Back contact cells, back contact tandem cells and photovoltaic modules

Abstract

This application relates to the photovoltaic field. Embodiments of this application provide a back-contact battery, a back-contact tandem battery, and a photovoltaic module. The back-contact battery's grid includes a first grid and a second grid. The first grid is connected to an edge grid line, and the second grid is spaced apart from the edge grid line. The second grid includes at least a first sub-grid, a second sub-grid, and a third sub-grid. Along a second direction, the length of the second sub-grid is greater than the length of the first sub-grid and less than the length of the third sub-grid. The vertical distances L1 between the first sub-grid and the chamfered edge, L2 between the second sub-grid and the chamfered edge, and L3 between the third sub-grid and the second edge are all 0.8mm to 1.2mm. The chamfered edge can disperse stress in the edge region of the battery, improve the battery's mechanical strength, and reduce defect areas. The chamfered edge structure combined with the arrangement of the second grid improves the electrical reliability of the edge region of the back-contact battery, thereby enhancing the photoelectric conversion efficiency of the back-contact battery.

Description

Technical Field

[0001] This application relates to the photovoltaic field, specifically to a back-contact battery, a back-contact tandem battery, and a photovoltaic module. Background Technology

[0002] The positive and negative grid lines of the back contact cell are both located on its back side, and there are no grid lines blocking its light-facing side. Compared with conventional photovoltaic cells, this can reduce the light energy loss caused by grid line shading and has a higher photoelectric conversion efficiency.

[0003] Existing back-contact solar cells typically feature chamfered edges. These chamfers eliminate sharp edges and corners of the silicon wafer, reducing edge damage. However, existing back-contact solar cells with chamfered edges still suffer from relatively low photoelectric conversion efficiency. Utility Model Content

[0004] In view of this, this application provides a back-contact battery, a back-contact tandem battery, and a photovoltaic module to help solve the problem of low photoelectric conversion efficiency of back-contact batteries in the prior art.

[0005] In a first aspect, embodiments of this application provide a back-contact battery, comprising: a body having a first side, a second side, and a chamfered side, the two ends of the chamfered side being connected to the first side and the second side, respectively; an edge grid line disposed on the back-light surface of the body; and a fine grid disposed on the back-light surface of the body, the fine grid comprising a first fine grid and a second fine grid alternately distributed in a first direction, wherein, along a second direction, the end of the first fine grid is connected to the edge grid line, and the end of the second fine grid is spaced apart from the edge grid line; the second fine grid includes at least a first sub-fine grid, a second sub-fine grid, and a third sub-fine grid. In the first direction, the first sub-grid, the second sub-grid, and the third sub-grid are arranged sequentially away from the first side; in the second direction, the length of the second sub-grid is greater than the length of the first sub-grid and less than the length of the third sub-grid; the vertical distance between the first sub-grid and the chamfered edge is L1, the vertical distance between the second sub-grid and the chamfered edge is L2, and the vertical distance between the third sub-grid and the second side is L3, where L1, L2, and L3 are all 0.8mm to 1.2mm; the first direction intersects the second direction.

[0006] In one possible implementation, the vertical distance L1 between the first sub-grid and the chamfered edge, the vertical distance L2 between the second sub-grid and the chamfered edge, and the vertical distance L3 between the third sub-grid and the second edge satisfy: L1=L2=L3.

[0007] In one possible implementation, along the second direction, the vertical distance L4 between the first sub-gate and the extension line of the second side is 2mm to 2.2mm; and / or, along the second direction, the vertical distance L5 between the second sub-gate and the extension line of the second side is 1.15mm to 1.35mm.

[0008] In one possible implementation, the first side is provided with chamfered edges at both ends along the second direction; the body is also provided with a third side, which is distributed opposite to the first side along the first direction, and the second side is provided at both ends along the second direction, and the third side is connected to the second side.

[0009] In one possible implementation, along the second direction, the length of the third side is L6, the length of the first side is L7, and L6 and L7 satisfy: 0.991≤L7:L6≤0.994; and / or, along the first direction, the distance between the first side and the third side is L8, the length of the second side is L9, and L8 and L9 satisfy: 0.96≤L9:L8≤0.99.

[0010] In one possible implementation, the length L6 of the third side is 180mm to 184mm; and / or, the distance L8 between the first side and the third side is 90mm to 93mm.

[0011] In one possible implementation, the length L7 of the first side is 177mm to 179mm; and / or, the length L9 of the second side is 89mm to 92mm.

[0012] In one possible implementation, the back contact battery further includes an insulating member extending along the second direction; the insulating member includes a first insulating member and a second insulating member, the first insulating member covering at least a portion of the first fine grid and the second insulating member covering at least a portion of the second fine grid.

[0013] In one possible implementation, the back contact battery further includes a main grid, which is disposed on the back surface of the body and extends along the first direction; the main grid includes a first main grid and a second main grid, the first fine grid is connected to the first main grid, and the second fine grid is spaced apart from the first main grid; the second fine grid is connected to the second main grid, and the first fine grid is spaced apart from the second main grid.

[0014] In one possible implementation, the back contact battery further includes an insulating member extending along the second direction; the insulating member includes a third insulating member and a fourth insulating member, the third insulating member covering the ends of the first fine grid located on both sides of the second main grid; the fourth insulating member covering the ends of the second fine grid located on both sides of the first main grid.

[0015] In one possible implementation, the insulating element further includes a fifth insulating element extending along the second direction, at least a portion of which covers the end of the second fine grid near the edge grid line.

[0016] Secondly, embodiments of this application provide a back-contact stacked battery, including a back-contact bottom battery and a perovskite top battery, wherein the perovskite top battery and the back-contact bottom battery are electrically connected to each other on their light-facing surfaces; the back-contact bottom battery includes: a body having a first side, a second side, and a chamfered side, wherein the two ends of the chamfered side are respectively connected to the first side and the second side; an edge grid line disposed on the back-facing surface of the body; and a fine grid disposed on the back-facing surface of the body, wherein the fine grid includes a first fine grid and a second fine grid alternately distributed in a first direction, and along a second direction, the end of the first fine grid is connected to the edge grid line, and the end of the second fine grid is spaced apart from the edge grid line; The second fine grid includes at least a first sub-fine grid, a second sub-fine grid, and a third sub-fine grid. In the first direction, the first sub-fine grid, the second sub-fine grid, and the third sub-fine grid are arranged sequentially in a direction away from the first side. In the second direction, the length of the second sub-fine grid is greater than the length of the first sub-fine grid and less than the length of the third sub-fine grid. The vertical distance between the first sub-fine grid and the chamfered edge is L1, the vertical distance between the second sub-fine grid and the chamfered edge is L2, and the vertical distance between the third sub-fine grid and the second side is L3. L1, L2, and L3 are all 0.8 mm to 1 mm. The first direction intersects with the second direction.

[0017] Thirdly, embodiments of this application provide a photovoltaic module, including: a plurality of photovoltaic cells, wherein the photovoltaic cells are back-contact cells as described above, or the photovoltaic cells are back-contact tandem cells as described above; and a solder strip, wherein two adjacent photovoltaic cells along the second direction are connected by the solder strip.

