A back contact solar cell, cell assembly and photovoltaic system

Abstract

The application is suitable for the photovoltaic technical field, and provides a back contact solar cell, a cell assembly and a photovoltaic system.The back contact solar cell comprises a silicon substrate, the silicon substrate comprises a back surface, a doped layer is arranged on the back surface, the doped layer comprises a first doped part and a second doped part, the first doped part extends along a first direction, the first doped part and the second doped part are spaced apart to form a first mark area in the first direction, and a first mark structure is located in the first mark area and is spaced apart from the first doped part and the second doped part.The mark structure of the back contact solar cell of the application can be easily recognized by a visual system, and the probability of recognition failure or misjudgment of the visual system can be reduced.

Description

Technical Field

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

[0002] In related technologies, during the fabrication of back-contact solar cells, it is typically necessary to set a marking structure on the back of the cell. A vision system is used to grasp the marking structure to locate the cell, thereby enabling accurate printing of the back grid lines, insulating adhesive, or solder paste. However, the marking structure on the back of a back-contact solar cell usually lacks sufficient contrast with the surrounding area, making it difficult for the vision system to accurately identify the marking structure. This can easily lead to recognition failures or misjudgments, which is detrimental to the printing process of back-contact solar cells. Summary of the Invention

[0003] This invention provides a back-contact solar cell, which aims to solve the problem that the marking structure of existing back-contact solar cells is not conducive to visual system recognition, and is prone to recognition failure or misjudgment.

[0004] This invention is implemented by providing a back-contact solar cell, comprising: Silicon substrate, the silicon substrate including a back side; A doped layer is disposed on the back side, the doped layer including a first doped portion and a second doped portion, the first doped portion extending along a first direction; the first doped portion and the second doped portion are spaced apart in the first direction to form a first marking region; and A first identification structure is located in the first identification area, and the first identification structure is spaced apart from the first doped portion and the second doped portion.

[0005] Preferably, the doped layer includes a first doped layer and a second doped layer with opposite doping types, and the first doped layer and the second doped layer are spaced apart; the second doped layer includes the first doped portion and the second doped portion; or, the first doped layer includes the first doped portion and the second doped layer includes the second doped portion.

[0006] Preferably, the first doped layer and the second doped layer extend along the first direction, and at least a portion of the first doped layer and at least a portion of the second doped layer are alternately spaced along the second direction, which intersects with the first direction.

[0007] Preferred options also include: A plurality of fine gates are disposed on the back side, each fine gate being disposed on a corresponding doped layer, the fine gates extending along the first direction, and the plurality of fine gates being alternately spaced along the second direction.

[0008] Preferably, the fine gates are respectively provided on the first doped portion and the second doped portion, and the fine gates on the first doped portion and the fine gates on the second doped portion are spaced apart in the first marking area; The spacing between two adjacent fine gates in the second direction is d, and the ratio of the distance from the center of the first marking structure along the second direction to the center line of the fine gate on the first doped portion to d is 0 to 0.2; and / or, the ratio of the distance from the center of the first marking structure along the second direction to the center line of the fine gate on the second doped portion to d is 0 to 0.2.

[0009] Preferably, the first marking structure is spaced apart from the adjacent doped layer in the second direction.

[0010] Preferably, the first marking structure includes a first marking base disposed on the back side and a first marking point disposed on the first marking base; The first identification substrate has the opposite or the same doping type as the first doped portion, and the first identification substrate has the opposite or the same doping type as the second doped portion.

[0011] Preferably, the doped layer further includes a third doped portion and a fourth doped portion, the third doped portion extending along the first direction, and the third doped portion and the fourth doped portion being spaced apart in the first direction to form a second marking region; the back contact solar cell includes: The second identification structure is located in the second identification area, and the second identification structure is spaced apart from the third doped portion and the fourth doped portion.

[0012] Preferably, the second identification structure is connected to the adjacent doped layer in the second direction.

[0013] Preferably, the second marking structure includes a second marking substrate disposed on the back side and a second marking point disposed on the second marking substrate. The doping type of the second marking substrate is opposite to or the same as that of the third doped portion, and the doping type of the second marking substrate is opposite to or the same as that of the fourth doped portion.

[0014] Preferably, the second marking substrate has the opposite doping type to the first marking substrate.

[0015] Preferably, the doped layer further includes a fifth doped portion and a sixth doped portion, the fifth doped portion extending along the first direction, and the fifth doped portion and the sixth doped portion being spaced apart in the first direction to form a third marking region; the back contact solar cell includes: A third identification structure is located in the third identification region, and the third identification structure is spaced apart from the fifth doped portion and the sixth doped portion.

[0016] Preferably, the third identification structure is spaced apart from the adjacent doped layer in the second direction.

[0017] Preferably, the third identification structure includes a third identification substrate disposed on the back side, a fourth identification substrate stacked on the third identification substrate, and a third marking point disposed on the fourth identification substrate, wherein the doping types of the third identification substrate and the fourth identification substrate are opposite.

[0018] Preferably, the first marking base is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the first marking point is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

[0019] Preferably, the second marking base is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the second marking point is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

[0020] Preferably, the third and fourth marking bases are each one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, and octagon; and / or, the third marking point is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, and octagon.

[0021] Preferably, the first and second marking structures are located on one side of the centerline of the silicon substrate, and the third marking structure is located on the other side of the centerline of the silicon substrate.

[0022] Preferably, the total number of the first and second identifier structures is different from the number of the third identifier structures.

[0023] Preferably, each of the first identifier structures is arranged adjacent to a corresponding second identifier structure to form a marker group.

[0024] Preferably, the spacing between two adjacent fine grids in the second direction is d, and the spacing between the first identification structure and the second identification structure of each mark group is D1, satisfying 2d < D1 < 10d.

[0025] Preferably, the number of the marker groups is at least two, and the at least two marker groups are spaced apart along the first direction.

[0026] Preferably, the ratio of the spacing between the first marking structures of two adjacent marking groups to the dimension of the silicon substrate along the first direction is 0.25 to 0.8; and or, the ratio of the spacing between the second marking structures of two adjacent marking groups to the dimension of the silicon substrate along the first direction is 0.25 to 0.8.

[0027] Preferably, the back side includes a plurality of serial connection areas for setting solder strips, the plurality of serial connection areas are alternately spaced along the first direction, and the serial connection areas extend along the second direction; the solder strips of two adjacent serial connection areas have opposite polarities, and the solder strips of each serial connection area are used to electrically connect the fine grids of the same polarity; The fine grid includes a widened portion located at the serial connection area of ​​the same polarity solder strip, and a non-widened portion located outside the serial connection area of ​​the same polarity solder strip, wherein the dimension of the widened portion along the second direction is larger than the dimension of the non-widened portion along the second direction.

[0028] Preferably, the ratio of the dimension of the widened portion along the second direction to the dimension of the non-widened portion along the second direction is 1.2 to 6.

[0029] Preferably, the fine grid further includes a protruding structure formed at the corner of the widened portion.

