Photovoltaic cell, module, and system

Abstract

The present disclosure is applicable to the technical field of solar cells, and provides a photovoltaic cell, a module, and a system. The cell comprises first busbars, first solder joints, and second solder joints. The distance between two adjacent first fingers in a second direction is d, the lengths of each first solder joint and each second solder joint in the second direction are greater than d, and the offset distance between each second solder joint and an adjacent first solder joint in the second direction is greater than or equal to 0.5d.

Description

Photovoltaic cells, modules and systems

[0001] Cross-references

[0002] This disclosure incorporates, in its entirety, Chinese Patent Application No. 202423261109.9, filed on December 27, 2024, entitled “A Back Contact Solar Cell, Battery Module and Photovoltaic System”. Technical Field

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

[0004] Interdigitated back contact (IBC) solar cells, also known as interdigitated back contact cells, have both positive and negative electrode grids located on the back of the cell. This completely eliminates the shading caused by metal grids on the front surface, preventing optical losses. Furthermore, the electrode width can be designed to be wider than existing methods, reducing series resistance losses and significantly improving cell conversion efficiency. Additionally, the electrode-free design on the front results in a more aesthetically pleasing product, making it suitable for various applications.

[0005] In related technologies, as shown in Figure 1, the back side of a back-contact solar cell typically includes a first main grid 1, a second main grid 2, a first fine grid 3, and a second fine grid 4. The first main grid 1 has a first solder joint 5, and the second main grid 2 has a second solder joint 6. The first main grid 1 and the second main grid 2 are spaced apart along a first direction X, and the first main grid 1 and the second main grid 2 have opposite polarities. The first fine grid 3 and the second fine grid 4 are alternately spaced along a second direction Y, and the second direction Y intersects with the first direction X. The first fine grid 3 is connected to the first main grid 1, and the second fine grid 4 is connected to the second main grid 2. The first solder joint 5 and the adjacent second solder joint 6 are usually flush. However, since the back-contact solar cell needs to avoid the position of the opposite-polarity fine grid during the laser formation of the P-region or N-region, if the adjacent solder joints of the main grids with different polarities are flush, a large number of first fine grids 3 need to be increased in distance to avoid the laser pattern area 8 corresponding to the second solder joint 6. This results in a reduction in the length of the opposite-polarity fine grid corresponding to the solder joint, affecting the current collection effect of the fine grid and thus affecting the cell efficiency.

[0006] Public content

[0007] This disclosure provides a back-contact solar cell, which aims to solve the problem that in related technologies, the adjacent solder joints of different polarity main grids in back-contact solar cells are set flush, resulting in a reduction in the length of the corresponding non-polar fine grid, which affects the current collection effect of the fine grid and thus affects the cell efficiency.

[0008] This disclosure provides a back-contact solar cell, including a first main grid, a second main grid, a first fine grid, and a second fine grid disposed on the back side of the back-contact solar cell. The first main grid is provided with a first solder joint, and the second main grid is provided with a second solder joint.

[0009] The first main gate and the second main gate are spaced apart along a first direction, and the polarities of the first main gate and the second main gate are opposite; the first fine gate and the second fine gate are alternately spaced along a second direction, the second direction intersects the first direction, the first fine gate is connected to the first main gate, and the second fine gate is connected to the second main gate;

[0010] Wherein, the distance between two adjacent first fine grids in the second direction is d, the length of the first solder joint and the second solder joint along the second direction is greater than d, the second solder joint and the adjacent first solder joint are staggered in the second direction, and the staggered distance between the second solder joint and the adjacent first solder joint in the second direction is greater than or equal to 0.5d.

[0011] In some embodiments, the lengths of both the second solder joint and the first solder joint along the second direction are less than or equal to 2d.

[0012] In some embodiments, the distance between the center point of the second solder joint and the center point of the adjacent first solder joint in the second direction is greater than or equal to 0.5d.

