Solar cell, cell module and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a solar cell, a cell module and a photovoltaic system, and the solar cell comprises a silicon substrate which is provided with a first surface and a second surface which are oppositely arranged; the silicon substrate comprises a first surface and a second surface, the first surface is arranged on the silicon substrate, the second surface is arranged on the silicon substrate, the deposition layer is arranged on the first surface of the silicon substrate and is arranged on the second surface of the silicon substrate in a winding and plating mode in the thickness direction of the silicon substrate, and the deposition layer is arranged on the first surface of the silicon substrate and is arranged on the second surface of the silicon substrate in a winding and plating mode in the thickness direction of the silicon substrate. According to the solar cell, the edge part of the cell can be covered, the edge part of the cell is provided with a film layer structure consistent with the first surface, and the edge part can be efficiently passivated, so that the recombination of the edge part is reduced, and the conversion efficiency of the solar cell is improved; the part of the silicon substrate in the first region and the other part of the silicon substrate in the second region are different in thickness, so that the problem of stress concentration on the surface of the silicon substrate is effectively avoided.

Description

Technical Field

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

[0002] Solar cell power generation is a sustainable source of clean energy, which uses the photovoltaic effect of semiconductor pn junction to convert sunlight into electrical energy. In solar cells, a doping layer is provided on the front and / or back of the silicon substrate, and a passivation film layer is provided on the doping layer to passivate the cell. During the film formation process, the chemical reaction on the surface of the silicon wafer may be affected by the edge effect, resulting in a decrease in the chemical reaction rate at the edge of the silicon wafer, thereby affecting the formation of the film layer, resulting in a relatively weak film structure at the edge of the cell, so that recombination is likely to occur at the edge of the cell.

[0003] Application Contents

[0004] The present application provides a solar cell, aiming to solve the problem that the film structure at the edge of the cell is relatively weak, so that recombination is easily caused at the edge of the cell.

[0005] The present application is implemented as follows: a solar cell includes a silicon substrate, the silicon substrate having a first surface and a second surface arranged opposite to each other; and a deposition layer arranged on the first surface of the silicon substrate and coated around the second surface of the silicon substrate along the thickness direction of the silicon substrate, the second surface includes a first area and a second area that do not overlap each other, the first area is covered with the deposition layer, the second area is the silicon substrate exposed to the outside, and the portion of the silicon substrate located in the first area and the other portion of the silicon substrate located in the second area have different thicknesses.

[0006] Optionally, the first region has a first micro-unit structure, and a plurality of the first micro-unit structures form a first velvet structure. In a first target region on the surface of the first velvet structure, the average longitudinal size of the first target micro-unit structure is h1 target. The second region has a second micro-unit structure, and a plurality of the second micro-unit structures form a second velvet structure. In a second target region on the surface of the second velvet structure, the average longitudinal size of the second target micro-unit structure is h2 target; h1 target < h2 target; the first target micro-unit structure is: the three first micro-unit structures with the largest longitudinal size in the first target region; the second target micro-unit structure is: the three second micro-unit structures with the largest longitudinal size in the second target region; the first target region is a 10μm×20μm rectangular region selected from the first region; the second target region is a 10μm×20μm rectangular region selected from the second region.

[0007] Optionally, it also includes a second passivation layer arranged in the second area, the second passivation layer is a continuous film layer structure, the second passivation layer extends outward, the second passivation layer covers the deposition layer and is plated around the first surface along the thickness direction of the silicon substrate.

[0008] Optionally, the first region includes an edge region around the second surface, the second region includes a central region of the second surface, and the second region is enclosed in the first region.

[0009] Optionally, a thickness of the silicon substrate in the first region is greater than a thickness of the silicon substrate in the second region.

[0010] Optionally, a difference between a thickness of the silicon substrate in the first region and a thickness of the silicon substrate in the second region is 2 micrometers to 5 micrometers.

[0011] Optionally, an area of ​​the first region is at least 5% of an area of ​​the second surface.

[0012] Optionally, the first region includes at least a first edge region, a second edge region, a third edge region and a fourth edge region distributed along the edges of the silicon substrate, and the average width of the first edge region is smaller than the average width of any one of the second edge region, the third edge region and the fourth edge region.

[0013] Optionally, the edge portion of the silicon substrate at least includes the deposition layer and the second passivation layer stacked in sequence.

