etc. The reflectivity at different wavelengths can be tested to obtain the test results, and a special reflectivity measuring instrument can also be used for measurement, which is not limited in the present invention.

[0097] If there is a difference in reflectivity between the first area 110 and the second area 120, there must be a high reflectivity area and a first low reflectivity area. Between the first area 110 and the second area 120, the area with a relatively high reflectivity is a high reflectivity area, and the area with a relatively low reflectivity is a low reflectivity area. The high reflectivity area can reflect more light to the device visual recognition system, and the low reflectivity area reflects less light to the device visual recognition system. The device visual recognition system collects a difference in the intensity of the reflected light from the first area 110 and the second area 120, and such a difference is conducive to the device identifying and locating the two areas.

[0098] In this embodiment, by setting the first area 110 and the second area 120, the absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the second area 120 is greater than 0.05%, and an extension portion 111 is extended from the first area 110 to the adjacent second area 120 to form a marking point. Due to the difference in reflectivity, the contrast of the first area 110 and the second area 120 is different, so that the marking point formed by the extension portion 111 can be identified, and then the equipment is quickly positioned and calibrated through the marking point, thereby greatly improving the recognition accuracy and efficiency of the machine vision system.

[0099] In some embodiments, for light in the wavelength range of 250-400 nm, 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% and less than 5%.

[0100] The 250-400nm band mainly covers ultraviolet (UV) light, including UVA (320-400nm) and UVB (280-320nm).

[0101] The absolute value of the difference in reflectivity is greater than 0.05%, which ensures that under ultraviolet conditions, the difference in reflectivity between the first area 110 and the second area 120 is still obvious enough to be recognized by a machine vision system. Even under very weak lighting conditions, a 0.05% difference in reflectivity can provide sufficient contrast.

[0102] The absolute value of the difference in reflectivity is less than 5%. This upper limit ensures that the difference in reflectivity is not too large, thereby avoiding excessive reflection or absorption under certain extreme lighting conditions, which makes it difficult to identify the marking point. At the same time, a smaller difference in reflectivity can reduce the thickness of the film layer and reduce the manufacturing cost of the photovoltaic cell 100.

[0103] In some embodiments, for light in the wavelength range of 400-600 nm, 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% and less than 25%.

[0104] The 400-600nm band includes blue (470-490nm), green (530-580nm) and part of yellow (580-600nm) visible light.

[0105] The absolute value of the difference in reflectivity is greater than 0.05%. This lower limit ensures that under low light conditions, the difference in reflectivity between the first area 110 and the second area 120 is still obvious and sufficient to be recognized by the machine vision system. If the difference in reflectivity is less than 0.05%, the contrast difference between the first area 110 and the second area 120 is too small, and the two areas are difficult to distinguish.

[0106] The absolute value of the reflectivity difference is less than the upper limit of 25%, which ensures that the reflectivity difference will not be too large, avoiding excessive reflection under certain extreme lighting conditions, exceeding the machine detection limit and affecting the response of the recognition system.

[0107] In some embodiments, for light in the wavelength range of 600-900 nm, 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 0.5% and less than 35%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0108] In some embodiments, for light in the wavelength range of 900-1200 nm, 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 2% and less than 15%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0109] In some embodiments, for light in the wavelength range of 1200-1400 nm, 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% and less than 10%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0110] Embodiment 2

[0111] like Figure 1As shown, in one embodiment, on the backlight surface of the photovoltaic cell 100, the first area 110 and the second area 120 are alternately arranged along the first direction, the first area 110 and the second area 120 extend along the second direction, and the first direction and the second direction intersect;

[0112] At least one first region 110 extends an extension portion 111 toward an adjacent second region 120 along a first direction at a preset position to form a marking point, and the first region 110 and the second region 120 have different polarities.