[0013] In some embodiments, the first solder joint includes a first end and a second end disposed along the second direction, and the second solder joint includes a third end and a fourth end disposed along the second direction, wherein the third end of the second solder joint is disposed close to the first end, and the fourth end of the second solder joint is disposed close to the second end;

[0014] The distance between the third end of the second solder joint and the first end of the first solder joint in the second direction is greater than or equal to 0.5d; or, the distance between the fourth end of the second solder joint and the second end of the first solder joint in the second direction is greater than or equal to 0.5d; or, the distance between the third end of the second solder joint and the first end of the first solder joint in the second direction is greater than or equal to 0.5d and the distance between the fourth end of the second solder joint and the second end of the first solder joint in the second direction is greater than or equal to 0.5d.

[0015] In some implementations, it also includes:

[0016] A laser pattern area corresponding to each of the second solder joints, the laser pattern area covering only two of the first fine grids along the second direction.

[0017] In some embodiments, the first fine gate includes a first fine gate, a second fine gate, a third fine gate, and a fourth fine gate that are sequentially spaced apart along the second direction; the second fine gate and the third fine gate are arranged in the area corresponding to the second solder joint, and the first fine gate and the fourth fine gate are arranged in the area corresponding to the second main gate.

[0018] In some embodiments, the second and third first fine gates form a first break in the region of the second solder joint, and the first and fourth first fine gates form a second break in the region corresponding to the second main gate, wherein the width of the first break is greater than the width of the second break.

[0019] In some embodiments, the second fine gate includes a first second fine gate, a second second fine gate, and a third second fine gate arranged sequentially at intervals along the second direction, the second solder joint is located between the first second fine gate and the third second fine gate, and the second solder joint is intersecting with the second second fine gate.

[0020] In some implementations, the first solder joint and the second solder joint have the same length along the second direction.

[0021] This disclosure also provides a battery assembly including the aforementioned back-contact solar cell.

[0022] This disclosure also provides a photovoltaic system including the aforementioned battery module.

[0023] The back-contact solar cell disclosed herein is provided by staggering the second solder point with the adjacent first solder point in the second direction. The distance between two adjacent first grids in the second direction is d, the length of the second solder point is greater than d, and the stagger distance between the second solder point and the adjacent first solder point is greater than 0.5d. This can reduce the number of first grids that need to avoid the laser pattern area corresponding to the second solder point, increase the total length and total area of ​​the first grids, improve the current collection effect of the first grids, and thus improve the cell efficiency of the back-contact solar cell.

[0024] Explanation of reference numerals in the attached diagram: 1. First main grid; 2. Second main grid; 3. First fine grid; 4. Second fine grid; 5. First solder joint; 6. Second solder joint; 8. Laser pattern area; 31. First fine grid; 32. Second fine grid; 33. Third fine grid; 34. Fourth fine grid; 35. First break; 36. Second break; 41. First fine grid; 42. Second fine grid; 43. Third fine grid; 51. First end; 52. Second end; 61. Third end; 62. Fourth end. Attached Figure Description

[0025] Figure 1 is a partial schematic diagram of the back side of a back-contact solar cell of a related technology;

[0026] Figure 2 is a partial schematic diagram of the back side of a back-contact solar cell provided in an embodiment of this disclosure;

[0027] Figure 3 is a partial schematic diagram of the back side of another back-contact solar cell provided in an embodiment of this disclosure;

[0028] Figure 4 is a schematic diagram of the second solder joint and the adjacent first solder joint of a back-contact solar cell provided in an embodiment of this disclosure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this disclosure.

[0030] The back-contact solar cell provided in this disclosure provides a method to offset the second solder point from the adjacent first solder point in the second direction. The distance between two adjacent first grids in the second direction is d, the length of the second solder point is greater than d, and the offset distance between the second solder point and the adjacent first solder point is greater than 0.5d. This method can reduce the number of first grids that need to avoid the laser pattern area corresponding to the second solder point, increase the total length and total area of ​​the first grids, improve the current collection effect of the first grids, and thus improve the cell efficiency of the back-contact solar cell.

[0031] Please refer to Figures 2-4. This disclosure provides a back-contact solar cell, including a first main grid 1, a second main grid 2, a first fine grid 3 and a second fine grid 4 disposed on the back side of the back-contact solar cell. The first main grid 1 is provided with a first solder joint 5 and the second main grid 2 is provided with a second solder joint 6.