[0018] The beneficial effects of this application are: by setting chamfered edges, the sharp edge structure can be improved, making the edge of the back contact cell smoother, dispersing the stress at the edge, increasing the mechanical strength of the edge region of the back contact cell, thereby reducing the risk of microcracks or breakage of the back contact cell edge due to external forces. Furthermore, the edge region of the originally cut silicon wafer usually has certain lattice defects and dangling bonds, which easily lead to short circuits. By setting chamfered edges, a portion of the defective area at the edge can be cut off, reducing the risk of charge carriers merging or leaking in the defective area of ​​the back contact cell edge, which is beneficial to improving the reliability and photoelectric conversion efficiency of the back contact cell. Along the second direction, the length of the second sub-gate is greater than the length of the first sub-gate and less than the length of the third sub-gate, so that the lengths of the first, second, and third sub-gates vary with the shape of the chamfered region of the back contact cell. On the one hand, the first, second, and third sub-grids can all maintain a reasonable distance from the edge of the back contact cell, ensuring that the ends of the first, second, and third sub-grids form a relatively wide safety isolation area between themselves and the edge of the back contact cell. This reduces the risk of carrier recombination or leakage in the edge defect region, and can reduce the additional resistance loss caused by the edge effect, thereby improving the photoelectric conversion efficiency of the back contact cell. On the other hand, the first, second, and third sub-grids can all maintain a reasonable distance from the edge grid lines, reducing the risk of short circuits caused by the first, second, or third sub-grids connecting to the edge grid lines, thus improving the reliability of the back contact cell. The back contact cell is equipped with a chamfered edge to reduce the edge defect region, and the first, second, and third sub-grids are arranged in the above manner, so that the second grid and the chamfered structure work synergistically to enhance the electrical reliability of the edge region of the back contact cell, thereby further improving the photoelectric conversion efficiency of the back contact cell. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the backlight surface of the back contact battery provided in the embodiments of this application in a second embodiment;

[0021] Figure 2 for Figure 1 A partial structural diagram of the back contact battery in the first embodiment;

[0022] Figure 3A schematic diagram of the backlight surface of the back contact battery provided in the embodiments of this application in a second embodiment;

[0023] Figure 4 for Figure 1 A partial structural diagram of the back contact battery in the second embodiment;

[0024] Figure 5 A schematic diagram of the backlight surface of the back contact battery provided in the embodiments of this application in a third embodiment;

[0025] Figure 6 for Figure 5 A partial structural diagram of the back contact battery in the first embodiment;

[0026] Figure 7 for Figure 5 A partial structural diagram of the back contact battery in the second embodiment;

[0027] Figure 8 for Figure 5 A partial structural diagram of the back contact battery in the third embodiment.

[0028] Figure 9 for Figure 5 A partial structural diagram of the back contact battery in the fourth embodiment.

[0029] Figure 10 This is a schematic diagram of the structure of the back contact stacked battery provided in the embodiments of this application;

[0030] Figure 11 This is a schematic diagram of the structure of the photovoltaic module provided in the first embodiment of this application;

[0031] Figure 12 This is a schematic diagram of the structure of the photovoltaic module provided in the second embodiment of this application.

[0032] Figure label:

[0033] 10-Back contact battery;

[0034] 20-Back contact stacked battery;

[0035] 201-Back contact bottom battery;

[0036] 202-Perovskite Top Cell;

[0037] 30 - Welding strip;

[0038] 40-front plate;

[0039] 50 - Front encapsulation layer;

[0040] 60 - Backside encapsulation layer;

[0041] 70-back panel;

[0042] 1-Ontology;

[0043] 11 - First side;

[0044] 12 - Second side;

[0045] 13- Chamfered edge;

[0046] 14 - Third side;

[0047] 2-Edge grid lines;

[0048] 3-Fine grid;

[0049] 31 - First fine grid;

[0050] 32 - Second fine grid;

[0051] 321 - First sub-grid;

[0052] 322 - Second sub-grid;

[0053] 323 - Third sub-grid;

[0054] 324 - Fourth sub-grid;

[0055] 4-Insulating components;

[0056] 41-First insulating element;

[0057] 411 - First Covering Section;

[0058] 412 - First extension;

[0059] 42 - Second insulating element;

[0060] 421 - Second Cover Section;

[0061] 422 - Second extension;

[0062] 43 - Third insulating component;

[0063] 431 - Third Cover Section;

[0064] 432 - Third extension;

[0065] 44 - Fourth insulating component;

[0066] 441 - Fourth Covering Section;

[0067] 442 - Fourth extension;

[0068] 45 - Fifth insulating component;

[0069] 451 - Fifth Covering Section;

[0070] 452 - Fifth Extension;

[0071] 5-Main gate;

[0072] 51 - First main gate;

[0073] 52 - Second main gate. Detailed Implementation

[0074] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0075] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0076] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0077] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0078] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0079] This application provides a back contact battery 10, such as Figure 1As shown, the back contact battery 10 includes a body 1, which has a first side 11, a second side 12, a third side 14, and a chamfered edge 13. The third side 14 and the first side 11 are distributed opposite to each other along a first direction X. Along a second direction Y, the third side 14 has a second side 12 at both ends, and the two ends of the third side 14 are respectively connected to the two second sides 12. The two ends of the chamfered edge 13 are respectively connected to the first side 11 and the second side 12. Along the second direction Y, the first side 11 has a chamfered edge 13 at both ends, and the two ends of the first side 11 are respectively connected to the two second sides 12. The ends of the two chamfered edges 13 away from the first side 11 are respectively connected to the two second sides 12. In this embodiment, by setting the chamfered edge 13, the sharp edge structure can be improved, making the edge of the back contact battery 10 smoother, dispersing the stress at the edge, increasing the mechanical strength of the edge area of ​​the back contact battery 10, thereby reducing the risk of the edge of the back contact battery 10 cracking or breaking due to external force. Furthermore, the edges of the original cut silicon wafers typically contain lattice defects and dangling bonds, making them prone to short circuits. By adding chamfered edges 13, a portion of these defective areas can be removed, reducing the risk of charge carriers merging or leaking at the edge defect areas of the back contact cell 10. This improves the reliability and photoelectric conversion efficiency of the back contact cell 10. Moreover, in this embodiment, the back contact cell 10 has two symmetrically distributed chamfered edges 13, resulting in more uniform stress distribution. When multiple back contact cells 10 are arranged to form a photovoltaic module, this helps reduce the breakage rate during stringing or lamination, thereby improving the yield rate of the photovoltaic module. The chamfered edges 13 also facilitate the alignment of adjacent back contact cells 10 during layout, improving not only the assembly efficiency of the photovoltaic module but also the regularity of the photovoltaic module's layout structure and its aesthetic appeal.

[0080] like Figure 1As shown, the back surface of the main body 1 is provided with edge grid lines 2 and fine grids 3. The fine grids 3 include a first fine grid 31 and a second fine grid 32 alternately distributed in the first direction X. Both the first fine grid 31 and the second fine grid 32 extend along the second direction Y and are used to collect and guide the photocurrent generated in the main body 1. The first fine grid 31 and the second fine grid 32 have opposite polarities, one of which is the positive electrode fine grid of the back contact battery 10, and the other is the negative electrode fine grid of the back contact battery 10. Edge grid lines 2 are provided at both ends of the back contact battery 10 along the second direction Y, and the edge grid lines 2 extend along the first direction X. The polarities of the two edge grid lines 2 located at the two ends of the back contact battery 10 along the second direction Y can be the same or opposite. This embodiment is described using the example of two edge grid lines 2 having the same polarity. In this embodiment, the edge gate line 2 has the same polarity as the first fine gate 31 and the opposite polarity to the second fine gate 32. Along the second direction Y, the end of the first fine gate 31 intersects with the edge gate line 2 and forms an electrical connection to collect the current on the first fine gate 31. The end of the second fine gate 32 is spaced apart from the edge gate line 2 to avoid short circuit caused by the second fine gate 32 forming an electrical connection with the edge gate line 2.