[0113] Specifically, on the backlight surface of the photovoltaic cell 100, a plurality of first regions 110 and a plurality of second regions 120 are arranged alternately. Doping layers of different polarities are respectively arranged in the first region 110 and the second region 120, so that the first region 110 and the second region 120 present different polarities. Specifically, the first region 110 may be a P-type region and the second region 120 may be an N-type region, or the first region 110 may be an N-type region and the second region 120 may be a P-type region. The first region 110 and the second region 120 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of carriers.

[0114] In this embodiment, a plurality of first regions 110 and a plurality of second regions 120 are alternately arranged on the backlight surface of the photovoltaic cell 100, and the electrodes are arranged on the backlight surface, which can minimize the blocking of light by the electrodes and improve the light absorption efficiency, thereby improving the overall photoelectric conversion efficiency of the cell.

[0115] Embodiment 3

[0116] like Figure 2 As shown, in some embodiments, at a preset position, the first area 110 extends an extension portion 111 along a first direction toward the second areas 120 adjacent to both sides to form a marking point.

[0117] At the preset position, the first area 110 extends an extension portion 111 along the first direction to the adjacent second areas 120 on both sides, so that the area of ​​the marking point is larger, which is convenient for the recognition of the machine vision system. The extension portions 111 extending from the first area 110 to the adjacent second areas 120 on both sides can be symmetrical on both sides, or can be other asymmetrical settings, which are not limited here.

[0118] Specifically, the first area 110 extends rectangular extension portions 111 toward the second areas 120 adjacent to both sides, the two extension portions 111 are symmetrically arranged, and the two extension portions 111 and the first area 110 connecting the two extension portions 111 together constitute a square marking point.

[0119] Embodiment 4

[0120] like Figure 3 As shown, in some embodiments, the photovoltaic cell 100 further includes a silicon substrate 101 , and in the first region 110 and the second region 120 , includes a tunneling oxide layer 102 , a first doping layer 103 , and a first insulating layer 104 sequentially stacked on the silicon substrate 101 .

[0121] In some embodiments, the first insulating layer 104 in the first region 110 and the second region 120 have different thicknesses.

[0122] Two different regions are arranged on the backlight surface of the silicon substrate 101, namely, a first region 110 and a second region 120, and the two regions are arranged alternately. Specifically, a plurality of first regions 110 and a plurality of second regions 120 are arranged alternately along a first direction, and both the first region 110 and the second region 120 extend along a second direction, and the second direction intersects the first direction. The first region 110 and the second region 120 may be arranged alternately along the lateral direction of the silicon substrate 101 and both extend along the longitudinal direction, that is, the first direction may be the lateral direction of the back contact battery, and the second direction may 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 may also be other directions, for example, both may be diagonal directions of the silicon substrate 101, and the specifics are not limited here. The first region 110 and the second region 120 do not overlap each other, and the first region 110 and the second region 120 are arranged adjacent to each other.

[0123] The tunnel oxide layer 102 is usually in contact with the silicon substrate 101 on one side and in contact with the adjacent doped layer on the other side. The tunnel oxide layer 102 is usually made of silicon dioxide (SiO2) and has a very thin thickness, usually between 1-2nm. A tunneling effect can occur in the tunnel oxide layer 102, allowing electrons to be transferred from the silicon substrate 101 to the adjacent doped layer through the tunneling effect. Although very thin, the tunnel oxide layer 102 provides additional insulation properties to prevent unnecessary leakage of charges between different regions.

[0124] The first doped layer 103 forms a highly conductive region for electrode connection or additional charge transfer. The first doped layer 103 can be doped polysilicon, doped microcrystalline silicon, doped amorphous silicon, or other types of doped layers, which are not limited here.

[0125] In the first region 110 and the second region 120 , the first doped layer 103 may be in direct contact with the tunneling oxide layer 102 , or may be in indirect contact with the tunneling oxide layer 102 through other functional layers (i.e., other functional layers are provided between the tunneling oxide layer 102 and the first doped layer 103 ), which is not limited here.