[0032] The first main grid 1 and the second main grid 2 are spaced apart along the first direction X, and the polarities of the first main grid 1 and the second main grid 2 are opposite; the first fine grid 3 and the second fine grid 4 are alternately spaced along the second direction Y, and the second direction Y intersects the first direction X. The first fine grid 3 is connected to the first main grid 1, and the second fine grid 4 is connected to the second main grid 2.

[0033] Wherein, the distance between two adjacent first fine grids 3 in the second direction Y is d, the lengths of the first solder point 5 and the second solder point 6 in the second direction Y are both greater than or equal to d, the second solder point 6 and the adjacent first solder point 5 are staggered in the second direction Y, and the stagger distance H between the second solder point 6 and the adjacent first solder point 5 in the second direction Y is greater than or equal to 0.5d.

[0034] In this embodiment, the first main grid 1, the second main grid 2, the first fine grid 3, and the second fine grid 4 are all disposed on the back side of the back-contact solar cell. The specific number of the first main grid 1 and the second main grid 2 is not limited, and the first main grid 1 and the second main grid 2 are alternately disposed on the back side of the back-contact solar cell along the first direction X. One of the first main grid 1 and the second main grid 2 is the positive electrode, and the other is the negative electrode. The first main grid 1 and the first fine grid 3 have the same polarity, and the second main grid 2 and the second fine grid 4 have the same polarity. The specific number of the first fine grid 3 and the second fine grid 4 is not limited, and the first fine grid 3 and the second fine grid 4 are alternately disposed on the back side of the back-contact solar cell at equal intervals along the second direction Y. The first fine grid 3 is spaced apart from the second main grid 2 and the second solder joint 6, and the second fine grid 4 is spaced apart from the first main grid 1 and the first solder joint 5.

[0035] The second direction Y and the first direction X can be perpendicular to each other or not perpendicular. In some embodiments, the second direction Y is set perpendicular to the first direction X.

[0036] In this embodiment, a plurality of first solder points 5 are provided on the first main gate 1, and the plurality of first solder points 5 are sequentially spaced along the second direction Y on the first main gate 1. A plurality of second solder points 6 are provided on the second main gate 2, and the plurality of second solder points 6 are sequentially spaced along the second direction Y on the second main gate 2. The number of first solder points 5 on the first main gate 1 and the number of second solder points 6 on the second main gate 2 may be equal or unequal. Furthermore, the shape and size of the first solder points 5 and the second solder points 6 may be the same or different; that is, the shape and size of the first solder points 5 on the first main gate 1 and the shape and size of the second solder points 6 on the second main gate 2 may be the same or different. In some embodiments, the shape and size of the first solder points 5 on the first main gate 1 and the shape and size of the second solder points 6 on the second main gate 2 are the same. In some embodiments, both the first solder points 5 and the second solder points 6 are square, polygonal, or circular.

[0037] In this embodiment, the adjacent first solder point 5 of the second solder point 6 is the first solder point 5 closest to the second solder point 6. The second solder point 6 and the adjacent first solder point 5 are offset in the second direction Y. This can be understood as the geometric center of the second solder point 6 and the geometric center of the adjacent first solder point 5 having a certain offset distance in the second direction Y. Of course, if the length of the first solder point 5 along the second direction Y is the same as the length of the second solder point 6 along the second direction Y, it can also be understood that the upper end of the second solder point 6 and the upper end of the adjacent first solder point 5 have a certain distance in the second direction Y, or the lower end of the second solder point 6 and the lower end of the adjacent first solder point 5 have a certain distance in the second direction Y.

[0038] Specifically, the misalignment distance between the second solder point 6 and the adjacent first solder point 5 is greater than or equal to 0.5d. That is, the distance between the geometric center of the second solder point 6 and the geometric center of the adjacent first solder point 5 in the second direction Y is greater than or equal to 0.5d; or, the length of the first solder point 5 along the second direction Y is the same as the length of the second solder point 6 along the second direction Y, and the distance between the same end of the second solder point 6 and the adjacent first solder point 5 in the second direction Y is greater than 0.5d. A misalignment distance of 0.5d between the second solder point 6 and the adjacent first solder point 5 is sufficient. For example, the misalignment distance between the second solder point 6 and the adjacent first solder point 5 can be 0.5d, d, 1.2d, 1.5d, 1.8d, 2d, or 2.5d. Figure 2 illustrates a misalignment distance of 0.5d between the second solder point 6 and the adjacent first solder point 5, and Figure 3 illustrates a misalignment distance of 2.5d between the second solder point 6 and the adjacent first solder point 5.