[0081] It should be noted that the first direction X intersects with the second direction Y, such as... Figure 1 As shown, one of the first direction X and the second direction Y can be the length direction of the back contact battery 10, and the other can be the width direction of the back contact battery 10.

[0082] The accompanying drawings provided in this application use lines of different thicknesses to distinguish the first fine gate 31 and the second fine gate 32. This is not a limitation on the relative width between the first fine gate 31 and the second fine gate 32. The width of the first fine gate 31 and the width of the second fine gate 32 may be equal or unequal.

[0083] like Figure 2As shown, the second fine grid 32 includes at least a first sub-fine grid 321, a second sub-fine grid 322, and a third sub-fine grid 323. In the first direction X, the first sub-fine grid 321, the second sub-fine grid 322, and the third sub-fine grid 323 are arranged sequentially in a direction away from the first side 11. In the second direction Y, the length of the second sub-fine grid 322 is greater than the length of the first sub-fine grid 321 and less than the length of the third sub-fine grid 323, so that the lengths of the first sub-fine grid 321, the second sub-fine grid 322, and the third sub-fine grid 323 vary with the shape of the chamfered region of the back contact battery 10. On the one hand, the first sub-grid 321, the second sub-grid 322, and the third sub-grid 323 can all maintain a reasonable distance from the edge of the back contact battery 10, ensuring that the ends of the first sub-grid 321, the second sub-grid 322, and the third sub-grid 323 form a relatively wide safety isolation area between themselves and the edge of the back contact battery 10. This reduces the risk of carrier recombination or leakage in the edge defect region, and can reduce the additional resistance loss of the back contact battery 10 caused by the edge effect, thereby improving the photoelectric conversion efficiency of the back contact battery 10. On the other hand, the first sub-grid 321, the second sub-grid 322, and the third sub-grid 323 can all maintain a reasonable distance from the edge grid line 2, reducing the risk of short circuits caused by the first sub-grid 321, the second sub-grid 322, or the third sub-grid 323 connecting to the edge grid line 2, thereby improving the reliability of the back contact battery 10.

[0084] In some embodiments, the vertical distance between the first sub-grid 321 and the chamfered edge 13 is L1, the vertical distance between the second sub-grid 322 and the chamfered edge 13 is L2, and the vertical distance between the third sub-grid 323 and the second edge 12 is L3, where L1, L2, and L3 are all 0.8mm to 1.2mm. When L1, L2, and L3 satisfy the above ranges, the ends of the first sub-grid 321, the second sub-grid 322, and the third sub-grid 323 form a suitable width of safety isolation area with the edge of the back contact battery 10. This reduces the additional resistance loss of the back contact battery 10 due to the edge effect, while preventing the lengths of L1, L2, and L3 from being too short, thus avoiding too much loss of effective power generation area and reducing the photoelectric conversion efficiency loss of the back contact battery 10, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0085] Optionally, the vertical distance L1 between the first sub-fine grid 321 and the chamfered edge 13 is 0.8mm to 1mm. L1 can be 0.8mm, 0.82mm, 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm or 1mm, or other values ​​within the above range. This embodiment does not limit this value.

[0086] Optionally, the vertical distance L1 between the first sub-fine grid 321 and the chamfered edge 13 is 1mm to 1.2mm. L1 can be 1mm, 1.02mm, 1.04mm, 1.06mm, 1.08mm, 1.1mm, 1.12mm, 1.14mm, 1.16mm, 1.18mm or 1.2mm, or other values ​​within the above range. This embodiment does not limit this value.

[0087] Optionally, the vertical distance L2 between the second sub-grid 322 and the chamfered edge 13 is 0.8mm to 1mm. L2 can be 0.8mm, 0.82mm, 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm or 1mm, or other values ​​within the above range. This embodiment does not limit this value.

[0088] Optionally, the vertical distance L2 between the second sub-grid 322 and the chamfered edge 13 is 1mm to 1.2mm. L2 can be 1mm, 1.02mm, 1.04mm, 1.06mm, 1.08mm, 1.1mm, 1.12mm, 1.14mm, 1.16mm, 1.18mm or 1.2mm, or other values ​​within the above range. This embodiment does not limit this value.

[0089] Optionally, the vertical distance L3 between the third sub-grid 323 and the second side 12 is 0.8mm to 1mm. L3 can be 0.8mm, 0.82mm, 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm or 1mm, or other values ​​within the above range. This embodiment does not limit this value.

[0090] Optionally, the vertical distance L3 between the third sub-grid 323 and the second side 12 is 1mm to 1.2mm. L3 can be 1mm, 1.02mm, 1.04mm, 1.06mm, 1.08mm, 1.1mm, 1.12mm, 1.14mm, 1.16mm, 1.18mm or 1.2mm, or other values ​​within the above range. This embodiment does not limit this value.

[0091] In this embodiment, the values ​​of L1, L2, and L3 can be equal or unequal; this is not a limitation. When L1=L2=L3, the distances from the first sub-grid 321, the second sub-grid 322, and the third sub-grid 323 to the edge of the back contact battery 10 are equal, which optimizes the current distribution. This avoids uneven current distribution caused by some second grids 32 being too close to the battery edge, improves the overall current collection uniformity of the second grids 32, and reduces the risk of local overheating of the back contact battery 10 due to uneven current distribution. Moreover, a safe isolation area of ​​equal width can be formed between the second grids 32 and the edge of the back contact battery 10, which helps to further reduce the risk of edge effects. In addition, when L1=L2=L3, it can ensure that the stress on the edge of the back contact battery 10 is evenly distributed, reducing the risk of breakage due to stress concentration at the edge of the back contact battery 10. Meanwhile, the uniform edge distance facilitates the printing of the second fine grid 32 and also facilitates subsequent cutting and encapsulation steps of the back contact cell 10, which helps to reduce the process difficulty of the back contact cell 10 and photovoltaic module and improve the yield of the back contact cell 10 and photovoltaic module.

[0092] In this embodiment, the back contact battery 10 is provided with a chamfered edge 13 to reduce the edge defect area. At the same time, the first sub-fine grid 321, the second sub-fine grid 322 and the third sub-fine grid 323 are arranged in the manner described above, so that the second fine grid 32 and the chamfered structure work together to enhance the electrical reliability of the edge area of ​​the back contact battery 10, thereby further improving the photoelectric conversion efficiency of the back contact battery 10.

[0093] In addition, the second fine grid 32 also includes multiple fourth sub-fine grids 324. Along the first direction X, the fourth sub-fine grids 324 are located on the side of the third sub-fine grid 323 away from the second sub-fine grid 322. The length of the fourth sub-fine grid 324 is equal to the length of the third sub-fine grid 322. The vertical distance between each fourth sub-fine grid 324 and the second side 12 is equal to the vertical distance between the third sub-fine grid 323 and the second side 12, which is L3. This will not be elaborated further here.

