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, a second area and a third area, the third area is arranged between the first area and the second area, and the first area extends from a preset position to the adjacent third area to form a first extension part to form an identification point; the absolute value of the difference between the reflectivity of the first area and the reflectivity of the third area is larger than 6%. Due to the fact that the contrast of the first area and the contrast of the third area are different due to the difference of the reflectivity, the identification point formed by the first extending part can be identified, the equipment can be rapidly positioned and calibrated through the identification point, and the identification accuracy and efficiency of the machine vision system are greatly improved. The identification points are formed in the preparation process of the silicon substrate and do not cause extra damage to the surface of the battery.

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] Marking points play a vital role in the manufacturing process of photovoltaic cells. These marking points are mainly used to mark the location of the cutting lines on the silicon wafer, helping the cutting equipment to achieve precise alignment and efficient cutting in large-scale production.

[0003] In the prior art, marking points are usually formed by further processing on the surface of a silicon substrate (including a silicon substrate, i.e., various functional layers arranged on the silicon substrate) that has been prepared. When processing the marking points, the surface of the silicon substrate may be damaged, resulting in reduced battery electrical performance or increased crack risk, thereby reducing the battery life. Summary of the invention

[0004] The present invention provides a photovoltaic cell, aiming to solve the problem that traditional marking points easily cause battery damage and affect battery performance.

[0005] The present invention is implemented as follows: a photovoltaic cell, characterized in that it includes a first area, a second area and a third area, the third area is arranged between the first area and the second area, and the first area extends a first extension portion toward the adjacent third area at a preset position to form a mark;

[0006] An absolute value of a difference between a reflectivity of the first region and a reflectivity of the third region is greater than or equal to 6%.

[0007] 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 third region is greater than 19% and less than 23%.

[0008] 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 third region is greater than 28% and less than 31%.

[0009] Optionally, for light in the wavelength band of 600-900 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the third region is greater than 6% and less than 27%.

[0010] 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 third region is greater than 13% and less than 24%.

[0011] 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 third region is greater than 10% and less than 27%.

[0012] Optionally, on the backlight surface of the photovoltaic cell, a plurality of the first regions and a plurality of the second regions are alternately arranged along a first direction, the first region, the second region and the third region all extend along a second direction, and the second direction intersects the first direction;

[0013] At least one of the first regions extends a first extension portion toward the adjacent third 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.

[0014] Optionally, at the preset position, the first area extends a first extension portion along the first direction toward the third areas adjacent to both sides to form a marking point.

[0015] Optionally, the third region includes a second extension portion, and the second extension portion extends toward the second region along an extension direction of the first extension portion.

[0016] Optionally, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 6%.

[0017] Optionally, for light in the wavelength band of 250-400 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 17% and less than 26%.

[0018] Optionally, for light in the wavelength band of 400-600 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 24% and less than 38%.

[0019] Optionally, for light in the wavelength band of 600-900 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 6 and less than 28%.

[0020] Optionally, for light in a wavelength band of 900-1200 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 14% and less than 18%.

[0021] Optionally, for light in a wavelength band of 1200-1400 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 11% and less than 26%.

[0022] Optionally, comprising a silicon substrate;

[0023] In the first region, a first tunneling oxide layer and a first doping layer are sequentially stacked on the silicon substrate; in the second region, a second tunneling oxide layer and a second doping layer are sequentially stacked on the silicon substrate; and the first doping layer and the second doping layer are separated by the third region.

[0024] Optionally, the first doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0025] Optionally, the first doped layer is a P-type doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0026] Optionally, the first tunneling oxide layer and the second tunneling oxide layer are composed of one or more layers of an oxide layer, a nitride layer, an oxynitride layer, a carbide layer, or an amorphous silicon layer.

[0027] Optionally, the second doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0028] Optionally, the second doped layer is an N-type doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0029] Optionally, it also includes a first passivation film layer, a second passivation film and a third passivation film layer. In the first region, the first passivation film layer is stacked on the first doped layer. In the second region, the second passivation film layer is stacked on the second doped layer. The third passivation film layer is stacked on the silicon substrate. The thickness of the second passivation film layer is greater than the thickness of the first passivation film layer and greater than the thickness of the third passivation film layer.

[0030] Optionally, the thickness of the first passivation film is 1.3-1.5 times the thickness of the third passivation film.

[0031] Optionally, a difference in thickness between the second passivation film layer and the first passivation film layer is in a range of 5-30 nm.