[0039] During the production process of back-contact solar cells, a laser is used to etch the first doped polysilicon layer in the first region on the back of the solar cell to form a laser pattern area. The first doped polysilicon layer in the second region on the back of the solar cell is retained, and then a second doped polysilicon layer is deposited in the laser pattern area. The first doped polysilicon layer and the second doped polysilicon layer are respectively a P-type polysilicon layer and an N-type polysilicon layer. The fine grid area needs to avoid the laser pattern area corresponding to the solder joints on the heterogeneous main grid.

[0040] The back-contact solar cell provided in this embodiment is configured by staggering the second solder point 6 with the adjacent first solder point 5 in the second direction Y. The distance between two adjacent second grids 4 in the second direction Y is d. The lengths of the first solder point 5 and the second solder point 6 in the second direction Y are greater than or equal to d, and the staggered distance between the second solder point 6 and the adjacent first solder point 5 is greater than or equal to 0.5d. Compared with the method of aligning the first solder point 5 and the second solder point 6, the length of the laser pattern area 8 corresponding to the second solder point 6 in the second direction Y can be reduced. This reduces the number of first grids 3 that need to avoid the laser pattern area corresponding to the second solder point 6, thereby increasing the overall length of the first grids 3, improving the current collection effect of the first grids 3, and thus increasing the overall grid length of the back-contact solar cell, improving the current collection effect of the grids, and thus improving the cell efficiency. Moreover, the area of ​​the laser pattern area corresponding to the second solder point 6 can be reduced, which is beneficial to increasing production capacity.

[0041] As an embodiment of this disclosure, the back-contact solar cell further includes:

[0042] The laser pattern area 8 corresponding to each second solder point 6 is covered by only two first fine grids 3 along the second direction Y.

[0043] In this embodiment, when the laser forms the area where the second solder joint 6 is located, the laser pattern area 8 only spans two first fine grids 3 along the second direction Y, thereby reducing the number of first fine grids 3 that need to be avoided in the laser pattern area 8, thereby increasing the overall length and area of ​​the first fine grids 3 that are in contact with the battery, improving the current collection effect of the first fine grids 3, and thus improving the battery efficiency.

[0044] For example, Figure 1 illustrates that in the related technology, the laser pattern area 8 corresponding to the second solder point 6 spans three first fine grids 3 along the second direction Y. Therefore, three first fine grids 3 need to increase the gap in the laser pattern area corresponding to the second solder point 6 to avoid the laser pattern area 8 of the second solder point 6. In the present disclosure shown in Figure 2, because the first solder point 5 and the adjacent second solder point 6 are staggered, the laser pattern area 8 corresponding to the second solder point 6 only spans two first fine grids 3 along the second direction Y. Only two first fine grids 3 need to increase the gap to avoid the laser pattern area 8 corresponding to the second solder point 6. In the present disclosure, each second solder point 6 can reduce one first fine grid 3 to avoid the laser pattern area 8 corresponding to the second solder point 6. Therefore, the present disclosure can increase the total length of the first fine grid 3 close to the laser pattern area 8 corresponding to the second solder point 6, thereby increasing the overall length and area of ​​the first fine grid 3 in the back contact with the battery, improving the current collection effect of the first fine grid 3, and thus improving the battery efficiency.

[0045] As some embodiments of this disclosure, the first solder joint 5 includes a first end 51 and a second end 52 disposed along the second direction Y, and the second solder joint 6 includes a third end 61 and a fourth end 62 disposed along the second direction Y. The third end 61 of the second solder joint 6 is disposed close to the first end 51, and the fourth end 62 of the second solder joint 6 is disposed close to the second end 52.

