Back contact cell and photovoltaic module

Abstract

The application discloses a back contact cell and a photovoltaic module. The back contact cell comprises a cell body, a light-receiving surface of the cell body has a middle area and an edge area surrounding the middle area, and at least part of the edge area is provided with a first protrusion. The first protrusion comprises a protruding part and an extending part. The protruding part protrudes from the light-receiving surface of the cell body. The extending part extends from the protruding part towards a direction away from the protruding part. The extending direction of the extending part is not parallel to the extending direction of the adjacent side edge of the cell body. In the storage and transportation process, the back contact cells are stacked in a box, that is, the light-receiving surface of the back contact cell is stacked with another cell, and the stacking is sequentially performed. The first protrusion can avoid damage of the warped side edge of the adjacent cell to the edge area of the light-receiving surface of the cell body, improve the protection effect on the edge area of the cell body, and reduce the risk of scratching the edge of the cell body due to the warping of the back contact cell.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a back-contact solar cell and a photovoltaic module. Background Technology

[0002] In back-contact (BC) solar cells, both the positive and negative electrodes are located on the back side of the cell, preventing the electrodes from blocking the front of the cell and thus improving the conversion efficiency of the solar cell. During the manufacturing process of back-contact solar cells, cassettes are used to store and transport the cells. To prevent scratching between cells, adjacent cells need to be isolated.

[0003] In related technologies, a transparent material layer is placed on the front side of the solar cell to provide isolation and protection during the stacking process. While this method can protect most of the front area of ​​the solar cell, the edges of the cell are still susceptible to scratches due to warping that occurs during the fabrication of the back-contact solar cells. Utility Model Content

[0004] This application aims to provide a back-contact solar cell and photovoltaic module that can solve the problem that back-contact solar cells in the related technology will have a certain warping during the manufacturing process, resulting in scratches on the edge area of ​​the solar cell.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a back-contact battery cell, comprising: a battery cell body, wherein the light-receiving surface of the battery cell body has a central region and an edge region surrounding the central region; at least a portion of the edge region is provided with a first protrusion, the first protrusion comprising a protruding portion and an extension portion, the protruding portion protruding from the light-receiving surface of the battery cell body, the extension portion extending from the protruding portion in a direction away from the protruding portion, and the extension direction of the extension portion is not parallel to the extension direction of the adjacent side of the battery cell body.

[0007] Optionally, the side includes two oppositely arranged long sides and two oppositely arranged short sides, the length of the long sides being greater than the length of the short sides; the first protrusion is at least provided in the edge area corresponding to the short side, and the extension extends obliquely relative to the corresponding short side.

[0008] Optionally, the distance between the first protrusion and the corresponding short side is less than or equal to 9 mm.

[0009] Optionally, the extension direction of the extension portion forms an angle A with the corresponding side edge, satisfying: 10°≤A≤90°;

[0010] And / or, the edge region is provided with a plurality of first protrusions arranged at intervals, and the extensions of at least two of the first protrusions have different extension directions.

[0011] Optionally, the extension has a first end and a second end disposed opposite to each other, the first end being connected to the protrusion; the cross-sectional area of ​​the extension decreases from the first end to the second end.

[0012] Optionally, the height of the extension decreases from the first end to the second end; and / or the width of the extension decreases.

[0013] Optionally, the extension extends continuously.

[0014] Optionally, the back contact cell must satisfy at least one of the following conditions:

[0015] A. Along the extending direction of the extension, the length of the extension is L1; along any direction parallel to the light-receiving surface of the battery cell body, the width of the protrusion is L2, satisfying: 2.5≤L1 / L2≤3.5;

[0016] B. Along a direction perpendicular to the extension direction and parallel to the light-receiving surface, the maximum width of the extension is L3; along any direction parallel to the light-receiving surface of the battery cell body, the width of the protrusion is L2, satisfying: 4≤L2 / L3≤6.

[0017] C. Along the extending direction of the extension, the length L1 of the extension satisfies: 500μm≤L1≤700μm;

[0018] D. Along any direction parallel to the light-receiving surface of the battery cell body, the width L2 of the protrusion satisfies 160nm≤L2≤200nm;

[0019] E. Along the direction perpendicular to the light-receiving surface, the maximum height of the extension is less than the maximum height of the protrusion.

[0020] F. Along the direction perpendicular to the light-receiving surface, the maximum height of the protrusion is H1, which satisfies: 6μm≤H1≤10μm;

[0021] G. Along the direction perpendicular to the light-receiving surface, the maximum height of the extension is H2, satisfying: 0.5μm≤H2≤1.5μm.

[0022] H. At least a portion of the extension contains air bubbles.

[0023] Optionally, the edge area is further provided with a second protrusion, the second protrusion protruding from the light-receiving surface, and the second protrusion being spaced apart from the first protrusion;

[0024] And / or, the intermediate area is further provided with a plurality of third protrusions, the third protrusions protruding from the light-receiving surface, and the plurality of third protrusions are arranged at intervals.

[0025] Optionally, the battery cell body also has a backlight surface disposed opposite to the light-receiving surface, and the backlight surface is provided with a plurality of electrodes arranged at intervals.

[0026] Secondly, embodiments of this application provide a photovoltaic module, including: a front panel, a back panel, an encapsulating film layer, and the back contact solar cell described in the first aspect;

[0027] The front panel and the back panel are stacked, the encapsulation film layer is disposed between the front panel and the back panel, and the back contact battery cell is embedded in the encapsulation film layer.

[0028] Thirdly, embodiments of this application propose a photovoltaic module, including a back contact cell and an encapsulating film layer, wherein the back contact cell is the back contact cell described in the first aspect;

[0029] The battery cell body has a light-receiving surface and a backlighting surface. The backlighting surface is provided with an electrode. The light-receiving surface is provided with a plurality of spaced-apart isolation protrusions. The isolation protrusions include at least the first protrusion. The surface of the isolation protrusion corresponding to the electrode has a recessed area. The light-receiving surface is provided with the encapsulating film layer, which covers the recessed area.

