Solar cell, solar cell module and photovoltaic system

Abstract

The utility model relates to the technical field of solar cells, and discloses a solar cell sheet, a solar cell module and a photovoltaic system, the solar cell sheet comprises a cell sheet substrate and an identification structure arranged on the front side and / or the back side of the cell sheet substrate, the identification structure comprises a first identification structure and a second identification structure, the first identification structure and the second identification structure are at least partially overlapped. According to the utility model, when the solar cell is printed, coarse positioning is firstly carried out through the first identification structure, then more accurate positioning is realized by taking the second identification structure as a positioning reference when a finer structure is printed, and the reliability and the performance stability of the solar cell are improved.

Description

Technical Field

[0001] This utility model relates to the technical field of solar cells, and in particular to a solar cell, a solar cell module, and a photovoltaic system. Background Technology

[0002] In the fabrication of solar cells, marking structures are typically placed outside the laser-grooved area of ​​the cell substrate. During grid line printing, a camera is used to capture the marking structures, ensuring alignment between the grid lines and the laser-grooved area. Traditionally, these marking structures are placed at the four corners of the cell substrate and symmetrically distributed horizontally and vertically. Over multiple processing steps, errors accumulate, leading to positioning deviations. This results in displacement of the printed pattern, affecting cell performance. This is especially problematic for printing smaller structures later on; using traditional marking structures as a positioning reference exacerbates the errors, making precise positioning impossible. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a solar cell, solar cell module and photovoltaic system, which improves the problem of large positioning error during the printing of solar cells, especially the positioning error of printing small-sized structures, and at the same time increases the reliability and performance stability of the solar cells.

[0004] To address the aforementioned technical problems, the present invention provides a solar cell, comprising: a cell substrate and an identification structure disposed on the front and / or back of the cell substrate, wherein the identification structure includes a first identification structure and a second identification structure, and the first identification structure and the second identification structure at least partially overlap.

[0005] As an improvement to the above scheme, the area of ​​the second identification structure is smaller than the area of ​​the first identification structure. The first identification structure is used for the first identification and positioning of the solar cell, and the second identification structure is used for the second identification and positioning of the solar cell.

[0006] As an improvement to the above solution, the second identification structure is disposed inside the first identification structure, and the second identification structure extends out of the first identification structure.

[0007] As an improvement to the above solution, the second identification structure is disposed inside the first identification structure, and the first identification structure encloses the second identification structure.

[0008] As an improvement to the above scheme, the second marking structure is disposed at 1 / 3 to 2 / 3 of the first marking structure along the first direction and / or the second direction.

[0009] As an improvement to the above solution, the second identification structure is disposed at the middle position of the first identification structure along the first direction and / or the second direction.

[0010] As an improvement to the above solution, the first marking structure and the second marking structure have a color difference, which is used for precise identification and positioning when printing on the battery cell substrate.

[0011] As an improvement to the above scheme, the width of the first identification structure is greater than or equal to the width of a P area or an N area, and the width of the second identification structure is less than or equal to the width of a P area or an N area.

[0012] As an improvement to the above scheme, the height difference between the first marking structure and the P region is 1μm to 5μm, the height difference between the first marking structure and the N region is 0.5μm to 3μm, and the depth of the second marking region is 60nm to 140nm.

[0013] As an improvement to the above scheme, at least one second identification structure is provided within the first identification structure.

[0014] As an improvement to the above scheme, the shape of the first identifier structure is one of the following: circle, square, rectangle, trapezoid, pentagon, and pentagram;

[0015] The shape of the second identifier structure is one of the following: circle, square, rectangle, trapezoid, pentagon, or pentagram.

[0016] As an improvement to the above scheme, the shape of the first identification structure is the same as the shape of the second identification structure.

[0017] As an improvement to the above scheme, the shape of the first identification structure is different from the shape of the second identification structure.

[0018] As an improvement to the above solution, the battery cell substrate has four corner regions, and the first marking structure is disposed in the four corner regions.

[0019] As an improvement to the above scheme, the first identification structure is symmetrically arranged in the four corner regions.

[0020] As an improvement to the above scheme, the second identification structure is also disposed on the asymmetry axis of the first identification structure.