[0094] In some embodiments, such as Figure 2 As shown, along the second direction Y, the vertical distance L4 between the first sub-grid 321 and the extension line of the second side 12 is 2mm to 2.2mm. When L4 meets the above range, the length of the first sub-grid 321 is appropriate. It is neither too long, which would cause a short circuit between the first sub-grid 321 and the edge grid line 2, nor too short, which would result in a loss of the effective power generation area of ​​the back contact battery 10. This is beneficial to improving the reliability and photoelectric conversion efficiency of the back contact battery 10. At the same time, when L4 meets the above range, it is also convenient to print the first sub-grid 321, which helps to reduce the process difficulty of the back contact battery 10 and improve the production efficiency and yield of the back contact battery 10.

[0095] Optionally, the vertical distance L4 between the first sub-grid 321 and the extension line of the second side 12 is 2mm to 2.1mm. L4 can be 2.01mm, 2.02mm, 2.03mm, 2.04mm, 2.05mm, 2.06mm, 2.07mm, 2.08mm, 2.09mm or 2.1mm, or other values ​​within the above range. This embodiment does not limit this value.

[0096] Optionally, the vertical distance L4 between the first sub-grid 321 and the extension line of the second side 12 is 2.1mm to 2.2mm. L4 can be 2.11mm, 2.12mm, 2.13mm, 2.14mm, 2.15mm, 2.16mm, 2.17mm, 2.18mm, 2.19mm or 2.2mm, or other values ​​within the above range. This embodiment does not limit this value.

[0097] In some embodiments, such as Figure 2 As shown, along the second direction Y, the vertical distance L5 between the second sub-grid 322 and the extension line of the second side 12 is 1.15mm to 1.35mm. When L5 meets the above range, the length of the second sub-grid 322 is appropriate. It is neither too long, which would cause a short circuit between the second sub-grid 322 and the edge grid line 2, nor too short, which would result in a loss of the effective power generation area of ​​the back contact battery 10. This is beneficial to improving the reliability and photoelectric conversion efficiency of the back contact battery 10. At the same time, when L5 meets the above range, it is also convenient to print the second sub-grid 322, which helps to reduce the process difficulty of the back contact battery 10 and improve the production efficiency and yield of the back contact battery 10.

[0098] Optionally, the vertical distance L5 between the second sub-grid 322 and the extension line of the second side 12 is 1.15mm to 1.25mm. L5 can be 1.15mm, 1.16mm, 1.17mm, 1.18mm, 1.19mm, 1.2mm, 1.21mm, 1.22mm, 1.23mm, 1.24mm or 1.25mm, or other values ​​within the above range. This embodiment does not limit this value.

[0099] Optionally, the vertical distance L5 between the second sub-grid 322 and the extension line of the second side 12 is 1.25mm to 1.35mm. L5 can be 1.25mm, 1.26mm, 1.27mm, 1.28mm, 1.29mm, 1.3mm, 1.31mm, 1.32mm, 1.33mm, 1.34mm or 1.35mm, or other values ​​within the above range. This embodiment does not limit this value.

[0100] It should be noted that, Figure 2The partial structure of the back contact battery 10 shown is the structure of the area where one chamfered edge 13 is located, and the structure of the area where the other chamfered edge 13 is located is the same as... Figure 2 The structure shown is symmetrical about the first direction X.

[0101] The back contact battery 10 provided in this application embodiment can be a whole battery or a sliced ​​battery. Specifically, the sliced ​​battery can be a two-slice battery, a three-slice battery, a four-slice battery, or an eight-slice battery. The following will take the two-slice battery as an example to describe the specific structure of the back contact battery 10 in detail.

[0102] In some embodiments, such as Figure 1 As shown, the length L6 of the third side 14 is 180mm~184mm, that is, the length of the back contact battery 10 provided in this application embodiment is 180mm~184mm, which is beneficial to increase the effective light-receiving area of ​​the back contact battery 10, thereby improving the photoelectric conversion efficiency of the back contact battery 10.

[0103] Optionally, the length L6 of the third side 14 is 180mm~182mm. L6 can be 180mm, 180.2mm, 180.4mm, 180.6mm, 180.8mm, 181mm, 181.2mm, 181.4mm, 181.6mm, 181.8mm or 182mm, or other values ​​within the above range. This embodiment does not limit this.

[0104] Optionally, the length L6 of the third side 14 is 182mm~184mm. L6 can be 182mm, 182.2mm, 182.4mm, 182.6mm, 182.8mm, 183mm, 183.2mm, 183.4mm, 183.6mm, 183.8mm or 184mm, or other values ​​within the above range. This embodiment does not limit this.

[0105] In some embodiments, such as Figure 1 As shown, the distance L8 between the first side 11 and the third side 14 is 90mm~93mm, that is, the width of the back contact battery 10 is 90mm~93mm, which is beneficial to increase the effective light-receiving area of ​​the back contact battery 10, thereby improving the photoelectric conversion efficiency of the back contact battery 10.

[0106] Optionally, the distance L8 between the first side 11 and the third side 14 is 90mm~91mm. L8 can be 90mm, 90.1mm, 90.2mm, 90.3mm, 90.4mm, 90.5mm, 90.6mm, 90.7mm, 90.8mm, 90.9mm or 91mm, or other values ​​within the above range. This embodiment does not limit this value.

[0107] Optionally, the distance L8 between the first side 11 and the third side 14 is 91mm~92mm. L8 can be 91mm, 91.1mm, 91.2mm, 91.3mm, 91.4mm, 91.5mm, 91.6mm, 91.7mm, 91.8mm, 91.9mm or 92mm, or other values ​​within the above range. This embodiment does not limit this value.

[0108] Optionally, the distance L8 between the first side 11 and the third side 14 is 92mm~93mm. L8 can be 92mm, 92.1mm, 92.2mm, 92.3mm, 92.4mm, 92.5mm, 92.6mm, 92.7mm, 92.8mm, 92.9mm or 93mm, or other values ​​within the above range. This embodiment does not limit this value.

[0109] In some embodiments, such as Figure 1 As shown, the length L7 of the first side 11 is 177mm~179mm. When L7 meets the above range, the size of the chamfer structure of the back contact battery 10 in the second direction Y can be increased, which is beneficial to optimize the stress distribution in the surrounding area of ​​the chamfer edge 13 and improve the mechanical strength of the surrounding area of ​​the chamfer edge 13.

[0110] Optionally, the length L7 of the first side 11 is 177mm~178mm. L7 can be 177mm, 177.1mm, 177.2mm, 177.3mm, 177.4mm, 177.5mm, 177.6mm, 177.7mm, 177.8mm, 177.9mm or 178mm, or other values ​​within the above range. This embodiment does not limit this.

[0111] Optionally, the length L7 of the first side 11 is 178mm~179mm. L7 can be 178mm, 178.1mm, 178.2mm, 178.3mm, 178.4mm, 178.5mm, 178.6mm, 178.7mm, 178.8mm, 178.9mm or 179mm, or other values ​​within the above range. This embodiment does not limit this.