[0030] Optionally, the depth of the recessed area is less than or equal to 100 μm along a direction perpendicular to the light-receiving surface;

[0031] And / or, along any direction parallel to the light-receiving surface, the width of the recessed area is less than or equal to 100 μm.

[0032] In the embodiments of this application, by providing a first protrusion on the edge area of ​​the light-receiving surface of the battery cell body, during storage and transportation, the back-contact battery cells are stacked in the material box, that is, another battery cell is stacked on top of the light-receiving surface of the back-contact battery cell. The first protrusion can isolate and protect the light-receiving surface of the battery cell body. The first protrusion includes a protruding portion and an extension portion. The protruding portion protrudes from the battery cell body, and the extension portion extends from the protruding portion in a direction away from the protruding portion. In this way, without increasing the amount of material used or with a small increase in material used, the protected area covered by the first protrusion can be increased, thereby achieving the best match between material cost and protective effect.

[0033] Furthermore, back-contact solar cells can warp during manufacturing. When the warping of the upper and lower layers of cells differs during stacking, the warped side of the upper cell can easily come into contact with the edge of the light-receiving surface of the lower cell, causing scratches on the lower cell's light-receiving surface. To address this, this application provides a first protrusion at the edge of the light-receiving surface. The extension direction of the protrusion is not parallel to the extension direction of the side of the solar cell body. When the warped side of the upper cell falls on the edge of the light-receiving surface of the solar cell body, the warped side and the extension are staggered, ensuring that the extension provides isolation and support for the warped side. This prevents damage to the edge of the light-receiving surface of the solar cell body from the warped side of the upper cell, improving protection of the edge of the solar cell body and reducing the risk of scratches on the edge of the solar cell body due to warping of the back-contact solar cells.

[0034] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein:

[0036] Figure 1 This is a schematic diagram of a solar cell according to an embodiment of this application;

[0037] Figure 2 yes Figure 1 An enlarged view of section B, shown in the center circle;

[0038] Figure 3 This is a cross-sectional view of the solar cell at the first protrusion according to an embodiment of this application;

[0039] Figure 4 This is one of the images of a first protrusion on a solar cell according to an embodiment of this application;

[0040] Figure 5 This is a second image of the first protrusion on the solar cell according to an embodiment of this application;

[0041] Figure 6 This is a schematic diagram of a photovoltaic module according to an embodiment of this application;

[0042] Figure 7 This is a schematic diagram of the structure of the isolation protrusion on the light-receiving surface and the electrode on the back-lighting surface of the solar cell according to an embodiment of this application;

[0043] Figure 8 This is a schematic diagram of the recessed area on the isolated protruding surface of a solar cell according to an embodiment of this application.

[0044] Figure label:

[0045] 10: Cell body; 10a: Middle area; 10b: Edge area; 100: Side; 101: Long side; 102: Short side; 20: First protrusion; 21: Protrusion portion; 22: Extension portion; 22a: First end; 22b: Second end; 30: Second protrusion; 40: Third protrusion; 51: Isolation protrusion; 511: Recessed area; 52: Electrode; 60: Front plate; 70: Back plate; 80: Encapsulating film layer. Detailed Implementation

[0046] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated 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. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0047] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0048] 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.

[0049] 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0050] Before explaining the photovoltaic modules in the embodiments of this application, the application scenarios of photovoltaic modules will be introduced first:

[0051] Back-contact (BC) solar cells are currently the most promising next-generation silicon-based photovoltaic cells. Their most significant characteristic is that all electrodes are distributed on the back side of the cell, avoiding shading of the light-receiving side. Because the electrodes of a back-contact cell are all located on its back side, during the cell fabrication process, factors such as the shrinkage of the slurry during high-temperature sintering and the shrinkage of the insulating adhesive during high-temperature drying often cause the fabricated back-contact cells to warp towards the back.

[0052] In photovoltaic module manufacturing, multiple solar cells are typically stored and transported using cassettes. This requires stacking the cells, where the light-receiving surface of the lower cell faces the back-lighting surface of the upper cell. This makes the light-receiving surface of the lower cell susceptible to scratches from friction by the electrodes on the back-lighting surface of the upper cell. Related technologies use transparent insulating protrusions on the light-receiving surface of the cells to protect it from scratches during stacking. However, for back-contact cells, their inherent warping means that scratches still occur at the edges.

[0053] Therefore, this application provides a back-contact solar cell and a photovoltaic module to solve the technical problems existing in the prior art. The back-contact solar cell and photovoltaic module provided in this application will be described in detail below with reference to the accompanying drawings and specific embodiments and application scenarios.

[0054] like Figures 1 to 5As shown, a back-contact battery cell according to some embodiments of this application includes: a battery cell body 10, the light-receiving surface of the battery cell body 10 having a central region 10a and an edge region 10b surrounding the central region 10a; at least a portion of the edge region 10b is provided with a first protrusion 20, the first protrusion 20 including a protrusion portion 21 and an extension portion 22, the protrusion portion 21 protruding from the light-receiving surface of the battery cell body 10, the extension portion 22 extending from the protrusion portion 21 toward a direction away from the protrusion portion 21, and the extension direction of the extension portion 22 is not parallel to the extension direction of the adjacent side 100 of the battery cell body 10.