[0126] The thickness and material of the tunneling oxide layer 102 disposed in the first region 110 and the tunneling oxide layer 102 disposed in the second region 120 may be the same, or the thickness and / or material of the tunneling oxide layer 102 disposed in the first region 110 and the tunneling oxide layer 102 disposed in the second region 120 may be different. Specifically, the material and thickness of the tunneling oxide layer 102 in the first region 110 and the second region 120 are related to the doping layers disposed in the corresponding regions, and are not limited here.

[0127] The first insulating layer 104 provides good insulation performance to prevent charge leakage between different regions. The first insulating layer 104 in the first region 110 and the second region 120 has different thicknesses. Reflectivity is an optical property of a material. When the thickness of a 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.

[0128] The first insulating layer 104 can usually be deposited by chemical vapor deposition technology CVD (Chemical Vapor Deposition), and the thickness of the first insulating layer 104 in each area can be conveniently controlled and adjusted, which is convenient for production and manufacturing. Moreover, by setting the thickness of the first insulating layer 104 in the first area 110 and the second area 120 to be different, the reflectivity of the first area 110 and the second area 120 can be different by changing the thickness of the first insulating layer 104, resulting in different contrast between the first area 110 and the second area 120, thereby facilitating the identification of the first area and the second area, and improving the recognition of the two.

[0129] In some embodiments, the absolute value of the difference between the thickness of the first insulating layer 104 in the first region 110 and the thickness of the first insulating layer 104 in the second region 120 is 5-45 nm, for example, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 45 nm. This allows the first region 110 and the second region 120 to be accurately distinguished, thereby enhancing the recognition of the two regions.

[0130] In some embodiments, the first insulating layer 104 is a silicon oxide layer containing a first dopant source.

[0131] Silicon oxide has good insulating properties and chemical stability as an insulating layer. Doping the first doping source in silicon oxide is conducive to improving the doping uniformity of the doping layer, thereby improving the electrical performance of the photovoltaic cell 100. The first doping source can be a boron doping source, and the boron-doped silicon oxide layer is a borosilicate glass layer (BSG layer), or a phosphorus doping source, and the phosphorus-doped silicon oxide layer is a phosphorus silicon glass layer (PSG layer). It is not limited here, and is selected specifically according to the actual performance requirements of the photovoltaic cell 100. Since both the boron-doped silicon oxide layer and the phosphorus-doped silicon oxide layer are formed by preparing the doping layer in the diffusion process, the doping diffusion process of the silicon wafer can be optimized, the uniform diffusion of the dopant can be achieved, the diffusion efficiency can be improved, the pollution can be reduced, and the performance and reliability of the device can be improved. .

[0132] In some embodiments, the first insulating layer 104 is a silicon oxide layer containing a phosphorus doping source. That is, the first insulating layer 104 is a phosphorus-doped silicon oxide layer, and the phosphorus-doped silicon oxide improves the doping uniformity of the underlying doping layer, which is beneficial to improving the charge transfer performance of the photovoltaic cell 100, and is also beneficial to improving the optical contrast and recognition accuracy of the marking point, thereby improving the manufacturing accuracy of the photovoltaic cell 100.

[0133] In some embodiments, the first doped layer 103 is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0134] Doping polysilicon layer, microcrystalline silicon layer or 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 transfer selectivity, and extending minority carrier lifetime. The doping concentration and thickness of the doped polysilicon layer, microcrystalline silicon layer or amorphous silicon layer can be precisely controlled through a variety of processes, with high process flexibility.

[0135] In some embodiments, the first doped layer 103 is an N-type doped polysilicon layer or an N-type doped microcrystalline silicon layer or an N-type doped amorphous silicon layer. Specifically, the doping source of the first doped layer 103 is phosphorus, and the first doped layer 103 is a phosphorus-doped polysilicon layer or a phosphorus-doped microcrystalline silicon layer or a phosphorus-doped amorphous silicon layer. Setting the first doped layer as an N-type doped polysilicon layer or 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.