[0112] In some embodiments, the length L6 of the third side 14 and the length L7 of the first side 11 satisfy: 0.991≤L7:L6≤0.994. In this case, the chamfer size of the back contact battery 10 is appropriate. It will not result in insufficient stress dispersion in the edge area of ​​the back contact battery 10 due to the chamfer being too small, nor will it result in loss of the effective power generation area of ​​the back contact battery 10 due to the chamfer being too large. This is beneficial to improving the reliability and photoelectric conversion efficiency of the back contact battery 10.

[0113] Optionally, the values ​​of L7:L6 can be 0.991, 0.9915, 0.992, 0.9925, 0.993, 0.9935 or 0.994, or other values ​​within the above range. This embodiment does not limit these values.

[0114] In some embodiments, such as Figure 1 As shown, the length L9 of the second side 12 is 89mm~92mm. When L9 meets the above range, the size of the chamfer structure of the back contact battery 10 in the first direction X can be increased, which is beneficial to optimize the stress distribution in the surrounding area of ​​the chamfer edge 13 and improve the mechanical strength of the surrounding area of ​​the chamfer edge 13.

[0115] Optionally, the length L9 of the second side 12 is 89mm to 90mm. L9 can be 89mm, 89.1mm, 89.2mm, 89.3mm, 89.4mm, 89.5mm, 89.6mm, 89.7mm, 89.8mm, 89.9mm or 90mm, or other values ​​within the above range. This embodiment does not limit this.

[0116] Optionally, the length L9 of the second side 12 is 90mm~91mm. L9 can be 90mm, 90.1mm, 90.2mm, 90.3mm, 90.4mm, 90.5mm, 90.6mm, 90.7mm, 90.8mm, 90.9mm or 91mm, or other values ​​within the above range. This embodiment does not limit this.

[0117] Optionally, the length L9 of the second side 12 is 91mm~92mm. L9 can be 91mm, 91.1mm, 91.2mm, 91.3mm, 91.4mm, 91.5mm, 91.6mm, 91.7mm, 91.8mm, 91.9mm or 92mm, or other values ​​within the above range. This embodiment does not limit this.

[0118] In some embodiments, the distance L8 between the first side 11 and the third side 14, and the length L9 of the second side 12 satisfy: 0.96≤L9:L8≤0.99. In this case, the chamfer size of the back contact battery 10 is appropriate. It will not result in insufficient stress dispersion in the edge area of ​​the back contact battery 10 due to the chamfer being too small, nor will it result in loss of the effective power generation area of ​​the back contact battery 10 due to the chamfer being too large. This is beneficial to improving the reliability and photoelectric conversion efficiency of the back contact battery 10.

[0119] Optionally, the values ​​of L9:L8 can be 0.96, 0.965, 0.97, 0.975, 0.98, 0.985 or 0.99, or other values ​​within the above range. This embodiment does not limit these values.

[0120] In other embodiments, such as Figure 3 As shown, chamfered edges 13 can be provided at all four corners of the back contact battery 10. In this case, the structures of the two chamfered areas above the back contact battery 10 and the structures of the two chamfered areas below are symmetrical about the second direction Y.

[0121] In some embodiments, the back contact cell 10 can be a gridless cell, with pads or conductive adhesive (not shown) respectively provided on the first fine grid 31 and the second fine grid 32. When multiple gridless back contact cells 10 are assembled into a photovoltaic module, adjacent back contact cells 10 are electrically connected by solder ribbon. One end of the solder ribbon is electrically connected to the pads or conductive adhesive on the first fine grid 31 of one of the back contact cells 10, and the other end is electrically connected to the pads or conductive adhesive on the second fine grid 32 of the other back contact cell 10, so that the solder ribbon can collect and conduct current from the fine grid 32.

[0122] The back contact battery 10 also includes an insulating element 4, such as Figure 2 As shown, the insulating element 4 extends along the second direction Y to form an insulating effect between the solder strip and the fine grid 3, preventing the same solder strip from being electrically connected to the first fine grid 31 and the second fine grid 32 with opposite polarities simultaneously, thus avoiding a short circuit. This embodiment uses insulating adhesive as an example to illustrate the insulating element 4.

[0123] The insulating element 4 includes a first insulating element 41 and a second insulating element 42. The first insulating element 41 covers at least a portion of the first fine grid 31 and is used to form an insulating effect between the first fine grid 31 and the solder strip. The second insulating element 42 covers at least a portion of the second fine grid 32 and is used to form an insulating effect between the second fine grid 32 and the solder strip.

[0124] In some embodiments, such as Figure 2 As shown, the first insulating member 41 includes a first covering portion 411 and a first extension portion 412 connected to each other. The first covering portion 411 extends along the second direction Y, and at least a portion of the first covering portion 411 covers the first fine grid 31, forming an insulating effect between the first fine grid 31 and the solder strip, and also providing a certain degree of protection for the first fine grid 31. The first covering portion 411 has a first extension portion 412 connected to each end along the second direction Y. The first extension portion 412 extends along the second direction Y and covers the first fine grid 31. By providing the first extension portion 412, the total area of ​​the first insulating member 41 can be increased, improving the insulation reliability of the first insulating member 41. Moreover, the first extension portion 412 covering the first fine grid 31 can also provide a certain degree of protection for the first fine grid 31, buffering external impact forces and reducing the risk of breakage of the first fine grid 31.

[0125] Along the first direction X, the width of the first extension 412 is less than or equal to the width of the first cover 411. When the width of the first extension 412 is equal to the width of the first cover 411, printing is easier, which helps reduce the manufacturing difficulty of the first insulating member 41 and improves the production efficiency of the back contact battery 10. When the width of the first extension 412 is less than the width of the first cover 411, the raw materials of the first insulating member 41 can be saved, the manufacturing cost of the back contact battery 10 can be reduced, and the risk of warping of the back contact battery 10 due to volume shrinkage of the first insulating member 41 during the curing process can also be reduced.

[0126] In some embodiments, such as Figure 4 As shown, the first insulating member 41 may also include only the first covering portion 411 without the first extension portion 412, which can save insulating adhesive material and reduce the production cost of the back contact battery 10. At the same time, it can also reduce the light blocking by the insulating adhesive, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0127] In some embodiments, such as Figure 2 As shown, the second insulating member 42 includes a second covering portion 421 and a second extension portion 422 connected to each other. The second covering portion 421 extends along the second direction Y, and at least a portion of the second covering portion 421 covers the second fine grid 32, forming an insulating effect between the second fine grid 32 and the solder strip, and also providing a certain degree of protection for the second fine grid 32. The second covering portion 421 has a second extension portion 422 connected to each end along the second direction Y. The second extension portion 422 extends along the second direction Y and covers the second fine grid 32. By providing the second extension portion 422, the total area of ​​the second insulating member 42 can be increased, improving the insulation reliability of the second insulating member 42. Moreover, the second extension portion 422 covering the second fine grid 32 can also provide a certain degree of protection for the second fine grid 32, buffering external impact forces and reducing the risk of breakage of the second fine grid 32. In the second insulating member 42 located near the edge grid line 2 at both ends of the back contact battery 10, the second extension 422 can cover the end of the second fine grid 32 near the edge grid line 2 to form an insulating effect between the second fine grid 32 and the edge grid line 2.

