Back contact solar cell

Abstract

A first area (111) and a second area (112) are arranged on the back face (11) of the back contact solar cell (100), and a first conductive contact structure (40) and a second conductive contact structure (50) are arranged in the first area (111) and the second area (112) respectively. The first electrically conductive contact structure (40) and the second electrically conductive contact structure (50) are for contact with a probe of a test device.

Description

Back contact solar cells

[0001] Priority information

[0002] This application claims priority and benefits to patent application No. 202420895917.1 filed with the China National Intellectual Property Administration on April 26, 2024, and patent application No. 202411163007.5 filed with the China National Intellectual Property Administration on August 22, 2024, both of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to the field of solar cell technology, and more particularly to a back-contact solar cell, a cell module, and a photovoltaic system. Background Technology

[0004] In order to reduce the use of paste, back-contact solar cells adopt a gridless design. However, on the one hand, in this technical solution, due to the gridless design on the back, when performing electrical performance (e.g., IV test) and hot spot performance tests on the back-contact solar cell, the back-contact solar cell and the test probe cannot make stable contact, which makes the test more difficult and results in poor reliability and stability. Summary of the Invention

[0005] This application provides a back-contact solar cell, a battery module, and a photovoltaic system.

[0006] This application provides a back-contact solar cell comprising:

[0007] A silicon wafer having opposing front and back sides, the back side having a plurality of first regions and a plurality of second regions;

[0008] A plurality of first fine grids and a plurality of second fine grids are disposed on the back side, the plurality of first fine grids and the plurality of second fine grids being arranged alternately and at intervals along a first direction, and all extending along a second direction, the second direction intersecting the first direction;

[0009] A plurality of first conductive contact structures are disposed within the first region, the first conductive contact structures being connected to a plurality of first fine gates, and the second fine gates being disconnected at the first conductive contact structures; and

[0010] A plurality of second conductive contact structures are disposed in the second region, the second conductive contact structures being connected to a plurality of second fine gates, and the first fine gates being disconnected at the second conductive contact structures.

[0011] Another back-contact solar cell provided in this application includes:

[0012] A silicon wafer having opposing front and back sides;

[0013] A plurality of first and second fine grids are disposed on the back side, the plurality of first and second fine grids being arranged alternately and spaced apart along a first direction and all extending along a second direction, the second direction intersecting the first direction; and

[0014] The first test contact structure and the second test contact structure are disposed on the back side;

[0015] The first test contact structure is electrically connected to all the first fine gates and intersects with a plurality of second fine gates. The second fine gates that intersect with the first test contact structure are disconnected at the first test contact structure. The second test contact structure is electrically connected to all the second fine gates and intersects with a plurality of first fine gates. The first fine gates that intersect with the second test contact structure are disconnected at the second test contact structure. The first test contact structure and the second test contact structure are respectively used to contact probes of different polarities in the test device.

[0016] The battery assembly provided in this application includes several back-contact solar cells as described above.

[0017] The photovoltaic system provided in this application includes the battery modules described above. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the photovoltaic system provided in an embodiment of this application;

[0019] Figure 2 is a schematic diagram of the battery assembly provided in an embodiment of this application;

[0020] Figure 3 is a schematic diagram of the planar structure of the back side of the back contact solar cell provided in Embodiment 1 of this application;

[0021] Figure 4 is a partially enlarged schematic diagram of the back-contact solar cell in Figure 3 at the first conductive contact structure.

[0022] Figure 5 is another enlarged schematic diagram of the back contact solar cell in Figure 3 at the first conductive contact structure.

[0023] Figure 6 is another partially enlarged schematic diagram of the back-contact solar cell in Figure 3 at the first conductive contact structure.

[0024] Figure 7 is another partially enlarged schematic diagram of the back contact solar cell in Figure 3 at the first conductive contact structure.

[0025] Figure 8 is a partially enlarged schematic diagram of the back-contact solar cell in Figure 3 at the second conductive contact structure.

[0026] Figure 9 is another enlarged schematic diagram of the back-contact solar cell in Figure 3 at the second conductive contact structure.

[0027] Figure 10 is another partially enlarged schematic diagram of the back-contact solar cell in Figure 3 at the second conductive contact structure.

[0028] Figure 11 is another partially enlarged schematic diagram of the back contact solar cell in Figure 3 at the second conductive contact structure.

[0029] Figure 12 is a schematic diagram of another planar structure of the back side of the back contact solar cell provided in Embodiment 1 of this application;

[0030] Figure 13 is another planar structural diagram of the back side of the back contact solar cell provided in Embodiment 1 of this application;

[0031] Figure 14 is a schematic diagram of the planar structure of the back-contact solar cell provided in Embodiment 2 of this application;

[0032] Figure 15 is an enlarged schematic diagram of the back-contact solar cell at point IV in Figure 14;

[0033] Figure 16 is another enlarged schematic diagram of the back-contact solar cell at point V in Figure 14;

[0034] Figure 17 is a schematic diagram of another planar structure of the back-contact solar cell provided in Embodiment 2 of this application;

[0035] Figure 18 is an enlarged schematic diagram of the back-contact solar cell at point VII in Figure 17;

[0036] Figure 19 is an enlarged schematic diagram of the back-contact solar cell at point VIII in Figure 17;

[0037] Figure 20 is another planar structural schematic diagram of the back-contact solar cell provided in Embodiment 2 of this application;

[0038] Figure 21 is another planar structural schematic diagram of the back-contact solar cell provided in Embodiment 2 of this application;

[0039] Figure 22 is an enlarged schematic diagram of the back-contact solar cell at point XI in Figure 20;

[0040] Figure 23 is another enlarged schematic diagram of the back-contact solar cell at point XI in Figure 20;

[0041] Figure 24 is an enlarged schematic diagram of the back-contact solar cell at point XIII in Figure 21;

[0042] Figure 25 is another enlarged schematic diagram of the back-contact solar cell at point XIII in Figure 21;

[0043] Figure 26 is another planar structural schematic diagram of the back-contact solar cell provided in Embodiment 2 of this application;

[0044] Figure 27 is another planar structural schematic diagram of the back-contact solar cell provided in Embodiment 2 of this application;

[0045] Figure 28 is another planar structural schematic diagram of the back-contact solar cell provided in Embodiment 2 of this application. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0047] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "several," "multiple," and "more than" mean two (roots) or more, unless otherwise explicitly specified.

[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, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0051] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0052] Please refer to Figures 1-2. The photovoltaic system 1000 in this embodiment may include the battery module 200 in this embodiment, and the battery module 200 may include a plurality of battery strings, which may include a plurality of back-contact solar cells 100 in this embodiment. Specifically, the back-contact solar cell 100 in this application may be a gridless back-contact solar cell.

[0053] In this application, multiple back-contact solar cells 100 in the battery module 200 can be connected in series with solder strips to form a battery string. The individual battery strings in the battery module 200 can be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between the individual battery strings can be achieved through busbars.

[0054] The back-contact solar cell 100 in different embodiments of this application will be described in detail below. It should be noted that in each corresponding embodiment, the same reference numeral always represents the same element, but in different embodiments, the same reference numeral may represent different elements.

[0055] Example 1

[0056] It should be noted that in this application, the structures shown in Figures 3-13 correspond to the content of Embodiment 1, and the component reference numerals in Embodiment 1 correspond to the reference numerals in Figures 3-13.

[0057] Please refer to Figure 3. The back contact solar cell 100 in this embodiment may include a silicon wafer 10, a plurality of first fine grids 20, a plurality of second fine grids 30, a plurality of first conductive contact structures 40 and a plurality of second conductive contact structures 50.

[0058] The silicon wafer 10 has a front side and a back side 11. The back side 11 has a plurality of first regions 111 and a plurality of second regions 112. A plurality of first fine gates 20 and a plurality of second fine gates 30 are disposed on the back side 11 of the silicon wafer 10. The plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged alternately along a first direction, and both the first fine gates 20 and the second fine gates 30 extend along a second direction, which intersects the first direction. Specifically, as shown in FIG3, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back-contact solar cell 100, respectively. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, they can be the diagonal directions of the silicon wafer 10, and there is no specific limitation here.

[0059] A first conductive contact structure 40 is disposed within a first region 111 and is connected to a plurality of first fine gates 20. A second fine gate 30 is disconnected at the first conductive contact structure 40. A second conductive contact structure 50 is disposed within a second region 112 and is connected to a plurality of second fine gates 30. A first fine gate 20 is disconnected at the second conductive contact structure 50.

[0060] In the back-contact solar cell 100, cell module 200, and photovoltaic system 1000 of Embodiment 1 of this application, a first conductive contact structure 40 is disposed in a first region 111 and a second region 112 on the back side 11 of the silicon wafer 10, and is connected to a plurality of first fine grids 20. A second conductive contact structure 50 is disposed in the second region 112 and is connected to a plurality of second fine grids 30. The first conductive contact structure 40 and the second conductive contact structure 50 can be used to contact the positive and negative electrode probes of the test equipment, respectively. In this way, by providing a plurality of first conductive contact structures 40 and a plurality of second conductive contact structures 50, the first conductive contact structures 40 and the second conductive contact structures 50 have a larger area than a single first fine grid 20 and a single fine grid 30. When performing hot spot, EL, and other tests on the back-contact solar cell 100, the positive and negative electrode probes of the test equipment can form a stable contact with the first conductive contact structures 40 and the second conductive contact structures 50, reducing the difficulty of testing and improving the reliability and stability of testing. Meanwhile, during subsequent welding of the welding strip, the first conductive contact structure 40 and the second conductive contact structure 50 can serve as welding points with the welding strip. Since the first conductive contact structure 40 and the second conductive contact structure 50 are respectively connected to a number of first fine grids 20 and a number of second fine grids 30, it is not necessary to set welding points or welding layers on all the fine grids during welding, which can reduce the use of welding paste.

[0061] Specifically, it can be understood that in this application, the back side 11 of the silicon wafer 10 has a plurality of first doped layers (not shown) and second doped layers (not shown), which are respectively P-type doped layers and N-type doped layers. A back passivation layer (not shown) is provided on the first doped layers and the second doped layers. A first fine gate 20 is correspondingly disposed above the first doped layer and penetrates the back passivation layer to form an ohmic contact with the first doped layer. A second fine gate 30 is correspondingly disposed on the second doped layer and penetrates the back passivation layer to form an ohmic contact with the second doped layer.

[0062] Taking hot spot testing as an example, when conducting hot spot testing on the back contact solar cell 100 of this application, the positive electrode probe and negative electrode probe of the testing equipment can form stable contact with the first conductive contact structure 40 and the second conductive contact structure 50, respectively. Then, the back contact solar cell 100 is simulated to observe the temperature at various points of the back contact solar cell 100.

[0063] In some embodiments, the area of ​​the first region 111 may be 5-60 mm. 2 That is, the projected area of ​​the first conductive contact structure 40 on the back side 11 can be 5-60 mm². 2 .

[0064] Thus, by setting the area of ​​the first region 111 within this reasonable range, it is possible to avoid the first conductive contact structure 40 failing to form a stable contact with the test probe if the area of ​​the first region 111 is too small, and also to avoid the current collection efficiency being affected if the area of ​​the first region 111 is too large and the area without the metal grid on the back side 11 is too small.

[0065] Specifically, in such an embodiment, the area of ​​the first region 111 may be, for example, 5 mm². 2 10mm 2 15mm 2 20mm 2 25mm 2 30mm 2 35mm 2 40mm 2 45mm 2 50mm 2 55mm 2 60mm 2 Or 5mm 2 -60mm 2 Any value between these ranges is acceptable, and no specific restrictions are imposed here.

[0066] In some embodiments, the area of ​​the second region 112 may be 5-60 mm². 2 That is, the projected area of ​​the second conductive contact structure 50 on the back side 11 can be 5-60 mm². 2 .

[0067] Thus, by setting the area of ​​the second region 112 within this reasonable range, it is possible to avoid the second conductive contact structure 50 failing to form a stable contact with the test probe if the area of ​​the second region 112 is too small, and also to avoid the current collection efficiency being affected if the area of ​​the second region 112 is too large and the area without the metal grid on the back side 11 is too small.

[0068] Specifically, in such an embodiment, the area of ​​the second region 112 may be, for example, 5 mm². 2 10mm 2 15mm 2 20mm 2 25mm 2 30mm 2 35mm 2 40mm 2 45mm 2 50mm 2 55mm 2 60mm 2 5mm 2 -60mm 2Any value between these ranges is acceptable, and no specific restrictions are imposed here.

[0069] In some embodiments, the first conductive contact structure 40 and the second conductive contact structure 50 may both be Pad points, that is, solder points used for welding with solder strips.