[0021] As an improvement to the above solution, the front and / or back of the battery cell substrate are provided with grid lines, which are in contact with the marking structure.

[0022] As an improvement to the above solution, the grid line is disposed on the second identification structure, and the grid line covers the second identification structure.

[0023] As an improvement to the above solution, the gate lines completely cover the second identification structure.

[0024] A second aspect of this invention also provides a solar cell module, including the aforementioned solar cell.

[0025] A third aspect of this utility model also provides a photovoltaic system, including the aforementioned solar cell module.

[0026] Implementing this utility model has the following beneficial effects:

[0027] In this invention, the front and / or back of the solar cell substrate are provided with marking structures, including a first marking structure and a second marking structure. The first and second marking structures at least partially overlap, facilitating rough positioning using the first marking structure during solar cell printing, followed by more precise positioning using the second marking structure as a positioning reference when printing finer structures. This also improves the reliability and performance stability of the solar cell. If the first and second marking structures are misaligned, on the one hand, setting the second marking structure will cause thermal damage to a larger area of ​​the surrounding solar cell, increasing the probability of microcracks and resulting in defective marking structures. On the other hand, if the color difference between the second marking structure and the upper structure of the solar cell is small, or if there are abnormal lighting conditions, the technical difficulty of simultaneously capturing the first and second marking structures increases. Attached Figure Description

[0028] Figure 1 : A schematic diagram of the structure of a solar cell in this utility model;

[0029] Figure 2 : A partial enlarged view of the marking structure in Embodiment 1 of this utility model;

[0030] Figure 3 : A partially enlarged view of the marking structure in Embodiment 2 of this utility model;

[0031] Figure 4 : A partial enlarged view of the marking structure in Embodiment 3 of this utility model;

[0032] Figure 5 : A schematic diagram of another type of solar cell in this utility model;

[0033] Figure 6 The connection relationship between the second marking structure and the grid line in this utility model.

[0034] Figure label:

[0035] 100 - Solar cell; 110 - Cell substrate; 120 - Identification structure; 121 - First identification structure; 122 - Second identification structure; 130 - P-region; 140 - N-region; 150 - Opening; 160 - Grid line. Detailed Implementation

[0036] To make the objectives, technical solutions and advantages of this utility model clearer, specific embodiments will be described in further detail below.

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided 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 denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0038] In the description of this application, it should be understood that the terms "upper", "lower", "back", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0039] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0041] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0042] In this document, references to "embodiment" or "implementation" mean that a particular feature, component, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0043] In existing technologies, the grid lines 160 are generally printed in stages using screen printing technology. Before printing the grid lines 160, multiple openings 150 need to be set at the preset grid line 160 positions using a laser to conduct current and connect the P-region 130, N-region 140 to the external circuit. During the printing of the grid lines 160, the multiple openings 150 need to be completely covered. The smaller the coverage width of the grid lines 160, the lower the light-blocking area, the higher the efficiency of the solar cell 100, and the higher the power generation of the solar cell 100. If the marking structure 120 is used as the positioning reference, the accuracy is poor, and there will be a larger error. It is also impossible to achieve complete coverage of the openings 150 with a smaller grid line 160, resulting in the grid line 160 width being larger than the preset value, or exposing some openings 150 on the surface of the layer structure, reducing the efficiency of the solar cell 100.

[0044] To address the aforementioned problems, the first aspect of this utility model provides a solar cell 100, please refer to [link / reference needed]. Figures 1-2 The solar cell 100 includes: a cell substrate 110 and an identification structure 120 disposed on the front and / or back of the cell substrate 110. The identification structure 120 includes a first identification structure 121 and a second identification structure 122, wherein the first identification structure 121 and the second identification structure 122 at least partially overlap.

[0045] In this invention, the marking structure 120 includes a first marking structure 121 and a second marking structure 122. The first marking structure 121 and the second marking structure 122 at least partially overlap, facilitating rough positioning using the first marking structure 121 during the printing of the solar cell 100. Subsequently, when printing finer structures, the second marking structure 122 serves as the positioning reference for more precise positioning, thus improving the reliability and performance stability of the solar cell. If the first marking structure 121 and the second marking structure 122 are misaligned, on the one hand, setting the second marking structure 122 will cause thermal damage to a larger area of ​​the surrounding solar cell 100, increasing the probability of microcracks in the cell and resulting in defective marking structures. On the other hand, if the color difference between the second marking structure and the upper structure of the solar cell 100 is small, or if there are abnormal lighting conditions, the technical difficulty of simultaneously capturing both the first and second marking structures increases.