[0030] Preferably, the ratio of the dimension of the protruding structure along the second direction to the dimension of the non-widened portion along the second direction is 1.1 to 3.

[0031] Preferably, the dimension of the widened portion along the first direction is greater than the width of the solder strip.

[0032] Preferably, the ratio of the dimension of the widened portion along the first direction to the width of the welding strip is 1.1 to 2.

[0033] Preferred options also include: A main grid is disposed on the back side, the main grid extending along the second direction, and each main grid is connected to at least a portion of the fine grids of the same polarity.

[0034] Preferably, at least one of the fine grids has a honeycomb structure; and / or, at least one of the main grids has a honeycomb structure.

[0035] The present invention also provides a battery assembly including the aforementioned back-contact solar cell.

[0036] The present invention also provides a photovoltaic system including the above-described battery module.

[0037] The back-contact solar cell provided by this invention has a plurality of doped layers on its back side. The doped layers are configured to include a first doped portion and a second doped portion, with the first doped portion extending along a first direction. The first doped portion and the second doped portion are spaced apart in the first direction to form a first marking region. A first marking structure is disposed in the first marking region, and the first marking structure is spaced apart from the first doped portion and the second doped portion. Since the first marking structure is spaced apart from the first doped portion and the second doped portion in the first direction, the doped layers are prevented from being continuous along the first direction at the location where the first marking structure is disposed. This facilitates a clear contrast between the first marking structure and the doped layers in the surrounding area, reduces the influence of the doped layers in the surrounding area on the visual system's recognition of the first marking structure, and makes the first marking structure easier for the visual system to recognize. This facilitates the visual system's rapid and accurate recognition of the first marking structure, reduces the probability of visual system recognition failure or misjudgment, and thus improves the printing yield of the back-contact solar cell. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the back side of a back-contact solar cell provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another back side of a back-contact solar cell provided in an embodiment of the present invention; Figure 3 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 4 This is a partial schematic diagram of another back-contact solar cell provided in an embodiment of the present invention; Figure 5 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 6 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 7 A partial schematic diagram of the back contact solar cell with solder strips provided in an embodiment of the present invention; Figure 8 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 9 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of a fine grid of a back-contact solar cell provided in an embodiment of the present invention; Figure 11 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 12 This is a partial schematic diagram of a back-contact solar cell provided in an embodiment of the present invention; Figure 13This is a partial cross-sectional schematic diagram of a back-contact solar cell provided in an embodiment of the present invention.

[0039] Explanation of key symbols: Back contact solar cell 100, silicon substrate 1, back surface 11, first direction X, second direction Y, doped layer 2, first doped layer 21, second doped layer 22, spacer region 23, first doped portion 201, second doped portion 202, first marking region 2011, first marking structure 6, first marking substrate 61, first marking point 62, third doped portion 203, fourth doped portion 204, second marking region 2012, second marking structure 7, second marking substrate 71, second marking point 72, fifth doped portion 205, sixth doped portion 206, third marking region 201 3. Third marking structure 8, third marking base 81, fourth marking base 82, third marking point 83, marking group 9, serial connection area 13, first serial connection area 131, second serial connection area 132, solder strip 200, fine grid 3, first fine grid 31, second fine grid 32, first edge 101, second edge 102, third edge 103, fourth edge 104, widened part 301, non-widened part 302, raised structure 303, honeycomb structure 305, main grid 4, edge main grid 41, connecting grid line 5, extension part 306, first area 208, second area 209. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] In the description of this invention, it should be understood that the terms "upper", "lower", "back", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention 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 invention.

[0042] In this invention, unless otherwise explicitly 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 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 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.

[0043] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. 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, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0044] Please refer to Figures 1-5 An embodiment of the present invention provides a back-contact solar cell 100, comprising: Silicon substrate 1, silicon substrate 1 includes a back surface 11; A plurality of doped layers 2 are disposed on the back side 11, each doped layer 2 including a first doped portion 201 and a second doped portion 202. The first doped portion 201 extends along a first direction X. The first doped portion 201 and the second doped portion 202 are spaced apart in the first direction X to form a first marking region 2011. The first identification structure 6 is located in the first identification area 2011, and the first identification structure 6 is spaced apart from the first doped part 201 and the second doped part 202.

[0045] The back-contact solar cell 100 provided in this embodiment of the invention has a plurality of doped layers 2 disposed on the back side 11. The doped layers 2 are configured to include a first doped portion 201 and a second doped portion 202. The first doped portion 201 extends along a first direction X. The first doped portion 201 and the second doped portion 202 are spaced apart in the first direction X to form a first marking area 2011. A first marking structure 6 is disposed in the first marking area 2011. The first marking structure 6 is spaced apart from the first doped portion 201 and the second doped portion 202. Since the first marking structure 6 is spaced apart from the first doped portion 201 and the second doped portion 202 in the first direction X, the doped layers 2 are not continuous along the first direction X at the position where the first marking structure 6 is disposed. This facilitates the formation of a significant contrast between the first marking structure 6 and the doped layers 2 in the surrounding area, reduces the influence of the doped layers 2 in the surrounding area of ​​the first marking structure 6 on the visual system's recognition of the first marking structure 6, and facilitates the visual system's rapid and accurate recognition of the first marking structure 6. The first marking structure 6 is more easily recognized by the visual system, which can reduce the situation of visual system recognition failure or misjudgment and improve the printing yield of the back-contact solar cell 100.

[0046] In this embodiment of the invention, the silicon substrate 1 includes a back side 11 and a front side (not labeled) disposed opposite to each other along its thickness direction. The back side 11 of the silicon substrate 1 is specifically the back-light side of the silicon substrate 1, and the front side of the silicon substrate 1 is specifically the light-facing side of the silicon substrate 1. The light-facing side of the silicon substrate 1 is the side that mainly receives sunlight when the back-contact solar cell 100 is working normally. Of course, the back-light side of the silicon substrate 1 can also receive some sunlight when the back-contact solar cell 100 is working normally.

[0047] The specific number of the first identifier structure 6 is not limited; there can be one, two, three, or more first identifier structures 6. Figure 1 The diagram shows that there are two of the first identifier structures 6.

[0048] In this embodiment of the invention, the first doped portion 201 extends along the first direction X, that is, the length direction of the first doped portion 201 is the first direction X. The distance between the first marking structure 6 and the first doped portion 201 along the first direction X, and the distance between the first marking structure 6 and the second doped portion 202 along the first direction X, are both greater than or equal to the dimension of the first marking structure 6 along the first direction X. This ensures that the distance between the first marking structure 6 and the first doped portion 201 and the second doped portion 202 along the first direction X is sufficiently large, which is more conducive to the accurate identification of the first marking structure 6 by the vision system. For example, the ratio of the distance between the first marking structure 6 and the first doped portion 201 along the first direction X to the dimension of the first marking structure 6 along the first direction X, and the ratio of the distance between the first marking structure 6 and the second doped portion 202 along the first direction X to the dimension of the first marking structure 6 along the first direction X, are both 1.1 to 3.