[0032] Optionally, the thickness of the first passivation film layer is in the range of 60 to 160 nm, the thickness of the second passivation film layer is in the range of 65 to 190 nm, and the thickness of the third passivation film layer is in the range of 40 to 125 nm.

[0033] Optionally, the first passivation film layer, the second passivation film layer and the third passivation film layer are connected.

[0034] Optionally, the first passivation film layer, the second passivation film layer and the third passivation film layer may be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon carbide and silicon oxynitride.

[0035] Optionally, the marking point is at least one of a circle, a square, a trapezoid, a diamond, a sector, and a triangle.

[0036] Optionally, the number of identification points is at least four.

[0037] 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.

[0038] 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.

[0039] Optionally, the roughness of the third region is greater than the roughness of the first region and the roughness of the second region.

[0040] Optionally, the surface of the silicon substrate in the third region is a suede surface, and the surfaces of the silicon substrate in the first region and the second region are at least one of a micro-suede surface and a polished surface.

[0041] Optionally, the velvet surface on the surface of the silicon substrate in the third region is at least one of a regular pyramid, a V-groove, an inverted pyramid, and a stacked regular pyramid.

[0042] The present invention also provides a battery assembly, comprising the above-mentioned photovoltaic cell.

[0043] The present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0044] The beneficial effect achieved by the present invention is that the first area, the second area and the third area are set, the third area is set between the first area and the second area, the first area extends a first extension portion to the adjacent third area to form a marking point, and the absolute value of the difference between the reflectivity of the first area and the reflectivity of the third area is greater than 6%. The difference in reflectivity leads to different contrasts between the first area and the third area, so that the marking point formed by the first extension portion can be identified, and then the equipment is quickly located and calibrated through the marking point, greatly improving the recognition accuracy and efficiency of the machine vision system. The marking point is formed during the preparation process of the silicon substrate and will not cause additional damage to the battery surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of a photovoltaic cell structure viewed from above provided by the present invention;

[0046] Figure 2 It is a schematic diagram of a top view structure of another photovoltaic cell provided by the present invention;

[0047] Figure 3 This is a schematic diagram of a top view structure of another photovoltaic cell provided by the present invention;

[0048] Figure 4 This is a schematic diagram of a cross-sectional structure of a photovoltaic cell provided by the present invention;

[0049] Figure 5 It is a schematic diagram of another cross-sectional structure of a photovoltaic cell provided by the present invention.

[0050] Description of reference numerals:

[0051] 100, photovoltaic cell; 110, first region; 111, first extension portion; 120, second region; 121, second extension portion; 101, silicon substrate; 102, first tunneling oxide layer; 103; first doped layer; 104, second tunneling oxide layer; 105, second doped layer; 106, first passivation film layer; 107, second passivation film; 108, third passivation film layer. DETAILED DESCRIPTION

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The present invention sets a first area, a second area and a third area, the third area is set between 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 third area is greater than 6%, and a first extension portion is extended from the first area to the adjacent third area to form a marking point. Due to the difference in reflectivity, the contrast of the first area and the third area is different, so that the marking point formed by the first extension portion can be identified, and then the marking point is quickly positioned and calibrated, thereby greatly improving the recognition accuracy and efficiency of the machine vision system. The marking point is formed during the battery preparation process and will not cause additional damage to the battery surface.

[0059] Embodiment 1

[0060] like Figure 1As shown, this embodiment provides a photovoltaic cell 100, including a first area 110, a second area 120 and a third area 130, the third area 130 is arranged between the first area 110 and the second area 120, and the first area 110 extends a first extension portion 111 toward the adjacent third area 130 at a preset position to form a marking point;

[0061] The absolute value of the difference between the reflectivity of the first region 110 and the reflectivity of the third region 130 is greater than 6%.

[0062] The first region 110 and the second region 120 can be regions of the same polarity (such as both P-type regions or both 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 N-type region), which is not limited here.

[0063] 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.

[0064] The first region 110 and the second region 120 may be disposed adjacently, that is, the first region 110 and the second region 120 may be disposed simultaneously on the same surface of the photovoltaic cell 100 (such as being disposed simultaneously on the backlight surface of the photovoltaic cell 100 or being disposed simultaneously on the light-facing surface of the photovoltaic cell 100). Specifically, the first region 110 and the second region 120 may be disposed side by side, or the first region 110 and the second region 120 may be in an enveloping state (the first region 110 envelops the second region 120 or the second region 120 envelops the first region 110), which is not limited here.

