Back contact cells, modules and systems

Abstract

The application is suitable for the photovoltaic technical field, and provides a back contact cell, a module and a system, including: a cell piece, the cell piece has a light receiving surface and a back light surface arranged oppositely; and an isolation layer arranged on the light receiving surface, the application sets the isolation layer on the light receiving surface of the cell piece, and sets the isolation layer as a first isolation part, a second isolation part and a third isolation part with different coverages according to different regions of the light receiving surface of the cell piece, and the different regions of different cell pieces are different in the isolation layer, in particular, the coverage of the first isolation part is set to be maximum in the corner region of the cell piece to cope with high degree of wear of the corner region of the cell piece, and the coverage of the third isolation part is set to be minimum in the central region of the cell piece, and the use of the isolation glue is reduced in the region with low wear risk of the cell piece, thereby the amount of the isolation glue is saved, and the production cost of the cell piece is reduced.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and in particular relates to a back contact cell, module and system. Background Technology

[0002] A photovoltaic (PV) cell is a thin film of photovoltaic semiconductors (also known as a solar cell or photovoltaic cell) that directly generates electricity using sunlight. As long as the illuminance meets certain conditions, it can output voltage and generate current when a circuit is present. Currently, crystalline silicon solar cells operating on the photovoltaic effect are the mainstream type of PV cell, which directly convert light energy into electrical energy through the photoelectric effect.

[0003] In back-contact battery design, both the positive and negative electrodes are located on the back of the battery. Due to the gridless structure of back-contact solar cells, to avoid damage to the gridless surface of the finished cells, separator paper or separator adhesive is usually used to protect adjacent cells during stacking, transportation and use. However, this method will affect the stacking efficiency of the cells and increase the transportation cost of the cells.

[0004] Application content This application provides a back-contact battery, which aims to solve the problem that using separator paper or separator adhesive to protect two adjacent battery cells affects the stacking efficiency of the battery cells and increases the transportation cost of the battery cells.

[0005] In a first aspect, this application is implemented as follows: a back-contact battery includes: a battery cell having a light-receiving surface and a back-lighting surface disposed opposite to each other; an isolation layer disposed on the light-receiving surface, the isolation layer including a first isolation portion disposed in a corner region of the battery cell, a second isolation portion disposed in an edge region of the battery cell, and a third isolation portion disposed in a central region of the battery cell; the coverage of the first isolation portion in the corner region is greater than the coverage of the second isolation portion in the edge region, and the coverage of the second isolation portion in the edge region is greater than the coverage of the third isolation portion in the central region.

[0006] Optionally, the first isolation section has a coverage rate of 10% to 90% in the corner area.

[0007] Optionally, the second isolation portion has a coverage rate of 5% to 90% in the edge area.

[0008] Optionally, the third isolation section has a coverage of 0-90% in the central area.

[0009] Optionally, the first isolation portion includes a first isolation grid and a plurality of first isolation protrusions disposed within the first isolation grid.

[0010] Optionally, the first isolation grid includes a plurality of first isolation strips and a plurality of second isolation strips, which are arranged in a corresponding and intersecting manner.

[0011] Optionally, the first isolation strip includes a plurality of first isolation sub-strips, which are arranged linearly in a first direction and are spaced apart in the first direction.

[0012] Optionally, if the length of the first isolation strip is L1 and the spacing between two adjacent first isolation sub-strips is D1, then 500≥L1 / D1>0.

[0013] Optionally, the second isolation strip includes a plurality of second isolation sub-strips, which are arranged linearly in a second direction and are spaced apart in the second direction.

[0014] Optionally, if the length of the second isolation strip is L2 and the spacing between two adjacent second isolation strips is D2, then 1000≥L2 / D2>0.

[0015] Optionally, the second isolation portion includes a plurality of third isolation strips spaced apart in a first direction and / or a plurality of second isolation protrusions disposed between adjacent third isolation strips.