[0049] Please refer to Figure 3 and Figure 4 As an embodiment of the present invention, the doped layer 2 includes a first doped layer 21 and a second doped layer 22 with opposite doping types, and the first doped layer 21 and the second doped layer 22 are disposed at intervals; the second doped layer 22 includes a first doped portion 201 and a second doped portion 202; or, the first doped layer 21 includes a first doped portion 201 and the second doped layer 22 includes a second doped portion 202.

[0050] In this embodiment, the specific doping types of the first doped layer 21 and the second doped layer 22 are not limited. Specifically, the first doped layer 21 can be a P-type doped layer and the second doped layer 22 can be an N-type doped layer; or, the first doped layer 21 can be an N-type doped layer and the second doped layer 22 can be a P-type doped layer. The P-type doped layer is doped with a P-type doping element, that is, it is doped with P-type doped atoms; the N-type doped layer is doped with an N-type doping element, that is, it is doped with N-type doped atoms. The P-type doping element is a Group IIIA element in the periodic table, and the N-type doping element is a Group VA element in the periodic table. For example, the P-type doping element can be boron, and the N-type doping element can be phosphorus. The first doped layer 21 and the second doped layer 22 are at least one of the following: a doped polycrystalline silicon layer, a doped amorphous silicon layer, a doped microcrystalline silicon layer, and a doped nanocrystalline silicon layer.

[0051] In this embodiment, a spacer region 23 may be provided between adjacent first doped layers 21 and second doped layers 22. The spacer region 23 may be a trench, and adjacent first doped layers 21 and second doped layers 22 are physically isolated by the spacer region 23.

[0052] Please refer to Figure 3As an embodiment of the present invention, the first doped layer 22 includes a first doped portion 201 and a second doped portion 202. That is, the first doped portion 201 is a part of the second doped layer 22, and the second doped portion 202 is a part of the second doped layer 22. The first doped portion 201 and the second doped portion 202 have the same doping type and are both the same as the doping type of the second doped layer 22. For example, the second doped layer 22 is a P-type doped layer, and the first doped portion 201 and the second doped portion 202 are both P-type doped layers; or, for another example, the second doped layer 22 is an N-type doped layer, and the first doped portion 201 and the second doped portion 202 are both N-type doped layers. In this embodiment, the first marking structure 6 is disposed between the first doped portion 201 and the second doped portion 202 spaced apart along the first direction X, and the first doped portion 201 and the second doped portion 202 have the same doping type. The first doped portion 201 and the second doped portion 202 can be prepared simultaneously. After the second doped layer 22 is deposited, the second doped layer 22 between the first marking structure 6 and the first doped portion 201 and the second doped layer 202 is locally removed by laser, thereby obtaining the first marking substrate 61 containing the first doped portion 201, the second doped portion 202, and the first marking structure 6, which facilitates the processing of the first marking structure 6. In some embodiments, the first doped layer 21 may also include the first doped portion 201 and the second doped portion 202.

[0053] Please refer to Figure 4 In another embodiment of the present invention, the first doped layer 21 includes a first doped portion 201, and the second doped layer 22 includes a second doped portion 202.

[0054] In this embodiment, the first doped layer 21 includes a first doped portion 201, and the second doped layer 22 includes a second doped portion 202. That is, the first doped portion 201 is a part of the first doped layer 21, and the second doped portion 202 is a part of the second doped layer 22. At this time, the doping types of the first doped portion 201 and the second doped portion 202 are opposite. For example, the first doped layer 21 is a P-type doped layer, the second doped layer 22 is an N-type doped layer, the first doped portion 201 is a P-type doped layer, and the second doped portion 202 is an N-type doped layer; or, for another example, the first doped layer 21 is an N-type doped layer, the second doped layer 22 is a P-type doped layer, the first doped portion 201 is an N-type doped layer, and the second doped portion 202 is a P-type doped layer.

[0055] In this embodiment, the first identification structure 6 is disposed between the first doped portion 201 and the second doped portion 202 spaced apart along the first direction X, and the doping types of the first doped portion 201 and the second doped portion 202 are opposite. Since the doping types of the first doped portion 201 and the second doped portion 202 are opposite, the first doped portion 201 and the second doped portion 202 exhibit a certain color difference. The first identification structure 6 is disposed between two doped layers 2 of different colors, which can improve the recognizability of the first identification structure 6, make the first identification structure 6 easier to be recognized by the vision system, and improve the recognition reliability of the vision system.

[0056] As an embodiment of the present invention, the first doped layer 21 and the second doped layer 22 are respectively extended along the first direction X, and at least a portion of the first doped layer 21 and at least a portion of the second doped layer 22 are alternately spaced along the second direction Y.

[0057] In this embodiment of the invention, the direction intersecting the first direction X is the second direction Y. The first direction X and the second direction Y may be perpendicular or not. Preferably, the first direction X and the second direction Y are perpendicular, that is, one of the first direction X and the second direction Y is the length direction of the silicon substrate 1, and the other is the width direction of the silicon substrate 1.

[0058] In this embodiment, the polarities of two adjacent doped layers 2 along the second direction Y are opposite, and one of the two adjacent doped layers 2 along the second direction Y is a P-type doped layer and the other is an N-type doped layer. In this embodiment, there are multiple first doped layers 21 and second doped layers 22. At least a portion of the first doped layers 21 and second doped layers 22 are alternately spaced along the second direction Y, and both the first doped layers 21 and second doped layers 22 extend along the first direction X, that is, the length direction of both the first doped layers 21 and second doped layers 22 is along the first direction X. Of course, some first doped layers 21 and second doped layers 22 can also be arranged relatively spaced along the first direction X, so that the first doped layer 21 forms the first doped portion 201 and the second doped layer 22 forms the second doped portion 202.

[0059] As one embodiment of the present invention, it also includes: A plurality of fine gates 3 are disposed on the back side 11, each fine gate 3 being disposed on a corresponding doped layer 2. The fine gates 3 extend along the first direction X, and the plurality of fine gates 3 are alternately spaced along the second direction Y.

[0060] In this embodiment, each fine gate 3 is disposed on a corresponding doped layer 2, and the fine gate 3 extends along the first direction X. Specifically, the fine gate 3 disposed on the P-type doped layer is a P-type fine gate, and the fine gate 3 disposed on the N-type doped layer is an N-type fine gate. More specifically, the plurality of fine gates 3 include a first fine gate 31 and a second fine gate 32 alternately disposed along the second direction Y. The first fine gate 31 is disposed on the first doped layer 21, and the second fine gate 32 is disposed on the second doped layer 22.

[0061] As an embodiment of the present invention, fine gates 3 are respectively provided on the first doped portion 201 and the second doped portion 202. The fine gates 3 on the first doped portion 201 and the fine gates 3 on the second doped portion 202 are spaced apart in the first marking area 2011. The spacing between two adjacent fine gates 3 in the second direction Y is d. The ratio of the distance from the center of the first marking structure 6 to the center line of the fine gate 3 on the first doped portion 201 along the second direction Y to d is 0 to 0.2. And / or, the ratio of the distance from the center of the first marking structure 6 to the center line of the fine gate 3 on the second doped portion 202 along the second direction Y to d is 0 to 0.2.