[0070] Thus, the first conductive contact structure 40 and the second conductive contact structure 50 can achieve stable and reliable contact with the test probe, and can also serve as solder joints for welding, thereby reducing the number of solder joints during subsequent welding.

[0071] Please refer to Figures 3-5. In some embodiments, the first conductive contact structure 40 may include a plurality of first conductive connecting lines 41 arranged at intervals along the second direction within the first region 111. The first conductive connecting lines 41 are intersected with and connected to a plurality of first fine gates 20.

[0072] Thus, the test probe only needs to contact any one of the first conductive connection lines 41 in the mesh structure within the first region 111 to form a stable electrical contact, thereby improving the reliability of the contact.

[0073] Further, as shown in FIG5, in such an embodiment, a plurality of first conductive connection lines 41 and a plurality of first fine gates 20 form a first filling region 411; or

[0074] As shown in Figure 6, a number of first conductive connecting lines 41 intersect with a number of first fine grids 20 to form a first mesh structure 412.

[0075] Thus, the first conductive connection line 41 and several first fine grids 20 form a first filling region 411 or a first mesh structure 412. During testing, the test probe only needs to contact any one of the first conductive connection lines 41 in the first region 111 or any one of the first conductive connection lines 41 in the first mesh structure 412 and the first fine grid 20 to form a stable electrical contact, thereby improving the reliability of the contact.

[0076] Furthermore, as shown in Figures 6 and 7, in some embodiments, to further improve the contact stability of the test probe, the first conductive contact structure 40 may also include a first conductive material 413 filled in the adjacent first filling region 411 or the first mesh structure 412. This increases the area of ​​the first conductive contact structure 40, thereby enabling the first conductive contact structure 40 to form a more reliable and stable contact with the test probe during testing. In such embodiments, when the first conductive contact structure 40 acts as a solder joint, the reliability of the soldering can be improved.

[0077] Of course, in some embodiments, the first conductive contact structure 40 may not be filled with the first conductive material 413. If the first conductive contact structure 40 is required to act as a solder joint, it can be filled with conductive welding materials such as solder in the first filling area 411 or the first mesh structure 412 during subsequent welding, so as to weld with the solder strip.

[0078] Please refer to Figures 8 and 9. In some embodiments, the second conductive contact structure 50 includes a plurality of second conductive connecting lines 51 arranged at intervals along the second direction within the second region 112. The second conductive connecting lines 51 are intersected with and connected to a plurality of second fine gates 30.

[0079] Thus, the test probe only needs to contact any one of the second conductive connection lines 51 in the mesh structure within the second region 112 to form a stable electrical contact, thereby improving the reliability of the contact.

[0080] Further, as shown in FIG9, in such an embodiment, a plurality of second conductive connection lines 51 and a plurality of second fine gates 30 form a second filling region 511; or

[0081] As shown in Figure 8, a number of second conductive connecting lines 51 intersect with a number of second fine grids 30 to form a second mesh structure 512.

[0082] Thus, the second conductive connection line 51 and several second fine grids 30 form a second filling region 511 or a second mesh structure 512. During testing, the test probe only needs to contact any one of the second conductive connection lines 51 in the second region 112 or any one of the second conductive connection lines 51 in the second mesh structure 512 and the second fine grid 30 to form a stable electrical contact, thereby improving the reliability of the contact.

[0083] Furthermore, as shown in Figures 10 and 11, in some embodiments, to further improve the contact stability of the test probe, the second conductive contact structure 50 may also include a second conductive material 513 filled in the adjacent second filling region 511 or the second mesh structure 512. This increases the area of ​​the second conductive contact structure 50, thereby enabling the second conductive contact structure 50 to form a more reliable and stable contact with the test probe during testing. Furthermore, in such embodiments, when the second conductive contact structure 50 acts as a solder joint, the reliability of the soldering can be improved.

[0084] Of course, in some embodiments, the second conductive contact structure 50 may not be filled with the second conductive material 513. If the second conductive contact structure 50 is required to act as a solder joint, it can be filled with conductive welding materials such as solder in the second filling area 511 or the second mesh structure 512 during subsequent welding, so as to weld with the solder strip.

[0085] Please refer to Figures 3-5. In some embodiments, each first conductive contact structure 40 is connected to 2-7 first fine gates 20.

[0086] In this way, the first conductive contact structure 40 can have a relatively large area. When it acts as a solder joint, the number of solder joints can be reduced by 2-7, thereby reducing the use of solder paste and improving the reliability of the soldering. It can also avoid the problem of too many first fine grids 20 connected to the first conductive contact structure 40, which would result in a large transmission loss.

[0087] Specifically, in such embodiments, the number of first fine gates 20 connected to each first conductive contact structure 40 can be, for example, 2, 3, 4, 5, 6, and 7. For example, as shown in FIG3, there are 7 first fine gates 20 connected to each first conductive contact structure 40.

[0088] Please refer to Figures 3, 8 and 9. In some embodiments, each second conductive contact structure 50 is connected to 2-7 second fine grids 30.

[0089] In this way, the second conductive contact structure 50 can have a relatively large area. When it acts as a solder joint, the number of solder joints can be reduced by 2-7, thereby reducing the use of slurry and improving the reliability of the soldering. It can also avoid the excessive number of second fine grids 30 connected to the second conductive contact structure 50, which would lead to greater transmission loss.

[0090] Specifically, in such embodiments, the number of second fine gates 30 connected to each second conductive contact structure 50 can be, for example, 2, 3, 4, 5, 6, and 7. For example, as shown in FIG3, there are 7 second fine gates 30 connected to each second conductive contact structure 50.

[0091] As described above, in some embodiments, the first conductive contact structure 40 and the second conductive contact structure 50 can both be used for welding to the solder joint. Specifically, the first conductive contact structure 40 can be welded to the solder strip used for merging and outputting the current collected by the first fine grid 20, and the second conductive contact structure 50 can be welded to the solder strip used for merging and outputting the current collected by the second fine grid 30.

[0092] Thus, the first conductive contact structure 40 and the second conductive contact structure 50 can serve as solder joints for the solder strip while achieving stable contact with the test probe, thus enabling functional reuse.

[0093] Specifically, in this case, the specific structures of the first conductive contact structure 40 and the second conductive contact structure 50 can be understood with reference to the above.

[0094] Please refer to Figure 3. In some embodiments, the silicon wafer 10 has a first edge 101 and a second edge 102 along a first direction. Both the first edge 101 and the second edge 102 have a plurality of first conductive contact structures 40 and second conductive contact structures 50.

[0095] At the first edge 101, a plurality of first conductive contact structures 40 and a plurality of second conductive contact structures 50 are arranged alternately along the second direction.

[0096] At the second edge 102, a plurality of first conductive contact structures 40 and a plurality of second conductive contact structures 50 are also arranged alternately along the second direction.

[0097] Thus, by placing both the first conductive contact structure 40 and the second conductive contact structure 50 on the edge of the silicon wafer 10, it is easy to make contact with the test probe.

[0098] Further, referring to Figure 3, in such an embodiment, the first conductive contact structure 40 located at the first edge 101 is connected to the first fine gate 20 closest to the first edge 101, and the second conductive contact structure 50 located at the first edge 101 is connected to the second fine gate 30 closest to the first edge 101; and / or

[0099] The first conductive contact structure 40 located at the second edge 102 is connected to the first fine gate 20 closest to the second edge 102, and the second conductive contact structure 50 located at the second edge 102 is connected to the second fine gate 30 closest to the second edge 102.

[0100] Thus, the first conductive contact structure 40 and the second conductive contact structure 50 are both located at the outermost edge of the first edge 101 and the outermost edge of the second edge 102. When the first conductive contact structure 40 and the second conductive contact structure 50 act as solder joints, they can serve as the starting point and / or the ending point during welding, thereby ensuring the stability of the welding.

[0101] Please refer to Figures 3 and 12. In some embodiments, the first conductive contact structure 40 located at the first edge 101 and the first conductive contact structure 40 located at the second edge 102 are aligned in a first direction.

[0102] The second conductive contact structure 50 located at the first edge 101 and the second conductive contact structure 50 located at the second edge 102 are aligned in the first direction.

[0103] Thus, the first conductive contact structure 40 of the first edge 101 is aligned with the first conductive contact structure 40 of the second edge 102, and the second conductive contact structure 50 of the first edge 101 is aligned with the second conductive contact structure 50 of the second edge 102. The two aligned first conductive contact structures 40 can respectively serve as the starting point and the ending point for welding the solder strip that carries the current of the first fine grid 20, and the two aligned second conductive contact structures 50 can respectively serve as the starting point and the ending point for welding the solder strip that carries the current of the second fine grid 30, thereby ensuring the reliability of the welding, and at the same time, there is no need to set additional starting points and ending points.

[0104] Referring to Figure 12, in some embodiments, between two first conductive contact structures 40 aligned in a first direction, there is also at least one first conductive contact structure 40 aligned with the first conductive contact structure 40 located at the first edge 101 and the second edge 102; and / or

[0105] Between the two second conductive contact structures 50 aligned in the first direction, there is also at least one second conductive contact structure 50 aligned with the second conductive contact structure 50 located at the first edge 101 and the second edge 102.

[0106] Thus, at least one first conductive contact structure 40 is provided between two first conductive contact structures 40 aligned in opposite directions. When the first conductive contact structure 40 acts as a solder joint, it can be welded to the solder joint by at least three first conductive contact structures 40, further ensuring the reliability of the welding. Similarly, at least one second conductive contact structure 50 is provided between two second conductive contact structures 50 aligned in opposite directions. When the second conductive contact structure 50 acts as a solder joint, it can be welded to the solder joint by at least three second conductive contact structures 50, further ensuring the reliability of the welding.

[0107] Please refer to Figures 3 and 4. In some embodiments, the silicon wafer 10 also has a third edge 103 and a fourth edge 104 opposite each other along the second direction, and a first edge busbar 60 is provided at the third edge 103.

[0108] When the conductive contact structure closest to the third edge 103 along the first direction is the first conductive contact structure 40, the first edge busbar 60 connects the portion of the second fine gate 30 that is broken at the first conductive contact structure 40 located at the third edge 103 and at least one second fine gate 30 that is not broken at the first conductive contact structure 40.

[0109] When the conductive contact structure closest to the third edge 103 along the first direction is the second conductive contact structure 50, the first edge busbar 60 connects the portion of the first fine gate 20 that is broken at the second conductive contact structure 50 located at the third edge 103 and at least one first fine gate 20 that is not broken at the first conductive contact structure 40.

[0110] Specifically, the conductive contact structure closest to the third edge 103 along the first direction is the first conductive contact structure 40. When the first conductive contact structure 40 closest to the third edge 103 acts as a solder joint for welding with the solder strip, the second fine gate 30 needs to be disconnected at the first conductive contact structure 40. In this case, the current of the portion of the second fine gate 30 located between the first conductive contact structure 40 and the third edge 103 cannot be collected and converged. In this embodiment, by setting the first edge busbar 60, the current collected by this portion of the second fine gate 30 can be converged to at least one unbroken second fine gate 30, thereby realizing the convergence of the current of this portion of the fine gate and reducing efficiency loss.

[0111] The conductive contact structure closest to the third edge 103 along the first direction is the second conductive contact structure 50. When the second conductive contact structure 50 closest to the third edge 103 acts as a solder joint for welding with the solder strip, the first fine gate 20 needs to be disconnected at the second conductive contact structure 50. In this case, the current of the portion of the first fine gate 20 located between the second conductive contact structure 50 and the third edge 103 cannot be collected and combined. In this embodiment, by setting the first edge busbar 60, the current collected by this portion of the first fine gate 20 can be combined to at least one unbroken first fine gate 20, thereby realizing the current of this portion of the fine gate and reducing efficiency loss.

[0112] Please refer to Figures 3 and 8. In some embodiments, a second edge busbar 70 is provided at the fourth edge 104.

[0113] When the conductive contact structure closest to the fourth edge 104 along the first direction is the first conductive contact structure 40, the second edge busbar 70 connects the portion of the second fine gate 30 that is broken at the first conductive contact structure 40 located at the fourth edge 104 and at least one second fine gate 30 that is not broken at the first conductive contact structure 40.

[0114] When the conductive contact structure closest to the fourth edge 104 along the first direction is the second conductive contact structure 50, the second edge busbar 70 connects the portion of the first fine gate 20 that is broken at the second conductive contact structure 50 located at the fourth edge 104 and at least one first fine gate 20 that is not broken at the first conductive contact structure 40.