[0055] In this embodiment, by providing a first protrusion 20 on the edge region 10b of the light-receiving surface of the battery cell body 10, during storage and transportation, the back-contact battery cells are stacked in the material box, that is, another battery cell is stacked on top of the light-receiving surface of the back-contact battery cell, and so on. The first protrusion 20 serves to isolate and protect the light-receiving surface of the battery cell body 10. The first protrusion 20 includes a protrusion 21 and an extension 22. The protrusion 21 protrudes from the battery cell body 10, and the extension 22 extends from the protrusion 21 in a direction away from the protrusion 21. In this way, without increasing the amount of material or with a small increase in the amount of material, the protected area covered by the first protrusion 20 can be increased, thereby achieving the best match between material cost and protective effect.

[0056] Furthermore, back-contact solar cells can warp during manufacturing. When the warping of the upper and lower solar cells differs during stacking, the warped side of the upper solar cell can easily come into contact with the edge of the light-receiving surface of the lower solar cell, causing scratches on the light-receiving surface. To address this, this application provides a first protrusion 20 in the edge area 10b of the light-receiving surface. The extension direction of the extension 22 in the first protrusion 20 is not parallel to the extension direction of the side 100 of the solar cell body 10. When the warped side of the upper solar cell falls on the edge area of ​​the light-receiving surface, the warped side and the extension 22 are staggered, ensuring that the extension 22 can form an isolation support for the warped side. This avoids damage to the edge area 10b of the light-receiving surface of the solar cell body 10 from the warped side of the upper solar cell, improving the protection of the edge area 10b of the solar cell body 10 and reducing the risk of scratches on the edge of the solar cell body 10 due to warping of the back-contact solar cells.

[0057] It is understood that the back contact solar cell includes a solar cell body 10, which has a light-receiving surface and a back-lighting surface. The light-receiving surface is the side of the solar cell body 10 that receives sunlight, and the back-lighting surface is the side of the solar cell body 10 that is away from the light-receiving surface. The electrodes of the back contact solar cell are all disposed on the back-lighting surface.

[0058] The back-contact solar cell has a central region 10a and an edge region 10b surrounding the central region 10a. A first protrusion 20 is provided in at least a portion of the edge region 10b. The first protrusion 20 includes a protruding portion 21 and an extension portion 22. The protruding portion 21 protrudes from the light-receiving surface of the solar cell body 10. Thus, when stacking back-contact solar cells, the first protrusion 20 can isolate the light-receiving surface of the solar cell body 10 from the electrodes on the back-lighting surface of adjacent solar cells, providing isolation and protection for the light-receiving surface. Simultaneously, the extension portion 22 is provided in the first protrusion 20, extending from the protruding portion 21 in a direction away from the protruding portion 21. This increases the overall protection range of the first protrusion 20 and, compared to the prior art which increases the coverage area of ​​the protrusion point, saves material usage, thus balancing material cost and protective effect. Furthermore, when the curved side 100 of the upper battery cell falls within the edge area 10b of the light-receiving surface, since the extension direction of the extension 22 is staggered with the extension direction of the side 100, it is ensured that the extension 22 can form an effective isolation support for the curved side 100, thereby avoiding the risk of scratches to the edge area 10b of the battery cell body 10 by the curved side of the adjacent battery cell.

[0059] In specific applications, the shape of the battery cell can be rectangular or square. Alternatively, chamfers can be provided at the four corners of the battery cell. The battery cell has four sides 100. A first protrusion 20 can be provided on the edge area 10b corresponding to one of the sides 100, or on two or more sides 100. As long as the edge area 10b that is easily scratched is provided with a first protrusion 20, it can be determined according to the actual structure of the back contact battery cell. No limitation is made here.

[0060] In some embodiments, a plurality of first protrusions 20 arranged at intervals may be provided in the edge region 10b. Among the plurality of first protrusions 20, at least two of the first protrusions 20 have extensions 22 with different extension directions, thereby increasing the protective effect of the first protrusions 20 on the light-receiving edge region 20b. The extension direction of the extension 22 in each first protrusion 20 can be flexibly set according to actual needs, as long as the extension direction of the extension 22 in the first protrusion 20 intersects with the side edge 100 of its adjacent battery cell body 10.

[0061] In some embodiments, the extension 22 may extend continuously to facilitate the processing and shaping of the extension 22. Alternatively, the extension 22 may extend intermittently to reduce the amount of material used in the extension 22 and lower manufacturing costs while still providing isolation and protection for the edge region 10b.

[0062] Furthermore, the extension 22 in each first protrusion 20 can extend in a straight line or in a curve. When the extension 22 extends in a straight line, the direction of the extension of the straight line is the direction of extension of the extension 22; while when the extension 22 extends in a curve, the direction of the line connecting the two ends of the extension 22 is the direction of extension of the extension 22.

[0063] Among them, the protrusion 21 in the first protrusion 20 can be a dot-shaped protrusion, a block-shaped protrusion, etc. The orthographic projection of the protrusion 21 on the light-receiving surface can be a regular shape such as a circle, an ellipse, or a polygon, or it can be an irregular shape formed by the combination of two or more regular shapes. The specific structure of the protrusion 21 can be flexibly set according to actual needs, and is not limited here.

[0064] In some embodiments, the first protrusion 20 may be made of a transparent material, such as acrylic resin, photosensitive adhesive, polyolefin elastomer (POE), ethylene-vinyl acetate copolymer (EVA), polyethylene terephthalate (PET), insulating adhesive, hot melt adhesive, etc.

[0065] It is understandable that in the photovoltaic module manufacturing process, encapsulating films are usually set on both sides of the cell body 10. The material of the first protrusion 20 can be the same as or similar to the material of the encapsulating film. In this way, the first protrusion 20 can be directly laminated into the interior of the photovoltaic module during lamination, which can simplify the operation steps and reduce the impact of the first protrusion 20 on the back contact cell receiving light.

[0066] Of course, the first protrusion 20 can also be made of other types of transparent materials, and this application embodiment does not limit this.