[0062] In this embodiment, the fine gate 3 on the first doped portion 201 and the fine gate 3 on the second doped portion 202 are spaced apart in the first marking area 2011. That is, a fine gate 3 arranged along the first direction X is intermittently arranged in the first marking area 2011, so that the fine gate 3 on the first doped portion 201 and the fine gate 3 on the second doped portion 202 are spaced apart from the first marking structure 6, which is more conducive to the visual system recognizing the first marking structure 6. The polarities of the fine gate 3 on the first doped portion 201 and the fine gate 3 on the second doped portion 202 can be the same or opposite. When the doping types of the first doped portion 201 and the second doped portion 202 are the same, the polarities of the fine gate 3 on both are the same; when the doping types of the first doped portion 201 and the second doped portion 202 are opposite, the polarities of the fine gate 3 on both are opposite.

[0063] In this embodiment, the center of the first marking structure 6 and the center line of the fine grid 3 on the first doped portion 201 may or may not be collinear; the center of the first marking structure 6 and the center line of the fine grid 3 on the second doped portion 202 may or may not be collinear. The ratio of the distance from the center of the first marking structure 6 along the second direction Y to the center line of the fine grid 3 on the first doped portion 201 to d is controlled to be 0~0.2. When the ratio is 0, the offset distance between the center of the first marking structure 6 and the center line of the fine grid 3 on the first doped portion 201 in the second direction Y is 0, and at this time, the center of the first marking structure 6 and the center line of the fine grid 3 on the first doped portion 201 are collinear in the first direction X. Controlling this ratio within the above range ensures a small offset distance between the center of the first marking structure 6 and the center line of the fine grid 3 on the first doped portion 201 in the second direction Y, ensuring the positioning effect of the first marking structure 6 on the battery and further facilitating battery printing accuracy. Further, the ratio of the distance from the center of the first marking structure 6 along the second direction Y to the center line of the fine grid 3 on the first doped portion 201 to d is 0~0.1.

[0064] Similarly, the ratio of the distance from the center of the first marking structure 6 along the second direction Y to the center line of the fine grid 3 on the second doped portion 202 to d is 0~0.2. When the ratio is 0, the offset distance between the center of the first marking structure 6 and the center line of the fine grid 3 on the second doped portion 202 in the second direction Y is 0. At this time, the center of the first marking structure 6 and the center line of the fine grid 3 on the second doped portion 202 are collinear in the first direction X. By controlling the ratio within the above range, the offset distance between the center of the first marking structure 6 and the center line of the fine grid 3 on the second doped portion 202 in the second direction Y is small, further ensuring the positioning effect of the first marking structure 6 on the battery and making it easier to ensure the battery printing accuracy. Furthermore, the ratio of the distance from the center of the first marking structure 6 along the second direction Y to the center line of the fine grid 3 on the second doped portion 202 to d is 0~0.1.

[0065] As an embodiment of the present invention, the first marking structure 6 is spaced apart from the adjacent doped layer 2 in the second direction Y.

[0066] In this embodiment, in the second direction Y, the first marking structure 6 is spaced apart from the adjacent doped layer 2, so that the first marking structure 6 is spaced apart from the doped layer 2 in both the first direction X and the second direction Y. The first marking structure 6 is an isolated structure independent of the surrounding doped layer 2, which is more conducive to distinguishing the first marking structure 6 from the surrounding doped layer 2 and more conducive to the visual system recognizing the first marking structure 6.

[0067] As an embodiment of the present invention, the first marking structure 6 includes a first marking base 61 disposed on the back side 11 and a first marking point 62 disposed on the first marking base 61; The first identification substrate 61 has the opposite or the same doping type as the first doped portion 201, and the first identification substrate 61 has the opposite or the same doping type as the second doped portion 202.

[0068] In this embodiment, the first identification substrate 61 can be a P-type doped layer or an N-type doped layer. Optionally, the doping type of the first identification substrate 61 is opposite to that of the first doped portion 201, and the doping type of the first identification substrate 61 is opposite to that of the second doped portion 202. This makes the colors of the first identification substrate 61, the first doped portion 201, and the second doped portion 202 different, making the contrast between the first identification substrate 61 and the surrounding area more obvious and facilitating the visual system to identify the first identification structure 6. For example, the first identification substrate 61 is a P-type doped layer, and the first doped portion 201 and the second doped portion 202 are both N-type doped layers; or, for another example, the first identification substrate 61 is an N-type doped layer, and the first doped portion 201 and the second doped portion 202 are both P-type doped layers.

[0069] In one embodiment of the present invention, the first identification substrate 61 and the first doped portion 201 have the same doping type and the same height, making them flush, which further facilitates the visual system's recognition of the first identification structure 6; or, the first identification substrate 61 and the second doped portion 202 have the same doping type and the same height, making them flush, which further facilitates the visual system's recognition of the first identification structure 6. Optionally, the first identification substrate 61 and the first doped portion 201 have the same doping type and the same height, and the first identification substrate 61 and the second doped portion 202 have the same doping type and the same height, which further facilitates the visual system's recognition of the first identification structure 6.

[0070] As an embodiment of the present invention, the doped layer 2 further includes a third doped portion 203 and a fourth doped portion 204, the third doped portion 203 extending along a first direction X, and the third doped portion 203 and the fourth doped portion 204 spaced apart in the first direction X to form a second marking region 2012; the back contact solar cell 100 includes: The second identification structure 7 is located in the second identification region 2012, and the second identification structure 7 is spaced apart from the third doped portion 203 and the fourth doped portion 204.

[0071] In this embodiment, a third doped portion 203 and a fourth doped portion 204 are provided. The third doped portion 203 extends along the first direction X, and the third doped portion 203 and the fourth doped portion 204 are spaced apart in the first direction X to form a second marking area 2012. A second marking structure 7 is provided in the second marking area 2012, and the second marking structure 7 is spaced apart from the third doped portion 203 and the fourth doped portion 204. By adding the second marking structure 7, the number of marking structures can be increased, which can further improve the alignment accuracy of the battery. Moreover, since the second marking structure 7 is spaced apart from the third doped portion 203 and the fourth doped portion 204 in the first direction X, it is beneficial for the second marking structure 7 to form a clear contrast with the features of the surrounding area, which is beneficial for the vision system to accurately identify the second marking structure 7. The second marking structure 7 is easily identified by the vision system, which can reduce the probability of vision system recognition failure or misjudgment, and is more conducive to the printing process of the back contact solar cell 100.

[0072] In this embodiment, the first doped layer 21 or the second doped layer 22 may include a third doped portion 203 and a fourth doped portion 204, or one of the first doped layer 21 and the second doped layer 22 may include a third doped portion 203 and the other may include a fourth doped portion 204.

[0073] In this embodiment, the number of second identifier structures 7 can be one, two, three, or more. Figure 1 The diagram shows that there are two of the second identifier structures 7.