[0016] Optionally, the third isolation strip includes a plurality of third isolation sub-strips, wherein the plurality of third isolation sub-strips are arranged linearly in the first direction and are spaced apart in the first direction; or, the plurality of third isolation sub-strips are arranged linearly in the second direction and are spaced apart in the second direction.

[0017] Optionally, the length of the third isolation strip is L3, the interval between two adjacent third isolation strips in the first direction is D3, and the interval between two adjacent third isolation strips in the second direction is D4, then 1000≥L3 / D3>L3 / D4>0.

[0018] Optionally, the third isolation section includes a plurality of third isolation bumps arranged in an array.

[0019] Optionally, a recognition area is provided in the central region of the battery cell, and a recognition part is provided in the recognition area, with at least a portion of the third isolation protrusions spaced around the outside of the recognition part.

[0020] Optionally, the thickness of the identification part is greater than or equal to 2 μm and less than or equal to 50 μm.

[0021] Optionally, the isolation layer is made of at least one of UV adhesive, photosensitive adhesive, POE, or EVA.

[0022] This application sets an insulating layer on the light-receiving surface of the solar cell, and sets the insulating layer into a first insulating part, a second insulating part, and a third insulating part with different coverage rates according to different areas of the light-receiving surface of the solar cell. The insulating layer is set differently in different areas of different solar cells. In particular, the coverage rate of the first insulating part is set to the maximum in the corner area of ​​the solar cell to cope with the high degree of wear in the corner area of ​​the solar cell. The coverage rate of the third insulating part is set to the minimum in the central area of ​​the solar cell, so as to reduce the use of insulating adhesive in areas with lower risk of wear, thereby saving the amount of insulating adhesive used and reducing the production cost of the solar cell.

[0023] Secondly, this application provides a battery assembly including the aforementioned back contact battery. The technical effects of this application are the same as those of the aforementioned battery assembly, and will not be repeated here.

[0024] Thirdly, this application provides a photovoltaic system including the aforementioned battery module. The technical effects of the photovoltaic system of this application are the same as those of the aforementioned battery module, and will not be repeated here. Attached Figure Description

[0025] Figure 1 This is a structural schematic diagram of the first type of back contact battery provided in the current application; Figures 2-8 This is a partial structural diagram of the various parts of the back contact battery provided in the current application; Figure 9 This is a structural schematic diagram of the second type of back contact battery provided in the current application; Figure 10 This is a structural schematic diagram of the third type of back contact battery provided in the current application.

[0026] Explanation of reference numerals in the attached figures: 100, Battery cell; 101, Light-receiving surface; 102, Backlighting surface; 200, Insulation layer; 201, First isolation section; 2011, First isolation network; 2011a, First isolation strip; 2011a1, First isolation sub-strip; 2011b, Second isolation strip; 2011b1, Second isolation sub-strip; 2012, First isolation bump; 202, Second isolation section; 2021, Third isolation strip; 2021a, Third isolation sub-strip; 2022, Second isolation bump; 203, Third isolation section; 2031, Third isolation bump; 300, Identification area; 400, Identification section; 500, Corner area; 600, Edge area; 700, Center area. Detailed Implementation

[0027] 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.

[0028] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this 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.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] In 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.

[0032] 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.