[0065] The third area 130 is disposed between the first area 110 and the second area 120, and the third area separates the first area 110 and the second area 120, and the first area 110 and the second area 120 are respectively in contact with two opposite sides of the third area 130. At a preset position, the first area 110 extends a first extension portion 111 toward the third area 130, and the first extension portion 111 protrudes from the original boundary of the first area 110 to form a marking point.

[0066] 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.

[0067] 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 will not significantly affect the light energy absorption of the photovoltaic cell 100, and at the same time facilitates the machine vision system to identify and detect. At the preset position, the first area 110 extends to the adjacent third area 130, and the first extension portion 111 protrudes from the first area 110 to form a specific shape. Specifically, the first extension portion 111 can be one or more of a square, a circle, a trapezoid, a diamond, a fan, a triangle, etc. The first extension portion 111 forms a visual mark to constitute an identification point through the difference in reflectivity between the first area and the second area. 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.

[0068] 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 first area 110 and the third area 130, the identification point extending from the first area 110 to the third area 130 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 110 and the reflectivity of the third area 130 needs to be greater than 6% to create a contrast difference between the two areas to facilitate the identification of the identification point.

[0069] The absolute value of the difference between the reflectivity of the first area 110 and the reflectivity of the third area 130 is greater than 6%, that is, the reflectivity of the first area 110 may be greater than that of the third area 130, or the reflectivity of the third area 130 may be greater than that of the first area 110, and the difference between the reflectivity of the two areas is less than or equal to -6%, or greater than or equal to 6%. Through experimental verification, when the absolute value of the difference between the reflectivity of the first area 110 and the third area 130 is less than 6%, 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 third area 130 needs to be set to be greater than 6% to facilitate identification of the difference in contrast or color between the two areas.

[0070] Specifically, 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 or equal to 6%, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc., and any other value greater than 6%. 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 be greater than or equal to 6%, 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, and the recognition of the two areas is enhanced.

[0071] It can be understood that the reflectivity of the second area 120 can be the same as the reflectivity of either the first area 110 or the third area 130, or it can be different from the reflectivity of both the first area 110 and the third area 130, without affecting the marking point formed by the first extension portion.

[0072] 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.

[0073] 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.

[0074] If there is a difference in reflectivity between the first area 110 and the third area 130, there must be a high reflectivity area and a first low reflectivity area. Between the first area 110 and the third area 130, the area with relatively high reflectivity is a high reflectivity area, and the area with relatively low reflectivity is a low reflectivity area. The high reflectivity area can reflect more light to the device visual recognition system. 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. Such a difference is conducive to the device identifying and locating the two areas.

[0075] In this embodiment, by setting the first area 110, the second area 120 and the third area 130, the third area 130 is set between 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 third area 130 is greater than 6%, and the first extension part 111 is extended from the first area 110 to the adjacent third area 130 to form a marking point. Due to the difference in reflectivity, the contrast of the first area 110 and the third area 130 is different, so that the marking point formed by the first extension part 111 can be identified, and then the equipment is quickly located and calibrated through the marking point, which greatly improves the recognition accuracy and efficiency of the machine vision system. The marking point is formed during the battery preparation process and will not cause additional damage to the battery surface.

[0076] 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 third region 130 is greater than 19% and less than 23%.

[0077] The 250-400nm band mainly covers ultraviolet (UV) light, including UVA (320-400nm) and UVB (280-320nm).

[0078] The absolute value of the difference in reflectivity is greater than 19%, which ensures that the difference in reflectivity between the first area 110 and the third area 130 is still obvious under ultraviolet conditions and is sufficient to be recognized by the machine vision system. Even under very weak lighting conditions, a 19% difference in reflectivity can provide sufficient contrast.

[0079] The absolute value of the difference in reflectivity is less than 23%. 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.

[0080] 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 third region 130 is greater than 28% and less than 31%.

[0081] The 400-600nm band includes blue (470-490nm), green (530-580nm) and part of yellow (580-600nm) visible light.

[0082] The absolute value of the difference in reflectivity is greater than 28%. This lower limit ensures that under low light conditions, the difference in reflectivity between the first area 110 and the third area 130 is still obvious and sufficient to be recognized by the machine vision system. If the difference in reflectivity is less than 28%, the contrast difference between the first area 110 and the third area 130 is too small, and the two areas are difficult to distinguish.

[0083] The absolute value of the reflectivity difference is less than the upper limit of 31%, which ensures that the reflectivity difference will not be too large, avoiding excessive reflection or absorption under certain extreme lighting conditions, exceeding the machine detection limit and affecting the response of the recognition system.