[0046] The first marking structure 121 is used for the initial identification and positioning of the solar cell 100, and the second marking structure 122 is used for the secondary identification and positioning of the solar cell 100. The first marking structure 121 can be used as a positioning reference during multiple printing processes on the solar cell 100, for initially identifying the printing position of materials on the silicon wafer and moving the silicon wafer or screen to adjust the printing position. Examples include the printing of insulating layers and the setting of multiple openings 150 at preset grid line 160 positions. The second marking structure 122 can be used as a positioning reference during the printing of smaller structures, such as grid lines 160, ensuring that the grid lines 160 completely cover the openings 150 to allow current to be conducted through the grid lines 160. The smaller width of the grid lines 160 effectively reduces the shading area and improves the efficiency of the solar cell 100. It is understood that the first marking structure 121 can also be applied to other solar cell processing technologies and photovoltaic module processing technologies. Specific application scenarios can be set as needed, and this application does not limit this application.

[0047] Understandably, the area of ​​the second identification structure 122 is smaller than that of the first identification structure 121, which facilitates more precise positioning of a smaller structure based on the positioning of the first identification structure 121, and also helps to form a more obvious distinction, enabling the camera to capture accurately at the same time.

[0048] In some implementations, please refer to Figure 2 The second marking structure 122 is partially disposed inside the first marking structure 121 and extends beyond the first marking structure 121. It can be used as a reference for coarse positioning and as a reference for fine positioning, resulting in better positioning effect. Moreover, the laser energy when the second marking structure 122 is set causes less thermal damage to the solar cell 100, and the probability of introducing defective marking structures is low.

[0049] In other implementations, please refer to Figure 3 and Figure 4 The second marking structure 122 is disposed inside the first marking structure 121, and the first marking structure 121 encloses the second marking structure 122. At this time, the setting of the second marking structure 122 has the least impact on the structure of other positions on the solar cell 100.

[0050] Further, please refer to Figure 3 The second marking structure 122 is disposed at 1 / 3 to 2 / 3 of the distance from the first marking structure 121 along the first direction and / or the second direction. That is, the second marking structure 122 is disposed at 1 / 3 to 2 / 3 of the distance from the first marking structure 121 along the first direction; or, the second marking structure 122 is disposed at 1 / 3 to 2 / 3 of the distance from the first marking structure 121 along the second direction; or, the second marking structure 122 is disposed at 1 / 3 to 2 / 3 of the distance from the first marking structure 121 along the first direction, and the second marking structure 122 is disposed at 1 / 3 to 2 / 3 of the distance from the first marking structure 121 along the second direction. It is understood that in this embodiment of the invention, the distance between the second marking structure 122 disposed along the first direction and the distance between the second marking structure 122 disposed along the second direction may be equal or unequal, and can be flexibly adjusted according to actual conditions.

[0051] It should be noted that the first direction and the second direction intersect. Preferably, the first direction and the second direction are perpendicular to each other; more preferably, the first direction is the transverse direction of the battery cell substrate 110, and the second direction is the longitudinal direction of the battery cell substrate 110, and the two are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, and this utility model does not specifically limit them.

[0052] Furthermore, the second marking structure 122 is disposed at the midpoint of the first marking structure 121 along the first direction and / or the second direction. For improving the efficiency and reliability of the solar cell 100, please refer to... Figure 4 The second identification structure 122 is positioned at the middle of the first identification structure 121 along the first and second directions.