[0115] Specifically, the conductive contact structure closest to the fourth edge 104 along the first direction is the first conductive contact structure 40. When the first conductive contact structure 40 closest to the fourth edge 104 acts as a solder joint for welding with the solder strip, the second fine gate 30 needs to be disconnected at the first conductive contact structure 40. In this case, the current of the portion of the second fine gate 30 located between the first conductive contact structure 40 and the fourth edge 104 cannot be collected and combined. In this embodiment, by setting the second edge busbar 70, the current collected by this portion of the second fine gate 30 can be combined to at least one unbroken second fine gate 30, thereby realizing the current of this portion of the fine gate and reducing efficiency loss.

[0116] The conductive contact structure closest to the fourth edge 104 along the first direction is the second conductive contact structure 50. When the second conductive contact structure 50 closest to the fourth edge 104 acts as a solder joint for welding with the solder strip, the first fine gate 20 needs to be disconnected at the second conductive contact structure 50. In this case, the current of the portion of the first fine gate 20 located between the second conductive contact structure 50 and the fourth edge 104 cannot be collected and combined. In this embodiment, by setting the second edge busbar 70, the current collected by this portion of the first fine gate 20 can be combined to at least one unbroken first fine gate 20, thereby realizing the current of this portion of the fine gate and reducing efficiency loss.

[0117] Please refer to Figure 13. In some embodiments, the silicon wafer 10 has a first center line L1 and a second center line L2 that are perpendicular to each other. The first center line L1 is parallel to a second direction, and the second center line L2 is parallel to the first direction. In the first direction, the silicon wafer 10 is symmetrical about the first center line L1, and in the second direction, the silicon wafer 10 is symmetrical about the second center line L2.

[0118] Both the first conductive contact structure 40 and the second conductive contact structure 50 are disposed on the first center line L1. In the first direction, the portions of the first conductive contact structure 40 located on both sides of the first center line L1 are symmetrically arranged about the first center line L1, and the portions of the second conductive contact structure 50 located on both sides of the first center line L1 are also symmetrically arranged about the first center line L1.

[0119] Among them, the first fine grids 20 on both sides of the first center line L1 are symmetrical about the first center line L1, and the second fine grids 30 on both sides of the first center line L1 are also symmetrical about the first center line L1.

[0120] A first conductive contact structure 40 and a second conductive contact structure 50 are provided on both sides of the second center line L2. The first conductive contact structures 40 on both sides of the second center line L2 are symmetrically arranged about the second center line L2, and the second conductive contact structures 50 on both sides of the second center line L2 are also symmetrically arranged about the second center line L2.

[0121] In this way, rotational symmetry of the first conductive contact structure 40 and the second conductive contact structure 50 can be achieved. Thus, during the manufacturing process, after the first conductive contact structure 40 is printed and the first fine grid 20 and the second fine grid 30 are set, the back contact solar cell 100 can be moved and swapped at will without the need for alignment and calibration.

[0122] Specifically, as shown in Figure 13, in this embodiment, the same number of first conductive contact structures 40 (e.g., 1, 2, or 3) are provided on both sides of the second center line L2. The first conductive contact structures 40 on both sides are symmetrical about the second center line L2. The same number of second conductive contact structures 50 are also provided, and the second conductive contact structures 50 on both sides are also symmetrical about the second center line L2. Furthermore, for each conductive contact structure, its center point is located on the first center line L1, and the portions of each conductive contact structure located on both sides of the first center line L1 are symmetrical about the first center line L1.

[0123] Furthermore, in such an embodiment, no additional fine gate may be provided at the first centerline L1. Of course, in order to maximize the utilization of the area of ​​the silicon wafer 10, a central fine gate 80 may also be provided at the first centerline L1. The central fine gate 80 has the same polarity as the fine gates (first fine gate 20 or second fine gate 30, Figure 13 shows the second fine gate 30) of the two edges (i.e., the first edge 101 and the second edge 102) closest to the silicon wafer 10 in the first direction.

[0124] Thus, by setting a central fine gate 80 with the same polarity as the fine gates closest to the first edge 101 and the second edge 102, all fine gates on both sides of the center gate line can be symmetrical about the central fine gate 80, thereby achieving the purpose of being able to move and interchange during the setting of the fine gates. It is easy to understand that in such an embodiment, a doped layer corresponding to its polarity can be present below the central fine gate 80, and the central fine gate 80 penetrates the passivation layer and contacts the underlying doped layer, thereby improving area utilization and current collection capability.

[0125] Specifically, as shown in Figure 13, when the fine gates closest to the first edge 101 and the second edge 102 are both second fine lines 30, the central fine gate 80 is the same gate line as the second fine gate 30. This is equivalent to the first fine gate 20 and the second fine gate 30 being evenly spaced and alternately arranged on the silicon wafer 10, with the fine gates located at the upper and lower edges in the first direction being both second fine gates 30. There are N second fine gates 30, and N-1 first fine gates 20. The extra second gate line 30 is the central fine gate 80 that coincides with the first center line L1. Similarly, when the fine gates closest to the first edge 101 and the second edge 102 are both first fine lines 20, the central fine gate 80 is a fine gate with the same polarity as the first fine gate 20. The specifics will not be elaborated here.

[0126] Please continue referring to Figure 13. In this embodiment, the first conductive contact structure 40 may include a first Pad point 401 located on the first center line L1 and two first connecting lines 402 connected to the two ends of the first Pad point and extending along the first direction. The first connecting lines 402 are connected to at least one first fine gate 20. The second conductive contact structure 50 may include a second Pad point 501 located on the first center line L1 and two second connecting lines 502 connected to the two ends of the second Pad point 501 and extending along the first direction. The second connecting lines 502 are connected to at least one second fine gate 30.

[0127] In this way, stable contact with the probe can be achieved through the pad point, and then a portion of the fine grid can be connected through the connecting wire, thereby achieving stable testing of electrical performance and hot spots.

[0128] Furthermore, in such an embodiment, the width of the first connecting line 402 may be greater than the width of the first fine gate 20, and the width of the second connecting line 502 may be greater than the width of the second fine gate 30. The widths of the first connecting line 402 and the second connecting line 502 refer to their lengths in the second direction, while the widths of the first fine gate 20 and the second fine gate 30 refer to their lengths in the first direction.

[0129] Example 2

[0130] It should be noted that in this application, the structures shown in Figures 14-28 correspond to the content of Embodiment 2, and the component reference numerals in Embodiment 2 correspond to the reference numerals in Figures 14-28.

[0131] Please refer to Figure 14. The back contact solar cell 100 in Embodiment 2 of this application may include a silicon wafer 10, a plurality of first fine grids 20, a plurality of second fine grids 30, a first test contact structure 40, and a second test contact structure 50.

[0132] The silicon wafer 10 has a front side and a back side 11. A plurality of first fine gates 20 and a plurality of second fine gates 30 are disposed on the back side 11 of the silicon wafer 10. The plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged alternately along a first direction. Furthermore, the first fine gates 20 and the second fine gates 30 both extend along a second direction, which intersects the first direction.

[0133] Specifically, as shown in Figure 14, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back-contact solar cell 100, respectively, and they are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, they can be the diagonal directions of the silicon wafer 10, and there is no specific limitation here.

[0134] Please refer to Figure 14. The first test contact structure 40 and the second test contact structure 50 are also located on the back side 11.

[0135] The first test contact structure 40 is electrically connected to all the first fine gates 20 and intersects with a number of second fine gates 30. The second fine gates 30 that intersect with the first test contact structure 40 are disconnected at the first test contact structure 40.

[0136] The second test contact structure 50 is electrically connected to all the second fine gates 30 and intersects with a number of first fine gates 20. The first fine gates 20 that intersect with the second test contact structure 50 are disconnected at the second test contact structure 50.

[0137] The first test contact structure 40 and the second test contact structure 50 are respectively used to contact probes of different polarities in the testing device. For example, the first test contact structure 40 can contact the first probe, and the second test contact structure 50 can contact the second probe, where one of the first probe and the second probe is a positive probe and the other is a negative probe.

[0138] It should be noted that in this application, "the first test contact structure 40 is electrically connected to all the first fine gates 20" means that when in contact with the probe of the test device, all the first fine gates 20 can be electrically connected to the probe of the test device through the first test contact structure 40. The arrangement can be that all the first fine gates 20 and the first test contact structure 40 are directly connected to form a whole, or connected to form a whole through other connection structures (such as the first bus electrode 60 mentioned below) and then electrically connected to the probe through the first test contact structure 40. Alternatively, the first test contact structure 40 can include multiple parts (such as multiple first test parts 41 mentioned below), and each first test part 41 is electrically connected to a portion of the first fine gates 20. During the test, the probes on each first test part 41 are used to electrically connect them, so that all the first fine gates 20 can be electrically connected to the probe of the test device during the test.

[0139] Similarly, "the second test contact structure 50 is conductively connected to all the second fine gates 30" means that when in contact with the probe of the test device, all the second fine gates 30 can be conductively connected to the probe of the test device through the second test contact structure 50. This can be achieved by directly connecting all the second fine gates 30 to the second test contact structure 50 as a whole, or by connecting them to the probe through other connecting structures (such as the second bus electrode 70 mentioned below), or by the second test contact structure 50 comprising multiple parts (such as multiple second test sections 51 mentioned below), each of which is conductively connected to a portion of the second fine gates 30. During the test, the probes on each second test section 51 are used to connect them, thus ensuring that all the second fine gates 30 are conductively connected to the probe of the test device during the test. The test device can be an IV test device, an EL test device, or similar equipment.

[0140] Furthermore, in this application, the intersection of the fine grid with other structural components (such as the test contact structure mentioned above, the test section mentioned below, etc.) can be understood as the fine grid being directly connected to other structures in the second direction and having an intersection point, or the extension line of the fine grid in the second direction intersecting with other structures and having an intersection point.

[0141] Furthermore, in this application, the term "the fine gates intersecting the test contact structure are broken at the test contact structure" means that the fine gates are discontinuous at the test contact structure, or that the fine gates intersecting the test contact structure only extend to one side of the test contact structure.

[0142] In the back-contact solar cell 100, cell module 200, and photovoltaic system 1000 of Embodiment 2 of this application, a first test contact structure 40 and a second test contact structure 50 are provided on the silicon wafer 10 for contacting probes of different polarities of the testing device. The first test contact structure 40 is electrically connected to all the first fine grids 20, and the second test contact structure 50 is electrically connected to all the second fine grids 30. Thus, by setting the first test contact structure 40 and the second test contact structure 50, the areas of the first test contact structure 40 and the second test contact structure 50 are larger than those of a single first fine grid 20 and a single fine grid 30. When performing electrical performance tests (e.g., IV tests), EL tests, and hot spot tests on the back-contact solar cell 100, the positive and negative electrode probes of the testing device can form stable contacts with the first test contact structure 40 and the second test contact structure 50, respectively, reducing the difficulty of testing and improving the reliability and stability of testing.

[0143] Specifically, it can be understood that in this application, the back surface 11 of the silicon wafer 10 has a plurality of first doped layers (not shown) and second doped layers (not shown), which are respectively P-type doped layers and N-type doped layers. A back passivation layer (not shown) is provided on the first and second doped layers. A first fine gate 20 is correspondingly disposed above the first doped layer and penetrates the back passivation layer to form an ohmic contact with the first doped layer. A second fine gate 30 is correspondingly disposed on the second doped layer and penetrates the back passivation layer to form an ohmic contact with the second doped layer. That is, the first fine gate 20 and the second fine gate 30 have opposite polarities, one of which is a positive fine gate and the other is a negative fine gate.

[0144] Taking IV testing as an example, when performing IV testing on the back contact solar cell 100 of this application, the positive electrode probe and the negative electrode probe of the testing device can form stable contact with the first test contact structure 40 and the second test contact structure 50, respectively, so as to obtain the IV test data of the back contact solar cell 100.

[0145] Taking hot spot testing as an example, when conducting hot spot testing on the back contact solar cell 100 of this application, the positive electrode probe and negative electrode probe of the testing device can form stable contact with the first test contact structure 40 and the second test contact structure 50 respectively, and then simulate the scenario where the back contact solar cell 100 is shaded to observe the temperature at various points of the back contact solar cell 100.

[0146] Please continue to refer to Figure 14. In some embodiments, the first test contact structure 40 may include a plurality of first test sections 41 arranged at intervals. Each first test section 41 is corresponding to intersecting with a plurality of first fine grids 20 and a plurality of second fine grids 30. The second fine grids 30 that intersect with the first test section 41 are disconnected at the first test section 41.

[0147] The second test contact structure 50 includes a plurality of second test sections 51 arranged at intervals. Each first test section 41 is corresponding to intersecting with a plurality of first fine grids 20 and a plurality of second fine grids 30. The first fine grids 20 intersecting with the second test sections 51 are disconnected at the second test sections 51.