[0014] Optionally, the deposition layer includes at least a doping layer and a first passivation layer which are stacked in sequence.

[0015] Optionally, a reflectivity of the solar cell located in the first region is lower than a reflectivity of the solar cell located in the second region.

[0016] Optionally, a boundary line between the first region and the second region includes an irregularly curved arc line.

[0017] The present application coats the deposition layer disposed on the first surface of the silicon substrate around the second surface of the silicon substrate along the thickness direction of the silicon substrate, so that the edge portion of the battery cell can be covered. The edge portion of the battery cell has a film layer structure consistent with the first surface, and the edge portion can be efficiently passivated, thereby reducing the recombination of the edge portion and improving the conversion efficiency of the solar cell. In addition, the thickness of the silicon substrate in the first area and the other part of the silicon substrate in the second area are different, which effectively avoids the problem of stress concentration on the surface of the silicon substrate and further strengthens the structural strength of the edge portion of the silicon substrate.

[0018] A battery assembly includes the above-mentioned solar cell. The technical effect of the present application is the same as the technical effect of the above-mentioned solar cell, which will not be repeated here.

[0019] A photovoltaic system includes the above-mentioned battery assembly. The technical effect of the present application is the same as the technical effect of the above-mentioned battery assembly, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the first solar cell provided in the present application;

[0021] Figure 2 It is a schematic diagram of the structure of the second solar cell provided in the present application;

[0022] Figure 3 It is a schematic diagram of the structure of the third solar cell provided in the present application;

[0023] Figure 4 is a schematic diagram of the structure of the fourth solar cell provided in the present application;

[0024] Figure 5 This is a schematic diagram of the structure of the fifth solar cell provided in the present application.

[0025] Figure 6 It is a schematic diagram of the structure of the sixth solar cell provided in the present application.

[0026] Description of reference numerals:

[0027] 100, silicon substrate; 101, first surface; 102, second surface; 103, first edge; 104, second edge; 105, third edge; 106, fourth edge; 1021, first region; 1022, second region; 103, side wall; 200, deposition layer; 201, doping layer; 202, first passivation layer; 300, second passivation layer; 400, first edge region; 500, second edge region; 600, third edge region; 700, fourth edge region. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application 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 application, and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0029] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application 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 should not be understood as a limitation on the present application.

[0030] 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. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In the description of this application, 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 this application can be understood according to specific circumstances.

[0032] In the present application, 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.

[0033] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, 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 application. In addition, the present application 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 various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0034] like Figure 1 and Figure 4 As shown, a solar cell includes a silicon substrate 100 having a first surface 101 and a second surface 102 arranged opposite to each other; and a deposition layer 200 arranged on the first surface 101 of the silicon substrate 100 and coated around the second surface 102 of the silicon substrate 100 along the thickness direction of the silicon substrate 100.

[0035] In the embodiment of the present application, the silicon substrate 100 serves as the support and foundation of the battery cell, and the silicon substrate 100 has excellent semiconductor performance and mechanical stability. The material of the silicon substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. Among them, the elemental semiconductor material may be single crystal, polycrystalline, amorphous or microcrystalline (a state having both single crystal and amorphous states is called microcrystalline), for example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. Preferably, the silicon substrate 100 is made of n-type single crystal silicon.

[0036] like Figure 3 As shown, the silicon substrate 100 has a first surface 101 and a second surface 102 arranged opposite to each other in the thickness direction. In the embodiment of the present application, the first surface 101 and the second surface 102 may be respectively the light-facing surface and the backlight surface of the silicon substrate 100. The light-facing surface may be understood as the side facing the sun when the solar cell 100 is installed, and the backlight surface may be understood as the side facing away from the sun when the solar cell 100 is installed. In some embodiments, the solar cell is a bifacial cell, that is, the first surface 101 and the second surface 102 of the silicon substrate 100 may both serve as light-receiving surfaces and may both be used to receive incident light.

[0037] It can be understood that the silicon substrate 100 also has a plurality of sidewall surfaces 103 connecting the first surface 101 and the second surface 102 . In the embodiment of the present application, the plurality of sidewall surfaces 103 , the first surface 101 and the second surface 102 constitute the entire outer surface structure of the silicon substrate 100 .