[0067] In some embodiments, a plurality of first protrusions 20 are provided at intervals in the edge region 10b along the circumference of the backlight surface. In each of the plurality of first protrusions 20, the extension 22 of each first protrusion 20 is located on the side of the corresponding protrusion 21 in a clockwise direction, or the extension 22 of each first protrusion 20 is located on the side of the corresponding protrusion 21 in a counterclockwise direction. This ensures that the edges of the battery cell body 10 can be isolated and protected using the first protrusions 20, while also facilitating the simultaneous processing and forming of the plurality of first protrusions 20 in the edge region 10b.

[0068] For example, such as Figure 1 As shown, in Figure 1On the battery cell body 10 shown, the extension 22 of each first protrusion 20 is located on one side of the corresponding protrusion 21 in a clockwise direction. Specifically, the extension 22 of the first protrusion 20 located near the left long side extends obliquely to the upper right of the corresponding protrusion 21; the extension 22 of the first protrusion 20 located near the upper short side extends obliquely to the upper right of the corresponding protrusion 21; the extension 22 of the first protrusion 20 located near the right long side extends obliquely to the upper left of the corresponding protrusion 21; and the extension 22 of the first protrusion 20 located near the lower short side extends obliquely to the upper left of the corresponding protrusion 21.

[0069] In some embodiments, such as Figure 1 As shown, the edge region 10b is also provided with a second protrusion 30, which protrudes from the light-receiving surface and is spaced apart from the first protrusion 20.

[0070] In this embodiment of the application, in addition to the first protrusion 20, a second protrusion 30 may also be provided in the edge area 10b, such that the second protrusion 30 is spaced apart from the first protrusion 20, and the second protrusion 30 protrudes from the light-receiving surface, so that the second protrusion 30 can play a supplementary protective role for the edge area 10b of the light-receiving surface.

[0071] It is understandable that the structure of the second protrusion 30 can be the same as or similar to the structure of the protrusion 21 in the first protrusion 20, that is, the second protrusion 30 does not have an extension 22. Since the first protrusion 20 has both a protrusion 21 and an extension 22, the protection range of the first protrusion 20 is larger, but the required manufacturing material is increased compared to the second protrusion 30. Therefore, by simultaneously providing the first protrusion 20 and the second protrusion 30 in the edge region 10b, both the protective effect and material cost can be balanced. Of course, the structure of the second protrusion 30 can also be different from that of the protrusion 21 in the first protrusion 20, and can be flexibly set according to actual needs.

[0072] The second protrusion 30 can be set as a dot-shaped protrusion, a block-shaped protrusion, or a strip-shaped protrusion, etc. The orthographic projection of the second protrusion 30 on the light-receiving surface can be a regular shape such as a circle, an ellipse, a polygon, or a strip, or it can be an irregular shape formed by the combination of two or more regular shapes. The specific structure of the second protrusion 30 can be flexibly set according to actual needs and is not limited here.

[0073] In other embodiments, such as Figure 1 As shown, a plurality of third protrusions 40 are provided in the middle area 10a of the light-receiving surface. The third protrusions 40 protrude from the light-receiving surface and are arranged at intervals.

[0074] In this embodiment of the application, by providing a plurality of third protrusions 40 in the middle area 10a of the light-receiving surface, the third protrusions 40 protrude from the light-receiving surface and are arranged at intervals, thereby the third protrusions 40 can play a role in isolating and protecting the middle area 10a of the light-receiving surface, so as to avoid the middle area 10a of the light-receiving surface being scratched during the battery stacking process.

[0075] It is understood that the structure of the third protrusion 40 can be the same as that of the first or second protrusion, or it can be different from both of the first and second protrusions. Specifically, the third protrusion 40 can be a dot-shaped protrusion, a block-shaped protrusion, or a strip-shaped protrusion, etc. The orthographic projection of the third protrusion 40 on the light-receiving surface can be a regular shape such as a circle, an ellipse, a polygon, or a strip, or it can be an irregular shape formed by the combination of two or more regular shapes. The specific structure of the third protrusion 40 can be flexibly set according to actual needs and is not limited here.

[0076] Optionally, such as Figure 1 As shown, the side 100 includes two oppositely arranged long sides 101 and two oppositely arranged short sides 102, the length of the long side 101 is greater than the length of the short side 102; the first protrusion 20 is provided at least in the edge area 10b corresponding to the short side 102, and the extension 22 extends obliquely relative to the corresponding short side 102.

[0077] Understandably, the inventors discovered through research that rectangular back-contact battery cells are more prone to bending deformation along their long side 101. Thus, when two battery cells are stacked, the difference in the degree of bending deformation between them prevents the short sides 102 of the stacked cells from being perfectly aligned. The warped side of the upper battery cell can scratch the edge area 10b of the light-receiving surface of the lower battery cell. Therefore, this application provides a first protrusion 20 on the edge area 10b corresponding to the short side 102 of the battery cell body 10, with the extension 22 of the first protrusion 20 extending obliquely relative to the corresponding short side 102. This provides focused protection for the edge area 10b on one side of the short side 102 of the battery cell body 10, better meeting practical usage requirements.

[0078] Optionally, the distance between the first protrusion 20 and the corresponding short side 102 is less than or equal to 9 mm.

[0079] In this embodiment of the application, by setting the distance from the first protrusion 20 to the short side 102 to be less than or equal to 9 mm, the position of the first protrusion 20 can be close to the short side 102, so that when the battery cells are stacked, the extension 22 in the first protrusion 20 can be used to support and isolate the curved side 100 of the battery cell placed above.

[0080] It is understandable that the distance from the first protrusion 20 to the corresponding short side 102 refers to the vertical distance between the protrusion 21 in the first protrusion 20 and the corresponding short side 102. Specifically, multiple first protrusions 20 can be provided for one short side 102. Among the multiple first protrusions 20, the first protrusion 20 that is farthest from the short side 102 is set as the target protrusion. Then, the distance between the protrusion 21 in the target protrusion and the corresponding short side 102 is less than or equal to 9mm.