[0033] like Figures 1-10 As shown, a back-contact battery includes a cell 100, which has a light-receiving surface 101 and a back-lighting surface 102 disposed opposite to each other. Typically, the cell 100 has a sheet-like structure; the side that absorbs light energy and converts it into electrical energy is called the light-receiving surface 101, and the other side is called the back-lighting surface 102. Furthermore, the light-receiving surface 101 of the back-contact cell 100 has no grid structure; the positive and negative grid lines are both disposed on the back-lighting surface 102. Therefore, when cells 100 are stacked, the grid structure of the back-lighting surface 102 of the upper cell 100 can easily damage the light-receiving surface 101 of the lower cell 100. For example, the grid structure of the back-lighting surface 102 of the upper cell 100 causes damage to the passivation layer of the light-receiving surface 101 of the lower cell 100, directly leading to a decrease in the efficiency of the cell 100, accelerated power decay, and severe deterioration of long-term reliability. The solar cell 100 is essentially rectangular. This rectangular shape can be, for example, a square or another type of rectangle, and can have standard corners, cut corners, or rounded corners, depending on actual production needs. No specific limitations are made here. The solar cell 100 can be a whole solar cell 100 or a half solar cell 100. For example, a half solar cell 100 can be obtained by cutting a whole solar cell 100. The solar cell 100 can also be obtained by cutting a whole solar cell 100 into three-quarters or four-quarters pieces, etc.

[0034] An insulating layer 200 is provided on the light-receiving surface 101 of the solar cell 100. The insulating layer 200 can be formed by screen printing or spraying an insulating adhesive onto the light-receiving surface 101 of the solar cell 100 in a predetermined shape. Specifically, the insulating adhesive can be made of a transparent material and does not need to be removed later. For example, it can be made of transparent materials such as UV adhesive, photosensitive adhesive, polyolefin elastomer (POE), and ethylene-vinyl acetate copolymer (EVA). Specifically, the insulating layer 200 can prevent the solar cells from being worn during stacking, thereby ensuring the quality of the finished solar cell 100; on the other hand, it can also eliminate the need for the use of separator paper between adjacent solar cells 100 during stacking, transportation, and use, eliminating the need for removal. Furthermore, the isolation layer 200 includes a first isolation portion 201 disposed in the corner region 500 of the solar cell 100, a second isolation portion 202 disposed in the edge region 600 of the solar cell 100, and a third isolation portion 203 disposed in the central region 700 of the solar cell 100. The coverage of the first isolation portion 201 in the corner region 500 is greater than the coverage of the second isolation portion 202 in the edge region 600, and the coverage of the second isolation portion 202 in the edge region 600 is greater than the coverage of the third isolation portion 203 in the central region 700. In this application, isolation portions with different coverage are provided according to the different degrees of wear that different areas of the light-receiving surface 101 of the solar cell 100 may be subjected to. By utilizing the differential distribution of the isolation layer 200, the protection problem of the corners and edges, which are most easily damaged during the stacking of the solar cells 100, is solved. Comprehensive and effective isolation is formed on the light-receiving surface of the solar cell, avoiding scratches, damage, or paste contamination of the light-receiving surface of the solar cell, thus effectively protecting the light-receiving surface of the solar cell. While meeting the requirements for stacked protection, concentrating the release liner in the areas most in need (corners, edges) instead of applying or laying it evenly on the entire light-receiving surface 101 can significantly save on the amount of release liner used and reduce production costs.

[0035] like Figure 9As shown, it can be understood that the corner region 500 of the battery cell 100 mentioned in this application refers to the region located near the four apex corners of the battery cell 100. It can be further defined as a rectangular region (or fan-shaped region) formed by extending a first distance H1 in a first direction and a second distance H2 in a second direction from each apex corner. These two distances are typically related to the size of the battery cell 100, for example, they can be 5%-10% of the side length of the battery cell 100. The edge region 600 refers to the surrounding region excluding the corner region 500. That is, it is located near the four edges of the battery cell 100, but excludes the portion already designated as the "corner region 500". It can be defined as a strip-shaped region extending inward from the four edges of the battery cell 100 to a third distance H3, but excluding the aforementioned corner region 500. The central region 700 refers to the core region of the battery cell 100 surrounded by the edge region 600, that is, the portion remaining after removing the corner region 500 and the edge region 600. Specifically, the battery cell 100 is rectangular, the corner region 500 refers to the region defined by extending H1 along the first direction and H2 along the second direction of the battery cell 100, starting from the four apex corners of the battery cell 100; the edge region 600 refers to the annular region located between the edge of the battery cell 100 and the central region 700, excluding the corner region 500; the central region 700 refers to the central rectangular region surrounded by the edge region 600.