[0084] 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 third region 130 is greater than 6% and less than 27%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0085] 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 third region 130 is greater than 13% and less than 24%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0086] 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 third region 130 is greater than 10% and less than 27%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0087] Embodiment 2

[0088] like Figure 1 As shown, in one embodiment, on the backlight surface of the photovoltaic cell 100, a plurality of first regions 110 and a plurality of second regions 120 are alternately arranged along a first direction, and the first region 110, the second region 102 and the third region 130 all extend along a second direction, and the second direction intersects the first direction;

[0089] At least one first region 110 extends a first extension portion 111 toward an adjacent third region 130 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.

[0090] By setting multiple groups of identification points, the accuracy of identification point positioning can be improved. At the same time, the identification points can also assist in determining the contour and shape of the battery cell. When it is necessary to use identification points to determine the contour and shape of the battery cell, multiple groups of identification points can be set.

[0091] Specifically, the first region 110, the second region 120, and the third region 130 may be alternately arranged along the lateral direction of the silicon substrate 101 and 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, the two may be diagonal directions of the silicon substrate 101, respectively, and are not specifically limited here.

[0092] On the backlight surface of the photovoltaic cell 100, a plurality of first regions 110 and a plurality of second regions 120 are alternately arranged. 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.

[0093] The third region 130 may be a Gap region, where Gap refers to a “band gap” and is disposed between the P-type region and the N-type region to isolate the P-type region and the N-type region, thereby avoiding leakage current between the P-type region and the N-type region and improving the overall performance of the solar cell.

[0094] For example, when the first region 110 is a P-type region (or an N-type region), when the second region 120 is an N-type region (or a P-type region), and the third region is a Gap region, the reflectivity of the first region 110 is greater than the reflectivity of the third region 130, and the difference between the reflectivity of the first region and the reflectivity of the third region is greater than 6%.

[0095] 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.

[0096] 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.

[0097] like Figure 2As shown, in some embodiments, at a preset position, the first region 110 extends a first extension portion 111 along a first direction toward the third regions 130 adjacent to both sides to form a marking point.

[0098] At the preset position, the first area 110 extends the first extension portion 111 to the third areas 130 adjacent to both sides along the first direction, so that the area of ​​the marking point is larger, which is convenient for the recognition of the machine vision system. The first extension portion 111 extending from the first area 110 to the third areas 130 adjacent to both sides can be symmetrical on both sides, or can be other asymmetrical settings, which is not limited here.

[0099] Specifically, the first area 110 extends rectangular first extension portions 111 to the third areas 130 adjacent to both sides, and the two first extension portions 111 are symmetrically arranged. The two first extension portions 111 and the first area 110 connecting the two first extension portions 111 together constitute a square identification point with a large graphic area and easy recognition.

[0100] like Figure 3 As shown, in some embodiments, the third region 130 includes a second extension portion, and the second extension portion extends toward the second region 120 along the extension direction of the first extension portion 111 .

[0101] Since the first extension portion 111 extends toward the third region 130, the original position of the third region 130 is occupied, so that the width of the third region 130 along the first direction is reduced, thereby reducing the isolation effect of the third region 130. In order to ensure that the third region 130 retains a sufficient effective width, the third region 130 extends a second extension portion toward the second region, and the second extension portion is arranged corresponding to the first extension portion, so that the third region 130 is isolated between the first region 110 and the second region 120 at any position, avoiding contact between the first region 110 and the second region 120.

[0102] In some embodiments, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 6%, so as to avoid the reflectivity difference being too small to cause identification difficulty.

[0103] In some embodiments, for light in the wavelength range of 250-400 nm, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 17% and less than 26%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0104] In some embodiments, for light in the wavelength range of 400-600 nm, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 24% and less than 38%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0105] In some embodiments, for light in the wavelength range of 600-900 nm, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 6 and less than 28%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0106] In some embodiments, for light in the wavelength range of 900-1200 nm, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 14% and less than 18%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0107] In some embodiments, for light in the wavelength range of 1200-1400 nm, the absolute value of the difference between the reflectivity of the second region 120 and the reflectivity of the third region 130 is greater than 11% and less than 26%, so as to avoid the reflectivity difference being too small to make identification difficult.