[0081] For example, the distance between the first protrusion 20 and the corresponding short side 102 can be set to: 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, etc.

[0082] Optionally, such as Figure 1 and Figure 2 As shown, the extension direction of the extension 22 forms an angle A with the corresponding side 100, satisfying: 10°≤A≤90°.

[0083] In this embodiment of the application, by setting the angle A between the extension direction of the extension 22 and the corresponding side 100 to be between 10° and 90°, that is, the extension 22 is inclined relative to the side 100, so that when another battery cell is stacked on the battery cell body 10, even if the side 100 of the other battery cell is warped, the extension 22 of the first protrusion 20 can still play an effective isolation and protection role.

[0084] It is understandable that during the process of loading back-contact solar cells into the container, when the upper solar cell falls, the side 100 of the back-contact solar cell warps, and the degree of warping varies among different solar cells. Therefore, when the upper solar cell falls, the position of its side 100 will be offset from that of the lower solar cell. Therefore, in this application, by setting the angle A between the extension direction of the extension 22 and the corresponding side 100 to between 10° and 90°, even if the side 100 of the upper solar cell warps during the stacking process, the inclined extension 22 can still provide isolation support for the side 100 of the upper solar cell.

[0085] Specifically, the angle A between the extension direction of the extension 22 and the corresponding side 100 can be set to any angle or a range between any two angles, such as 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 60°, 70°, 80°, 90°, etc.

[0086] Optionally, such as Figure 2As shown, the extension 22 has a first end 22a and a second end 22b disposed opposite to each other. The first end 22a is connected to the protrusion 21. The cross-sectional area of ​​the extension 22 decreases from the first end 22a to the second end 22b.

[0087] Understandably, during the stacking of solar cells, the first protrusion 20 serves to isolate and protect the light-receiving surface of the solar cell body 10. The first protrusion 20 includes a protrusion 21 and an extension 22. The extension 22 extends from the protrusion 21 in a direction away from the protrusion 21. This increases the overall coverage and protection range of the first protrusion 20 while also saving material costs. Furthermore, the inclined extension 22 can effectively isolate and support the warped sides of the upper solar cell.

[0088] Furthermore, in this application, the cross-sectional area of ​​the extension 22 is reduced from the first end 22a to the second end 22b. That is, the end of the extension 22 closer to the protrusion 21 is relatively thick, and the end farther from the protrusion 21 is relatively thin. This is to satisfy the function of using the extension 22 to isolate and support the curved side of the upper battery cell, while also reducing the material cost required to manufacture the extension 22.

[0089] In some embodiments, such as Figure 2 As shown, the width of the extension 22 decreases from the first end 22a to the second end 22b. By setting the width of the extension 22 to decrease from the first end 22a to the second end 22b, the amount of material used can be reduced while ensuring that the protective effect of the extension 22 remains unchanged, thereby reducing production costs.

[0090] In other embodiments, such as Figure 3 As shown, the height of the extension 22 decreases from the first end 22a to the second end 22b. By setting the height of the extension 22 to decrease from the first end 22a to the second end 22b, the amount of material used can be reduced while ensuring the protective effect of the extension 22 remains unchanged, thereby reducing production costs. Optionally, as... Figure 2 As shown, the length of the extension 22 is L1 along the extension direction of the extension 22; the width of the protrusion 21 is L2 along any direction parallel to the light-receiving surface of the battery cell body 10, satisfying: 2.5≤L1 / L2≤3.5.

[0091] In this embodiment, the ratio L1 / L2 of the length L1 of the extension 22 to the width L2 of the protrusion 21 is set to a range of 2.2-3.5, so that the length of the extension 22 can be reasonably set according to the width of the protrusion 21. Through the cooperation of the protrusion 21 and the extension 22, the protection area that the first protrusion 20 can cover as a whole can be increased, while saving material costs, thereby achieving the best match between material cost and protection effect.

[0092] Specifically, the ratio L1 / L2 of the length L1 of the extension 22 to the width L2 of the protrusion 21 can be set to: 2.5, 2.8, 3, 3.2, 3.5, etc.

[0093] It is understood that the width L2 of the protrusion 21 refers to the maximum width value of the protrusion 21 in any direction parallel to the light-receiving surface. This can be achieved by measuring multiple width values ​​of the protrusion 21 in the direction parallel to the light-receiving surface and taking the maximum width value as the width L2. The length L1 of the extension 22 refers to the straight-line distance between the end of the extension 22 connected to the protrusion 21 and the end away from the protrusion 21. This can be achieved by measuring multiple length values ​​from the first end 22a to the second end 22b of the extension 22 and taking the average of the multiple length values ​​as the length L1.

[0094] Optionally, such as Figure 2 As shown, the maximum width of the extension 22 is L3 along a direction perpendicular to the extension direction of the extension 22 and parallel to the light-receiving surface; the width of the protrusion 21 is L2 along any direction parallel to the light-receiving surface of the battery cell body 10, satisfying: 4≤L2 / L3≤6.

[0095] In this embodiment, by setting the range of the ratio L2 / L3 of the maximum width L2 of the protrusion 21 to the width L3 of the extension 22, the width of the extension 22 is reasonably set according to the width of the protrusion 21. This ensures that the extension 22 has a certain width to effectively support the curved side 100 of the stacked battery cells, while also avoiding the extension 22 being too wide and affecting the light absorption rate of the light-receiving surface. Furthermore, an excessively wide extension 22 would also increase material costs.

[0096] Specifically, the ratio L2 / L3 of the width L2 of the protrusion 21 to the maximum width L3 of the extension 22 can be set to: 4, 4.3, 4.5, 4.8, 5, 5.2, 5.5, 5.7, 6, etc.