[0053] Please see Figure 4 The width of the first identification structure 121 is the width of the first identification structure 121 along the second direction, and the width of the first identification structure 121 is D1; ​​the width of the P area 130 is the width of the P area 130 along the second direction, and the width of the P area 130 is D2; the width of the N area 140 is the width of the N area 140 along the second direction, and the width of the N area 140 is D3; the width of the second identification structure 122 is the width of the second identification structure 122 along the second direction, and the width of the first identification structure 121 is D4. The width D1 of the first identification structure 121 is greater than or equal to the width of a P area 130 or an N area 140 (D2 or D3), and the width D4 of the second identification structure 122 is less than or equal to the width of a P area 130 or an N area 140 (D2 or D3). If the width D1 of the first marking structure 121 is less than the width of a P-area 130 or an N-area 140, the positioning may be inaccurate during coarse identification, and the cumulative error will be even greater after multiple printings. If the width D4 of the second marking structure 122 is less than or greater than the width (D2 or D3) of a P-area 130 or an N-area 140, two large marking structures 120 will be formed on the solar cell 100, making fine identification impossible and thus failing to meet the printing requirements of the grid lines 160. To achieve higher positioning accuracy and reduce defective marking structures, the width D1 of the first marking structure 121 is greater than the width (D2 or D3) of a P-area 130 or an N-area 140, and the width D4 of the second marking structure 122 is less than the width (D2 or D3) of a P-area 130 or an N-area 140.

[0054] Furthermore, the first marking structure 121 is typically positioned before the screen printing step, and its depth facilitates the printing of insulating layers, anti-reflective layers, and other layers, as well as the setting of multiple openings 150 at the preset grid line 160 positions. The second marking structure 122, on the other hand, is positioned before the grid line 160 is printed, and its depth is much smaller, allowing for precise camera capture at the nanometer level. This facilitates the formation of a color difference between the first and second marking structures 121 and 122, resulting in a high contrast between light and dark areas. The color difference between the first and second marking structures 121 and 122 is used for precise identification and positioning during the printing operation on the battery cell substrate 110. The laser fabrication process for the second marking structure 122 offers multiple options. For example, the second marking structure 122 and the openings 150 can utilize the same laser system, forming the second marking structure 122 while simultaneously setting multiple openings 150. This not only increases the likelihood of recognizing the second marking structure 122 when printing smaller structures but also reduces the number of steps required.

[0055] In some specific and preferred embodiments, the height difference between the first marking structure 121 and the P region 130 is 1μm to 5μm, with exemplary height differences of 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, and 5μm, but not limited thereto. The height difference between the first marking structure 121 and the N region 140 is 0.5μm to 3μm, with exemplary height differences of 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, and 3μm, but not limited thereto. The depth of the second marking region is 60nm to 140nm, with exemplary depths of 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, and 140nm, but not limited thereto. It should be noted that the height difference between the first identification structure 121 and the P area 130 refers to the difference between the height of the first identification structure and the height of the P area 130, and the height of the first identification structure 121 is greater than the height of the P area 130; the height difference between the first identification structure 121 and the N area 140 refers to the difference between the height of the first identification structure and the height of the N area 140, and the height of the first identification structure 121 is greater than the height of the N area 140.

[0056] Preferably, the shape of the first marking structure 121 is one of a circle, square, rectangle, trapezoid, pentagon, or pentagram. This application does not specifically limit the shape of the first marking structure 121. The shape of the second marking structure 122 is one of a circle, square, rectangle, trapezoid, pentagon, or pentagram. The shape of the first marking structure 121 is the same as the shape of the second marking structure 122, or the shape of the first marking structure 121 is different from the shape of the second marking structure 122. The shape and size of the first marking structure 121 and the second marking structure 122 can be selected according to actual production needs, and this application does not specifically limit them. The shape of the second marking structure 122 can be the same as or different from the structure of the opening 150, as long as the second marking structure 122 is different from the opening 150 and can be accurately captured by the camera. Preferably, the shapes are different, which results in higher efficiency and accuracy of accurate recognition. Optionally, the trapezoid can be one of a right trapezoid, an isosceles trapezoid, or a general trapezoid. This application does not make a specific limitation. The pentagon can be a regular pentagon, such as a regular pentagon, or it can be an irregular pentagon. This application does not make a specific limitation.

[0057] Preferably, at least one second identification structure 122 is provided within the first identification structure 121. Increasing the number of second identification structures 122 can further improve the positioning accuracy during printing on the battery cell substrate 110; for example, there can be two, three, or more.