[0128] Along the first direction X, the width of the second extension 422 is less than or equal to the width of the second cover 421. When the width of the second extension 422 is equal to the width of the second cover 421, printing is easier, which helps reduce the manufacturing difficulty of the second insulating member 42 and improves the production efficiency of the back contact battery 10. When the width of the second extension 422 is less than the width of the second cover 421, the raw materials of the second insulating member 42 can be saved, the manufacturing cost of the back contact battery 10 can be reduced, and the risk of warping of the back contact battery 10 due to volume shrinkage of the second insulating member 42 during the curing process can also be reduced.

[0129] In the back contact battery 10 provided in this application, since the second grid line 32 can form a wider safety isolation area with the edge of the back contact battery 10, it can provide space for printing the second insulating element 42, so as to ensure that the raw material of the second insulating element 42 will not overflow from the edge of the back contact battery 10, which is beneficial to improving the production efficiency and yield of the back contact battery 10.

[0130] In some embodiments, such as Figure 4 As shown, in the second insulating member 42 located near the edge grid line 2 at both ends of the back contact battery 10, the second covering portion 421 and the second extension portion 422 can be a separate structure. The second extension portion 422 only covers the end of the second fine grid 32 near the edge grid line 2 to form an insulating effect between the second fine grid 32 and the edge grid line 2. The remaining second insulating member 42 located in the middle of the back contact battery 10 can only include the second covering portion 421 without the second extension portion 422, which can save insulating adhesive material and reduce the production cost of the back contact battery 10. At the same time, it can also reduce the light blocking of the insulating adhesive, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0131] In some embodiments, the back contact battery 10 can be a battery with a main grid, such as... Figure 5 As shown, the back surface of the back contact battery 10 with a main grid is provided with a main grid 5 extending along the first direction X. The main grid 5 includes a first main grid 51 and a second main grid 52 alternately distributed along the second direction Y. One of the first main grid 51 and the second main grid 52 is the positive main grid, and the other is the negative main grid. The first fine grid 31 has the same polarity as the first main grid 51. The first fine grid 31 intersects with the first main grid 51 and forms an electrical connection, so that the first main grid 51 can collect and output the photocurrent collected by the first fine grid 31. The second fine grid 32 is arranged at a distance from the first main grid 51, that is, the second fine grid 32 is disconnected at the first main grid 51 to avoid the second fine grid 32 being electrically connected to the first main grid 51 and causing a short circuit. The second fine gate 32 has the same polarity as the second main gate 52. The second fine gate 32 intersects with the second main gate 52 and forms an electrical connection so that the second main gate 52 can collect and output the photocurrent collected by the second fine gate 32. The first fine gate 31 is spaced apart from the second main gate 52, that is, the first fine gate 31 is disconnected at the second fine gate 32 to avoid a short circuit caused by the first fine gate 31 being electrically connected to the second main gate 52.

[0132] When the back contact cell 10 is a cell with a main grid, the first main grid 51 and the second main grid 52 are respectively provided with solder pads or conductive adhesive (not shown in the figure). When multiple back contact cells 10 with main grids are used to form a photovoltaic module, two adjacent back contact cells 10 are electrically connected by solder strips. One end of the solder strip is electrically connected to the first main grid 51 of one of the back contact cells 10, and the other end is electrically connected to the second main grid 52 of the other back contact cell 10.

[0133] The back contact battery 10 with a main grid also includes an insulating member 4. The insulating member 4 includes a third insulating member 43 and a fourth insulating member 44, both of which extend along the second direction Y. The first insulating member 41 covers at least a portion of the first fine grid 31, forming an insulating effect between the first fine grid 31 and the solder strip, and between the first fine grid 31 and the second main grid 52. The second insulating member 42 covers at least a portion of the second fine grid 32, forming an insulating effect between the second fine grid 32 and the solder strip, and between the second fine grid 32 and the first main grid 51. This embodiment uses insulating adhesive as an example for illustration.

[0134] The back contact battery 10 with main grid provided in this embodiment has the following structure: Figure 5 As shown, along the second direction Y, the main grids at both ends of the back contact battery 10 are both second main grids 52. The first fine grid 31 between the second main grids 52 at both ends and the edge grid line 2 is directly electrically connected to the solder ribbon through the solder pad or conductive adhesive.

[0135] In some embodiments, such as Figure 6 As shown, the third insulating member 43 may consist only of the third covering portion 431, which covers the ends of the first fine grids 31 located on both sides of the second main grid 52, thereby creating an insulating effect between the first fine grids 31 and the solder strip, and between the first fine grids 31 and the second main grid 52. When the third insulating member 43 consists only of the third covering portion 431, it can save insulating adhesive raw materials and reduce the production cost of the back contact battery 10. At the same time, it can also reduce the light blocking effect of the insulating adhesive, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0136] The third covering part 431 can be Figure 7 The structure shown, namely the third cover portion 431, is a split structure, used only to cover the ends of the first fine grids 31 located on both sides of the second main grid 52. This further reduces the amount of raw materials used in the third insulating member 43, thereby further reducing the production cost of the back contact battery 10 and further improving the photoelectric conversion efficiency of the back contact battery 10. Alternatively, the third cover portion 431 can also be... Figure 6The structure shown, namely the third cover 431, is an integral structure that at least partially covers the second main grid 52, which can improve the insulation effect between the second main grid 52 and the first fine grid 31. At the same time, the third cover 431 can also provide a certain degree of protection for the second main grid 52.

[0137] In some embodiments, the third insulating member 43 may further include a third extension 432 extending along the second direction Y, at least a portion of the third extension 432 covering the first fine gate 31. For example... Figure 8 As shown, when the third cover portion 431 has a split structure, the third extension portion 432 is connected to the end of the third cover portion 431 that is away from the second main gate 52. Figure 9 As shown, when the third cover 431 is an integral structure, the two ends of the third cover 431 along the second direction Y are respectively connected to the third extension 432. By providing the third extension 432, the total area of ​​the third insulating member 43 can be increased, thereby improving the insulation reliability of the third insulating member 43. Moreover, the third extension 432 covers the first fine grid 31, which can also provide a certain degree of protection for the first fine grid 31, buffering external impact forces and reducing the risk of breakage of the first fine grid 31.

[0138] Along the first direction X, the width of the third extension 432 is less than or equal to the width of the third cover 431. When the width of the third extension 432 is equal to the width of the third cover 431, printing is easier, which helps reduce the manufacturing difficulty of the third insulating member 43 and improves the production efficiency of the back contact battery 10. When the width of the third extension 432 is less than the width of the third cover 431, the raw materials of the third insulating member 43 can be saved, the manufacturing cost of the back contact battery 10 can be reduced, and the risk of warping of the back contact battery 10 due to volume shrinkage of the third insulating member 43 during the curing process can also be reduced.

[0139] In some embodiments, such as Figure 6 As shown, the fourth insulating member 44 may consist only of a fourth covering portion 441, which covers the ends of the second fine grids 32 located on both sides of the first main grid 51, forming an insulating effect between the second fine grids 32 and the solder strip, and between the second fine grids 32 and the first main grid 51. When the fourth insulating member 44 consists only of the fourth covering portion 441, it can save insulating adhesive raw materials and reduce the production cost of the back contact battery 10. At the same time, it can also reduce the light blocking by the insulating adhesive, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0140] The fourth covering part 441 can be Figure 7The structure shown, namely the fourth cover portion 441, is a split structure, used only to cover the ends of the second fine grids 32 located on both sides of the first main grid 51. This further reduces the amount of raw materials used in the fourth insulating member 44, thereby further reducing the production cost of the back contact battery 10 and further improving the photoelectric conversion efficiency of the back contact battery 10. Alternatively, the fourth cover portion 441 can also be... Figure 6 The structure shown, namely the fourth cover 441, is an integral structure that at least partially covers the first main grid 51, which can improve the insulation effect between the first main grid 51 and the second fine grid 32. At the same time, the fourth cover 441 can also provide a certain degree of protection for the first main grid 51.