[0097] It is understandable that the width of the extension 22 is measured at different positions along a direction perpendicular to the extension direction of the extension 22 and parallel to the light-receiving surface. Multiple width values ​​are obtained by measurement, and the largest width value is taken as the maximum width L3 of the extension 22.

[0098] In some embodiments, such as Figure 2 As shown, along the extension direction of the extension 22, the length L1 of the extension 22 satisfies: 500μm≤L1≤700μm. For example, the length L1 of the extension 22 can be set to: 500μm, 520μm, 550μm, 580μm, 600μm, 630μm, 650μm, 670μm, 700μm, etc.

[0099] Understandably, if the length L1 of the extension 22 is less than 500 μm, the extension 22 is too short and may not be able to effectively contact the curved side 100 of the upper battery cell, thus failing to ensure the isolation and support function of the extension 22 for the curved side 100. On the other hand, if the length L1 of the extension 22 is greater than 700 μm, the extension 22 is too long. On the one hand, the strength of the second end 22b of the excessively long extension 22 cannot be effectively guaranteed, which is not conducive to playing an effective isolation and support role. On the other hand, an excessively long extension 22 will also cause more shading on the light-receiving surface, thus affecting the light absorption rate, and more materials are required for its preparation.

[0100] Therefore, in this embodiment of the application, by setting the length L1 of the extension 22 to be between 500μm and 700μm, it is possible to ensure that the extension 22 can effectively support and isolate the side 100 of the battery cells stacked on it, while also taking into account the shading effect of the extension 22 on the light-receiving surface and reducing the amount of material used.

[0101] In some embodiments, along any direction parallel to the light-receiving surface of the battery cell body 10, the width L2 of the protrusion 21 satisfies 160nm≤L2≤200nm. For example, the width L2 of the protrusion 21 can be set to 160nm, 170nm, 180nm, 185nm, 190nm, 195nm, 200nm, etc.

[0102] In this embodiment of the application, the protrusion 21 in the first protrusion 20 is mainly used to contact the electrodes of the battery cells stacked above, so as to play a supporting and isolating role between the light-receiving surface and the upper electrode. Furthermore, the maximum width L2 of the protrusion 21 is set between 160nm and 200nm, which can ensure that the protrusion 21 has a certain structural strength to form an effective isolation support for the upper electrode, while avoiding the size of the protrusion 21 being too large and affecting the light absorption rate of the light-receiving surface of the battery cell body 10.

[0103] Optionally, such as Figure 3 As shown, along the direction perpendicular to the light-receiving surface, the maximum height H2 of the extension 22 is less than the maximum height H1 of the protrusion 21. During the stacking of the solar cells, the electrodes of the upper solar cells mainly contact the protrusion 21, so that the protrusion 21 forms a supporting and isolating effect between the light-receiving surface and the upper electrodes. The extension 22, as a supplementary protective structure, mainly plays a supporting and isolating role for the warped side 100 of the upper solar cells. Therefore, by setting the maximum height H2 of the extension 22 to be less than the maximum height H1 of the protrusion 21, the protection requirements for the edge area 10b can be better met.

[0104] In some embodiments, such as Figure 3As shown, along the direction perpendicular to the light-receiving surface, the maximum height of the protrusion 21 is H1, which satisfies: 6μm≤H1≤10μm.

[0105] In this application, the maximum height H1 of the protrusion 21 is set between 6μm and 10μm to ensure that the protrusion 21 has a certain height to support the electrodes of the upper solar cell, avoiding direct contact between the electrodes and the light-receiving surface, thereby preventing the light-receiving surface from being scratched by the electrodes. At the same time, it also avoids the protrusion 21 being too high, which would cause a large height difference at different positions on the solar cell, and could easily lead to local microcracks in the solar cell during subsequent lamination processes.

[0106] Specifically, the maximum height H1 of the protrusion 21 can be set to 6μm, 7μm, 8μm, 9μm, 10μm, etc. In practical applications, the maximum height H1 can be obtained by measuring the height values ​​of the protrusion 21 at different positions along the direction perpendicular to the light-receiving surface and taking the maximum value among the measured height values.

[0107] In other embodiments, such as Figure 3 As shown, along the direction perpendicular to the light-receiving surface, the maximum height of the extension 22 is H2, which satisfies: 0.5μm≤H2≤1.5μm.

[0108] In this application, the maximum height H2 of the extension 22 is set between 0.5μm and 1.5μm to ensure that the extension 22 has a certain height to support the curved side 100 of the upper battery cell, thus preventing the light-receiving surface from being scratched by the curved side 100 of the upper battery cell. At the same time, it also avoids the extension 22 being too high and directly lifting the upper battery cell, which would leave the upper battery cell in a suspended state and easily lead to cell cracking.

[0109] Specifically, the maximum height H2 of the extension 22 can be set to 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, etc. In practical applications, the maximum height H2 can be obtained by measuring the height of the extension 22 at different positions along the direction perpendicular to the light-receiving surface and taking the maximum value among the measured height values.

[0110] In some embodiments, at least a portion of the extension 22 contains air bubbles. It is understood that because the extension 22 contains air bubbles, when light shines on the area of ​​the extension 22 containing air bubbles, the light is refracted, allowing more light to enter the cell body 10 and be absorbed and utilized, thereby increasing the light absorption rate of the cell.

[0111] Optionally, the battery cell body 10 also has a backlight surface disposed opposite to the light-receiving surface, and the backlight surface is provided with a plurality of electrodes (not shown in the figure) arranged at intervals. In this application, the electrodes are all disposed on the backlight surface of the battery cell body 10, which can avoid the electrodes blocking the light-receiving surface, thereby improving the light absorption rate of the light-receiving surface.