[0038] It should be noted that the edge portion referred to in the present application should include the edge area of ​​the first surface 101, the edge area of ​​the second surface 102, and all the sidewall surfaces 103 of the silicon substrate 100. Further, the edge area of ​​the first surface 101 can be an area where the edge of the silicon substrate 100 extends a first preset distance to the center of the first surface 101, and the first preset distance can be flexibly set according to the size of the silicon substrate 100, and the present application is not limited by comparison. Exemplarily, the first preset distance can be 1 / 20 of the side length of the silicon substrate. Similarly, the edge area of ​​the second surface 102 can be an area where the edge of the silicon substrate 100 extends a second preset distance to the center of the second surface 102, and the second preset distance can be flexibly set according to the size of the silicon substrate 100, and the present application is not limited by comparison. Exemplarily, the second preset distance can be 1 / 20 of the side length of the silicon substrate.

[0039] The deposition layer 200 mentioned in the embodiment of the present application is arranged on the first surface 101 of the silicon substrate 100 and is coated on the second surface 102 of the silicon substrate 100 along the thickness direction of the silicon substrate 100, that is, the deposition layer 200 is arranged on the first surface 101 of the silicon substrate 100 and extends along the thickness direction of the silicon substrate 100 to cover the side wall surface 103 of the silicon substrate 100 and a partial area or the entire area of ​​the second surface 102 of the silicon substrate 100, that is, the deposition layer 200 wraps around the silicon substrate 100 to achieve reliable passivation of the edge portion of the silicon substrate 100, thereby reducing the recombination of the edge portion and improving the conversion efficiency of the solar cell.

[0040] In some embodiments, the deposition layer 200 includes at least a doping layer 201 and a first passivation layer 202 which are stacked in sequence. The doping layer 201 disposed at the edge of the silicon substrate 100 can reduce the dangling bonds and defect density at the edge of the silicon substrate 100, reduce the recombination rate at the edge of the silicon substrate 100, and improve the open circuit voltage and short circuit current of the cell. In particular, the doping layer 201 is disposed on the side wall surface 103 of the silicon substrate 100, which can change the electrical properties of the silicon substrate 100, improve its conductivity, help reduce the internal resistance of the silicon substrate 100, improve the current transmission efficiency, and thus improve the overall performance of the battery assembly. The first passivation layer 202 is disposed to improve the stability and passivation performance of the edge of the silicon substrate 100, improve the stress distribution at the edge of the silicon wafer, reduce the fracture and failure caused by stress concentration, and help improve the long-term stability and reliability of the solar cell. Of course, in other embodiments, the deposition layer 200 may also include a film structure such as an anti-reflection layer and a dielectric layer to further enhance the performance of the edge of the silicon substrate 100, and this application is not limited to this.

[0041] In some embodiments, Figure 1As shown, the second surface 102 includes a first area 1021 and a second area 1022 which do not overlap each other, the first area 1021 is covered with a deposition layer 200, and the second area 1022 is the silicon substrate 100 exposed to the outside. The first area is the edge area of ​​the second surface, and the second area is the central area of ​​the second surface, that is, the first area 1021 and the second area 1022 form two areas with clear boundaries, wherein the first area 1021 of the first surface 101 covers the deposition layer 200, forming protection for the first area 1021 of the first surface 101, strengthening the structural strength of the edge part of the silicon substrate, and the deposition layer 200 can protect the first area 1021 from corrosion by chemical substances such as acid and alkali. Preferably, the area of ​​the first area 1021 is at least 5% of the area of ​​the second surface 102. Ensure that the edge part of the silicon substrate 100 is fully protected and strengthen the structural stability of the edge part of the silicon substrate 100.

[0042] The second region 1022 of the first surface 101 is the silicon substrate 100 exposed to the outside, and the exposed silicon substrate 100 of the second region 1022 can be doped or combined with other materials to facilitate differential processing with the first region 1021. Further, the first region 1021 includes an edge region around the second surface 102, the second region 1022 includes a central region of the second surface 102, and the second region 1022 is enclosed in the first region 1021. In this way, the deposition layer 200 can be continuously disposed on the first surface 101, the side wall surface 103 and the first region 1021 of the second surface 102 of the silicon substrate 100, ensuring the integrity of the film structure of the deposition layer 200, and can strengthen the passivation effect of the edge portion of the silicon substrate 100, and improve its conductivity and structural strength. The second region 1022 is located in the central area of ​​the second surface 102. The second region 1022 is the core region of the photoelectric conversion of the battery cell. The surface treatment (such as texturing, coating, etc.) thereon can significantly improve the absorption efficiency of sunlight. The second region 1022 is enclosed in the first region 1021, which can protect the second region 1022 from direct erosion or damage by the external environment.