[0046] The distance between the third end 61 of the second solder point 6 and the first end 51 of the first solder point 5 in the second direction Y is greater than or equal to 0.5d; or the distance between the fourth end 62 of the second solder point 6 and the second end of the first solder point 5 in the second direction Y is greater than or equal to 0.5d; or the distance between the third end of the second solder point and the first end of the first solder point in the second direction is greater than or equal to 0.5d and the distance between the fourth end of the second solder point and the second end of the first solder point in the second direction is greater than or equal to 0.5d.

[0047] In this embodiment, the length of the first solder point 5 along the second direction Y is the same as the length of the second solder point 6 along the second direction Y. The distance between the third end 61 of the second solder point 6 and the first end 51 of the first solder point 5 in the second direction Y is greater than or equal to 0.5d. The distance between the third end of the second solder point 6 and the first end of the first solder point 5 in the second direction Y is greater than or equal to 0.5d, so that the second solder point 6 and the same end of the adjacent first solder point 5 are at a certain distance in the second direction Y, thereby realizing the staggered design of the second solder point 6 and the adjacent first solder point 5 in the second direction Y.

[0048] As some embodiments of this disclosure, the first solder joint 5 and the second solder joint 6 have the same length along the second direction Y, which facilitates the setting of the first solder joint 5 and the second solder joint 6. Of course, the lengths of the first solder joint 5 and the second solder joint 6 along the second direction Y may also be different.

[0049] As some embodiments of this disclosure, the lengths of the second solder joint 6 and the first solder joint 5 along the second direction Y are less than or equal to 2d, that is, the lengths of the second solder joint 6 and the first solder joint 5 are greater than or equal to d and less than or equal to 2d, which facilitates the processing of the second solder joint 6 and the first solder joint 5.

[0050] As some embodiments of this disclosure, the first fine gate 3 includes a first first fine gate 31, a second first fine gate 32, a third first fine gate 33, and a fourth first fine gate 34 arranged sequentially at intervals along the second direction Y; the second first fine gate 32 and the third first fine gate 33 are arranged in the area corresponding to the second solder joint 6, and the first first fine gate 31 and the fourth first fine gate 34 are arranged in the area corresponding to the second main gate 2.

[0051] In this embodiment, the second solder joint 6 spans only the second first fine gate 32 and the third first fine gate 33, that is, the second solder joint 6 spans only the two first fine gates 3. The first first fine gate 31 and the fourth first fine gate 34 do not need to have their opening width widened, thus the total length of the first first fine gate 31 and the fourth first fine gate 34 can be increased, thereby improving the current collection effect of the first fine gate 3.

[0052] As some embodiments of this disclosure, the second first fine gate 32 and the third first fine gate 33 form a first break 35 in the region of the second solder joint 6, and the first first fine gate 31 and the fourth first fine gate 34 form a second break 36 in the region corresponding to the second main gate 2, and the width of the first break 35 is greater than the width of the second break 36.

[0053] In this embodiment, a wider first interruption 35 is formed only in the region corresponding to the second solder joint 6 of the second first fine gate 32 and the third first fine gate 33. The first first fine gate 31 and the fourth first fine gate 34 do not need to be widened in the region corresponding to the second main gate 2. This can increase the total length of the first first fine gate 31 and the fourth first fine gate 34, thereby improving the current collection effect of the first fine gate 3.

[0054] As some embodiments of this disclosure, the second fine gate 4 includes a first second fine gate 41, a second second fine gate 42, and a third second fine gate 43 arranged sequentially at intervals along the second direction Y. The second solder joint 6 is located between the first second fine gate 41 and the third second fine gate 43, and the second solder joint 6 is intersected with the second second fine gate 42.

[0055] In this embodiment, the second solder point 6 is positioned between the first second fine gate 41 and the third second fine gate 43, and intersects with the second second fine gate 42. This not only increases the total length of the first fine gate 3 and improves the current collection effect of the first fine gate 3, but also ensures that the second solder point 6 and the second fine gate 4 have a good current collection effect.

[0056] As some embodiments of this disclosure, the width of the first solder joint 5 is greater than the width of the first main gate 1, and the width of the second solder joint 6 is greater than the width of the second main gate 2, so that the first solder joint 5 and the second solder joint 6 have better conductivity and good welding performance.