[0036] In other embodiments, the light-receiving surface 101 of the battery cell 100 can also be divided into different regions based on the coverage of the isolation layer 200. Specifically, the corner region 500 is the region where the coverage of the isolation layer 200 is greater than a first threshold; the edge region 600 is the region where the coverage of the isolation layer 200 is between the first threshold and a second threshold; and the center region 700 is the region where the coverage of the isolation layer 200 is less than the second threshold. For example, the first threshold can be 50%, and the second threshold can be 30%.

[0037] For example, the first isolation portion 201 has a coverage rate of 10% to 90% in the corner region 500, preferably 60% to 90%. The corner region 500 is the area most susceptible to wear during cell transportation, and the isolation adhesive has a high coverage rate at the corner. This design provides redundant protection, especially suitable for ultra-thin or large-size silicon wafers, maximizing resistance to severe vibrations and impacts during transportation. The second isolation portion 202 has a coverage rate of 5% to 90% in the edge region 600, preferably 30% to 50%. The edge region 600 refers to the area near the entire outer periphery of the cell, where the isolation adhesive forms a continuous isolation band along the entire outer periphery of the cell. This is equivalent to embedding an isolation frame between every two cells. The wear level is lower in this area compared to the corner region 500, where the isolation adhesive provides a moderate level of coverage, mainly to prevent direct friction between the edges of adjacent cells and to prevent edge silicon debris contamination. The coverage rate of the third isolation portion 203 within the central region 700 is 0-90%, preferably 10-20%. The central region 700 is the core light-receiving surface for photoelectric conversion of the solar cell. A lower degree of coverage here minimizes the risk of damage and wear, as the front of the solar cell needs to receive maximum light. Sparse isolation can minimize light shading and ensure the photoelectric conversion efficiency of the solar cell. In this embodiment, the coverage rate of the first isolation portion 201 within the corner region 500 is the ratio of the projected area of ​​the first isolation portion on the light-receiving surface to the area of ​​the corner region 500. The coverage rate of the second isolation portion 202 within the edge region 600 is the ratio of the projected area of ​​the second isolation portion on the light-receiving surface to the area of ​​the edge region 600. The coverage rate of the third isolation portion 203 within the central region 700 is the ratio of the projected area of ​​the third isolation portion 203 on the light-receiving surface to the area of ​​the central region 700. Understandably, to facilitate comparison of the coverage of the isolation portion in different areas, samples can be taken within the same area in different areas, such as measuring the area of ​​the corresponding isolation portion within 1cm×1cm, 1mm×1mm, or 1μm×1μm areas in different areas for direct comparison. It is understood that the structural shape of the isolation portion in different areas can be the same or different, and this application embodiment does not limit this.

[0038] The corners of the solar cell 100 are prone to warping. Therefore, a grid-like insulating structure is installed in the corner area of ​​the solar cell, and the edges are thickened to prevent edge abrasion between warped solar cells. Furthermore, the grid-like insulating strips are designed with a dotted line structure to reduce the curing stress of the insulating adhesive, further reducing problems such as solar cell warping, fragmentation, and microcracks. The insulating strips in different directions are arranged in an alternating pattern to effectively prevent the metal grid lines from abrading the light-receiving surface of the solar cell.

[0039] In some embodiments, the first isolation portion 201 includes a first isolation grid 2011 and a plurality of first isolation bumps 2012 disposed within the first isolation grid 2011. That is, in the corner region 500 of the battery cell 100, the first isolation grid 2011 provides basic support and isolation, forming a basic isolation structure. It is distributed in the corner region 500 of the battery cell 100, and is usually a continuous line (such as crisscrossing lines, or arc lines adapted to the shape of the corner), forming a grid. The first isolation bumps 2012 are discrete, point-like protrusions that are disposed inside the grid of the first isolation grid 2011 to cope with the undulating grid structure of the backlight surface 102 on the stacked adjacent battery cells 100. The first isolation bumps 2012 form an enhanced buffer within the grid to avoid scratches that may be caused to the surface of the battery cell 100 within the grid.