[0108] Embodiment 3

[0109] like Figure 4 As shown, in some embodiments, the photovoltaic cell 100 includes a silicon substrate 101, in a first region, a first tunneling oxide layer 102 and a first doping layer 103 are sequentially stacked on the silicon substrate, in a second region 120, a second tunneling oxide layer 104 and a second doping layer 105 are sequentially stacked on the silicon substrate 101, and a third region 130 separates the first doping layer 103 and the second doping layer 105.

[0110] Three different regions are arranged on the backlight surface of the silicon substrate 101, namely, a first region 110, a second region 120 and a third region 130. Several first regions 110 and several second regions 120 are alternately arranged along a first direction, and the third region 130 is disposed between the first region 110 and the second region 120.

[0111] A first doping layer is set in the first region 110, and a second doping layer 105 is set in the second region 120. The first doping layer 103 and the second doping layer 105 are doped with elements of different polarities (for example, one is doped with phosphorus and the other is doped with boron), so that the first region 110 and the second region 120 show different polarities.

[0112] The tunnel oxide layer is usually in contact with the silicon substrate 101 on one side and with the adjacent doped layer on the other side. The tunnel oxide layer is usually made of silicon dioxide (SiO2) and is very thin, usually between 1-2nm. Tunneling effect can occur in the tunnel oxide layer, allowing electrons to be transferred from the silicon substrate 101 to the adjacent doped layer through the tunnel effect. Although very thin, the tunnel oxide layer 102 provides additional insulation properties to prevent unnecessary leakage of charge between different regions.

[0113] In the first region 110, the first doped layer 103 may be in direct contact with the first tunnel oxide layer 102, or may be in indirect contact with the first tunnel oxide layer 102 through other functional layers (i.e., other functional layers are provided between the first tunnel oxide layer 102 and the first doped layer 103), which is not limited here.

[0114] In the second region 120 , the second doped layer 105 may be in direct contact with the second tunnel oxide layer 104 , or may be in indirect contact with the second tunnel oxide layer 104 through other functional layers (i.e., other functional layers are provided between the second tunnel oxide layer 104 and the second doped layer 105 ), which is not limited here.

[0115] The polarity of the second doping layer 105 is different from the polarity 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, which supports the formation of a PN junction and the separation of carriers.

[0116] The third region separates the first doping layer 103 and the second doping layer 105 . Specifically, the third region 130 may be configured as a groove, so that the first doping layer 103 and the second doping layer 105 are disconnected.

[0117] In some embodiments, the first doped layer 103 is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0118] 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.

[0119] 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 an N-type doped microcrystalline silicon layer or an N-type doped amorphous silicon layer. The N-type doped polysilicon layer or the N-type doped microcrystalline silicon layer or the 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.

[0120] In some embodiments, the first tunneling oxide layer 102 and the second tunneling oxide layer 104 are one or more of an oxide layer, a nitride layer, a nitride oxide layer, a carbide layer, and an amorphous silicon layer. For example, the first tunneling oxide layer 102 and the second tunneling oxide layer 104 may be composed of one or more layers of a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, a silicon nitride, and a silicon oxynitride. Advantages of using one or more layers of a titanium dioxide layer, a zinc oxide layer, a silicon oxide layer, an aluminum oxide layer, a silicon nitride, and a silicon oxynitride to form the tunneling oxide layer 102: The titanium dioxide (TiO2) layer has a high reflectivity (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 transmittance and conductivity of light. At the same time, zinc oxide has a low reflectivity (about 2.0%) and can reduce the reflection of light. The silicon dioxide (SiO2) layer has stable insulation properties, can prevent charge leakage, has a mature preparation process, and is easily prepared by 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 insulation properties, which can further improve the reliability of the device.

[0121] 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.

[0122] The first tunnel oxide layer 102 and the second tunnel oxide layer 104 may be made of different materials (for example, the first tunnel oxide layer 102 is a titanium dioxide layer, and the second tunnel oxide layer 104 is a silicon oxide layer), or may be made of the same material but with different thicknesses (for example, the first tunnel oxide layer 102 and the second tunnel oxide layer 104 are both titanium dioxide layers, and the thickness of the first tunnel oxide layer 102 is greater than that of the second tunnel oxide layer 104).

[0123] In some embodiments, the second doped layer 105 is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

[0124] 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.

[0125] 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.

[0126] Embodiment 4

[0127] like Figure 5 As shown, in some embodiments, it also includes a first passivation film layer 106, a second passivation film layer 107 and a third passivation film layer 108. In the first region, the first passivation film layer 106 is stacked on the first doped layer, in the second region, the second passivation film layer 107 is stacked on the second doped layer, and the third passivation film layer 108 is stacked on the silicon substrate. The thickness of the second passivation film layer 107 is greater than the thickness of the first passivation film and greater than the thickness of the third passivation film.