[0136] In some embodiments, the tunneling oxide layer 102 may be one or more of an oxide layer, a nitride layer, an oxynitride layer, a carbide layer, and an amorphous silicon layer. For example, the tunneling oxide layer 102 may be one or more of a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, silicon nitride, and silicon oxynitride.

[0137] Advantages of using one or more layers of titanium dioxide layer, zinc oxide layer, silicon oxide layer, aluminum oxide layer, silicon nitride, silicon oxynitride to form the tunneling oxide layer 102: The titanium dioxide (TiO2) layer has a higher refractive index (about 2.4%) and can be used as an anti-reflection layer to improve the light absorption rate. The zinc oxide (ZnO) layer is a transparent conductive material that can simultaneously improve the light transmittance and conductivity. At the same time, zinc oxide has a lower refractive index (about 2.0%), which can reduce light reflection. The silicon dioxide (SiO2) layer has stable insulating properties, can prevent charge leakage, has a mature preparation process, and can be easily prepared by mature processes such as thermal oxidation. The aluminum oxide (Al2O3) layer has a higher breakdown voltage and can work stably under high voltage. At the same time, aluminum oxide has excellent insulating properties, which can further improve the reliability of the device.

[0138] Specifically, the tunneling oxide layer 102 can be a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, or a titanium dioxide layer and a zinc oxide layer, or a zinc oxide layer, a silicon oxide layer, and an aluminum oxide layer, or any other combination of at least two of 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, which is not limited here.

[0139] Embodiment 5

[0140] like Figure 4 As shown, in some embodiments, the first region 110 or the second region 120 further includes a second doping layer 105 and a second insulating layer 106 which are sequentially stacked between the tunneling oxide layer 102 and the first doping layer 103 .

[0141] The second doping layer 105 and the second insulating layer 106 may be disposed in the first region 110 or in the second region 120. The polarity of the second doping layer 105 is different from that of the first doping layer 103. Specifically, the first doping layer 103 may be a P-type doping layer and the second doping layer 105 may be an N-type doping layer, or the first doping layer 103 may be an N-type doping layer and the second doping layer 105 may be a P-type doping layer. The first polarity doping layer and the second polarity doping layer form regions with different electrical characteristics, that is, the polarities of the first region 110 and the second region 120 are different, supporting the formation of a PN junction and the separation of carriers.

[0142] The second doping layer 105 and the second insulating layer 106 are arranged in any one of the first region 110 and the second region 120. The thickness difference between the two regions is caused by the different functional layers stacked in the first region 110 and the second region 120, so that the reflectivity of the two regions is different, which is conducive to accurately distinguishing the first region and the second region and enhancing the recognition of the two regions.

[0143] In some embodiments, when the thickness of the first insulating layer 104 of the first region 110 and the first insulating layer 104 of the second region 120 are different, the first region 110 or the second region 120 is configured to also include a second doping layer 105 and a second insulating layer 106 stacked in sequence between the tunneling oxide layer 102 and the first doping layer 103, and the second doping layer 105 and the second insulating layer 106 are set in any region of the first region 110 and the second region 120. The thickness difference between the two regions is caused by the different functional layers stacked in the first region 110 and the second region 120, and the thickness difference between the first region 110 and the second region 120 can be strengthened due to the different thickness of the first insulating layer 104 of the first region 110 and the first insulating layer 104 of the second region 120, so that the reflectivity of the two regions is different, which is more conducive to the first region 110 and the second region 120 can be accurately distinguished, and the recognition of the two regions is enhanced.

[0144] In some embodiments, the second insulating layer 106 is a silicon oxide layer containing a second dopant source.

[0145] Silicon oxide has good insulating properties and chemical stability as an insulating layer, and doping the second doping source in the silicon oxide is beneficial to improving the electrical properties of the photovoltaic cell 100. The second doping source can be a boron doping source, and the boron-doped silicon oxide layer is a borosilicate glass layer (BSG layer), or a phosphorus doping source, and the phosphorus-doped silicon oxide layer is a phosphorus silicon glass layer (PSG layer), which is not limited here and is specifically selected according to the actual performance requirements of the photovoltaic cell 100.