[0040] In this embodiment, the second direction intersects the first direction. Specifically, the second direction may be perpendicular to the first direction.

[0041] Furthermore, the first isolation grid 2011 includes a plurality of first isolation strips 2011a and a plurality of second isolation strips 2011b, which are correspondingly and intersectingly arranged. Specifically, the plurality of first isolation strips 2011a extend along a first direction and are spaced apart in a second direction, and the plurality of second isolation strips 2011b extend along the second direction and are spaced apart in the first direction. The first isolation strips 2011a and the second isolation strips 2011b intersect each other perpendicularly to form a grid structure, thereby forming a high-coverage isolation protection.

[0042] Preferably, the first isolation strip 2011a includes a plurality of first isolation sub-strips 2011a1, which are linearly arranged in a first direction and spaced apart in the first direction. That is, the first isolation sub-strips 2011a1 are configured as a multi-segment discrete structure to prevent the solid line structure from solidifying and shrinking, thus bending the solar cell 100 and improving product yield. This also reduces the amount of isolation adhesive used while ensuring the isolation effect. The plurality of first isolation sub-strips 2011a1 protrude from the light-receiving surface 101 of the solar cell 100, avoiding direct contact with the grid structure of the stacked solar cells 100, thus protecting the light-receiving surface 101 of the solar cell 100.

[0043] Furthermore, if the length of the first isolation strip is L1 and the spacing between two adjacent first isolation strips is D1, then 500 ≥ L1 / D1 > 0. The spacing between two adjacent first isolation strips refers to the length of the interval between two adjacent first isolation strips in the first direction. It should be noted that when the first isolation strip is a multi-segment structure, the length of the first isolation strip here includes the total length of multiple first isolation strips and the sum of the spacing between multiple first isolation strips. In this application, the ratio of the length of the first isolation strip to the spacing between two adjacent first isolation strips is set within the above range. The first isolation strips can form a dense segmented distribution, which can effectively prevent solid line solidification shrinkage and bending of the battery cell while ensuring the isolation effect.

[0044] In some embodiments, the second isolation strip 2011b includes a plurality of second isolation sub-strips 2011b1, which are linearly arranged in a second direction and spaced apart in the second direction. That is, the second isolation sub-strips 2011b1 are configured as a multi-segment discrete structure to prevent the solid line structure from solidifying and shrinking, thus bending the solar cell 100 and improving product yield. This also reduces the amount of isolation adhesive used while ensuring the isolation effect. The plurality of second isolation sub-strips 2011b1 protrude from the light-receiving surface 101 of the solar cell 100, preventing direct contact between the grid structures of other solar cells 100 and forming protection for the light-receiving surface 101 of the solar cell 100.

[0045] Furthermore, the length of the second isolation strip is L2, and the spacing between two adjacent second isolation strips is D2, then 1000 ≥ L2 / D2 > 0. The spacing between two adjacent second isolation strips refers to the length of the interval between two adjacent second isolation strips in the second direction. It should be noted that when the second isolation strip is a multi-segment structure, the length of the second isolation strip here includes the length of multiple second isolation strips and the spacing between multiple second isolation strips. In this application, the ratio of the length of the second isolation strip to the spacing between two adjacent second isolation strips is set within the above range. The second isolation strips can form a dense segmented distribution, which can effectively prevent solid line solidification shrinkage and bending of the battery cell while ensuring the isolation effect.