[0058] Optionally, the solar cell substrate 110 has four corner regions, and the first marking structure 121 is disposed in the four corner regions so that when printing on the solar cell substrate 110, all four first marking structures 121 can be identified simultaneously to form a complete and accurate printing path, and the error of the first marking structure 121 in one corner region can be avoided from affecting the printing accuracy of the entire solar cell 100, thereby improving the accuracy of identification and positioning.

[0059] Furthermore, the first identification structure 121 is symmetrically arranged in the four corner regions, please refer to [reference needed]. Figure 1While the operation is simple, if the first marking structure 121 is asymmetrically arranged in the four corner regions, the laser path of the first marking structure 121 becomes complex during laser formation, affecting the laser production capacity of the solar cell 100. However, if the first marking structure 121 is symmetrically arranged in the four corner regions, the solar cell 100 does not have a foolproof function. If the cell substrate 110 is rotated 180° during the printing of the grid lines 160, the symmetrically distributed first marking structure 121 cannot accurately identify the placement direction of the cell substrate 110, resulting in a misalignment between the grid line 160 position on the screen printing plate and the grid line 160 printing position on the cell substrate 110. Especially during the printing of the grid lines 160 on the back of the IBC solar cell, the inverted cell substrate 110 may even cause misalignment of the grid lines 160 printing in the N region 140 and the P region 130, seriously affecting the performance and quality of the solar cell 100.

[0060] Therefore, please refer to Figure 5 The second marking structure 122 is also disposed on the asymmetry axis of the first marking structure 121, so that the solar cell 100 does not have a central symmetry characteristic. This serves as a foolproof structure for the solar cell 100, facilitating the identification of the printing orientation of the solar cell 100 and ensuring its correct installation. It should be noted that the symmetry axis here refers to any axis of symmetry between the four first marking structures 121 disposed in the four corner regions. The number of second marking structures 122 disposed on the asymmetry axis of the first marking structure 121 can be one or more, such as two, three, or more. This application does not specifically limit the number of second marking structures 122 used for foolproof purposes, but an excessive number can cause light shading and adversely affect the efficiency of the solar cell 100. The second marking structure 122 can be prepared simultaneously with the formation of a second marking structure 122 that at least partially overlaps with the first marking structure 121.

[0061] Exemplarily, the front and / or back sides of the solar cell substrate 110 are provided with grid lines 160, which contact the marking structure 120. It is understood that the first marking structure 121 may be disposed at the edge of the grid line 160 and contact the edge of the grid line 160, or the first marking structure 121 may be disposed inside the grid line 160. This can be understood as the first marking structure 121 being disposed between the grid lines 160 structures of the solar cell 100 or on the grid lines 160 of the solar cell 100, such that the first marking structure 121 and / or the second marking structure 122 contact the grid lines 160. In some preferred embodiments, the grid lines 160 are disposed on the second marking structure 122, and the grid lines 160 cover the second marking structure 122. Please refer to [link to relevant documentation]. Figure 6 This can be understood as follows: when the second identifier is used as a fine positioning reference during the printing of the gate line 160, the center of the first identifier structure 121 and the corresponding opening 150 of the gate line 160 are on the same horizontal line, resulting in a smaller positioning error during the printing of the gate line 160. The gate line 160 can be an aluminum gate line 160, a silver gate line 160, a copper gate line 160, a silver-plated copper gate line 160, a tin gate line 160, a titanium gate line 160, a tungsten gate line 160, etc. This application does not specifically limit the main components of the gate line 160.

[0062] Accordingly, this utility model also provides a solar cell module, including the aforementioned solar cell 100.

[0063] Understandably, the solar cell module may also include a metal frame, a front panel, a back panel, and an encapsulant film.

[0064] The backplate can protect and support the battery series, and has reliable insulation, water resistance and aging resistance. The backplate can be selected from multiple materials, such as tempered glass, plexiglass, aluminum alloy TPT composite film, KPC, CPC, etc. The specific design can be set according to the specific situation, and no specific limitation is made in this application.