[0148] Thus, during testing, each first test section 41 and second test section 51 can contact one or more test probes, thereby enabling all first fine gates 20 to conduct with one polarity of the testing device, and enabling all second fine gates 30 to conduct with the other polarity of the testing device. Simultaneously, by configuring the first test contact structure 40 to include a plurality of spaced-apart first test sections 41, and the second test contact structure 50 to include a plurality of spaced-apart second test sections 51, multiple shorter transmission paths can be provided during testing, reducing losses and improving test accuracy.

[0149] Specifically, in such an embodiment, each first test section 41 and each second test section 51 can be in contact with a corresponding probe. The test device has a probe array. During the test, the probes on the probe array with the same polarity as the first test section 41 are in contact with the first test section 41 and conduct electricity. The probes on the probe array with the same polarity as the second test section 51 are in contact with the second test section 51 and conduct electricity. The probes with the same polarity on the probe array conduct electricity together.

[0150] In some embodiments, the area of ​​a single first test portion 41 and a single second test portion 51 may be 1.5 mm. 2 -20mm 2 .

[0151] Thus, by setting the areas of the first test section 41 and the second test section 51 within this reasonable range, it is possible to avoid the first test section 41 and the second test section 51 being too small, which would prevent the first test section 41 and the second test section 51 from forming a stable contact with the test probe. It is also possible to avoid the first test section 41 and the second test section 51 being too large, which would result in a small area on the back side 1111 where no metal grid is set, thus affecting the current collection efficiency.

[0152] Specifically, in such an embodiment, the area of ​​the first test section 41 and the second test section 51 can be, for example, 1.5 mm². 2 2mm 2 2.5mm 2 2.78mm 2 3mm 2 3.5mm 2 4mm 2 4.5mm 2 5mm 2 5.5mm 2 6mm 2 6.5mm 2 7.5mm 2 8mm 2 8.5mm 2 9mm 2 9.5mm 2 10mm 2 11mm 2 12mm 2 13mm 2 14mm 2 15mm 2 16mm 2 17mm 2 18mm 2 19mm 2 20mm 2 Or 1.5mm2 -20mm 2 Any value between these ranges is acceptable, and no specific restrictions are imposed here.

[0153] It should be noted that, in the embodiments of this application, both the first test section 41 and the second test section 51 can be filled with solid points of welding material or metal material, or they can be a mesh structure composed of multiple metal wires, and no specific limitation is made here.

[0154] Please refer to Figure 14. In some embodiments, the silicon wafer 10 has a first edge 101 and a second edge 102 at both ends in the second direction. A first bus electrode 60 is provided at the first edge 101, and a second bus electrode 70 is provided at the second edge 102.

[0155] The first bus electrode 60 is electrically connected to all the first fine gates 20, and the second bus electrode 70 is electrically connected to all the second fine gates 30.

[0156] Thus, by setting the first bus electrode 60 and the second bus electrode 70 at the first edge 101 and the second edge 102 respectively, the first bus electrode 60 can connect all the first fine gates 20 into a whole, and then conduct to the probe through a plurality of first test parts 41. The second bus electrode 70 can connect all the second fine gates 30 into a whole, and then conduct to the probe through a plurality of first test parts 41.

[0157] Specifically, as shown in Figure 14, in this embodiment, the first bus electrode 60 is disposed close to the first edge 101, and all the first fine gates 20 and all the second fine gates 30 are located on the side of the first bus electrode 60 facing the second edge 102. The second bus electrode 70 is disposed close to the second edge 102, and all the first fine gates 20 and all the second fine gates 30 are located on the side of the second bus electrode 70 facing the first edge 101. That is to say, in this embodiment, the first bus electrode 60 and the second bus electrode 70 are respectively located at the two end positions of the first fine gates 20 and the second fine gates 30 in the first direction. There are no fine gates between the first bus electrode 60 and the first edge 101, and there are no fine gates between the second bus electrode 70 and the second edge 102.

[0158] Furthermore, in such embodiments, the first bus electrode 60 and the second bus electrode 70 may not penetrate the back passivation layer to contact the underlying doped layer, but may only serve the function of bus conduction. Alternatively, the first bus electrode 60 may only contact the doped layer located below the first bus electrode 60 and having the same polarity as the first bus electrode 60, and the second bus electrode 70 may only contact the doped layer located below the second bus electrode 70 and having the same polarity as the second bus electrode 70.

[0159] In some embodiments, in the second direction, the distance between the first bus electrode 60 and the first edge 101 is 0.5 mm to 2 mm.

[0160] Thus, by setting the distance between the first bus electrode 60 and the first edge 101 within this reasonable range, it is possible to effectively avoid excessive efficiency loss caused by an excessively large distance between the two, which would result in an excessively large area of ​​the edge region without fine grids.

[0161] Specifically, in such an embodiment, the distance between the first bus electrode 60 and the first edge 101 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or 0.5mm-2mm, and is not limited here.

[0162] Similarly, in some embodiments, in the second direction, the distance between the second bus electrode 70 and the second edge 102 is 0.5mm-2mm.

[0163] Thus, by setting the distance between the second bus electrode 70 and the second edge 102 within this reasonable range, it is possible to effectively avoid excessive efficiency loss caused by an excessively large distance between the two, which would result in an excessively large area of ​​the edge region without fine grids.

[0164] Specifically, in such an embodiment, the distance between the second bus electrode 70 and the second edge 102 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or 0.5mm-2mm, and is not limited here.

[0165] In some embodiments, the width of the first bus electrode 60 is greater than the width of the first fine gate 20, and the width of the second bus electrode 70 is greater than the width of the second fine gate 30.

[0166] Thus, by thickening the width of the first bus electrode 60 and the second bus electrode 70, transmission loss can be reduced.

[0167] Further, referring to Figures 14 and 15, in some embodiments, the second fine gate 30 includes a first discontinuous fine gate 31 and a first continuous fine gate 32. The first continuous fine gate 32 does not intersect with the first test section 41, while the first discontinuous fine gate 31 intersects with and is insulated from the first test section 41. At least a portion of the first discontinuous fine gate 31 forms a first gate segment 35 between the first test section 41 and the first bus electrode 60. The first gate segment 35 is insulated from the first test section 41 and the first bus electrode 60. The first gate segment 35 is connected to the first continuous fine gate 32 closest to the first gate segment 35.

[0168] It is understandable that, since the first grid segment 35 has the opposite polarity to the first test section 41, the first grid segment 35 is an isolated grid segment located between the first test section 41 and the first edge 101, and the current collected by it cannot be efficiently channeled. Therefore, in this embodiment, by connecting the first grid segment 35 to the adjacent first continuous fine grid 32, the current collected by the first grid segment 35 can be channeled to the adjacent first continuous fine grid 32 to achieve current channeling, thereby improving the efficiency of the back contact solar cell 100.

[0169] Further, referring to FIG15, in such an embodiment, the first fine grid 20 located between the first grid line segment 35 and the first continuous fine grid 32 closest to the first grid line segment 35 has a first partition region 23, and the first grid line segment 35 and the first continuous fine grid 32 closest to the first grid line segment 35 are connected by a first connecting line 80 passing through the first partition region 23 along a first direction.

[0170] Thus, by setting up the first partition zone 23 and the first connecting line 80, the first grid segment 35 can be connected and transmitted, improving efficiency.

[0171] Specifically, in such an embodiment, the first connection line 80 may not penetrate the back passivation layer and contact the underlying doped layer to avoid contact with doped layers of different polarities, which could lead to leakage. That is, in such an embodiment, the first connection line 80 may only serve as a current-carrying conductor and may not contact the doped layer.

[0172] Of course, such embodiments are only preferred embodiments. It is understood that in some embodiments, the first gate segment 35 may not be connected to the adjacent first continuous fine gate 32 to realize current convergence (that is, the first isolation area 23 and the first connecting line 80 are not set), but the current transmission convergence is realized through the body area. No specific restrictions are made here.

[0173] Referring to Figure 15, in some embodiments, the number of first fine grids 20 intersecting each first test section 41 is 3, and the number of second fine grids 30 intersecting each first test section 41 is 2.

[0174] In this way, while ensuring the area of ​​the first test section 41, it is possible to avoid excessive number of first grid segments 35, which would lead to significant efficiency loss. At the same time, it is also unnecessary to open the first discontinuity region 23 on a large number of first fine grids 20.

[0175] Further, referring to Figures 14 and 16, in some embodiments, the first fine gate 20 may include a second discontinuous fine gate 21 and a second continuous fine gate 22. The second continuous fine gate 22 does not intersect with the second test section 51, while the second discontinuous fine gate 21 intersects with and is insulated from the second test section 51. At least a portion of the second discontinuous fine gate 21 forms a second gate segment 25 between the second test section 51 and the second bus electrode 70. The second gate segment 25 is insulated from the second test section 51 and the second bus electrode 70. The second gate segment 25 is connected to the second continuous fine gate 22 closest to the second gate segment 25.

[0176] It is understandable that, since the second grid segment 25 has the opposite polarity to the second test section 51, the second grid segment 25 is an isolated grid segment located between the second test section 51 and the second edge 102, and the current collected by it cannot be efficiently collected. Therefore, in this embodiment, by connecting the second grid segment 25 to the adjacent second continuous fine grid 22, the current collected by the second grid segment 25 can be collected into the adjacent second continuous fine grid 22, thereby improving the efficiency of the back contact solar cell 100.

[0177] Further, referring to FIG16, in such an embodiment, the second fine grid 30 located between the second grid line segment 25 and the second continuous fine grid 22 closest to the second grid line segment 25 has a second partition region 33, and the second grid line segment 25 and the second continuous fine grid 22 closest to the second grid line segment 25 are connected by a second connecting line 90 passing through the second partition region 33 along the first direction.

[0178] Thus, by setting the second partition zone 33 and the second connecting line 90, the bus transmission of the second grid segment 25 can be realized, improving efficiency.

[0179] Specifically, in such an embodiment, the second connection line 90 may not penetrate the back passivation layer and contact the underlying doped layer to avoid contact with doped layers of different polarities, which could lead to leakage. In other words, in such an embodiment, the second connection line 90 may only serve as a current-carrying conductor and may not contact the doped layer.

[0180] Of course, it is easy to understand that such an embodiment is only a preferred embodiment. It is understood that in some embodiments, the second gate segment 25 may not be connected to the adjacent first continuous fine gate 32 to realize current convergence (that is, the second partition area 33 and the second connecting line 90 are not provided), but the current transmission convergence is realized through the body area. The specifics are not limited here.

[0181] Referring to Figure 16, in some embodiments, the number of second fine grids 30 intersecting each second test section 51 is 3, and the number of first fine grids 20 intersecting each second test section 51 is 2.

[0182] In this way, while ensuring the area of ​​the second test section 51, it is possible to avoid excessive number of second grid segments 25, which would lead to significant efficiency loss. At the same time, it is not necessary to open the second discontinuity region 33 on a large number of second fine grids 30.

[0183] Please refer to Figures 17 and 18. In some embodiments, in the first discontinuous fine grid 31 that intersects with the first test section 41, at least one of the first discontinuous fine grids 31 does not extend between the first test section 41 and the first bus electrode 60.

[0184] On the extension line of the first discontinuous fine grid 31 that does not extend between the first test section 41 and the first busbar electrode 60, the back contact solar cell 100 is provided with a first enhancement electrode 110. The first enhancement electrode 110 is located between the first test section 41 and the first busbar electrode 60 and its two ends are respectively connected to the first busbar electrode 60 and the first test section 41.

[0185] Thus, by setting the first reinforcing electrode 110, the loss during the process of current flowing to the first test section 41 can be reduced, and the efficiency can be improved.

[0186] Specifically, as shown in FIG18, the difference between this embodiment and the embodiment shown in FIG14 is that one or more of the first gate segments 35 in FIG14 are replaced with a first enhancement electrode 110 connecting the first bus electrode 60 and the first test section 41. The first enhancement electrode 110 may not penetrate the back passivation layer and contact the doped layer below to avoid short circuit.

[0187] In such an embodiment, to further reduce transmission loss, conductive material can be filled in the spacer region formed by the first reinforcing electrode 110 and the two adjacent first fine gates 20.

[0188] In such an embodiment, since the carriers in the doped layer below the first enhancement electrode 110 cannot be directly collected by the second fine gate 30, but can only be collected by the second fine gate 30 through transverse transport in the body region, in order to ensure efficiency, as shown in FIG18, in this application, each first test section 41 can preferably be provided with only one first enhancement electrode 110.

[0189] In some embodiments, the width of the first enhancement electrode 110 is greater than the width of the first fine gate 20 and the second fine gate 30. Thus, by thickening the width of the first enhancement electrode 110, transmission loss can be reduced.