[0146] In some embodiments, the second insulating layer 106 is a silicon oxide layer containing a boron doping source. That is, the second insulating layer 106 is a boron-doped silicon oxide layer, and boron doping can reduce the surface recombination of the silicon substrate 101, improve the open circuit voltage and photoelectric conversion efficiency of the battery, optimize the electrical performance of the photovoltaic cell 100, and at the same time, it is beneficial to improve the optical contrast and recognition accuracy of the marking point, and also improve the overall performance of the photovoltaic cell 100.

[0147] In some embodiments, the second doped layer 105 is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0148] Doping polycrystalline silicon layer, doping microcrystalline silicon layer or doping amorphous silicon layer can provide a barrier effect, effectively transmit photogenerated carriers, and improve the electrical performance of the battery. In addition, the doping concentration and thickness of the doped polycrystalline silicon layer, doping microcrystalline silicon layer or doping amorphous silicon layer can be precisely controlled through a variety of processes, with high process flexibility.

[0149] In some embodiments, the second doped layer 105 is a P-type doped polysilicon layer or a P-type doped microcrystalline silicon layer or a P-type doped amorphous silicon layer. Specifically, the doping source of the second doped layer 105 is boron, and the second doped layer 105 is a boron-doped polysilicon layer or a boron-doped microcrystalline silicon layer or a boron-doped amorphous silicon layer. Setting the second doped layer as a P-type doped polysilicon layer or 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.

[0150] In some embodiments, the thickness of the second doping layer 105 is 50-300 nm. Through laboratory verification, when the thickness of the second doping layer 105 is 50-300 nm, the contrast difference between the first region 110 and the second region 120 is large, which is more conducive to identifying the first region and the second region. For example, it can be set to 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0151] In some embodiments, the thickness of the second insulating layer 106 is 5 to 100 nm. Through laboratory verification, when the thickness of the second insulating layer 106 is 5 to 100 nm, the contrast difference between the first region 110 and the second region 120 is large, which is more conducive to identifying the first region and the second region. For example, the thickness can be set to 5 nm, 6 nm, 7 nm, 80 nm, 90 nm, 100 nm, etc.

[0152] Embodiment 6

[0153] In some embodiments, the number of identification points is at least four.

[0154] The production of photovoltaic cells 100 requires multiple processes such as cleaning, diffusion, patterning, and metallization. The purpose is to perform specific processes on different areas of the cell. If it cannot be accurately positioned, it will lead to serious process errors and cause the cell to fail. The purpose of the design of the identification points is to accurately position the cell, and place a large silicon wafer (including the silicon substrate 101 and the functional layers deposited on the silicon substrate 101) in a correct process position with the help of a camera recognition system and automated equipment. Setting the number of identification points to at least four is conducive to accurately positioning the cell, ensuring that a specific process is achieved in a specific area of ​​each cell, avoiding process errors caused by inaccurate cell positioning, and affecting production efficiency and battery performance.

[0155] In some embodiments, the number of identification points can be set to five, six, seven, eight, etc. When it is necessary to accurately locate the identification points on the battery cell, the number of identification points can be increased to improve the accuracy of positioning.

[0156] Specifically, the identification points are arranged on both sides of the battery cell along the extension direction of the battery cell, and the distances between any identification point and the end points of the battery cell are different.

[0157] Embodiment 7

[0158] In some embodiments, the identification points are set on at least one main grid on the backlight surface of the photovoltaic cell 100, and are evenly distributed along at least one main grid. When the photovoltaic cell 100 is provided with multiple main grids, the multiple identification points can be evenly distributed along the extension direction of the main grid in the second direction. For example, the distance between the centers of two adjacent identification points on the same main grid can be set to be 50 mm to 200 mm. In some embodiments, the multiple identification points can also be set to be unevenly distributed along the extension direction of the main grid in the second direction. For example, multiple dense identification points are set where precise identification and positioning are required, and a small number of identification points are set where precise identification and positioning are not required. The present invention does not limit this.