[0065] A front panel, such as photovoltaic glass, can cover the encapsulant film on the light-receiving surface of the solar cell. The front panel can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of ultra-clear glass can reach over 92%, which can protect the solar cell 1 without affecting its efficiency as much as possible. Simultaneously, the encapsulant film can bond the front panel and the solar cell together. The encapsulant film can seal, insulate, and waterproof and moisture-proof the solar cell. Multiple encapsulant films are available, including but not limited to one or more layers of EPE encapsulant film, EVA encapsulant film, POE encapsulant film, and EVA-POE encapsulant film. The back panel, solar cell, encapsulant film, and front panel can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire solar cell module and can stably support and install the solar cell module. For example, the solar cell module can be installed at the desired location using the metal frame.

[0066] Accordingly, this utility model also provides a photovoltaic system, which includes the aforementioned solar cell modules. It is understood that the various solar cell modules can be electrically connected in parallel or in series, depending on actual needs.

[0067] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0068] The above-disclosed embodiment is merely a preferred embodiment of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A solar cell, characterized by, The solar cell piece substrate, the identification structure arranged on the front surface and / or back surface of the solar cell piece substrate, the identification structure comprising a first identification structure and a second identification structure, the first identification structure and the second identification structure at least partially overlapping. The area of the second identification structure is smaller than the area of the first identification structure, the first identification structure being used for first identification positioning of the solar cell piece, and the second identification structure being used for second identification positioning of the solar cell piece.

2. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The second identification structure is partially arranged inside the first identification structure, and the second identification structure partially extends out of the first identification structure.

3. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The second identification structure is arranged inside the first identification structure, and the first identification structure wraps the second identification structure.

4. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The second identification structure is arranged at 1 / 3-2 / 3 of the first identification structure along a first direction and / or a second direction.

5. The solar cell as claimed in claim 3 or 4, wherein the first and second electrodes are formed of a material having a work function of 4.5 eV or more. The second identification structure is arranged at a middle position of the first identification structure along a first direction and / or a second direction.

6. The solar cell as claimed in claim 5, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The first identification structure and the second identification structure have color difference, and are used for fine identification positioning during printing operation of the solar cell piece substrate.

7. The solar cell as claimed in any one of claims 1 to 4, wherein the back surface of the solar cell is provided with a back surface field. The width of the first identification structure is greater than or equal to the width of one P region or one N region, and the width of the second identification structure is less than or equal to the width of one P region or one N region.

8. The solar cell as claimed in any one of claims 1 to 4, wherein the back surface of the solar cell is provided with a back surface field. The height difference between the first identification structure and the P region is 1-5 μm, the height difference between the first identification structure and the N region is 0.5-3 μm, and the depth of the second identification structure is 60-140 nm.

9. The solar cell of claim 8, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. At least one second identification structure is arranged in the first identification structure.

10. The solar cell as claimed in any one of claims 1 to 4, wherein The shape of the first identification structure is one of a circle, a square, a rectangle, a trapezoid, a pentagon, and a pentagram.

11. The solar cell according to any one of claims 1 to 4, characterized in that, The shape of the second identification structure is one of a circle, a square, a rectangle, a trapezoid, a pentagon, and a pentagram. The shape of the first identification structure is the same as the shape of the second identification structure.

12. The solar cell of claim 11, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. The shape of the first identification structure is different from the shape of the second identification structure.

13. The solar cell of claim 11, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. The solar cell piece substrate has four corner regions, and the first identification structure is arranged in the four corner regions.

14. The solar cell as claimed in claim 1, characterized in that, The first identification structure is symmetrically arranged in the four corner regions.

15. The solar cell of claim 14, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. The second identification structure is also arranged on the non-symmetry axis of the first identification structure.

16. The solar cell of claim 15, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. The front surface and / or back surface of the solar cell piece substrate is provided with a grid line, and the grid line is in contact with the identification structure.

17. The solar cell of claim 1, wherein the back surface is textured. The grid line is arranged on the second identification structure, and the grid line covers the second identification structure.

18. The solar cell of claim 17, wherein the first and second conductive layers are formed of a material selected from the group consisting of silver, aluminum, copper, and combinations thereof. The grid line completely covers the second identification structure.

19. The solar cell as claimed in claim 17 or 18, wherein the back surface is provided with a plurality of protrusions. The solar cell piece comprises the solar cell piece according to any one of claims 1-19.

20. A solar cell module, characterized by, The solar cell module comprises the solar cell piece according to claim 20.

21. A photovoltaic system characterized by, ​

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