[0190] Please refer to Figures 17 and 19. In some embodiments, in the second discontinuous fine grid 21 that intersects with the second test section 51, at least one second discontinuous fine grid 21 does not extend between the second test section 51 and the second bus electrode 70.

[0191] On the extension line of the second discontinuous fine grid 21 that does not extend between the second test section 51 and the second busbar electrode 70, the back contact solar cell 100 is provided with a second enhancement electrode 120. The second enhancement electrode 120 is located between the second test section 51 and the second busbar electrode 70 and its two ends are respectively connected to the second busbar electrode 70 and the second test section 51.

[0192] Thus, by setting the second reinforcing electrode 120, the loss during the process of current flowing to the second test section 51 can be reduced, and the efficiency can be improved.

[0193] Specifically, as shown in FIG19, the difference between this embodiment and the embodiment in FIG15 is that one or more of the second gate segments 25 in FIG15 are replaced with a second enhancement electrode 120 connecting the second bus electrode 70 and the second test section 51. The second enhancement electrode 120 may not penetrate the back passivation layer and contact the doped layer below to avoid short circuit.

[0194] In such an embodiment, to further reduce transmission loss, conductive material can be filled in the spacer region formed by the second reinforcing electrode 120 and the two adjacent second fine gates 30.

[0195] In such an embodiment, since the carriers in the doped layer below the second enhancement electrode 120 cannot be directly collected by the first fine gate 20, but can only be collected by the first fine gate 20 through transverse transport in the body region, in order to ensure efficiency, as shown in FIG19, in this application, each second test section 51 can preferably be provided with only one second enhancement electrode 120.

[0196] In some embodiments, the width of the second enhancement electrode 120 is greater than the width of the first fine gate 20 and the second fine gate 30. Thus, by thickening the width of the second enhancement electrode 120, transmission loss can be reduced.

[0197] Referring to Figure 20, in some embodiments, the silicon wafer 10 has a first edge 101 and a second edge 102 at both ends in the second direction, and a third edge 103 and a fourth edge 104 at both ends in the first direction.

[0198] Along the direction from the third edge 103 toward the fourth edge 104, the back surface 11 includes a first edge region 105, a middle region 107, and a second edge region 106. The first test part 41 disposed in the first edge region 105 is a first edge test part 411, the first test part 41 disposed in the second edge region 106 is a second edge test part 412, and the first test part 41 disposed in the middle region 107 is a first middle test part 413.

[0199] In this configuration, the first edge testing section 411 is electrically connected to all the first fine gates 20 in the first edge region 105. The second fine gates 30 in the first edge region 105 that intersect with the first edge testing section 411 each have a first isolated segment 36 between the first edge testing section 411 and the first edge 101. In the first edge region 105, a first connecting electrode 130 is provided at the first edge 101 that is connected to all the first isolated segments 36. The first connecting electrode 130 is also electrically connected to the second fine gates 30 in the first edge region 105 that do not intersect with the first edge testing section 411.

[0200] The second edge test section 412 is electrically connected to all the first fine gates 20 in the second edge region 106. The second fine gates 30 in the second edge region 106 that intersect with the second edge test section 412 have second isolated segments 37 between the second edge test section 412 and the first edge 101. In the second edge region 106, a second connecting electrode 140 is provided at the first edge 101 that is connected to all the second isolated segments 37. The second connecting electrode 140 is electrically connected to the second fine gates 30 in the second edge region 106 that do not intersect with the second edge test section 412.

[0201] Within the intermediate region 107, a third connecting electrode 150 is also provided at the first edge 101, and the third connecting electrode 150 connects all the first fine grids 20 within the intermediate region 107.

[0202] Thus, by setting the first connecting electrode 130 and the second connecting electrode 140, the isolated segments in the upper and lower edge regions can be connected, and by setting the third connecting electrode 150, all the first fine grids 20 in the middle region 107 can be connected.

[0203] Specifically, in such an embodiment, the first connecting electrode 130, the third connecting electrode 150, and the second connecting electrode 140 can all extend along a first direction and be arranged at intervals. The first connecting electrode 130, the third connecting electrode 150, and the second connecting electrode 140 can all be located at the end positions of the first fine gate 20 and the second fine gate 30, and there can be no fine gate between the first connecting electrode 130, the third connecting electrode 150, and the second connecting electrode 140 and the first edge 101.

[0204] Furthermore, in such an embodiment, in the second direction, the distance between the first connecting electrode 130, the third connecting electrode 150, and the second connecting electrode 140 and the first edge 101 can be 0.5mm-2mm.

[0205] In this way, we can effectively avoid excessive efficiency loss caused by excessively large spacing, which would result in an excessively large area of ​​the edge region without fine grids.

[0206] Specifically, in such an embodiment, the distance between the first connecting electrode 130, the third connecting electrode 150, the second connecting electrode 140 and the first edge 101 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or 0.5mm-2mm, and is not limited here.

[0207] In some implementations, the widths of the first connecting electrode 130, the third connecting electrode 150, and the second connecting electrode 140 are greater than the widths of the first fine gate 20 and the second fine gate. This reduces transmission loss.

[0208] In such an embodiment, to ensure that all first fine gates 20 can be combined for test bus output during the test, and all second fine gates 30 can also be combined for test bus output, the following two embodiments can be used:

[0209] First embodiment: Referring to FIG20, in some embodiments, a fourth connecting electrode 160 may be provided at the second edge 102, and the fourth connecting electrode 160 may be electrically connected to all the second test sections 51 and all the second fine gates 30.

[0210] In this configuration, both the first connecting electrode 130 and the second connecting electrode 140 can be directly connected to the fourth connecting electrode 160 via the second fine gate 30, thereby connecting all the second fine gates 30 together to conduct with the probe. For the bus output of the first fine gate 20, conduction of all the first fine gates 20 can be achieved during testing by connecting them to the probes on the first edge test section 411, the second edge test section 412, and the first intermediate test section 413.

[0211] That is to say, in such an embodiment, the first connecting electrode 130, the second connecting electrode 140 and the third connecting electrode 150 replace the first bus electrode 60 mentioned above, while the fourth connecting electrode 160 is equivalent to the second bus electrode 70 mentioned above.

[0212] In some implementations, the width of the fourth connecting electrode 160 is greater than the width of the first fine gate 20 and the second fine gate. This reduces transmission loss.

[0213] In some embodiments, in the second direction, the distance between the fourth connecting electrode 160 and the second edge 102 may be 0.5mm-2mm.

[0214] Specifically, in such an embodiment, the distance between the fourth connecting electrode 160 and the second edge 102 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or 0.5mm-2mm, and is not limited here.

[0215] Second embodiment: Please refer to FIG21. In some embodiments, the second test part 51 provided in the first edge region 105 is the third edge test part 511, the second test part 51 provided in the second edge region 106 is the fourth edge test part 512, and the second test part 51 provided in the middle region 107 is the second middle test part 513.

[0216] In this context, the third edge test section 511 is cross-connected with all the second fine gates 30 in the first edge region 105. The first fine gates 20 in the first edge region 105 that cross the third edge test section 511 have a fourth isolated segment 26 between the third edge test section 511 and the first edge 101. In the first edge region 105, a fifth connecting electrode 190 is provided at the second edge 102, which is connected to all the fourth isolated segments 26. The fifth connecting electrode 190 is also electrically connected to the first fine gates 20 in the first edge region 105 that do not cross the third edge test section 511.

[0217] The fourth edge test section 512 is cross-connected with all the first fine gates 20 in the second edge region 106. The second fine gates 30 in the second edge region 106 that cross the fourth edge test section 512 have a fifth isolated segment 27 between the fourth edge test section 512 and the first edge 101. In the second edge region 106, a sixth connecting electrode 1100 is provided at the second edge 102 that is connected to all the fifth isolated segments 27. The sixth connecting electrode 1100 is electrically connected to the first fine gates 20 in the second edge region 106 that do not cross the fourth edge test section 512.

[0218] The fifth connecting electrode 190 and the sixth connecting electrode 1100 are both connected to the third connecting electrode 150 through the first fine grid 20;

[0219] Within the intermediate region 107, a seventh connecting electrode 1110 is also provided at the second edge 102, which connects all the second fine grids 30 within the intermediate region 107.

[0220] In this configuration, a first connecting electrode 130 and a fifth connecting electrode 190 are disposed on both sides of the first edge region 105, a second connecting electrode 140 and a sixth connecting electrode 1100 are disposed on both sides of the second edge region 106, and a third connecting electrode 150 and a seventh connecting electrode 1110 are disposed on both sides of the middle region 107. Both the fifth connecting electrode 190 and the sixth connecting electrode 1100 are connected to the third connecting electrode 150 via the first fine grid 20, allowing all the first fine grids 20 to be directly connected together. For the bus output of the second fine grids 30, conduction of all the second fine grids 30 can be achieved during testing by connecting them to probes on the third edge test section 511, the fourth edge test section 512, and the second middle test section 513.

[0221] Specifically, in such an embodiment, the fifth connecting electrode 190, the seventh connecting electrode 1110, and the sixth connecting electrode 1100 can all extend along a first direction and be arranged at intervals. The fifth connecting electrode 190, the seventh connecting electrode 1110, and the sixth connecting electrode 1100 can all be located at the end positions of the first fine gate 20 and the second fine gate 30, and there can be no fine gate between the fifth connecting electrode 190, the seventh connecting electrode 1110, and the sixth connecting electrode 1100 and the second edge 102.

[0222] Furthermore, in such an embodiment, in the second direction, the distance between the fifth connecting electrode 190, the seventh connecting electrode 1110 and the sixth connecting electrode 1100 and the second edge 102 can be 0.5mm-2mm.

[0223] In this way, we can effectively avoid excessive efficiency loss caused by excessively large spacing, which would result in an excessively large area of ​​the edge region without fine grids.

[0224] Specifically, in such an embodiment, the distances between the fifth connecting electrode 190, the seventh connecting electrode 1110, and the sixth connecting electrode 1100 and the second edge 102 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, or 0.5mm-2mm, and are not limited herein.

[0225] In some embodiments, the widths of the fifth connecting electrode 190, the seventh connecting electrode 1110, and the sixth connecting electrode 1100 are greater than the widths of the first fine gate 20 and the second fine gate. This reduces transmission loss.

[0226] Referring to Figure 22, in some embodiments, in the intermediate region 107, the second fine gate 30, which at least partially intersects the first intermediate test section 413, has a third isolated segment 38 (similar to the first gate line segment 35 mentioned above) between the first intermediate test section 413 and the third connecting electrode 150. The third isolated segment 38 and the second fine gate 30 (similar to the first continuous fine gate 32 mentioned above) closest to the third isolated segment 38 and not intersecting the first intermediate test section 413 are connected.

[0227] Understandably, because the third isolated segment 38 has the opposite polarity to the first intermediate test section 413, and is an isolated grid line segment located between the first intermediate test section 413 and the first edge 101, the current collected by the third isolated segment 38 cannot be efficiently collected. Therefore, in this embodiment, by connecting the third isolated segment 38 to the adjacent second fine grid 30, the current collected by the third isolated segment 38 can be collected into the adjacent second fine grid 30, thereby improving the efficiency of the back contact solar cell 100.

[0228] Further, referring to FIG22, in such an embodiment, the first grid 20 located between the third isolated segment 38 and the second grid 30 closest to the third isolated segment 38 has a first discontinuity 24 (similar to the first partition 23 mentioned above), and the third isolated segment 38 and the first grid 20 closest to the third isolated segment 38 are connected by a first busbar 170 (similar to the first connecting line 80 mentioned above) passing through the first discontinuity 24 in a first direction.

[0229] Thus, by setting up the first interruption zone 24 and the first bus line 170, the bus transmission of the third isolated segment 38 can be realized, improving efficiency.

[0230] Specifically, in such an embodiment, the first bus line 170 may not penetrate the back passivation layer and contact the underlying doped layer to avoid contact with doped layers of different polarities, which could lead to leakage. In other words, in such an embodiment, the first bus line 170 may only serve the function of current collection and transmission and may not contact the doped layer.

[0231] Of course, such embodiments are only preferred embodiments. It is understood that in some embodiments, the third isolated segment 38 may not be connected to the adjacent first fine gate 20 to realize current convergence (that is, the first discontinuity section 24 and the first bus line 170 are not set), but the current transmission and convergence are realized through the body region. No specific restrictions are made here.

[0232] In some embodiments, the number of first fine gates 20 intersecting each first intermediate test section 413 is 3, and the number of second fine gates 30 intersecting each first intermediate test section 413 is 2.