[0074] As an embodiment of the present invention, fine gates 3 are respectively provided on the third doped portion 203 and the fourth doped portion 204. The fine gates 3 on the third doped portion 203 and the fine gates 3 on the fourth doped portion 204 are spaced apart in the second marking region 2012. The center line of the fine gate 3 on the third doped portion 203 at the center of the second marking structure 7 may be collinear or non-collinear in the first direction X. The center line of the second marking structure 7 and the center line of the fine gate 3 on the fourth doped portion 204 may be collinear or non-collinear in the first direction X.

[0075] As an embodiment of the present invention, the second marking structure 7 includes a second marking substrate 71 disposed on the back side 11 and a second marking point 72 disposed on the second marking substrate 71. The doping type of the second marking substrate 71 is opposite to or the same as that of the third doped portion 203, and the doping type of the second marking substrate 71 is opposite to or the same as that of the fourth doped portion 204.

[0076] In this embodiment, the second identification substrate 71 can be a P-type doped layer or an N-type doped layer. Preferably, the doping type of the second identification substrate 71 is opposite to that of the third doped portion 203, and the doping type of the second identification substrate 71 is opposite to that of the fourth doped portion 204. This makes the color of the second identification substrate 71 different from that of the third doped portion 203 and the fourth doped portion 204, making the contrast between the second identification substrate 71 and the surrounding area more obvious and facilitating the visual system to identify the second identification structure 7. For example, the second identification substrate 71 can be an N-type doped layer, and the third doped portion 203 and the fourth doped portion 204 can both be P-type doped layers; or, for example, the second identification substrate 71 can be a P-type doped layer, and the third doped portion 203 and the fourth doped portion 204 can both be N-type doped layers.

[0077] As an embodiment of the present invention, the second identification structure 7 is connected to the adjacent doped layer 21 in the second direction Y.

[0078] Specifically, the second identifier substrate 71 of the second identifier structure 7 is connected to the adjacent doped layer 2 in the second direction Y. In this embodiment, the second identifier substrate 71 and the adjacent doped layer 2 in the second direction Y have the same doping type. For example, the second identifier substrate 71 is a P-type doped layer, and the two doped layers 2 adjacent to the second identifier structure 7 in the second direction Y are both P-type doped layers. The second identifier substrate 71 is connected to the two adjacent P-type doped layers in the second direction Y.

[0079] In this embodiment, the second identification structure 7 is connected to the adjacent doped layer 2 in the second direction Y, while the first identification structure 6 is spaced apart from the adjacent doped layer 2 in the second direction Y. This makes the second identification structure 7 and the first identification structure 6 present two different image features, which helps the vision system to distinguish between the second identification structure 7 and the first identification structure 6 and can better reduce the probability of misjudgment by the vision system.

[0080] As an embodiment of the present invention, the second identification substrate 71 has the opposite doping type to the first identification substrate 61.

[0081] In this embodiment, the second marking substrate 71 has the opposite doping type to the first marking substrate 61; that is, one of the second marking substrate 71 and the first marking substrate 61 is a P-type doped layer, and the other is an N-type doped layer. Because the material properties, doping concentration, and colors formed after processing differ between the P-type and N-type doped layers, the first marking substrate 61 and the second marking substrate 71 will exhibit a certain color difference. This allows the first marking structure 6 and the second marking structure 7 to form two completely different imaging features in the optical vision system. The visual recognition system can better distinguish between the first marking structure 6 and the second marking structure 7, reducing the probability of misidentification and thus improving the alignment reliability of the back-contact solar cell 100. Furthermore, by utilizing the color difference between the marking substrates of the first marking structure 6 and the second marking structure 7, and combining this with the structural difference of the second marking structure 7 being connected to the adjacent doped layer 2 in the second direction Y, while the first marking structure 6 is spaced apart from the adjacent doped layer 2 in the second direction Y, the visual recognition system can better distinguish between the first marking structure 6 and the second marking structure 7, greatly improving the alignment reliability of the cell.

[0082] Please refer to the reference. Figure 1 , Figure 2 and Figure 5 As an embodiment of the present invention, the doped layer 2 further includes a fifth doped portion 205 and a sixth doped portion 206, the fifth doped portion 205 extending along the first direction X, and the fifth doped portion 205 and the sixth doped portion 206 spaced apart in the first direction X to form a third marking region 2013; the back contact solar cell 100 includes: The third identification structure 8 is located in the third identification region 2013, and the third identification structure 8 is spaced apart from the fifth doped part 205 and the sixth doped part 206.

[0083] In this embodiment, by setting the third identification structure 8, the number of identification structures can be further increased. By using multiple identification structures for alignment, the alignment accuracy of the battery can be further improved. Moreover, since the third identification structure 8 is spaced apart from the fifth doped portion 205 and the sixth doped portion 206 in the first direction X, it is beneficial for the third identification structure 8 to form a clear contrast with the features of the surrounding area, which is beneficial for the vision system to accurately identify the third identification structure 8. The third identification structure 8 is easily identified by the vision system, which can reduce the probability of vision system recognition failure or misjudgment, and is more conducive to the printing process of the back contact solar cell 100.

[0084] In this embodiment, the first doped layer 21 or the second doped layer 22 may include a fifth doped portion 205 and a sixth doped portion 206, or one of the first doped layer 21 and the second doped layer 22 may include a fifth doped portion 205 and the other may include a sixth doped portion 206.

[0085] The number of third identifier structures 8 can be one, two, three, or more. Figure 1 The diagram shows that there are two of the third identifier structures, 8.

[0086] As an embodiment of the present invention, the third identification structure 8 is spaced apart from the adjacent doped layer 2 in the second direction Y.

[0087] In this embodiment, in the second direction Y, the third identification structure 8 is spaced apart from the adjacent doped layer 2, such that the third identification structure 8 is spaced apart from the doped layer 2 in both the first direction X and the second direction Y. The third identification structure 8 is independent of the surrounding first doped layer 21 and second doped layer 22, which makes it easier to distinguish the third identification structure 8 from the first doped layer 21 and second doped layer 22, and makes it easier for the vision system to recognize the third identification structure 8.

[0088] In one embodiment of the present invention, fine gates 3 are respectively provided on the fifth doped portion 205 and the sixth doped portion 206, and the fine gates 3 on the fifth doped portion 205 and the sixth doped portion 206 are spaced apart in the third marking region 2013. Preferably, in the first direction X, the center of the third marking structure 8 is on the same straight line as the center line of the fine gate 3 of the fifth doped portion 205 and the center line of the fine gate 3 of the sixth doped portion 206, which is beneficial to improving the alignment effect of the third marking structure 8.

[0089] As an embodiment of the present invention, the third identification structure 8 includes a third identification substrate 81 disposed on the back side 11, a fourth identification substrate 82 stacked on the third identification substrate 81, and a third marking point 83 disposed on the fourth identification substrate 82. The doping types of the third identification substrate 81 and the fourth identification substrate 82 are opposite.