[0046] In some embodiments, the second isolation portion 202 includes a plurality of third isolation strips 2021 spaced apart in a first direction and / or a plurality of second isolation protrusions 2022 disposed between adjacent third isolation strips 2021. Compared to the corner region 500 of the battery cell 100, the edge region 600 of the battery cell 100 experiences less wear. Therefore, the structure of the second isolation portion 202 can be simplified. Only a plurality of third isolation strips 2021 and second isolation protrusions 2022 disposed between the third isolation strips 2021 are required in the edge region 600 of the battery cell 100. While meeting the protection requirements of the edge region 600 of the battery cell 100, the amount of insulating adhesive used can also be reduced, effectively controlling the production cost of the battery cell 100.

[0047] Preferably, the third isolation strip 2021 includes a plurality of third isolation sub-strips 2021a, wherein the plurality of third isolation sub-strips 2021a are arranged linearly in a first direction and are spaced apart in the first direction; or, the plurality of third isolation sub-strips 2021a are arranged linearly in a second direction and are spaced apart in the second direction. The arrangement of the third isolation strip 2021 is the same as that of the first isolation strip 2011a or the second isolation strip 2011b, and it has the same technical effect, which will not be described again here.

[0048] Furthermore, the length of the third isolation strip 2021 is L3. In the first direction, the spacing between two adjacent third isolation strips 2021a is D3; in the second direction, the spacing between two adjacent third isolation strips 2021a is D4. Therefore, 1000 ≥ L3 / D3 > L3 / D4 > 0. In this application, the dashed arrangement of the third isolation strip 2021 can reduce the curing stress of the isolation strip, thereby reducing problems such as cell warping, fragmentation, and microcracks. Moreover, the third isolation strip 2021 has different spacing in different directions, which can effectively optimize the cost of using the isolation strip. The staggered arrangement of the isolation strips in different directions effectively isolates the grid lines from abrasion on the light-receiving surface.

[0049] In some embodiments, the third isolation portion 203 includes a plurality of third isolation bumps 2031 arranged in an array. Since the central region 700 of the battery cell 100 is least at risk of wear, the third isolation portion 203 is configured with a plurality of third isolation bumps 2031 arranged in an array to achieve isolation and protection of the central region 700 of the battery cell 100.

[0050] A recognition area 300 is provided within the central region 700 of the solar cell 100, and a recognition part 400 is provided within the recognition area 300. At least a portion of the third isolation bumps 2031 are spaced around the outside of the recognition part 400. In this application, the recognition part 400 and the third isolation bumps 2031 are independently provided to ensure the structural integrity of the recognition part 400. The recognition part 400 can include any information from the solar cell manufacturing process, such as the size specifications of the solar cell 100, the film color information of the solar cell 100, etc. This facilitates the unified scheduling of solar cells 100 of the same type during subsequent assembly of the solar cell module, providing corresponding data support for intelligent quality control. Understandably, the spaced third isolation bumps 2031 on the outside of the recognition part 400 are beneficial for subsequent information reading and improve the production efficiency of the module.

[0051] In some embodiments, the thickness of the identification part 400 is greater than or equal to 2 μm and less than or equal to 50 μm. Exemplarily, the thickness of the identification part can be 2 μm, 5 μm, 10 μm, 20 μm, or 50 μm, etc., and this application does not limit this. Since the identification part 400 is only used for information identification or information writing, its thickness can be set to be less than the thickness of the insulating layer 200 to reduce the use of insulating adhesive and improve the light absorption capacity of the surface of the battery cell 100. With the thickness of the identification part 400 within the above range, the identification part 400 can be effectively hidden from the user's view, improving the aesthetic appearance of the battery assembly.

[0052] A battery assembly includes the aforementioned back-contact battery. Based on the aforementioned back-contact battery, those skilled in the art will understand that a corresponding battery assembly can be obtained using multiple such solar cells and / or other corresponding existing accessories.