[0043] In addition, in this article, a certain film layer covering a certain surface or a certain film layer may be that the film layer is directly stacked on the surface or a certain film layer, or other film layers may be arranged between the film layer and the surface or film layer. Covering is only used to limit the specific setting range of the film layer.

[0044] In some embodiments, the first region 1021 has a first microcell structure, and multiple first microcell structures form a first velvet structure. In the first target region on the surface of the first velvet structure, the average longitudinal size of the first target microcell structure is h1 target. The second region 1022 has a second microcell structure, and multiple second microcell structures form a second velvet structure. In the second target region on the surface of the second velvet structure, the average longitudinal size of the second target microcell structure is h2 target; h1 target < h2 target; the first target microcell structure is: the three first microcell structures with the largest longitudinal size in the first target region; the second target microcell structure is: the three second microcell structures with the largest longitudinal size in the second target region; the first target region is a 10μm×20μm rectangular region selected from the first region 1021; the second target region is a 10μm×20μm rectangular region selected from the second region 1022.

[0045] In the embodiment of the present application, the longitudinal dimension refers to the vertical distance from the top of the pyramid-shaped micro-unit structure to the bottom surface of the tower. The first target area and the second target area can be randomly selected rectangular areas with the same area size. The present application does not limit the size of the first target area and the second target area. By controlling the h1 target < h2 target, when the light is transmitted from the front of the solar cell into the silicon substrate, since the size of the second micro-unit structure in the second area is larger than the size of the first micro-unit structure in the first area, the second area is used as the core area of ​​photoelectric conversion, and the size of the second velvet structure in the second area is larger, which is conducive to reducing the reflectivity of the light in the second area, improving the utilization rate of the light, and improving the photoelectric conversion efficiency of the solar cell. In addition, the first velvet structure is smaller in size, has a smaller roughness, is less prone to passivation dead corners, and is conducive to improving the film quality of the passivation layer in the first area.

[0046] In some embodiments, the boundary line between the first region 1021 and the second region 1022 includes an irregularly curved arc line. Compared with a straight line boundary, the arc boundary line can better disperse the stress generated by the battery cell when it is subjected to force, which helps to reduce the risk of battery cell damage or performance degradation due to stress concentration. The deposition layer 200 covers the first region 1021, which helps to improve the edge strength of the battery cell and prevent damage or failure due to external stress.

[0047] In some embodiments, Figure 2As shown, the first region 1021 at least includes a first edge region 400, a second edge region 500, a third edge region 600 and a fourth edge region 700 distributed along the edges of the silicon substrate 100, and the average width of the first edge region 400 is less than the average width of any one of the second edge region 500, the third edge region 600 and the fourth edge region 700. Specifically, the edges of the silicon substrate 100 include a first edge 103, a second edge 104, a third edge 105 and a fourth edge 106, and the first region 1021 is divided into a first edge region 400, a second edge region 500, a third edge region 600 and a fourth edge region 700 according to the corresponding edges of the silicon substrate 100, wherein the first edge region 400 and the third edge region 600 are arranged opposite to each other, and the second edge region 500 and the fourth edge region 700 are arranged opposite to each other, and the average width of the edge region is specifically the average distance between the boundary line of each edge region and the second region and the edge corresponding to the silicon substrate, as shown For example, the average width of the first edge region 400 is the average distance between the boundary line of the first edge region 400 and the second region 1022 and the first edge 103, the average width of the second edge region 500 is the average distance between the boundary line of the second edge region 500 and the second region 1022 and the second edge 104, the average width of the third edge region 600 is the average distance between the boundary line of the third edge region 600 and the second region 1022 and the third edge 105, and the average width of the fourth edge region 700 is the average distance between the boundary line of the fourth edge region 700 and the second region 1022 and the fourth edge 106. By differentially setting the edge regions of the first region along the edge of the silicon substrate, the flow path of the current inside the battery is optimized, which helps to distribute the current more evenly, reduce current congestion and energy loss, and thus improve the efficiency of the battery.