[0141] In some embodiments, the fourth insulating member 44 may further include a fourth extension 442 extending along the second direction Y, at least a portion of the fourth extension 442 covering the second fine gate 32. For example... Figure 8 As shown, when the fourth cover portion 441 is a split structure, the fourth extension portion 442 is connected to the end of the fourth cover portion 441 that is away from the first main gate 51. Figure 9 As shown, when the fourth cover 441 is an integral structure, the fourth cover 441 has a fourth extension 442 connected to both ends along the second direction Y. By providing the fourth extension 442, the total area of ​​the fourth insulating member 44 can be increased, thereby improving the insulation reliability of the fourth insulating member 44. Moreover, since the fourth extension 442 covers the second fine grid 32, it can also provide a certain degree of protection for the second fine grid 32, buffering external impact forces and reducing the risk of breakage of the second fine grid 32.

[0142] Along the first direction X, the width of the fourth extension 442 is less than or equal to the width of the fourth cover 441. When the width of the fourth extension 442 is equal to the width of the fourth cover 441, it is easier to print, which helps to reduce the manufacturing difficulty of the third insulating member 43 and improve the production efficiency of the back contact battery 10. When the width of the fourth extension 442 is less than the width of the fourth cover 441, it can save raw materials for the fourth insulating member 44, reduce the manufacturing cost of the back contact battery 10, and also reduce the risk of the back contact battery 10 warping due to volume shrinkage of the fourth insulating member 44 during the curing process.

[0143] In some embodiments, the insulating member 4 further includes a fifth insulating member 45, which is located at both ends of the back contact battery 10 near the edge grid line 2. The fifth insulating member 45 extends along the second direction Y, and at least a portion of the fifth insulating member 45 covers the end of the second fine grid 32 near the edge grid line 2, thereby forming an insulating effect between the second fine grid 32 and the edge grid line 2.

[0144] like Figure 6As shown, the fifth insulating member 45 may include a separate fifth covering portion 451 and a fifth extension portion 452. The fifth extension portion 452 covers only the end of the second fine grid 32 near the edge grid line 2 to form an insulating effect between the second fine grid 32 and the edge grid line 2. At least a portion of the fifth covering portion 451 covers the second fine grid 32 to form an insulating effect between the second fine grid 32 and the solder strip. The separate structure of the fifth insulating member 45 can save insulating adhesive raw materials and reduce the production cost of the back contact battery 10. At the same time, it can also reduce the light blocking by the insulating adhesive, which is beneficial to improving the photoelectric conversion efficiency of the back contact battery 10.

[0145] like Figure 8 As shown, the fifth cover portion 451 and the fifth extension portion 452 can also be an integral structure, which can increase the total area of ​​the fifth insulating member 45 and improve the insulation reliability of the fifth insulating member 45. Moreover, it can also improve the protective effect of the fifth insulating member 45 on the second fine grid 32, buffer the external impact force, and reduce the risk of the second fine grid 32 breaking.

[0146] Along the first direction X, the width of the fifth extension 452 is less than or equal to the width of the fifth cover 451. When the width of the fifth extension 452 is equal to the width of the fifth cover 451, it is easier to print, which helps to reduce the manufacturing difficulty of the fifth insulating member 45 and improve the production efficiency of the back contact battery 10. When the width of the fifth extension 452 is less than the width of the fifth cover 451, it can save raw materials for the fifth insulating member 45, reduce the manufacturing cost of the back contact battery 10, and also reduce the risk of the back contact battery 10 warping due to volume shrinkage of the fifth insulating member 45 during the curing process.

[0147] In some embodiments, the back contact cell 10 can be one of the following: interdigitated back contact (IBC), heterojunction back contact (HBC), or tunnel oxide back contact (TBC). For an IBC cell, along its thickness direction, the IBC cell sequentially includes a silicon nitride inversion layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride antireflection layer, and a silver electrode. IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precise controllable junction depth. The absence of grid lines on the front of the cell eliminates light-blocking current loss from metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to the back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front-surface recombination rates and surface reflections.

[0148] HBC cells effectively combine the advantages of IBC and heterojunction cells. Their front surface passivation layer uses hydrogenated amorphous silicon, while N-type and P-type amorphous silicon films are deposited on the back side to form a heterojunction. HBC cells fully utilize the superior surface passivation properties of amorphous silicon, and the heterojunction structure formed on the back side exhibits excellent passivation, enabling the simultaneous achievement of higher short-circuit current and open-circuit voltage, thereby improving photoelectric conversion efficiency.

[0149] For TBC cells, the advantages of both Topcon's tunneling oxide layer technology and IBC back-side electrode arrangement are combined, resulting in significantly improved passivation and open-circuit voltage, achieving higher cell conversion efficiency while maintaining economic viability. The complete TBC cell production process mainly includes depositing the tunneling oxide layer and P+ polycrystalline silicon, depositing the passivation film, and printing electrodes on the back of the silicon wafer. Building upon the TOPCon production process, TBC cells require additional back-side electrode processes such as masking, laser grooving, PN region fabrication, and etching. Masking is primarily performed using APCVD or PECVD, PN region fabrication is mainly done using PECVD, etching primarily employs traditional wet processing equipment, and grooving is performed using laser equipment.

[0150] This application also provides a back-contact stacked battery 20, such as Figure 10As shown, the back-contact tandem solar cell 20 includes a back-contact bottom cell 201 and a perovskite top cell 202, with the perovskite top cell 202 electrically connected to the light-facing surface of the back-contact bottom cell 201. The back-contact bottom cell 201 can be either a back-contact cell 10 with a main grid or a back-contact cell 10 without a main grid, as described above. The perovskite top cell 202 is a thin-film solar cell with perovskite material as the photoactive layer. The structure of the perovskite top cell 202 mainly consists of the following key components: a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. These components work together to enable the perovskite top cell 202 to effectively absorb sunlight and convert it into electrical energy. The perovskite material in the perovskite light-absorbing layer has excellent light absorption performance, absorbing a wider spectral range and effectively converting short-wavelength spectra, giving the perovskite top cell 202 high photoelectric conversion efficiency.

[0151] This application also provides a photovoltaic module, such as... Figure 11 and Figure 12 As shown, the photovoltaic module includes multiple photovoltaic cells and solder ribbons 30. The photovoltaic cells are either the back-contact cells 10 described above, or the back-contact tandem cells 20 described above. The main grids 5 of two adjacent photovoltaic cells along the second direction Y are connected by solder ribbons 30.