[0053] In this embodiment, multiple solar cells in the battery module can be connected in series to form a battery string, thereby achieving series current collection and output. For example, the series connection of the cells can be achieved by setting solder strips (busbars, interconnecting strips), conductive backsheets, etc. It is understood that in such an embodiment, the battery module may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can be filled between the front and back of the back contact cells, the photovoltaic glass, adjacent cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be EVA film or POE film, and the specific choice can be made according to the actual situation, without limitation.

[0054] 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.

[0055] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back contact cell, characterized in that, include: A solar cell has a light-receiving surface and a backlighting surface disposed opposite to each other; an isolation layer disposed on the light-receiving surface, the isolation layer including a first isolation portion disposed in a corner area of ​​the solar cell, a second isolation portion disposed in an edge area of ​​the solar cell, and a third isolation portion disposed in a central area of ​​the solar cell; the coverage of the first isolation portion in the corner area is greater than the coverage of the second isolation portion in the edge area, and the coverage of the second isolation portion in the edge area is greater than the coverage of the third isolation portion in the central area.

2. The back contact battery as described in claim 1, characterized in that, The first isolation unit has a coverage rate of 10% to 90% in the corner area.

3. The back contact battery as described in claim 1, characterized in that, The second isolation section has a coverage rate of 5% to 90% in the edge area.

4. The back contact battery as described in claim 1, characterized in that, The third isolation section has a coverage rate of 0-90% in the central area.

5. The back contact battery as described in claim 1, characterized in that, The first isolation section includes a first isolation grid and a plurality of first isolation protrusions disposed within the first isolation grid.

6. The back contact battery as described in claim 5, characterized in that, The first isolation grid includes multiple first isolation strips and multiple second isolation strips, which are arranged in a corresponding and intersecting manner.

7. The back contact battery as described in claim 6, characterized in that, The first isolation strip includes a plurality of first isolation sub-strips, which are arranged linearly in a first direction and are spaced apart in the first direction.

8. The back contact battery as described in claim 7, characterized in that, The length of the first isolation strip is L1, and the interval between two adjacent first isolation sub-strips is D1, then 500≥L1 / D1>0.

9. The back contact battery as described in claim 6, characterized in that, The second isolation strip includes a plurality of second isolation sub-strips, which are arranged linearly in a second direction and are spaced apart in the second direction.

10. The back contact battery as described in claim 9, characterized in that, The length of the second isolation strip is L2, and the interval between two adjacent second isolation strips is D2. Then 1000≥L2 / D2>0.

11. The back contact battery as claimed in claim 1, characterized in that, The second isolation section includes a plurality of third isolation strips spaced apart in a first direction and / or a second direction, and a plurality of second isolation protrusions disposed between the third isolation strips.

12. The back contact battery as described in claim 11, characterized in that, The third isolation strip includes a plurality of third isolation sub-strips, wherein the plurality of third isolation sub-strips are arranged linearly in the first direction and are spaced apart in the first direction; or, the plurality of third isolation sub-strips are arranged linearly in the second direction and are spaced apart in the second direction.

13. The back contact battery as described in claim 12, characterized in that, The length of the third isolation strip is L3. In the first direction, the interval between two adjacent third isolation strips is D3; in the second direction, the interval between two adjacent third isolation strips is D4. Then 1000≥L3 / D3>L3 / D4>0.

14. The back contact battery as described in claim 1, characterized in that, The third isolation section includes a plurality of third isolation bumps arranged in an array.

15. The back contact battery as described in claim 14, characterized in that, A recognition area is provided in the central region of the battery cell, and a recognition part is provided in the recognition area. At least a portion of the third isolation protrusions are spaced around the outside of the recognition part.

16. The back contact battery as described in claim 15, characterized in that, The thickness of the identification part is greater than or equal to 2 μm and less than or equal to 50 μm.

17. The back contact battery as claimed in claim 1, characterized in that, The isolation layer is made of at least one of UV adhesive, photosensitive adhesive, POE, or EVA.

18. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1-17.

19. A photovoltaic system, characterized in that, Includes the battery assembly described in claim 18.

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