[0048] In some embodiments, Figure 6 As shown, the solar cell further includes a second passivation layer 300 disposed in the second region 1022, the second passivation layer 300 is a continuous film structure, the second passivation layer 300 extends outward, the second passivation layer 300 covers the deposition layer 200 and is plated around the first surface 101 along the thickness direction of the silicon substrate 100. That is to say, the second passivation layer 300 completely covers the second region 1022, completes the passivation of the second region 1022, and the second passivation layer 300 extends from the second region 1022 until it covers the first region 1021, the sidewall surface 103 of the silicon substrate 100 and a partial region or the entire region of the first surface 101 of the silicon substrate 100, and further strengthens the passivation effect on the edge portion of the silicon substrate 100, so that the edge portion of the silicon substrate 100 is covered with at least two layers of passivation film structure, has a high structural strength, and when the electrode or the battery string is subsequently set or the welding ribbon is welded in series, it will not be subject to external force, thereby improving the yield rate of the solar cell.

[0049] It should be noted that in the embodiments of the present application, "continuous film layer structure" refers to the second passivation layer 300 being a continuous film layer structure formed during the preparation process. After the preparation is completed, the second passivation layer 300 does not have a disconnected structure, that is, the second passivation layer 300 is a continuous and uninterrupted structure. It can be understood that in the solar cell, it also has a metal electrode (not shown in the figure), and the metal electrode will burn through the second passivation layer 300 so that part of the second passivation layer 300 is ablated. The second passivation layer 300 is a continuous structure, which can be understood as that, except for the position burned through by the metal electrode, the other areas are continuous and uninterrupted structures.

[0050] In the embodiment of the present application, the silicon substrate 100 can be substantially in the shape of a cuboid or a cube, and can be a right-angled rectangle or a chamfered rectangle, which is not specifically limited here. The first passivation layer 202 and the second passivation layer 300 can both be passivation film layers such as silicon nitride film layers and silicon oxynitride film layers, which are not specifically limited here.

[0051] In some embodiments, the thickness of the portion of the silicon substrate 100 located in the first region and the other portion of the silicon substrate 100 located in the second region are different, that is, the silicon substrate 100 has an uneven morphology on the second surface, which effectively avoids the problem of stress concentration at the edge of the silicon substrate, and further strengthens the structural strength of the edge of the silicon substrate. Specifically, the thickness of the silicon substrate 100 in the first region 1021 is greater than the thickness of the silicon substrate 100 in the second region 1022. By forming a thickness difference and a height difference on the first surface 101 of the silicon substrate 100, the unevenness of the surface of the battery can be increased to a certain extent. This uneven surface structure helps to capture and reflect more light, thereby improving the absorption efficiency of the solar cell to light, especially when the light is incident at different angles. More light is captured and converted into electrical energy, thereby improving the photoelectric conversion efficiency of the solar cell. In addition, by changing the thickness of the silicon substrate 100, the stress distribution inside the solar cell can be adjusted. Especially for the edge of the silicon substrate 100, there is a situation of stress concentration. This design may help to enhance the structural stability of the battery and reduce the risk of rupture or damage caused by stress concentration. Preferably, the difference between the thickness of the silicon substrate in the first region and the thickness of the silicon substrate in the second region is 2 to 5 microns. Specifically, the thickness of the silicon substrate in the first region is 2 to 5 microns higher than the thickness of the silicon substrate in the second region.

[0052] In some embodiments, Figure 5As shown, the edge portion of the silicon substrate 100 includes at least a deposition layer 200 and a second passivation layer 300 stacked in sequence. The deposition layer 200 includes at least a doping layer 201 and a first passivation layer 202, so that the edge portion of the silicon substrate 100 is at least stacked with a doping layer 201, a first passivation layer 202 and a second passivation layer 300, and the edge portion of the silicon substrate 100 is covered with at least two layers of passivation film layers, which can efficiently passivate the edge portion, thereby reducing edge recombination and improving the conversion efficiency of the solar cell. Further, the doping layer 201 includes an N-type doping layer and / or a P-type doping. Specifically, in a back contact cell, the doping layer 201 includes an N-type doping layer and a P-type doping layer alternately arranged. In a bifacial cell, exemplarily, the doping layer 201 includes an N-type doping layer, and correspondingly, a P-type doping layer is arranged in the second region 1022 of the second surface 102 of the silicon substrate 100.