[0112] The electrodes on the back surface of the solar cell body 10 may include interconnected current collector electrodes and current bus electrodes. The current bus electrodes collect the current generated by the solar cell body 10, and the current bus electrodes collect and discharge the current collected by the current bus electrodes. Alternatively, the electrodes on the back surface of the solar cell body 10 may only include current bus electrodes, meaning the solar cell in this application is a grid-less solar cell. Of course, the electrode structure on the back surface of the solar cell body 10 can be flexibly configured according to actual needs, and is not limited here.

[0113] Optionally, such as Figure 6 As shown in the figure, this application embodiment also provides a photovoltaic module, including: a front panel 60, a back panel 70, an encapsulating film layer 80, and a back contact solar cell as described in the above embodiment; the front panel 60 and the back panel 70 are stacked, the encapsulating film layer 80 is disposed between the front panel 60 and the back panel 70, and the back contact solar cell is embedded in the encapsulating film layer 80.

[0114] In this embodiment, the back contact battery is positioned between the front plate 60 and the back plate 70, where the front plate 60 and the back plate 70 provide support and protection. Simultaneously, an encapsulating film layer 80 encapsulates and protects the back contact battery. Furthermore, by providing a first protrusion 20 on the edge region 10b of the light-receiving surface of the battery cell body 10, the back contact battery cells are stacked in the storage and transportation box during storage and transportation. That is, one battery cell is stacked on top of the light-receiving surface of the back contact battery cell, and so on. The first protrusion 20 provides isolation and protection for the light-receiving surface of the battery cell body 10. Furthermore, the first protrusion 20 includes a protrusion 21 and an extension 22. The protrusion 21 protrudes from the battery cell body 10, and the extension 22 extends from the protrusion 21 in a direction away from the protrusion 21. Thus, without increasing material usage or with only a small increase in material usage, the overall protected area covered by the first protrusion 20 can be increased, achieving an optimal balance between material cost and protective effect.

[0115] Furthermore, back-contact solar cells can warp during manufacturing. When the warping of the upper and lower solar cells differs during stacking, the warped side of the upper solar cell can easily come into contact with the edge of the light-receiving surface of the lower solar cell, causing scratches on the light-receiving surface. To address this, this application provides a first protrusion 20 on the edge area 10b of the light-receiving surface. The extension direction of the extension 22 in the first protrusion 20 is not parallel to the extension direction of the side 100 of the solar cell body 10. When the warped side of the upper solar cell falls on the edge area of ​​the light-receiving surface, the warped side and the extension 22 are staggered, ensuring that the extension 22 can provide isolation support for the warped side. This prevents damage to the edge area 10b of the light-receiving surface of the solar cell body 10 from the warped side of the upper solar cell, improving the protection of the edge area 10b of the solar cell body 10 and reducing the risk of scratches on the edge of the solar cell body 10 due to warping of the back-contact solar cells.

[0116] In the manufacturing process of photovoltaic modules, multiple back-contact solar cells can be connected in series using interconnecting devices to form a cell string. These cell strings are then electrically connected to form a cell layer. The layers are then stacked in the following order: backsheet 70, rear encapsulating film, cell layer, front encapsulating film, and front sheet 60, forming the structure to be laminated. This structure is then fed into a laminating machine and hot-pressed to melt the rear and front encapsulating films, forming an encapsulating film layer 80 to encapsulate and protect the cell layer. The encapsulating film layer 80 can be an EVA layer, a POE layer, or a composite of both.

[0117] Optionally, such as Figures 6 to 8 As shown in the figure, this application embodiment also provides a photovoltaic module, including a back contact cell and an encapsulating film layer 80. The back contact cell adopts the back contact cell of the above embodiment. The cell body 10 has a light-receiving surface and a back-lighting surface. The back-lighting surface is provided with an electrode 52, and the light-receiving surface is provided with a plurality of spaced isolation protrusions 51. The isolation protrusions 51 include at least a first protrusion 20. A recessed area 511 is formed on the surface of the isolation protrusions 51 corresponding to the electrode 52. An encapsulating film layer 80 is provided on the light-receiving surface, and the encapsulating film layer 80 covers the recessed area 511.

[0118] In this embodiment, the backlight surface of the battery cell body 10 is provided with an electrode 52. The current generated by the battery cell body 10 can be collected and transmitted through the electrode 52. The electrode 52 is connected to the interconnecting member, and multiple battery cells can be connected in series or parallel to form a battery cell. Furthermore, by forming a recessed area 511 on the surface of the isolation protrusion 51 corresponding to the electrode 52, during the process of encapsulating the battery cell with the encapsulating film layer 80, at least a portion of the encapsulating film layer 80 material can be embedded in the recessed area 511, which can increase the bonding strength between the encapsulating film layer 80 and the isolation protrusion 51, thereby improving the encapsulation effect of the encapsulating film layer 80 on the battery cell.

[0119] It is understood that the light-receiving surface of the back contact cell includes a central region 10a and an edge region 10b surrounding the central region 10a. The isolation protrusion 51 may include a first protrusion 20 disposed on the edge region 10b. The isolation protrusion 51 may also include a second protrusion 30 disposed on the edge region 10b and a third protrusion 40 disposed on the central region 10a. The structure of the second protrusion 30 and the third protrusion 40 can be referred to the content of the foregoing embodiment, and will not be repeated here. Furthermore, a recessed region 511 may also be formed on the surface of the second protrusion 30 and / or the third protrusion 40 to increase the bonding force between the encapsulation film layer 80 and the second protrusion 30 and the third protrusion 40.

[0120] It should be noted that the electrode 52 of this application may include interconnected bus electrodes, current collector electrodes, pads or solder joints, etc.

[0121] For example, the electrode 52 in this application only includes the current collector electrode, that is, the battery cell in this application is a gridless battery cell, which is electrically connected to the current collector electrode through interconnects to connect multiple battery cells in series and parallel to form a battery cell.