[0057] This disclosure also provides a battery assembly including the back-contact solar cell described above. It should be noted that this battery assembly has the same or similar beneficial effects as the back-contact solar cell described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0058] In this embodiment, multiple back-contact solar cells in the battery module can be connected in series to form a battery string, thereby achieving series current output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0059] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the back-contact solar cell, the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0060] Photovoltaic glass can be applied to the encapsulating film on the front side of the back-contact solar cell. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%. It can protect the back-contact solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back-contact solar cell together, providing sealing, insulation, and waterproofing / moisture protection for the back-contact solar cell.

[0061] The backsheet can be attached to the adhesive film on the back of the back-contact solar cell. The backsheet protects and supports the solar cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite adhesive film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, back-contact solar cell, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire back-contact solar cell module, providing stable support and installation. For example, the back-contact solar cell module can be installed at the desired location using the metal frame.

[0062] This disclosure also provides a photovoltaic system including the battery module described above. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back-contact solar cell described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0063] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple back-contact solar cell modules. For example, multiple back-contact solar cell modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0064] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A back-contact solar cell, comprising a first main grid, a second main grid, a first fine grid, and a second fine grid disposed on the back side of the back-contact solar cell, wherein the first main grid has a first solder joint and the second main grid has a second solder joint; The first main gate and the second main gate are spaced apart along a first direction, and the polarities of the first main gate and the second main gate are opposite; the first fine gate and the second fine gate are alternately spaced along a second direction, the second direction intersects the first direction, the first fine gate is connected to the first main gate, and the second fine gate is connected to the second main gate; in, The distance between two adjacent first fine grids in the second direction is d. The lengths of the first solder joint and the second solder joint along the second direction are both greater than d. The second solder joint and the adjacent first solder joint are staggered in the second direction, and the staggered distance between the second solder joint and the adjacent first solder joint in the second direction is greater than or equal to 0.5d.

2. The back-contact solar cell according to claim 1, wherein, The lengths of both the second solder joint and the first solder joint along the second direction are less than or equal to 2d.

3. The back-contact solar cell according to claim 1, wherein, The distance between the center point of the second solder joint and the center point of the adjacent first solder joint in the second direction is greater than or equal to 0.5d.

4. The back-contact solar cell according to claim 1, wherein, The first solder joint includes a first end and a second end disposed along the second direction, and the second solder joint includes a third end and a fourth end disposed along the second direction, wherein the third end of the second solder joint is disposed close to the first end, and the fourth end of the second solder joint is disposed close to the second end; The distance between the third end of the second solder joint and the first end of the first solder joint in the second direction is greater than or equal to 0.5d; or, the distance between the fourth end of the second solder joint and the second end of the first solder joint in the second direction is greater than or equal to 0.5d; or, the distance between the third end of the second solder joint and the first end of the first solder joint in the second direction is greater than or equal to 0.5d and the distance between the fourth end of the second solder joint and the second end of the first solder joint in the second direction is greater than or equal to 0.5d.

5. The back-contact solar cell according to claim 1, wherein, Also includes: A laser pattern area corresponding to each of the second solder joints, the laser pattern area covering only two of the first fine grids along the second direction.

6. The back-contact solar cell according to claim 1, wherein, The first fine gate includes a first fine gate, a second fine gate, a third fine gate, and a fourth fine gate arranged sequentially at intervals along the second direction; the second fine gate and the third fine gate are arranged in the area corresponding to the second solder joint, and the first fine gate and the fourth fine gate are arranged in the area corresponding to the second main gate.

7. The back-contact solar cell according to claim 6, wherein, The second and third first fine gates form a first break in the region of the second solder joint, and the first and fourth first fine gates form a second break in the region corresponding to the second main gate, wherein the width of the first break is greater than the width of the second break.

8. The back-contact solar cell according to claim 1, wherein, The second fine grid includes a first second fine grid, a second second fine grid, and a third second fine grid arranged sequentially at intervals along the second direction. The second solder joint is located between the first second fine grid and the third second fine grid, and the second solder joint intersects with the second second fine grid.

9. The back-contact solar cell according to claim 1, wherein, The first solder joint and the second solder joint have the same length along the second direction.

10. A battery assembly comprising a back-contact solar cell as described in any one of claims 1 to 9.

11. A photovoltaic system comprising the battery module as described in claim 10.

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