[0152] The photovoltaic module also includes a front panel 40, a front encapsulation layer 50, a back encapsulation layer 60, and a backsheet 70. The front panel 40 and the backsheet 70 together sandwich the front encapsulation layer 50, photovoltaic cells, solder ribbons 30, and back encapsulation layer 60, and form a photovoltaic module through lamination. The front encapsulation layer 50 protects the light-facing side of the photovoltaic cells, and the back encapsulation layer 60 protects the back-facing side of the photovoltaic cells. During the lamination process, the front encapsulation layer 50 and the back encapsulation layer 60 encapsulate and protect the photovoltaic cells and solder ribbons 30, preventing external environmental factors from affecting their performance. They also bond the front panel 40, backsheet 70, photovoltaic cells, and solder ribbons 30 into a single unit.

[0153] The front panel 40 and back panel 70 can be made of rigid materials such as tempered glass, polyethylene terephthalate (PET), and polycarbonate (PC), or flexible materials such as polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF). The front encapsulation layer 50 and the back encapsulation layer 60 are adhesive films, which can be made of materials such as ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and polyvinyl butyral (PVB). The front encapsulation layer 50 and the back encapsulation layer 60 can also be EPE film (EVA-POE-EVA co-extrusion structure) or EP film (EVA-POE co-extrusion structure).

[0154] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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: The body (1) is provided with a first side (11), a second side (12) and a chamfered side (13), the two ends of the chamfered side (13) being connected to the first side (11) and the second side (12) respectively; Edge grid lines (2) are disposed on the back surface of the body (1); A fine grid (3) is disposed on the backlight surface of the body (1). The fine grid (3) includes a first fine grid (31) and a second fine grid (32) that are alternately distributed in a first direction. Along the second direction, the end of the first fine grid (31) is connected to the edge grid line (2), and the end of the second fine grid (32) is spaced apart from the edge grid line (2). The second fine gate (32) includes at least a first sub-fine gate (321), a second sub-fine gate (322), and a third sub-fine gate (323). In the first direction, the first sub-fine gate (321), the second sub-fine gate (322), and the third sub-fine gate (323) are arranged sequentially in a direction away from the first side (11). Along the second direction, the length of the second sub-gate (322) is greater than the length of the first sub-gate (321) and less than the length of the third sub-gate (323); The vertical distance between the first sub-grid (321) and the chamfered edge (13) is L1, the vertical distance between the second sub-grid (322) and the chamfered edge (13) is L2, and the vertical distance between the third sub-grid (323) and the second edge (12) is L3. L1, L2, and L3 are all 0.8mm~1.2mm. The first direction intersects with the second direction.

2. The back contact cell of claim 1, wherein, The vertical distance L1 between the first sub-fine grid (321) and the chamfered edge (13), the vertical distance L2 between the second sub-fine grid (322) and the chamfered edge (13), and the vertical distance L3 between the third sub-fine grid (323) and the second edge (12) satisfy: L1=L2=L3.

3. The back contact cell of claim 1, wherein, Along the second direction, the vertical distance L4 between the first sub-grid (321) and the extension line of the second side (12) is 2mm~2.2mm; And / or, along the second direction, the vertical distance L5 between the second sub-grid (322) and the extension line of the second side (12) is 1.15mm~1.35mm.

4. The back contact battery according to claim 1, characterized in that, Along the second direction, both ends of the first side (11) are provided with the chamfered edge (13). The body (1) is also provided with a third side (14), which is distributed opposite to the first side (11) along the first direction. The third side (14) is provided with a second side (12) at both ends along the second direction, and the third side (14) is connected to the second side (12).

5. The back contact battery according to claim 4, characterized in that, Along the second direction, the length of the third side (14) is L6, and the length of the first side (11) is L7. L6 and L7 satisfy: 0.991≤L7:L6≤0.994; And / or, along the first direction, the distance between the first side (11) and the third side (14) is L8, and the length of the second side (12) is L9, and L8 and L9 satisfy: 0.96≤L9: L8≤0.

99.

6. The back contact battery according to claim 5, characterized in that, The length L6 of the third side (14) is 180mm~184mm; And / or, the distance L8 between the first side (11) and the third side (14) is 90mm~93mm.

7. The back contact battery according to claim 5, characterized in that, The length L7 of the first side (11) is 177mm~179mm; And / or, the length L9 of the second side (12) is 89mm~92mm.

8. The back contact battery according to claim 1, characterized in that, The back contact battery (10) also includes an insulating member (4) that extends along the second direction; The insulating element (4) includes a first insulating element (41) and a second insulating element (42), the first insulating element (41) covering at least a portion of the first fine grid (31) and the second insulating element (42) covering at least a portion of the second fine grid (32).

9. The back contact battery according to claim 1, characterized in that, The back contact battery (10) also includes a main grid (5), which is disposed on the back surface of the body (1) and extends along the first direction; The main grid (5) includes a first main grid (51) and a second main grid (52), the first fine grid (31) is connected to the first main grid (51), and the second fine grid (32) is spaced apart from the first main grid (51); The second fine grid (32) is connected to the second main grid (52), and the first fine grid (31) and the second main grid (52) are spaced apart.

10. The back contact battery according to claim 9, characterized in that, The back contact battery (10) also includes an insulating member (4) that extends along the second direction; The insulating element (4) includes a third insulating element (43) and a fourth insulating element (44), wherein the third insulating element (43) covers the ends of the first fine grid (31) located on both sides of the second main grid (52); The fourth insulating element (44) covers the ends of the second fine grid (32) located on both sides of the first main grid (51).

11. The back contact battery according to claim 10, characterized in that, The insulating element (4) further includes a fifth insulating element (45) extending along the second direction, at least a portion of which covers the end of the second fine grid (32) near the edge grid line (2).

12. A back-contact stacked battery, characterized in that, It includes a back contact bottom cell (201) and a perovskite top cell (202), wherein the perovskite top cell (202) is electrically connected to the light-facing surface of the back contact bottom cell (201); The back contact bottom battery (201) includes: a body (1) having a first side (11), a second side (12) and a chamfered side (13), wherein the two ends of the chamfered side (13) are respectively connected to the first side (11) and the second side (12); Edge grid lines (2) are disposed on the back surface of the body (1); A fine grid (3) is disposed on the backlight surface of the body (1). The fine grid (3) includes a first fine grid (31) and a second fine grid (32) that are alternately distributed in a first direction. Along the second direction, the end of the first fine grid (31) is connected to the edge grid line (2), and the end of the second fine grid (32) is spaced apart from the edge grid line (2). The second fine gate (32) includes at least a first sub-fine gate (321), a second sub-fine gate (322), and a third sub-fine gate (323). In the first direction, the first sub-fine gate (321), the second sub-fine gate (322), and the third sub-fine gate (323) are arranged sequentially in a direction away from the first side (11). Along the second direction, the length of the second sub-gate (322) is greater than the length of the first sub-gate (321) and less than the length of the third sub-gate (323); The vertical distance between the first sub-grid (321) and the chamfered edge (13) is L1, the vertical distance between the second sub-grid (322) and the chamfered edge (13) is L2, and the vertical distance between the third sub-grid (323) and the second edge (12) is L3. L1, L2, and L3 are all 0.8mm~1mm. The first direction intersects with the second direction.

13. A photovoltaic module, characterized in that, include: Multiple photovoltaic cells, wherein the photovoltaic cells are back-contact cells (10) as described in any one of claims 1-11, or the photovoltaic cells are back-contact tandem cells (20) as described in claim 12. The welding strip (30) connects two adjacent photovoltaic cells along the second direction.

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