[0090] In this embodiment, the third marker point 83 is disposed on the stacked region of the third marker substrate 81 and the fourth marker substrate 82, and the doping types of the third marker substrate 81 and the fourth marker substrate 82 are opposite, that is, one of the third marker substrate 81 and the fourth marker substrate 82 is a P-type doped layer and the other is an N-type doped layer. Since the P-type doped layer and the N-type doped layer overlap, the resulting color is different from the color of the first doped layer 21 and the second doped layer 22. Therefore, the imaging feature formed by the third marker structure 8 in the optical vision system is different from the imaging feature formed by the first marker structure 6 and the second marker structure 7 in the optical vision system. This is beneficial for the vision system to distinguish the first marker structure 6, the second marker structure 7 and the third marker structure 8, which can better prevent battery alignment errors and further improve the alignment reliability of the back contact solar cell 100. Moreover, since the third marker structure 8 includes the third marker substrate 81 and the fourth marker substrate 82 stacked on the third marker substrate 81, the height of the third marker structure 8 can be increased, which can reduce the distance between the recognition device of the vision system and the third marker structure 8, making it easier for the vision system to recognize the third marker structure 8.

[0091] As an embodiment of the present invention, the first marking base 61 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the first marking point 62 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

[0092] In this embodiment, the shapes of the first identifier base 61 and the first marker point 62 can be the same or different. The first identifier base 61 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; the first marker point 62 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon. Optionally, both the first identifier base 61 and the first marker point 62 are circular, which facilitates the fabrication of the first identifier structure 6. In some embodiments, the shapes of the first identifier base 61 and the first marker point 62 are different, making their outlines different, which is more conducive to the vision system grasping the first identifier structure 6.

[0093] As an embodiment of the present invention, the second marking base 71 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the second marking point 72 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

[0094] In this embodiment, the shapes of the second identifier base 71 and the second marker point 72 can be the same or different. The second identifier base 71 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; the second marker point 72 is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon. Optionally, the second identifier base 71 is a quadrilateral and the second marker point 72 is a circle, so that the outline shapes of the second identifier base 71 and the second marker point 72 are different, which is more conducive to the visual system grasping the second identifier structure 7.

[0095] As an embodiment of the present invention, the third marking base 81 and the fourth marking base 82 are respectively one of a circle, a quadrilateral, a triangle, a trapezoid, a pentagon, a hexagon, and an octagon; and / or, the third marking point 83 is one of a circle, a quadrilateral, a triangle, a trapezoid, a pentagon, a hexagon, and an octagon.

[0096] In this embodiment, the shapes of the third identifier base 81 and the fourth identifier base 82 can be the same or different. Optionally, both the third identifier base 81 and the fourth identifier base 82 are circular, and the third marker point 83 is circular, which facilitates the fabrication of the third identifier structure 8. In some embodiments, the shapes of the third identifier base 81, the fourth identifier base 82, and the third marker point 83 are different, making their outlines different, which is more conducive to the vision system grasping the third identifier structure 8.

[0097] In this embodiment of the invention, the first marker point 62 may or may not completely cover the first identifier base 61. In some embodiments, the first marker point 62 may cover 50% to 90% of the area of ​​the first identifier base 61, which facilitates the visual system to identify the first identifier structure 6 based on the colors of the first marker point 62 and the first identifier base 61, thereby improving the recognition reliability of the first identifier structure 6. Similarly, the second marker point 72 may or may not completely cover the second identifier base 71. In some embodiments, the second marker point 72 may cover 50% to 90% of the area of ​​the second identifier base 71, which facilitates the visual system to identify the second identifier structure 7 based on the colors of the second marker point 72 and the second identifier base 71, thereby improving the recognition reliability of the second identifier structure 7. Moreover, it also facilitates the visual system to distinguish the first identifier structure 6 and the second identifier structure 7 based on the color difference between the first identifier base 61 and the second identifier base 71.

[0098] In some embodiments, the area of ​​the fourth identifier base 82 is smaller than the area of ​​the third identifier base 81, and the area of ​​the third marker point 83 is smaller than the area of ​​the fourth identifier base 82, so that the third identifier structure 8 can present the edge contours of the three, which is more conducive to the visual system recognizing the third identifier structure 8. The centers of the third identifier base 81, the fourth identifier base 82, and the third marker point 83 may or may not coincide.

[0099] As an embodiment of the present invention, the first marking point 62, the second marking point 72, and the third marking point 83 can specifically be metal layers, and can be prepared by printing. The paste of the first marking point 62, the second marking point 72, and the third marking point 83 can be the same as or different from the paste of the fine grid 3. For example, the first marking point 62, the second marking point 72, and the third marking point 83 can be printed with silver paste or aluminum paste.

[0100] Please refer to this again. Figure 1 As an embodiment of the present invention, the first marking structure 6 and the second marking structure 7 are located on one side of the center line L of the silicon substrate 1, and the third marking structure 8 is located on the other side of the center line L of the silicon substrate 1.

[0101] In this embodiment, the first marking structure 6 and the second marking structure 7 are both located on one side of the center line L of the silicon substrate 1, and the third marking structure 8 is located on the other side of the center line L of the silicon substrate 1. Since the structures of the first marking structure 6 and the second marking structure 7 are different from the third marking structure 8, setting the first marking structure 6 and the second marking structure 7 on one side of the center line L of the silicon substrate 1 and setting the third marking structure 8 on the other side of the center line L of the silicon substrate 1 makes the marking structures on both sides of the center line L of the silicon substrate 1 asymmetrically arranged. This ensures that each marking structure on the solar cell has a unique correspondence with the correct placement of the solar cell, and can quickly detect situations where the placement direction of the solar cell is opposite to the preset direction, avoiding printing errors caused by reversed solar cells.

[0102] As an embodiment of the present invention, the total number of the first identification structure 6 and the second identification structure 7 is different from the number of the third identification structure 8.

[0103] In this embodiment, the total number of the first marking structure 6 and the second marking structure 7 is further set to be different from the number of the third marking structure 8. That is, the number of marking structures on both sides of the center line L of the silicon substrate 1 is also asymmetrically arranged, that is, the number of marking structures in the upper half of the battery is different from the number of marking structures in the lower half of the battery. This can further prevent printing errors caused by the battery being reversed. In this embodiment, the total number of the first marking structure 6 and the second marking structure 7 can be four, and the number of the third marking structure 8 can be two; wherein, the number of the first marking structure 6 can be two, and the number of the second marking structure 7 can be two. Alternatively, the total number of the first marking structure 6 and the second marking structure 7 can be three, and the number of the third marking structure 8 can be two; wherein, the number of the first marking structure 6 can be one, and the number of the second marking structure 7 can be two.

[0104] As an embodiment of the present invention, each first identifier structure 6 is arranged adjacent to a corresponding second identifier structure 7 to form a mark group.

[0105] In this embodiment, the first identification structure 6 and the second identification structure 7 within the marking group 9 are spaced apart along the second direction Y. Of course, the first identification structure 6 and the second identification structure 7 within the marking group 9 can also be spaced apart along the first direction X or other directions. Each first identification structure 6 is arranged adjacent to a corresponding second identification structure 7 to form a marking group 9. This combination of the first identification structure 6 and the second identification structure 7 allows for simultaneous alignment of the battery cells, further improving positioning accuracy. Alternatively, each marking group 9 can include multiple first identification structures 6 and multiple second identification structures 7.