[0233] In this way, while ensuring the area of ​​the first intermediate test section 413, it is possible to avoid excessive number of third isolated sections 38, which would result in significant efficiency loss. At the same time, it is not necessary to open the first discontinuity section 24 on a large number of first fine grids 20.

[0234] Referring to Figure 23, in some embodiments, in the second fine gate 30 that intersects with the first intermediate test section 413, at least one second fine gate 30 does not extend between the first intermediate test section 413 and the third connecting electrode 150 (that is, at least one second fine gate 30 does not have the third isolated segment 38).

[0235] In this case, on the extension line of the second fine grid 30 that does not extend between the first intermediate test section 413 and the third connecting electrode 150, the back contact solar cell 100 is provided with a first transmission electrode 180 (similar to the first enhancement electrode 110 mentioned above). The first transmission electrode 180 is located between the first intermediate test section 413 and the third connecting electrode 150 and its two ends are respectively connected to the first intermediate test section 413 and the third connecting electrode 150.

[0236] Thus, by setting the first transmission electrode 180, the loss during the process of converging to the first test section 41 can be reduced, and the efficiency can be improved.

[0237] Specifically, as shown in FIG23, the difference between this embodiment and the embodiment in FIG22 is that one or more of the third isolated segments 38 in FIG22 are replaced with the first transmission electrode 180 connecting the third connection electrode 150 and the first intermediate test section 413. The first transmission electrode 180 may not penetrate the back passivation layer and contact the doped layer below to avoid short circuit.

[0238] In such an embodiment, to further reduce transmission loss, conductive material can be filled in the spacer region formed by the first transmission electrode 180 and the two adjacent first fine gates 20.

[0239] In some embodiments, the width of the first transmission electrode 180 is greater than the width of the first fine gate 20 and the second fine gate 30. Thus, by thickening the width of the first transmission electrode 180, transmission loss can be reduced.

[0240] Referring to Figures 21 and 24, in some embodiments, in the intermediate region 107, the first fine gate 20, which at least partially intersects the second intermediate test section 513, has a sixth isolated segment 28 (similar to the second gate line segment 25 mentioned above) between the second intermediate test section 513 and the seventh connecting electrode 1110. The sixth isolated segment 28 and the first fine gate 20 (similar to the second continuous fine gate 22 mentioned above) closest to the sixth isolated segment 28 and not intersecting the second intermediate test section 513 are connected.

[0241] Understandably, because the sixth isolated segment 28 has the opposite polarity to the second intermediate test section 513, and is an isolated grid line segment located between the second intermediate test section 513 and the first edge 101, the current collected by the sixth isolated segment 28 cannot be efficiently collected. Therefore, in this embodiment, by connecting the sixth isolated segment 28 to the adjacent first fine grid 20, the current collected by the sixth isolated segment 28 can be collected into the adjacent first fine grid 20, thereby improving the efficiency of the back contact solar cell 100.

[0242] Referring to Figure 24, in some embodiments, the second grid 30 located between the sixth isolated segment 28 and the first grid 20 closest to the sixth isolated segment 28 has a second discontinuity 34 (similar to the first discontinuity 23 mentioned above), and the sixth isolated segment 28 and the first grid 20 closest to the sixth isolated segment 28 are connected by a second bus line 1120 (similar to the second connecting line 90 mentioned above) passing through the second discontinuity 34 in a first direction.

[0243] Thus, by setting up the second interruption zone 34 and the second bus line 1120, the bus transmission of the sixth isolated segment 28 can be realized, improving efficiency.

[0244] Specifically, in such an embodiment, the second bus 1120 may not penetrate the back passivation layer and contact the underlying doped layer to avoid contact with doped layers of different polarities, which could lead to leakage. In other words, in such an embodiment, the second bus 1120 may only serve the function of current collection and transmission and may not contact the doped layer.

[0245] Of course, such embodiments are only preferred embodiments. It is understood that in some embodiments, the sixth isolated segment 28 may not be connected to the adjacent first fine gate 20 to realize current convergence (that is, the second discontinuity section 34 and the second bus line 1120 are not provided), but the current convergence is realized through the body region. No specific restrictions are made here.

[0246] Referring to Figure 24, in some embodiments, the number of second fine grids 30 intersecting each second intermediate test section 513 is 3, and the number of first fine grids 20 intersecting each second intermediate test section 513 is 2.

[0247] In this way, while ensuring the area of ​​the second intermediate test section 513, it is possible to avoid excessive number of sixth isolated sections 28, which would lead to significant efficiency loss.

[0248] Referring to Figure 25, in some embodiments, in the first fine gate 20 that intersects with the second intermediate test section 513, at least one of the first fine gates 20 does not extend between the second intermediate test section 513 and the seventh connecting electrode 1110.

[0249] On the extension line of the first fine grid 20 that does not extend between the second intermediate test section 513 and the seventh connecting electrode 1110, the back contact solar cell 100 is provided with a second transmission electrode 1130 (similar to the first enhancement electrode 110 mentioned above). The second transmission electrode 1130 is located between the second intermediate test section 513 and the seventh connecting electrode 1110 and its two ends are respectively connected to the second intermediate test section 513 and the seventh connecting electrode 1110.

[0250] Thus, by setting the second transmission electrode 1130, the loss during the process of merging to the first test section 41 can be reduced, and the efficiency can be improved.

[0251] Specifically, as shown in FIG25, the difference between this embodiment and the embodiment in FIG24 is that one or more of the sixth isolated segments 28 in FIG24 are replaced with the second transmission electrode 1130 connecting the seventh connecting electrode 1110 and the second intermediate test section 513. The second transmission electrode 1130 may not penetrate the back passivation layer and contact the doped layer below to avoid short circuit.

[0252] In such an embodiment, to further reduce transmission loss, conductive material can be filled in the spacer region formed by the second transmission electrode 1130 and the two adjacent second fine gates 30.

[0253] In some embodiments, the width of the second transmission electrode 1130 is greater than the width of the first fine gate 20 and the second fine gate 30. Thus, by thickening the width of the second transmission electrode 1130, transmission loss can be reduced.

[0254] Please refer to Figures 14, 17, 20, and 21. In some embodiments, all first test sections 41 are disposed close to the first edge 101 (i.e., the distance between the first test section 41 and the first edge 101 is less than the distance between the first test section 41 and the second edge 102) and are arranged in a row at intervals in the first direction.

[0255] All second test sections 51 are positioned close to the second edge 102 (i.e., the distance between the second test section 51 and the second edge 102 is less than the distance between the second test section 51 and the first edge 101) and are arranged in a row in the first direction.

[0256] In this way, by arranging the first test section 41 in a row and the second test section 51 in a row, the process difficulty in the preparation process can be reduced.

[0257] In such an embodiment, the first test section 41 is used for welding with the solder strip; and / or, the second test section 51 is used for welding with the solder strip.

[0258] In this way, the first test section 41 and the second test section 51 can be used for testing and can also serve as solder joints in the subsequent welding process to form battery strings, thus achieving functional reuse and reducing the use of slurry.

[0259] Specifically, in such an embodiment, it is preferable that both the first test section 41 and the second test section 51 are used for welding with solder strips, and the polarity of the solder strip welded with the first test section 41 is different from the polarity of the solder strip welded with the second test section 51.

[0260] In such an embodiment, in the second direction, the distance between the first test section 41 and the first edge 101 is greater than or equal to 2 mm.

[0261] In this way, the distance between the first test section 41 and the first edge 101 can be kept too close, which could lead to cracking during the welding process. In other words, this setting can reduce the risk of cracking of the first test section 41 during welding.

[0262] Furthermore, in such an embodiment, the distance between the first test portion 41 and the first edge 101 in the second direction is preferably 3mm-10mm.

[0263] In this way, while reducing the risk of chip breakage, it is possible to avoid the situation where the length of the first reinforcing electrode 110 (first transport electrode 180) disposed between the first test section 41 and the first edge 101 is too long, which would result in an excessively large area of ​​the non-metallized doped region and affect efficiency.

[0264] Specifically, in such an embodiment, the distance between the first test section 41 and the first edge 101 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0265] Furthermore, in some embodiments, in the second direction, the distance between the second test section 51 and the second edge 102 is greater than or equal to 2 mm.

[0266] In this way, the distance between the second test section 51 and the second edge 102 can be kept from being too close, which could cause cracks during the welding process. In other words, this arrangement can reduce the risk of cracks in the second test section 51 during welding.

[0267] Furthermore, in such an embodiment, the distance between the second test section 51 and the second edge 102 in the second direction is preferably 3mm-10mm.

[0268] In this way, while reducing the risk of chip breakage, it is possible to avoid the first reinforcing electrode 110 (first transport electrode 180) located between the second test section 51 and the second edge 102 being too long, which would result in an excessively large area of ​​the non-metallized doped region and affect efficiency.

[0269] Specifically, in such an embodiment, the distance between the second test section 51 and the second edge 102 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0270] Referring to Figure 26, in some embodiments, all the first test sections 41 and the second test sections 51 may be disposed close to the first edge 101, and in the first direction, the first test sections 41 and the second test sections 51 may be arranged alternately in a row.

[0271] In this case, the first test section 41 and the second test section 51 are located in the same column. To avoid leakage, neither the first test section 41 nor the second test section 51 needs to be used for soldering. Of course, in one possible embodiment, either the first test section 41 or the second test section 51 can also be used for soldering the solder strip, as long as an insulating layer is covered on the other for insulation during soldering.

[0272] Referring to Figure 27, in some embodiments, all first test sections 41 and second test sections 51 are disposed close to the first edge 101 (that is, the distance between the first test section 41 and the second test section 51 and the first edge 101 is less than the distance between the first test section 41 and the second test section 51 and the second edge 102). In the first direction, the first test section 41 and the second test section 51 are disposed alternately at intervals, with the first test section 41 arranged in a row and the second test section 51 arranged in a row. In the first direction, the first test section 41 is closer to the first edge 101 than the second test section 51.

[0273] In this case, the first test section 41 can be used for welding with the solder strip. The second test section 51 can also be used for welding.

[0274] Referring to Figure 28, in some embodiments, the first test portion 41 closest to the third edge 103 (i.e., the first edge test portion 411 closest to the third edge 103 within the first edge region 105) includes a first welding portion 414 and a first connecting portion 415 connected to the first welding portion 414 on the side facing the third edge 103. The first welding portion 414 is used for welding with the welding strip. In the first direction, the distance between the first welding portion 414 and the third edge 103 is greater than 2 mm.

[0275] In this way, the distance between the first welded part 414 and the third edge 103 can be avoided from being too small, which could easily lead to cracks during the welding process.

[0276] In such an embodiment, in the first direction, the distance between the first welded portion 414 and the third edge 103 is 3mm-10mm.

[0277] In this way, it can be avoided that the distance between the first welding part 414 and the third edge 103 is too small, which may easily lead to cracks during the welding process, and it can also be avoided that the distance is too large, which may lead to excessive slurry usage and increased costs.

[0278] Specifically, the distance between the first welded portion 414 and the third edge 103 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0279] In some embodiments, the first test portion 41 closest to the fourth edge 104 (and the first edge test portion 411 closest to the fourth edge 104 within the first edge region 105) includes a second welding portion 416 and a second connecting portion 417 connected to the second welding portion 416 on the side facing the fourth edge 104. The second welding portion 416 is used for welding with a welding strip. In a first direction, the distance between the second welding portion 416 and the fourth edge 104 is greater than 2 mm.

[0280] This avoids the situation where the distance between the second welded part 416 and the fourth edge 104 is too small, which could easily lead to cracks during the welding process.

[0281] In such an embodiment, the distance between the second welded portion 416 and the fourth edge 104 in the first direction is 3mm-10mm.

[0282] In this way, it can be avoided that the distance between the second welding part 416 and the fourth edge 104 is too small, which may easily lead to cracks during the welding process, and it can also be avoided that the distance is too large, which may lead to excessive slurry usage and increased costs.

[0283] Specifically, the distance between the second welded portion 416 and the fourth edge 104 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0284] Referring to Figure 28, in some embodiments, the first test portion 51 closest to the third edge 103 (i.e., the third edge test portion 511 closest to the third edge 103 within the first edge region 105) includes a third welding portion 514 and a third connecting portion 515 connected to the side of the third welding portion 514 facing the third edge 103. The third welding portion 514 is used for welding with the welding strip. In the first direction, the distance between the third welding portion 514 and the third edge 103 is greater than 2 mm.

[0285] This avoids the situation where the distance between the third welded part 514 and the third edge 103 is too small, which could easily lead to cracks during the welding process.

[0286] In such an embodiment, in the first direction, the distance between the third weld portion 514 and the third edge 103 is 3mm-10mm.