[0128] Photovoltaic cells usually include a silicon substrate and various functional layers covering the silicon substrate. The passivation film layer usually covers the outermost functional layer, covering the top and side surfaces of other stacked functional layers to provide physical protection and prevent surface damage, contamination and chemical corrosion. At the same time, the passivation film can reduce the defect state density on the semiconductor surface, reduce the surface recombination rate, and improve the quantum efficiency of optoelectronic devices.

[0129] The first passivation film layer 106, the second passivation film and the third passivation film layer 108 cover the first area 110, the second area 120 and the third area 130 respectively. The thickness of the second passivation film layer 107 is greater than the thickness of the first passivation film layer 106 and the thickness of the third passivation film layer 108. The thickness of the passivation film layer will affect its refraction of light. When light propagates in different passivation film layers, passivation film layers of different thicknesses will cause different phase changes and optical path differences, changing the propagation mode of light in different passivation film layers, including reflection, refraction and transmission, etc. Different reflectivities lead to different contrasts in each area, so that the first area 110, the second area 120 and the third area 130 can be accurately distinguished and the marking point can be identified.

[0130] In some embodiments, the thickness of the first passivation film layer 106 is 1.3-1.5 times the thickness of the third passivation film layer 108 .

[0131] Specifically, the thickness of the first passivation film layer 106 may be 1.3 times, 1.35 times, 1.4 times, 1.48 times, 1.5 times the thickness of the third passivation film layer 108, or other multiples between 1.3-1.5 times, which are not limited here. When the thickness of the first passivation film layer 106 is 1.3-1.5 times the thickness of the third passivation film layer 108, the contrast difference between the first region 110 and the third region 130 is obvious, which is easy to identify.

[0132] In some embodiments, the difference in thickness between the second passivation film layer 107 and the first passivation film layer 106 is in the range of 5 to 30 nm.

[0133] Specifically, the thickness of the second passivation film layer 107 is greater than the thickness of the first passivation film layer 106. The thickness of the second passivation film layer 107 is 5 to 30 nm thicker than the first passivation film layer 106, and can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, or other values ​​between 5 and 30 nm, which are not limited here. When the thickness difference between the second passivation film layer 107 and the first passivation film layer 106 is in the range of 5 to 30 nm, there is a clear contrast difference between the second region and the first region, which is easy to identify.

[0134] In some embodiments, the thickness of the first passivation film layer 106 is in the range of 60 to 160 nm, the thickness of the second passivation film layer is in the range of 65 to 190 nm, and the thickness of the third passivation film layer 108 is in the range of 40 to 125 nm.

[0135] Specifically, the thickness of the first passivation film layer 106 may be 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, or other values ​​between 60 and 160 nm, which are not limited here.

[0136] The thickness of the second passivation film layer 107 can be 65nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 165nm, 175nm, 185nm, 190nm, or other values ​​between 65 and 190nm, which are not limited here.

[0137] The thickness of the third passivation film layer 108 may be 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 115 nm, 120 nm, 125 nm, or other values ​​between 40 and 125 nm, which is not limited here.

[0138] The thicknesses of the first passivation film layer 106 , the second passivation film layer 107 and the third passivation film layer 108 are respectively within the above thickness ranges, and the first region 110 , the second region 120 and the third region 130 have obvious contrast differences, which are easy to identify.

[0139] In some embodiments, the first passivation film layer 106 , the second passivation film layer 107 , and the third passivation film layer 108 are connected.

[0140] The functional layers stacked in the first region 110, the second region 120 and the third region 130 are different, resulting in different distances between the first passivation film layer 106, the second passivation film layer 107 and the third passivation film layer 108 and the surface of the silicon substrate. The first passivation film layer 106, the second passivation film layer 107 and the third passivation film layer 108 are connected, that is, the sides of the positions where the first passivation film layer 106, the second passivation film layer 107 and the third passivation film layer 108 have height differences are also covered by the passivation film layer, which can provide better protection for the functional layers stacked on the silicon substrate.

[0141] In some embodiments, the first passivation film layer 106 , the second passivation film layer 107 , and the third passivation film layer 108 may be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon carbide, and silicon oxynitride.