[0106] Please refer to this again. Figure 3 As an embodiment of the present invention, the spacing between two adjacent fine grids 3 in the second direction Y is d, and the spacing between the first identification structure 6 and the second identification structure 7 of each mark group 9 is D1, satisfying 2d < D1 < 10d.

[0107] In this embodiment, the spacing between two adjacent fine grids 3 is the distance between the center lines of two adjacent fine grids 3 along the second direction Y. The spacing between the first identification structure 6 and the second identification structure 7 of each mark group 9 is the distance between the center of the first identification structure 6 and the center of the second identification structure 7. D1 and d satisfy: 2d < D1 < 10d. This avoids the distance between the first identification structure 6 and the second identification structure 7 of the mark group 9 being too small, which helps the vision system to better distinguish between the first identification structure 6 and the second identification structure 7, and avoids the center distance between the first identification structure 6 and the second identification structure 7 being too large, which would make it difficult for the vision system to simultaneously capture the first identification structure 6 and the second identification structure 7. Furthermore, satisfying 2d < D1 < 5d further facilitates the vision system in recognizing the first identification structure 6 and the second identification structure 7.

[0108] As an embodiment of the present invention, the number of marker groups 9 is at least two, and at least two marker groups 9 are arranged at intervals along the first direction X.

[0109] In this embodiment, the number of marker groups 9 is set to at least two. By using at least two marker groups 9 in combination, the positioning accuracy of the back contact solar cell 100 can be further improved. Figure 1 The diagram illustrates two marker groups 9, which are spaced apart along the first direction X. However, in some embodiments, the number of marker groups 9 may be only one.

[0110] As an embodiment of the present invention, the ratio of the spacing D2 between the first identification structures 6 of two adjacent marking groups 9 to the dimension L11 of the silicon substrate 1 along the first direction X is 0.25 to 0.8; and or, the ratio of the spacing D3 between the second identification structures 7 of two adjacent marking groups 9 to the dimension of the silicon substrate 1 along the first direction X is 0.25 to 0.8.

[0111] In this embodiment, the spacing between the first identification structures 6 of two adjacent marker groups 9 is the center-to-center spacing of the first identification structures 6 of two adjacent marker groups 9, which is also the center-to-center spacing of two adjacent first marker points 62; the spacing between the second identification structures 7 of two adjacent marker groups 9 is the center-to-center spacing of the second identification structures 7 of two adjacent marker groups 9, which is also the center-to-center spacing of two adjacent second marker points 72; controlling the ratio of D2 to L11 to 0.25~0.8, and / or the ratio of D3 to L11 to 0.25~0.8, makes the spacing between two adjacent marker groups 9 more reasonable, avoids the spacing between adjacent marker groups 9 being too small, which is more conducive to improving the positioning accuracy of the marker group 9 for the battery cell, and avoids the spacing between adjacent marker groups 9 being too large, which makes it convenient for the vision system to grasp each marker group 9 at the same time, and can improve the positioning reliability of each marker group 9.

[0112] Please refer to the reference. Figure 2 , Figure 6 , Figure 7 As an embodiment of the present invention, the back surface 11 includes a plurality of serial connection areas 13 for setting solder strips 200. The plurality of serial connection areas 13 are alternately spaced along a first direction X and the serial connection areas 13 extend along a second direction Y. The solder strips 200 of two adjacent serial connection areas 13 have opposite polarities, and the solder strips 200 of each serial connection area 13 are used to electrically connect fine grids 3 of the same polarity.

[0113] In this embodiment, multiple series connection regions 13 are used to set solder ribbons 200 so that back-contact solar cells 100 are connected in series to form a battery module. The solder ribbons 200 of two adjacent series connection regions 13 are connected to fine grids 3 of different polarities, so that the polarities of the solder ribbons 200 of two adjacent series connection regions 13 are opposite. The multiple series connection regions 13 are alternately spaced along a first direction X, and each series connection region 13 extends along a second direction Y, with the solder ribbons 200 extending along the second direction Y within the series connection region 13. The fine grids 3 are continuous in the series connection regions 13 of solder ribbons 200 of the same polarity and are spaced apart in the series connection regions 13 of solder ribbons 200 of different polarities, so that the solder ribbons 200 in the series connection regions 13 are electrically connected to the fine grids 3 of the same polarity, and the solder ribbons 200 in the series connection regions 13 are not electrically connected to the fine grids 3 of different polarities.

[0114] In this embodiment, the polarity of the solder strip 200 in the series connection region 13 is the same as the polarity of the fine gate 3 it is electrically connected to. For example, if the solder strip 200 in the series connection region 13 is electrically connected to a P-type fine gate, then the polarity of the solder strip 200 in the series connection region 13 is P-type; if the solder strip 200 in the series connection region 13 is electrically connected to an N-type fine gate, then the polarity of the solder strip 200 in the series connection region 13 is N-type. The solder strips 200 of adjacent series connection regions 13 have opposite polarities. This can be understood as the solder strips 200 of adjacent series connection regions 13 being electrically connected to fine gates 3 of different polarities. In any two adjacent series connection regions 13, if the solder strip 200 of one series connection region 13 is electrically connected to a P-type fine gate, then the polarity of the solder strip 200 in the series connection region 13 is P-type; if the solder strip 200 of the other series connection region 13 is electrically connected to an N-type fine gate, then the polarity of the solder strip 200 in the series connection region 13 is N-type.

[0115] As an embodiment of the present invention, the plurality of serial connection areas 13 include a first serial connection area 131 and a second serial connection area 132 that are alternately arranged along the first direction X. The solder strip 200 of the first cascade region 131 is used for electrical connection of the first fine gate 31, and the solder strip 200 of the second cascade region 132 is used for electrical connection of the second fine gate 32.

[0116] In this embodiment, the solder strip 200 of the first serial connection area 131 is electrically connected to the first fine gate 31, and the solder strip 200 of the first serial connection area 131 is not connected to the second fine gate 32; the solder strip 200 of the second serial connection area 132 is electrically connected to the second fine gate 32, and the solder strip 200 of the second serial connection area 132 is not connected to the first fine gate 31.

[0117] In this embodiment, the silicon substrate 1 includes a first edge 101 and a second edge 102 disposed opposite to each other along the second direction Y, and a third edge 103 and a fourth edge 104 disposed opposite to each other along the first direction X.

[0118] Please refer to Figure 8As an embodiment of the present invention, the fine grid 3 includes a widened portion 301 located at the serial connection area 13 of the same polarity solder strip 200, and a non-widened portion 302 located outside the serial connection area 13 of the same polarity solder strip 200. The dimension L5 of the widened portion 301 along the second direction Y is greater than the dimension L6 of the non-widened portion 302 along the second direction Y.