[0287] In this way, it can be avoided that the distance between the third welding part 514 and the third edge 103 is too small, which may easily lead to cracks during the welding process, and it can also be avoided that the distance is too large, which may lead to excessive slurry usage and increased costs.

[0288] Specifically, the distance between the third welded portion 514 and the third edge 103 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0289] In some embodiments, the second test portion 51 closest to the fourth edge 104 (and the fourth edge test portion 512 closest to the fourth edge 104 within the second edge region 106) includes a fourth welding portion 516 and a fourth connecting portion 517 connected to the fourth welding portion 516 on the side facing the fourth edge 104. The fourth welding portion 516 is used for welding with a welding strip. In a first direction, the distance between the fourth welding portion 516 and the fourth edge 104 is greater than 2 mm.

[0290] This avoids the situation where the distance between the fourth welding part 516 and the fourth edge 104 is too small, which could easily lead to cracks during the welding process.

[0291] In such an embodiment, the distance between the fourth weld portion 516 and the fourth edge 104 in the first direction is 3mm-10mm.

[0292] In this way, it can be avoided that the distance between the fourth welding part 516 and the fourth edge 104 is too small, which may easily lead to cracks during the welding process, and it can also be avoided that the distance is too large, which may lead to excessive slurry usage and increased costs.

[0293] Specifically, the distance between the fourth welded part 516 and the fourth edge 104 can be, for example, any value between 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 3mm-10mm.

[0294] Referring to Figure 28, in some embodiments, within the first edge region 105, the number of the first edge test section 411 and the third edge test section 511 can both be a single unit. The first edge test section 411 is disposed close to the first edge 101, and the third edge test section 511 is disposed close to the second edge 102.

[0295] Within the first edge region 105, a plurality of first PAD points 210 and a plurality of second PAD points 220 are provided. The plurality of first PAD points 210 and the plurality of second PAD points 220 are arranged alternately along the second direction. In the second direction, the plurality of first PAD points 210 and the plurality of second PAD points 220 are all located between the first edge test section 411 and the third edge test section 511. The first PAD points 210 and the second PAD points 220 are both used for welding with the solder strip.

[0296] The first PAD point 210 is connected to the first fine grid 20 within the first edge region 105 and is insulated from the second fine grid 30. The second PAD point 220 is connected to the second fine grid 30 within the first edge region 105 and is insulated from the first fine grid 20.

[0297] Thus, the first PAD point 210 and the second PAD point 220 can be used as the starting point for welding the solder strip, thereby improving the reliability of the welding.

[0298] Specifically, in such an embodiment, one of the first PAD point 210 and the second PAD point 220 has the same structure as the first edge test section 411 and is located on the same straight line as the first edge test section 411 in the second direction, and the other has the same structure as the third edge test section 511 and is located on the same straight line as the third edge test section 511 in the second direction.

[0299] Furthermore, in some embodiments, within the second edge region 106, the number of the second edge test section 412 and the fourth edge test section 512 can both be a single unit, with the second edge test section 412 disposed close to the first edge 101 and the fourth edge test section 512 disposed close to the second edge 102.

[0300] Within the second edge region 106, a plurality of third PAD points 230 and a plurality of fourth PAD points 240 are also provided. The plurality of third PAD points 230 and the plurality of fourth PAD points 240 are arranged alternately along the second direction. In the second direction, the plurality of third PAD points 230 and the plurality of fourth PAD points 240 are all located between the second edge test section 412 and the fourth edge test section 512. The third PAD points 230 and the fourth PAD points 240 are all used for welding with the solder strip.

[0301] The third PAD point 230 is connected to the first fine grid 20 in the second edge region 106 and is insulated from the second fine grid 30; the fourth PAD point 240 is connected to the second fine grid 30 in the second edge region 106 and is insulated from the first fine grid 20.

[0302] The third PAD point 230 is aligned with the first PAD point 210 in the second direction, and the fourth PAD point 240 is aligned with the second PAD point 220 in the second direction.

[0303] Thus, the first PAD point 210 and the third PAD point 230 can be used as the starting and ending points of the same solder strip, and the second PAD point 220 and the third PAD point 230 can be used as the starting and ending points of the same solder strip, thereby further improving the reliability of the welding.

[0304] Specifically, in such an embodiment, one of the third PAD point 230 and the fourth PAD point 240 has the same structure as the second edge test section 412 and is located on the same straight line as the second edge test section 412 in the second direction, and the other has the same structure as the fourth edge test section 512 and is located on the same straight line as the fourth edge test section 512 in the second direction.

[0305] In the description of this specification, the references to terms such as "Embodiment 1," "Embodiment 2," "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the 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.

[0306] 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.

[0307] The above are merely optional embodiments of this application and are 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 scope of the claims of this application.

Claims

1. A back-contact solar cell, characterized in that, include: A silicon wafer having opposing front and back sides, the back side having a plurality of first regions and a plurality of second regions; A plurality of first fine grids and a plurality of second fine grids are disposed on the back side, the plurality of first fine grids and the plurality of second fine grids being arranged alternately and at intervals along a first direction, and all extending along a second direction, the second direction intersecting the first direction; A plurality of first conductive contact structures are disposed in the first region, the first conductive contact structures are connected to a plurality of first fine grids, and the second fine grids are disconnected at the first conductive contact structures; and A plurality of second conductive contact structures are disposed in the second region, the second conductive contact structures being connected to a plurality of second fine gates, and the first fine gates being disconnected at the second conductive contact structures.

2. The back-contact solar cell according to claim 1, characterized in that, The area of ​​the first region is 5-60 mm. 2 ; and / or the area of ​​the second region is 5-60 mm 2 .

3. The back-contact solar cell according to claim 1, characterized in that, The first conductive contact structure includes a plurality of first conductive connecting lines arranged at intervals along the second direction in the first region. The first conductive connecting lines intersect with the first fine grid and are connected to the plurality of the first fine grids.

4. The back-contact solar cell according to claim 3, characterized in that, A plurality of the first conductive connecting lines and a plurality of the first fine gates form a first filling region; or A plurality of the first conductive connecting lines intersect with a plurality of the first fine grids to form a first mesh structure.

5. The back-contact solar cell according to claim 4, characterized in that, The first conductive contact structure further includes a first conductive material filled in the first filling region or the first mesh structure.

6. The back-contact solar cell according to claim 1, characterized in that, The second conductive contact structure includes a plurality of second conductive connecting lines arranged at intervals along the second direction within the second region. The second conductive connecting lines intersect with the second fine grid and are connected to the plurality of second fine grids.

7. The back-contact solar cell according to claim 6, characterized in that, A plurality of the second conductive connecting lines and a plurality of the second fine gates form a second filling region; or A plurality of the second conductive connecting lines intersect with a plurality of the second fine grids to form a second mesh structure.

8. The back-contact solar cell according to claim 7, characterized in that, The second filling region or the second mesh structure is filled with a second conductive material.

9. The back-contact solar cell according to claim 1, characterized in that, The silicon wafer has a first edge and a second edge along a first direction, and both the first edge and the second edge have a plurality of first conductive contact structures and second conductive contact structures. At the first edge, a plurality of first conductive contact structures and a plurality of second conductive contact structures are arranged alternately and at intervals along the second direction. At the second edge, a plurality of first conductive contact structures and a plurality of second conductive contact structures are also arranged alternately along the second direction.

10. The back-contact solar cell according to claim 9, characterized in that, The first conductive connection structure located at the first edge and the first conductive connection structure located at the second edge are aligned in the first direction; The second conductive connection structure located at the first edge and the second conductive connection structure located at the second edge are aligned in the first direction.

11. The back-contact solar cell according to claim 10, characterized in that, Between the two first conductive connection structures aligned in the first direction, there is also at least one first conductive connection structure aligned with the first conductive connection structure located at the first edge and the second edge; and / or Between the two second conductive connection structures aligned in the first direction, there is also at least one second conductive connection structure aligned with the second conductive connection structures located at the first edge and the second edge.

12. The back-contact solar cell according to claim 1, characterized in that, The silicon wafer has a first center line and a second center line that are perpendicular to each other. The first center line is parallel to the second direction, and the second center line is parallel to the first direction. In the first direction, the silicon wafer is symmetrical about the first center line, and in the second direction, the silicon wafer is symmetrical about the second center line. Both the first conductive contact structure and the second conductive contact structure are disposed on the first center line. In the first direction, the portions of the first conductive contact structure located on both sides of the first center line are symmetrically arranged about the first center line, and the portions of the second conductive contact structure located on both sides of the first center line are also symmetrically arranged about the first center line. The first fine gates on both sides of the first center line are symmetrical about the first center line, and the second fine gates on both sides of the first center line are also symmetrical about the first center line. The first conductive contact structure and the second conductive contact structure are provided on both sides of the second center line. The first conductive contact structures on both sides of the second center line are symmetrically arranged about the second center line, and the second conductive contact structures on both sides of the second center line are also symmetrically arranged about the second center line.

13. The back-contact solar cell according to claim 12, characterized in that, No fine grid is provided at the first centerline; or A central fine gate is provided at the first center line, and the polarity of the central gate line is the same as that of the two fine gates closest to the opposite edges of the silicon wafer in the first direction.

14. The back-contact solar cell according to claim 12, characterized in that, The first conductive contact structure includes a first Pad point located on the first center line and two first connecting lines connected to the two ends of the first Pad point and extending along the first direction. The first connecting lines are connected to at least one of the first fine gates. The second conductive contact structure includes a second Pad point located on the first center line and two second connecting lines that are respectively connected to both ends of the second Pad point and extend along the first direction. The second connecting lines are connected to at least one second fine gate.

15. A back-contact solar cell, characterized in that, include: A silicon wafer having opposing front and back sides; A plurality of first fine grids and a plurality of second fine grids are disposed on the back side, the plurality of first fine grids and the plurality of second fine grids being arranged alternately and spaced apart along a first direction and all extending along a second direction, the second direction intersecting the first direction; and The first test contact structure and the second test contact structure are disposed on the back side; The first test contact structure is electrically connected to all the first fine gates and intersects with a plurality of second fine gates. The second fine gates that intersect with the first test contact structure are disconnected at the first test contact structure. The second test contact structure is electrically connected to all the second fine gates and intersects with a plurality of first fine gates. The first fine gates that intersect with the second test contact structure are disconnected at the second test contact structure. The first test contact structure and the second test contact structure are respectively used to contact probes of different polarities in the test device.

16. The back-contact solar cell according to claim 15, characterized in that, The first test contact structure includes a plurality of first test sections spaced apart, each of the first test sections corresponding to a plurality of first fine grids and a plurality of second fine grids intersecting, and the second fine grids intersecting the first test sections are disconnected at the first test sections; The second test contact structure includes several second test sections spaced apart. Each first test section corresponds to multiple first fine grids and multiple second fine grids intersecting. The first fine grids intersecting the second test sections are disconnected at the second test sections.

17. The back-contact solar cell according to claim 16, characterized in that, The silicon wafer has a first edge and a second edge at both ends in the second direction, a first bus electrode is provided at the first edge, and a second bus electrode is provided at the second edge; The first bus electrode is conductively connected to all of the first fine gates, and the second bus electrode is conductively connected to all of the second fine gates.

18. The back-contact solar cell according to claim 17, characterized in that, The width of the first bus electrode is greater than the width of the first fine gate, and the width of the second bus electrode is greater than the width of the second fine gate; and / or The distance between the first bus electrode and the first edge is 0.5mm-2mm; and / or The distance between the second bus electrode and the second edge is 0.5mm-2mm.

19. The back-contact solar cell according to claim 17, characterized in that, The second fine gate includes a first discontinuous fine gate and a first continuous fine gate. The first continuous fine gate does not intersect with the first test section. The first discontinuous fine gate intersects with the first test section and is insulated from the first test section. At least a portion of the first discontinuous fine gate forms a first gate segment between the first test section and the first bus electrode. The first gate segment is insulated from the first test section and the first bus electrode. The first gate segment is connected to the first continuous fine gate closest to the first gate segment.

20. The back-contact solar cell according to claim 19, characterized in that, The first fine grid located between the first grid line segment and the first continuous fine grid closest to the first grid line segment has a first partition area, and the first grid line segment and the first continuous fine grid closest to the first grid line segment are connected by a first connecting line passing through the first partition area along the first direction.

21. The back-contact solar cell according to claim 19, characterized in that, In the first discontinuous fine grid that intersects with the first test section, at least one of the first discontinuous fine grids does not extend between the first test section and the first bus electrode; On the extension line of the first discontinuous fine grid that does not extend between the first test section and the first busbar electrode, the back contact solar cell is provided with a first enhancement electrode, which is located between the first test section and the first busbar electrode and has its two ends connected to the first busbar electrode and the first test section, respectively.