[0159] In some embodiments, the identification points can also be set on the edge of the grid line structure of the photovoltaic cell 100, 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 main grid-free structure, multiple fine grids are arranged in sequence. At this time, the identification 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 edges, or set on the silicon wafer directly below the welding strip and evenly distributed along the extension direction of the welding strip.

[0160] The gate line is set on the silicon wafer (including the silicon substrate 101 and the functional layers deposited on the silicon substrate 101) to collect and transmit photogenerated carriers. The identification point is set at the edge of the gate line structure to avoid the identification point from affecting the light absorption and electrical performance of the battery, while ensuring that the gate line structure can be accurately positioned during the battery process.

[0161] Embodiment 8

[0162] This embodiment provides a battery assembly, including the photovoltaic cell 100 in the above embodiment.

[0163] The battery assembly may include multiple photovoltaic cells 100. The multiple photovoltaic cells 100 in the battery assembly may be connected in series in sequence to form a battery string. The battery strings may be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the connection between the battery cells may be achieved by welding welding strips, and the connection between the battery strings may be achieved by bus bars.

[0164] The battery assembly may also include a metal frame, a back plate, photovoltaic glass and an adhesive film (not shown in the figure). The adhesive film may be filled between the front and photovoltaic glass, the back and the back plate of the photovoltaic cell 100, and between adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmission and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0165] Photovoltaic glass can cover the adhesive film on the front of the photovoltaic cell 100. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the photovoltaic cell 100 without affecting the efficiency of the photovoltaic cell 100 as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the photovoltaic cell 100 together, and the presence of the adhesive film can seal and insulate the photovoltaic cell 100 and prevent it from being waterproof and moisture-proof.

[0166] The backplane can be attached to the adhesive film on the back of the photovoltaic cell 100. The backplane can protect and support the photovoltaic cell 100 and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to specific circumstances and is not limited here. The whole composed of the backplane, photovoltaic cell 100, adhesive film and photovoltaic glass can be set on a metal frame. The metal frame serves as the main external support structure of the entire battery assembly and can stably support and install the battery assembly. For example, the battery assembly can be installed at the required location through the metal frame.

[0167] The beneficial effects of the battery assembly of this embodiment are equivalent to the beneficial effects of the photovoltaic cell 100 described above, and will not be described in detail here.

[0168] Embodiment 9

[0169] This embodiment provides a photovoltaic system, including the battery assembly in the above embodiment.

[0170] Photovoltaic systems can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water power stations, etc., and can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it is understandable that the application scenarios of photovoltaic systems are not limited to this, that is to say, photovoltaic systems can be used in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple battery components. For example, multiple battery components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid. After that, it is connected to the mains network to realize solar power supply.

[0171] The beneficial effects of the photovoltaic system of this embodiment are equivalent to the beneficial effects of the above-mentioned battery assembly, and will not be described in detail here.

[0172] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A photovoltaic cell, characterized in that: It comprises a first region and a second region, wherein the first region and the second region are adjacently arranged, and an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05%.

2. The photovoltaic cell according to claim 1, characterized in that An absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is between 5% and 15%.

3. The photovoltaic cell according to claim 1, characterized in that For light in the wavelength range of 250-400 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05% and less than 5%.

4. The photovoltaic cell according to claim 1, characterized in that For light in the wavelength range of 400-600 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.05% and less than 25%.

5. The photovoltaic cell according to claim 1, characterized in that: For light in the wavelength range of 600-900 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 0.5% and less than 35%.

6. The photovoltaic cell according to claim 1, characterized in that: For light in the wavelength range of 900-1200 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the second region is greater than 2% and less than 15%.

7. The photovoltaic cell according to claim 1, characterized in that: For light in the wavelength range of 1200-1400 nm, 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%.

8. The photovoltaic cell according to claim 1, characterized in that: Also includes: The first area extends an extension portion toward the adjacent second area at a preset position to form a marking point.