[0122] In some embodiments, the depth of the recessed area 511 along the direction perpendicular to the light-receiving surface is less than or equal to 100 μm. For example, the depth of the recessed area 511 can be 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc.

[0123] In this application, by controlling the depth of the recessed area 511 on the surface of the isolation protrusion 51 to be less than or equal to 100 μm, on the one hand, it ensures that the recessed area 511 in the isolation protrusion 51 has a certain depth, which can improve the bonding force with the encapsulation film layer 80. On the other hand, it avoids the recessed area 511 being too deep or even penetrating the isolation protrusion 51. During the stacking of the battery cells, the electrode of the upper battery cell can easily pass through the recessed area 511 and directly contact the battery cell body 10, causing the light-receiving surface to be scratched.

[0124] In other embodiments, the width of the recessed area 511 is less than or equal to 100 μm along any direction parallel to the light-receiving surface. For example, the width of the recessed area 511 can be set to: 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc.

[0125] In this application, the width of the recessed area 511 in the isolation protrusion 51 is controlled to be less than or equal to 100 μm, so as to avoid the width of the recessed area 511 in the isolation protrusion 51 being too large, thus affecting the isolation and protection function of the isolation protrusion 51.

[0126] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is 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 embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0127] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A back contact battery cell, characterized in that, include: The battery cell body has a light-receiving surface having a central area and an edge area surrounding the central area; at least a portion of the edge area has a first protrusion, the first protrusion including a protruding portion and an extension portion, the protruding portion protruding from the light-receiving surface of the battery cell body, the extension portion extending from the protruding portion in a direction away from the protruding portion, and the extension direction of the extension portion is not parallel to the extension direction of the adjacent side of the battery cell body.

2. The back contact battery cell according to claim 1, characterized in that, The side includes two oppositely arranged long sides and two oppositely arranged short sides, the length of the long side being greater than the length of the short side; the first protrusion is at least provided in the edge area corresponding to the short side, and the extension extends obliquely relative to the corresponding short side.

3. The back contact battery cell according to claim 2, characterized in that, The distance between the first protrusion and the corresponding short side is less than or equal to 9 mm.

4. The back contact battery cell according to claim 1, characterized in that, The extension direction of the extension portion forms an angle A with the corresponding side edge, satisfying: 10°≤A≤90°; And / or, the edge region is provided with a plurality of first protrusions arranged at intervals, and the extensions of at least two of the first protrusions have different extension directions.

5. The back contact battery cell according to claim 1, characterized in that, The extension has a first end and a second end that are disposed opposite to each other, the first end being connected to the protrusion; the cross-sectional area of ​​the extension decreases from the first end to the second end.

6. The back contact battery cell according to claim 5, characterized in that, From the first end to the second end, the height of the extension decreases; and / or, the width of the extension decreases.

7. The back contact battery cell according to claim 1, characterized in that, The extension extends continuously.

8. The back contact battery cell according to any one of claims 1-7, characterized in that, The back contact battery cell must satisfy at least one of the following conditions: A. Along the extending direction of the extension, the length of the extension is L1; along any direction parallel to the light-receiving surface of the battery cell body, the width of the protrusion is L2, satisfying: 2.5≤L1 / L2≤3.5; B. Along a direction perpendicular to the extension direction and parallel to the light-receiving surface, the maximum width of the extension is L3; along any direction parallel to the light-receiving surface of the battery cell body, the width of the protrusion is L2, satisfying: 4≤L2 / L3≤6. C. Along the extending direction of the extension, the length L1 of the extension satisfies: 500μm≤L1≤700μm; D. Along any direction parallel to the light-receiving surface of the battery cell body, the width L2 of the protrusion satisfies 160nm≤L2≤200nm; E. Along a direction perpendicular to the light-receiving surface, the maximum height of the extension is less than the maximum height of the protrusion; F. Along the direction perpendicular to the light-receiving surface, the maximum height of the protrusion is H1, which satisfies: 6μm≤H1≤10μm; G. Along the direction perpendicular to the light-receiving surface, the maximum height of the extension is H2, satisfying: 0.5μm≤H2≤1.5μm; H. At least a portion of the extension contains air bubbles.

9. The back contact battery cell according to any one of claims 1-7, characterized in that, The edge area is also provided with a second protrusion, which protrudes from the light-receiving surface and is spaced apart from the first protrusion; And / or, the intermediate area is further provided with a plurality of third protrusions, the third protrusions protruding from the light-receiving surface, and the plurality of third protrusions are arranged at intervals.

10. The back contact battery cell according to any one of claims 1-7, characterized in that, The battery cell body also has a backlight surface that is opposite to the light-receiving surface, and the backlight surface is provided with a plurality of electrodes arranged at intervals.

11. A photovoltaic module, characterized in that, include: Front panel, back panel, encapsulating film layer, and back contact cell as described in any one of claims 1-10; The front panel and the back panel are stacked, the encapsulation film layer is disposed between the front panel and the back panel, and the back contact battery cell is embedded in the encapsulation film layer.

12. A photovoltaic module, characterized in that, It includes a back contact cell and an encapsulating film layer, wherein the back contact cell is the back contact cell as described in any one of claims 1-10; The battery cell body has a light-receiving surface and a backlighting surface. The backlighting surface is provided with an electrode. The light-receiving surface is provided with a plurality of spaced-apart isolation protrusions. The isolation protrusions include at least the first protrusion. The surface of the isolation protrusion corresponding to the electrode has a recessed area. The light-receiving surface is provided with the encapsulating film layer, which covers the recessed area.

13. The photovoltaic module according to claim 12, characterized in that, Along a direction perpendicular to the light-receiving surface, the depth of the recessed area is less than or equal to 100 μm; And / or, along any direction parallel to the light-receiving surface, the width of the recessed area is less than or equal to 100 μm.

Images