[0053] The boundary line between the first region 1021 and the second region 1022 includes a plurality of irregularly curved arc lines, and the plurality of irregularly curved arc lines are connected to form an irregularly curved wavy boundary line. In this way, the first region 1021 and the second region 1022 form two regions with clear boundaries, which is convenient for subsequent processing or electrode setting. The irregularly curved wavy boundary line can further reduce stress concentration at the edge of the silicon substrate 100, forming a more beautiful appearance.

[0054] In some embodiments, since more film structures are coated around the edge of the solar cell, the reflectivity of the solar cell in the first area 1021 is lower than the reflectivity of the solar cell in the second area 1022, thereby improving the overall light utilization capability of the solar cell.

[0055] A battery assembly includes the above-mentioned solar cell. A battery assembly includes the above-mentioned solar cell. Based on the above-mentioned solar cell, those skilled in the art know that a corresponding battery assembly can be obtained by using a plurality of the solar cells and / or other corresponding existing accessories. In this embodiment, a plurality of solar cells in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series connection and bus output of current.

[0056] A photovoltaic system includes the above-mentioned battery assembly. In this embodiment, the photovoltaic system can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface 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 can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system 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 assemblies. For example, multiple battery assemblies 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 to convert it into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0057] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0058] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A solar cell, characterized in that: The invention comprises a silicon substrate, wherein the silicon substrate has a first surface and a second surface which are arranged opposite to each other; and a deposition layer which is arranged on the first surface of the silicon substrate and is coated around the second surface of the silicon substrate along the thickness direction of the silicon substrate, wherein the second surface comprises a first area and a second area which do not overlap each other, wherein the first area is covered with the deposition layer, and the second area is the silicon substrate exposed outwardly, and the thickness of a part of the silicon substrate located in the first area and another part of the silicon substrate located in the second area are different.

2. The solar cell according to claim 1, wherein: The first region has a first micro-unit structure, a plurality of the first micro-unit structures form a first suede structure, within a first target region on the surface of the first suede structure, the longitudinal average size of the first target micro-unit structure is h1 target, the second region has a second micro-unit structure, a plurality of the second micro-unit structures form a second suede structure, within a second target region on the surface of the second suede structure, the longitudinal average size of the second target micro-unit structure is h2 target; h1 target < h2 target; the first target micro unit structure is: the three first micro unit structures with the largest longitudinal dimensions in the first target area; the second target micro unit structure is: the three second micro unit structures with the largest longitudinal dimensions in the second target area; the first target area is a 10μm×20μm rectangular area selected from the first area; the second target area is a 10μm×20μm rectangular area selected from the second area.

3. The solar cell according to claim 1, wherein: It also includes a second passivation layer arranged in the second area, the second passivation layer is a continuous film layer structure, the second passivation layer extends outward, the second passivation layer covers the deposition layer and is plated around the first surface along the thickness direction of the silicon substrate.

4. The solar cell according to claim 1, wherein: The first area includes an edge area around the second surface, the second area includes a central area of ​​the second surface, and the second area is enclosed in the first area.

5. The solar cell according to claim 1, wherein: The thickness of the silicon substrate in the first region is greater than the thickness of the silicon substrate in the second region.

6. The solar cell according to claim 5, characterized in that The difference between the thickness of the silicon substrate in the first region and the thickness of the silicon substrate in the second region is 2 micrometers to 5 micrometers.

7. The solar cell according to claim 1, wherein: The area of ​​the first region is at least 5% of the area of ​​the second surface.

8. The solar cell according to claim 1, wherein: The first region includes at least a first edge region, a second edge region, a third edge region and a fourth edge region distributed along the edges of the silicon substrate, and the average width of the first edge region is smaller than the average width of any one of the second edge region, the third edge region and the fourth edge region.

9. The solar cell according to claim 3, characterized in that: The edge portion of the silicon substrate at least includes the deposition layer and the second passivation layer stacked in sequence.

10. The solar cell according to claim 1, wherein: The deposition layer at least includes a doping layer and a first passivation layer which are stacked in sequence.

11. The solar cell according to claim 1, wherein: The reflectivity of the solar cell located in the first region is lower than the reflectivity of the solar cell located in the second region.

12. The solar cell according to claim 1, wherein: A boundary line between the first region and the second region includes an irregularly curved arc line.

13. A battery assembly, characterized in that: A solar cell comprising any one of claims 1 to 12.

14. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 13.

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