9. The photovoltaic cell according to claim 8, characterized in that: On the backlight surface of the photovoltaic cell, the first area and the second area are alternately arranged along a first direction, the first area and the second area extend along a second direction, and the first direction and the second direction intersect; At least one of the first regions extends an extension portion toward an adjacent second region along the first direction at a preset position to form a marking point, and the first region and the second region have different polarities.

10. The photovoltaic cell according to claim 9, characterized in that At the preset position, the first area extends an extension portion toward the second areas adjacent to both sides along the first direction to form a marking point.

11. The photovoltaic cell according to claim 1, characterized in that: Also included is a silicon substrate; The first region and the second region include a tunneling oxide layer, a first doping layer, and a first insulating layer which are sequentially stacked on the silicon substrate.

12. The photovoltaic cell according to claim 11, characterized in that The thickness of the first insulating layer in the first region is different from that in the second region.

13. The photovoltaic cell according to claim 11, characterized in that: The first insulating layer is a silicon oxide layer containing a first doping source.

14. The photovoltaic cell according to claim 13, characterized in that The first insulating layer is a silicon oxide layer containing a phosphorus doping source.

15. The photovoltaic cell according to claim 11, characterized in that: The first doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

16. The photovoltaic cell according to claim 15, characterized in that The first doped layer is an N-type doped polysilicon layer, an N-type doped microcrystalline silicon layer, or an N-type doped amorphous silicon layer.

17. The photovoltaic cell according to claim 11, characterized in that: The tunneling oxide layer is composed of one or more of an oxide layer, a nitride layer, a nitride oxide layer, a carbide layer, and an amorphous silicon layer.

18. The photovoltaic cell according to claim 11, characterized in that: The first region or the second region further includes a second doping layer and a second insulating layer which are sequentially stacked between the tunneling oxide layer and the first doping layer.

19. The photovoltaic cell according to claim 12, characterized in that: The first region or the second region further includes a second doping layer and a second insulating layer which are sequentially stacked between the tunneling oxide layer and the first doping layer.

20. The photovoltaic cell according to claim 18, characterized in that The second insulating layer is a silicon oxide layer containing a second doping source.

21. The photovoltaic cell according to claim 20, characterized in that The second insulating layer is a silicon oxide layer containing a boron doping source.

22. The photovoltaic cell according to claim 18, characterized in that The second doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

23. The photovoltaic cell according to claim 22, characterized in that The second doped layer is a P-type doped polysilicon layer, a P-type doped microcrystalline silicon layer, or a P-type doped amorphous silicon layer.

24. The photovoltaic cell according to claim 18, characterized in that The thickness of the second doping layer is 50-300 nm.

25. The photovoltaic cell according to claim 18, characterized in that The thickness of the second insulating layer is 5-100 nm.

26. The photovoltaic cell according to claim 1, characterized in that The marking point is at least one of a circle, a square, a trapezoid, a diamond, a sector, and a triangle.

27. The photovoltaic cell according to claim 1, characterized in that The number of the identification points is at least four.

28. The photovoltaic cell according to claim 27, characterized in that The identification points are arranged on at least one main grid on the backlight surface of the photovoltaic cell and are evenly distributed along the at least one main grid.

29. The photovoltaic cell according to claim 27, characterized in that The identification points are arranged at the edge of the photovoltaic cell grid line structure and are evenly distributed along the four corners of the photovoltaic cell or evenly distributed along the edge of the photovoltaic cell.

30. The photovoltaic cell according to claim 1, characterized in that One of the first region and the second region is a P region and the other is an N region, or both of the first region and the second region are P regions or both are N regions.

31. The photovoltaic cell according to claim 12, characterized in that An absolute value of a difference between a thickness of the first insulating layer in the first region and a thickness of the first insulating layer in the second region is 5-45 nm.

32. A battery assembly, characterized in that: A photovoltaic cell comprising any one of claims 1 to 31.

33. A photovoltaic system, characterized in that: Comprising the battery assembly of claim 32.

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