[0142] The first passivation film layer 106, the second passivation film layer 107 and the third passivation film layer 108 can be made of the same material or different materials, which is not limited here. The first passivation film layer 106, the second passivation film layer 107 and the third passivation film layer 108 can be composed of one or more layers of a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, a silicon carbide layer, or a silicon oxynitride layer.

[0143] Silicon oxide has good insulation properties and optical transparency. Aluminum oxide has high dielectric constant and good interface properties. Silicon nitride has high hardness, heat resistance, antistatic ability and anti-metal diffusion. Silicon carbide has high hardness, high thermal conductivity and low resistivity, high power and high temperature resistance. Silicon oxynitride has adjustable refractive index, low stress and good interface properties.

[0144] Embodiment 5

[0145] In some embodiments, the number of identification points is at least four.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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 cutting process.

[0152] Embodiment 6

[0153] In some embodiments, the roughness of the third region 130 is greater than the roughness of the first region 110 .

[0154] Roughness is a physical quantity that measures the degree of unevenness of a surface. When light shines on a rough surface, the tiny unevenness of the surface will cause the light to scatter, that is, the light no longer reflects according to the law of mirror reflection, but is emitted in multiple directions, which will reduce the reflectivity of the surface. For smoother surfaces, the incident light follows the laws of mirror reflection and refraction more, and the surface reflectivity increases.

[0155] The third area 130 and the first area 110 have different roughness and different reflectivity of light, which leads to different contrast of the two areas, resulting in a large difference in brightness or color between the two areas, making the marking point easier to be recognized by the device.

[0156] In some embodiments, the surface of the silicon substrate in the third region is a suede surface, and the surfaces of the silicon substrate in the first region and the second region are at least one of a micro-suede surface and a polished surface.

[0157] The suede surface has an irregular microstructure and is usually prepared by chemical corrosion or physical etching, with a large surface roughness. The irregularity of the surface structure will cause multiple scattering of light on the surface, affecting the propagation path of light, resulting in a low reflectivity of the suede surface.

[0158] Specifically, the velvet surface of the silicon substrate surface in the third region 130 is at least one of a positive pyramid, a V-groove, an inverted pyramid, and a stacked positive pyramid. It may be only one structure among the positive pyramid, the V-groove, the inverted pyramid, and the stacked positive pyramid, or a combination of two or more structures, which is not limited here.

[0159] Micro-suede is made by high-precision etching technology, and its surface roughness is between that of suede and polished surface, with a certain microstructure. Micro-suede can also scatter light, but the degree of scattering is less than that of suede, so the reflectivity of micro-suede is between that of suede and polished surface.

[0160] The polished surface is smooth with very low surface roughness, usually prepared by chemical mechanical polishing (CMP) technology. The polished surface is highly reflective and transparent.

[0161] The surface of the silicon substrate 101 in the first region 110 can be a micro-textured surface, a polished surface, or a part of the micro-textured surface divided into a polished surface. The surface of the silicon substrate in the second region 120 can be a micro-textured surface, a polished surface, or a part of the micro-textured surface divided into a polished surface.

[0162] The surface of the silicon substrate 101 in the third region 130 is suede, and the reflectivity of the third region 130 is greater than the reflectivity of the first region 110 and the reflectivity of the second region 120 . The contrasts of the three regions are different, which facilitates identification.

[0163] Embodiment 7

[0164] This embodiment provides a battery assembly, including the photovoltaic cell 100 in the above embodiment.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] Embodiment 8

[0171] This embodiment provides a photovoltaic system, including the battery assembly in the above embodiment.

[0172] 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 may 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.

[0173] 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.

[0174] 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 includes a first area, a second area and a third area, wherein the third area is arranged between the first area and the second area, and the first area extends a first extension portion toward the adjacent third area at a preset position to form a mark; An absolute value of a difference between a reflectivity of the first region and a reflectivity of the third region is greater than or equal to 6%.

2. 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 third region is greater than 19% and less than 23%.

3. 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 third region is greater than 28% and less than 31%.

4. 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 third region is greater than 6% and less than 27%.

5. 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 third region is greater than 13% and less than 24%.

6. The photovoltaic cell according to claim 1, characterized in that: For light in the wavelength range of 1200-1400 nm, an absolute value of a difference between a reflectivity of the first region and a reflectivity of the third region is greater than 10% and less than 27%.

7. The photovoltaic cell according to claim 1, characterized in that On the backlight surface of the photovoltaic cell, a plurality of the first regions and a plurality of the second regions are alternately arranged along a first direction, the first regions, the second regions and the third regions all extend along a second direction, and the second direction intersects the first direction; At least one of the first regions extends a first extension portion toward the adjacent third 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.