22. The back-contact solar cell according to claim 21, characterized in that, The width of the first enhancement electrode is greater than the widths of the first fine gate and the second fine gate.

23. The back-contact solar cell according to claim 17, characterized in that, The first fine gate includes a second discontinuous fine gate and a second continuous fine gate. The second continuous fine gate does not intersect with the second test section. The second discontinuous fine gate intersects with the second test section and is insulated from the second test section. At least a portion of the second discontinuous fine gate forms a second gate segment between the second test section and the second bus electrode. The second gate segment is insulated from the second test section and the second bus electrode. The second gate segment is connected to the second continuous fine gate closest to the second gate segment.

24. The back-contact solar cell according to claim 23, characterized in that, The second fine grid located between the second grid line segment and the second continuous fine grid closest to the second grid line segment has a second partition region, and the second grid line segment and the second continuous fine grid closest to the second grid line segment are connected by a second connecting line passing through the second partition region along the first direction.

25. The back-contact solar cell according to claim 23, characterized in that, In the second discontinuous fine grid that intersects with the second test section, at least one of the second discontinuous fine grids does not extend between the second test section and the second bus electrode; On the extension line of the second discontinuous fine grid that does not extend between the second test section and the second busbar electrode, the back contact solar cell is provided with a second enhancement electrode, which is located between the second test section and the second busbar electrode and has its two ends connected to the second busbar electrode and the second test section, respectively.

26. The back-contact solar cell according to claim 25, characterized in that, The width of the second enhancement electrode is greater than the widths of the first and second fine gates.

27. The back-contact solar cell according to claim 16, characterized in that, The silicon wafer has a first edge and a second edge at both ends in the second direction, and a third edge and a fourth edge at both ends in the first direction; Along the direction from the third edge toward the fourth edge, the back surface includes a first edge region, a middle region, and a second edge region. The first test part disposed in the first edge region is a first edge test part, the first test part disposed in the second edge region is a second edge test part, and the first test part disposed in the middle region is a first middle test part. Wherein, the first edge test section is electrically connected to all the first fine gates in the first edge region, and the second fine gates in the first edge region that intersect with the first edge test section have a first isolated segment between the first edge test section and the first edge. In the first edge region, a first connecting electrode is provided at the first edge that is connected to all the first isolated segments, and the first connecting electrode is also electrically connected to the second fine gates in the first edge region that do not intersect with the first edge test section. The second edge test section is electrically connected to all the first fine gates in the second edge region. The second fine gates that intersect with the second edge test section in the second edge region each have a second isolated segment between the second edge test section and the first edge. In the second edge region, a second connecting electrode is provided at the first edge that is connected to all the second isolated segments. The second connecting electrode is electrically connected to the second fine gates in the second edge region that do not intersect with the second edge test section. Within the intermediate region, a third connecting electrode is also provided at the first edge, the third connecting electrode connecting all the first fine grids within the intermediate region.

28. The back-contact solar cell according to claim 27, characterized in that, In the second direction, the distance between the first connecting electrode, the third connecting electrode, the second connecting electrode and the first edge is 0.5mm-2mm; and / or The widths of the first connecting electrode, the third connecting electrode, and the second connecting electrode are greater than the widths of the first fine gate and the second fine gate.

29. The back-contact solar cell according to claim 27, characterized in that, A fourth connection electrode is provided at the second edge, and the fourth connection electrode is conductively connected to all the second test sections and all the second fine gates.

30. The back-contact solar cell according to claim 29, characterized in that, In the second direction, the distance between the fourth connecting electrode and the second edge is 0.5mm-2mm; and or The width of the fourth connecting electrode is greater than the width of the first fine gate and the second fine gate.

31. The back-contact solar cell according to claim 27, characterized in that, In the intermediate region, the second fine gate, which at least partially intersects with the first intermediate test section, has a third isolated segment between the first intermediate test section and the third connecting electrode. The third isolated segment and the second fine gate closest to the third isolated segment that does not intersect with the first intermediate test section are connected.

32. The back-contact solar cell according to claim 31, characterized in that, The first fine grid located between the third isolated segment and the second fine grid closest to the third isolated segment has a first discontinuity region, and the third isolated segment and the first fine grid closest to the third isolated segment are connected by a first busbar passing through the first discontinuity region along the first direction.

33. The back-contact solar cell according to claim 27, characterized in that, In the second fine gate that intersects with the first intermediate test section, at least one of the second fine gates does not extend between the first intermediate test section and the third connecting electrode; On the extension line of the second fine grid that does not extend between the first intermediate test section and the third connecting electrode, the back contact solar cell is provided with a first transmission electrode, which is located between the first intermediate test section and the third connecting electrode and its two ends are respectively connected to the first intermediate test section and the third connecting electrode.

34. The back-contact solar cell according to claim 33, characterized in that, The width of the first transmission electrode is greater than the width of the first fine gate and the second fine gate.

35. The back-contact solar cell according to claim 27, characterized in that, The second test section disposed in the first edge region is a third edge test section, the second test section disposed in the second edge region is a fourth edge test section, and the second test section disposed in the middle region is a second middle test section; Wherein, the third edge test section is electrically connected to all the second fine gates in the first edge region, and the first fine gates in the first edge region that intersect with the third edge test section have a fourth isolated segment between the third edge test section and the first edge. In the first edge region, a fifth connecting electrode is provided at the second edge that is connected to all the fourth isolated segments, and the fifth connecting electrode is also electrically connected to the first fine gates in the first edge region that do not intersect with the third edge test section. The fourth edge test section is cross-connected with all the first fine gates in the second edge region. The second fine gates in the second edge region that cross the fourth edge test section have a fifth isolated segment between the fourth edge test section and the first edge. In the second edge region, a sixth connecting electrode is provided at the second edge that is connected to all the fifth isolated segments. The sixth connecting electrode is conductively connected to the first fine gates in the second edge region that do not cross the fourth edge test section. Both the fifth connecting electrode and the sixth connecting electrode are connected to the third connecting electrode through the first fine grid; Within the intermediate region, a seventh connecting electrode is also provided at the second edge, the seventh connecting electrode connecting all the second fine grids within the intermediate region.

36. The back-contact solar cell according to claim 35, characterized in that, In the second direction, the distance between the fifth connecting electrode, the seventh connecting electrode, and the sixth connecting electrode and the second edge can be 0.5mm-2mm; and / or The widths of the fifth connecting electrode, the seventh connecting electrode, and the sixth connecting electrode are all greater than the widths of the first fine gate and the second fine gate.

37. The back-contact solar cell according to claim 35, characterized in that, In the intermediate region, the first fine gate that at least partially intersects with the second intermediate test section has a sixth isolated segment between the second intermediate test section and the third connecting electrode, and the sixth isolated segment is connected to the first fine gate that is closest to the sixth isolated segment and does not intersect with the second intermediate test section.

38. The back-contact solar cell according to claim 37, characterized in that, The second fine grid located between the sixth isolated segment and the first fine grid closest to the sixth isolated segment has a second discontinuity region, and the sixth isolated segment and the first fine grid closest to the sixth isolated segment are connected by a second busbar passing through the second discontinuity region along the first direction.

39. The back-contact solar cell according to claim 35, characterized in that, In the first fine gate that intersects with the second intermediate test section, at least one of the first fine gates does not extend between the second intermediate test section and the seventh connecting electrode; On the extension line of the first fine grid that does not extend between the second intermediate test section and the seventh connecting electrode, the back contact solar cell is provided with a second transmission electrode, which is located between the second intermediate test section and the seventh connecting electrode and is connected at both ends to the second intermediate test section and the seventh connecting electrode, respectively.

40. The back-contact solar cell according to claim 39, characterized in that, The width of the second transmission electrode is greater than the widths of the first and second fine gates.

41. The back-contact solar cell according to claim 16, characterized in that, The silicon wafer has a first edge and a second edge at both ends in the second direction, and a third edge and a fourth edge at both ends in the first direction; All the first test sections are arranged close to the first edge and in a row at intervals in the first direction; all the second test sections are arranged close to the second edge and in a row in the first direction.

42. The back-contact solar cell according to claim 41, characterized in that, The first test section is used for welding with solder strip; and / or The second test section is used for welding with the solder strip.

43. The back-contact solar cell according to claim 42, characterized in that, In the second direction, the distance between the first test part and the first edge is greater than or equal to 2 mm; and / or, in the second direction, the distance between the second test part and the second edge is greater than or equal to 2 mm.

44. The back-contact solar cell according to claim 42, characterized in that, In the second direction, the distance between the first test portion and the first edge is 3mm-10mm; and / or The distance between the second test section and the second edge is 3mm-10mm.

45. The back-contact solar cell according to claim 16, characterized in that, The silicon wafer has a first edge and a second edge at both ends in the second direction, and a third edge and a fourth edge at both ends in the first direction; all the first test sections and the second test sections are disposed close to the first edge, and in the first direction, the first test sections and the second test sections are arranged alternately in a row.

46. ​​The back-contact solar cell according to claim 16, characterized in that, The silicon wafer has a first edge and a second edge at both ends in the second direction, and a third edge and a fourth edge at both ends in the first direction; all the first test sections and the second test sections are disposed close to the first edge. In a first direction, the first test section and the second test section are alternately spaced, with the first test section arranged in a row and the second test section arranged in a row; in the first direction, the first test section is closer to the first edge than the second test section.

47. The back-contact solar cell according to claim 46, characterized in that, The first test section is used for welding with solder strip; and / or The second test section is used for welding with the solder strip.

48. The back-contact solar cell according to claim 42 or 47, characterized in that, The first test section closest to the third edge includes a first welding section and a first connecting section connected to the first welding section on the side facing the third edge, the first welding section being used for welding with a welding strip; the first test section closest to the fourth edge includes a second welding section and a second connecting section connected to the second welding section on the side facing the fourth edge, the second welding section being used for welding with a welding strip. In the first direction, the distance between the first welded part and the third edge is greater than 2mm, and the distance between the second welded part and the fourth edge is greater than 2mm; And / or, The second test part closest to the third edge includes a third welding part and a third connecting part connected to the third welding part on the side facing the third edge, the third welding part being used for welding with a welding strip; the second test part closest to the fourth edge includes a fourth welding part and a fourth connecting part connected to the fourth welding part on the side facing the fourth edge, the fourth welding part being used for welding with a welding strip. In the first direction, the distance between the third welded part and the third edge is greater than 2mm, and the distance between the fourth welded part and the fourth edge is greater than 2mm.

49. The back-contact solar cell according to claim 48, characterized in that, In the first direction, the distance between the first welded portion and the third edge is 3mm-10mm, and the distance between the second welded portion and the fourth edge is 3mm-10mm; and / or, In the first direction, the distance between the third welded part and the third edge is greater than 3mm-10mm, and the distance between the fourth welded part and the fourth edge is 3mm-10mm.

50. The back-contact solar cell according to claim 35, characterized in that, Within the first edge region, both the first edge testing unit and the third edge testing unit are single. The first edge testing unit is located close to the first edge, and the third edge testing unit is located close to the second edge. Within the first edge region, there are also a plurality of first PAD points and a plurality of second PAD points. The plurality of first PAD points and the plurality of second PAD points are alternately arranged along a second direction. In the second direction, the plurality of first PAD points and the plurality of second PAD points are all located between the first edge testing unit and the third edge testing unit. Both the first PAD point and the second PAD point are used for welding with the solder strip. The first PAD point is connected to the first fine gate in the first edge region and is insulated from the second fine gate. The second PAD point is connected to the second fine gate in the first edge region and is insulated from the first fine gate.

51. The back-contact solar cell according to claim 50, characterized in that, Within the second edge region, both the number of the second edge test section and the number of the fourth edge test section can be single. The second edge test section is located close to the first edge, and the fourth edge test section is located close to the second edge. A plurality of third PAD points and a plurality of fourth PAD points are also provided in the second edge region. The plurality of third PAD points and the plurality of fourth PAD points are arranged alternately along the second direction. In the second direction, the plurality of third PAD points and the plurality of fourth PAD points are all located between the second edge test section and the fourth edge test section. The third PAD points and the fourth PAD points are all used for welding with the solder strip. Wherein, the third PAD point is connected to the first fine gate in the second edge region and is insulated from the second fine gate, and the fourth PAD point is connected to the second fine gate in the second edge region and is insulated from the first fine gate; The third PAD point is aligned with the first PAD point in the second direction, and the fourth PAD point is aligned with the second PAD point in the second direction.

52. A battery assembly, characterized in that, Includes the back-contact solar cell according to any one of claims 1-51.

53. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 52.

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