8. The photovoltaic cell according to claim 7, characterized in that: At the preset position, the first area extends a first extension portion toward the third areas adjacent to both sides along the first direction to form a marking point.

9. The photovoltaic cell according to claim 1, characterized in that: The third region includes a second extension portion, and the second extension portion extends toward the second region along an extension direction of the first extension portion.

10. The photovoltaic cell according to claim 9, characterized in that: An absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 6%.

11. The photovoltaic cell according to claim 9, characterized in that: For light in the wavelength range of 250-400 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 17% and less than 26%.

12. The photovoltaic cell according to claim 9, characterized in that: For light in the wavelength range of 400-600 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 24% and less than 38%.

13. The photovoltaic cell according to claim 9, characterized in that: For light in the wavelength range of 600-900 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 6 and less than 28%.

14. The photovoltaic cell according to claim 9, characterized in that: For light in the wavelength range of 900-1200 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 14% and less than 18%.

15. The photovoltaic cell according to claim 9, characterized in that: For light in the wavelength range of 1200-1400 nm, an absolute value of a difference between a reflectivity of the second region and a reflectivity of the third region is greater than 11% and less than 26%.

16. The photovoltaic cell according to claim 7, characterized in that: including a silicon substrate; In the first region, a first tunneling oxide layer and a first doping layer are sequentially stacked on the silicon substrate; in the second region, a second tunneling oxide layer and a second doping layer are sequentially stacked on the silicon substrate; and the third region separates the first doping layer and the second doping layer.

17. The photovoltaic cell according to claim 16, characterized in that: The first doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

18. The photovoltaic cell according to claim 17, characterized in that The first doped layer is a P-type doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

19. The photovoltaic cell according to claim 16, characterized in that: The first tunneling oxide layer and the second tunneling oxide layer are composed of one or more layers of an oxide layer, a nitride layer, an oxynitride layer, a carbide layer, and an amorphous silicon layer.

20. The photovoltaic cell according to claim 16, characterized in that The second doped layer is a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

21. The photovoltaic cell according to claim 20, characterized in that The second doped layer is an N-type doped polysilicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon layer.

22. The photovoltaic cell according to claim 16, characterized in that It also includes a first passivation film layer, a second passivation film and a third passivation film layer. In the first region, the first passivation film layer is stacked on the first doped layer. In the second region, the second passivation film layer is stacked on the second doped layer. The third passivation film layer is stacked on the silicon substrate. The thickness of the second passivation film layer is greater than the thickness of the first passivation film layer and greater than the thickness of the third passivation film layer.

23. The photovoltaic cell according to claim 22, characterized in that The thickness of the first passivation film is 1.3-1.5 times the thickness of the third passivation film.

24. The photovoltaic cell according to claim 22, characterized in that The difference in thickness between the second passivation film layer and the first passivation film layer is in the range of 5-30 nm.

25. The photovoltaic cell according to claim 22, characterized in that The thickness of the first passivation film layer is in the range of 60 to 160 nm, the thickness of the second passivation film layer is in the range of 65 to 190 nm, and the thickness of the third passivation film layer is in the range of 40 to 125 nm.

26. The photovoltaic cell according to claim 22, characterized in that The first passivation film layer, the second passivation film layer and the third passivation film layer are in communication.

27. The photovoltaic cell according to any one of claims 22 to 26, characterized in that: The first passivation film layer, the second passivation film layer and the third passivation film layer may be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon carbide and silicon oxynitride.

28. 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.

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

30. The photovoltaic cell according to claim 29, 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.

31. The photovoltaic cell according to claim 29, 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.

32. The photovoltaic cell according to claim 1, characterized in that The roughness of the third region is greater than the roughness of the first region and the roughness of the second region.

33. The photovoltaic cell according to claim 32, characterized in that The surface of the silicon substrate in the third region is a suede surface, and the surfaces of the silicon substrate in the first region and the second region are at least one of a micro-suede surface and a polished surface.

34. The photovoltaic cell according to claim 33, characterized in that The textured surface of the silicon substrate surface in the third region is at least one of a regular pyramid, a V-groove, an inverted pyramid, and a stacked regular pyramid.

35. A battery assembly, characterized in that: A photovoltaic cell comprising any one of claims 1 to 34.

36. A photovoltaic system, characterized in that: Comprising the battery assembly of claim 35.

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