[0119] In this embodiment, the width of the fine grid 3 at the same polarity series connection region 13 is widened to form a widened portion 301, and the area of ​​the fine grid 3 that is not widened is a non-widened portion 302. This increases the contact area between the fine grid 3 and the same polarity solder ribbon 200, improves the welding effect between the fine grid 3 and the same polarity solder ribbon 200, and improves the current collection effect of the back contact solar cell 100. Specifically, the P-type fine grid forms a widened portion 301 at the series connection region 13 where the P-type solder ribbon is located, and the N-type fine grid forms a widened portion 301 at the series connection region 13 where the N-type solder ribbon is located.

[0120] As an embodiment of the present invention, the ratio of the dimension L5 of the widened portion 301 along the second direction Y to the dimension L6 of the non-widened portion 302 along the second direction Y is 1.2 to 6.

[0121] In this embodiment, the ratio of the dimension L5 of the widened portion 301 along the second direction Y to the dimension L6 of the non-widened portion 302 along the second direction Y is 1.2 to 6. This makes the difference between the dimension of the widened portion 301 and the non-widened portion 302 along the second direction Y more appropriate. This can increase the contact area between the widened portion 301 and the same polarity solder strip 200, improve the welding effect between the fine grid 3 and the same polarity solder strip 200, avoid the widened portion 301 being too large along the second direction Y, reduce production costs, and ensure good electrical isolation between the widened portion 301 and the adjacent non-polarity fine grid 3.

[0122] For example, the ratio of the dimension of the widened portion 301 along the second direction Y to the dimension of the non-widened portion 302 along the second direction Y can be any value among 1.2, 1.3, 1.5, 1.6, 1.8, 1.9, 2, 2.2, 2.5, 3, 3.4, 3.6, 3.8, 4, 4.1, 4.5, 5, 5.5, and 6.

[0123] Please refer to Figures 9-10 As an embodiment of the present invention, the fine grid 3 also includes a protruding structure 303 formed at the corner of the widened portion 301.

[0124] In this embodiment, a protruding structure 303 is provided at the corner of the widened portion 301, which further increases the contact area between the fine grid 3 and the solder ribbon 200. In particular, when the solder ribbon 200 shifts, the presence of the protruding structure 303 ensures that the solder ribbon 200 remains in contact with the protruding structure 303, guaranteeing a reliable electrical connection between the fine grid 3 and the solder ribbon 200. The protruding structure 303 can be formed at each corner of the widened portion 301, or it can be formed at only one corner. Preferably, the widened portion 301 is quadrilateral, and protruding structures 303 are formed at all four corners of the widened portion 301.

[0125] As an embodiment of the present invention, the protruding structure 303 extends along the second direction Y and away from the widened portion 301.

[0126] In this embodiment, the protruding structure 303 extends along the second direction Y, and extends away from the widened portion 301 where it is located. When the solder strip 200 shifts along the first direction X, the solder strip 200 can contact the protruding structure 303 due to its presence, thereby increasing the contact area between the solder strip 200 and the fine grid 3, ensuring a reliable electrical connection between the fine grid 3 and the solder strip 200. In other embodiments, the protruding structure 303 may also extend along the first direction X or in other directions.

[0127] As an embodiment of the present invention, the ratio of the dimension L7 of the protruding structure 303 along the second direction Y to the dimension L6 of the non-widened portion 302 along the second direction Y is 1.1 to 3.

[0128] In this embodiment, the dimension L7 of the protruding structure 303 along the second direction Y is the dimension of a single protruding structure 303 along the second direction Y. By controlling the ratio of the dimension of the protruding structure 303 along the second direction Y to the dimension of the non-widened portion 302 along the second direction Y to be 1.1 to 3, the contact area between the protruding structure 303 and the same polarity solder strip 200 can be well ensured, thereby improving the welding effect between the fine grid 3 and the same polarity solder strip 200. At the same time, the dimension of the protruding structure 303 along the second direction Y is not too large, which reduces production costs, and the good isolation effect between the protruding structure 303 and the adjacent dissimilar fine grid 3 is also ensured.

[0129] For example, the ratio of the dimension L7 of the protruding structure 303 along the second direction Y to the dimension L6 of the non-widened portion 302 along the second direction Y can be any value among 1.1, 1.15, 1.2, 1.26, 1.3, 1.4, 1.5, 1.55, 1.6, 1.8, 1.9, 2, 2.1, 2.3, 2.5, 2.6, 2.8, and 3.

[0130] As an embodiment of the present invention, the dimension L8 of the widened portion 301 along the first direction X is greater than the width W0 of the solder strip 200.

[0131] In this embodiment, the dimension L8 of the widened portion 301 along the first direction X is controlled to be greater than the width W0 of the solder strip 200. In this way, when the solder strip 200 is offset along the first direction X, it can still be guaranteed that the solder strip 200 is in contact with the widened portion 301, which can reduce the accuracy requirements of the position of the solder strip 200 and reduce the difficulty of the production process.

[0132] As an embodiment of the present invention, the ratio of the dimension L8 of the widened portion 301 along the first direction X to the width W0 of the solder strip 200 is 1.1 to 2.

[0133] In this embodiment, the ratio of the dimension L8 of the widened portion 301 along the first direction X to the width W0 of the welding strip 200 is controlled to be 1.1 to 2, so that the difference between the width of the widened portion 301 along the first direction X and the width of the welding strip 200 is more appropriate. When the welding strip 200 is offset along the first direction X, it can still be guaranteed that the welding strip 200 is in contact with the widened portion 301, which can reduce the accuracy requirements of the position of the welding strip 200 and reduce the difficulty of the production process.

[0134] For example, the ratio of the dimension L8 of the widened portion 301 along the first direction X to the width W0 of the solder strip 200 can be any value among 1.1, 1.2, 1.3, 1.5, 1.7, 1.9, and 2.

[0135] Please refer to this again. Figure 2 As one embodiment of the present invention, it further includes: A main grid 4 is provided on the back side 11, the main grid 4 extends along the second direction Y, and each main grid 4 is connected to at least a portion of the fine grid 3 of the same polarity.

[0136] In this embodiment, the main gate 4 can be disposed at the edge of the silicon substrate 1 or in the middle region of the silicon substrate 1. By disposing the main gate 4 on the back side 11, each main gate 4 is used for electrical connection with the solder ribbon 200 of the same polarity, and the main gate 4 can be used to better collect the current of the fine gate 3.

[0137] Please refer to Figure 11 As an embodiment of the present invention, at least one fine grid 3 has a honeycomb structure 305; and / or, at least one main grid 4 has a honeycomb structure 305.

[0138] In this embodiment, a honeycomb structure 305 is provided in at least a portion of at least one fine grid 3 and / or at least one main grid 4. That is, the surface of at least one fine grid 3 and / or at least one main grid 4 adopts a honeycomb-shaped perforated design, and the surface of at least one fine grid 3 and / or at least one main grid 4 has a porous structure. This increases the heat dissipation contact area of ​​the solar cell, improves its heat dissipation performance under high-temperature conditions, and helps to improve the output power and long-term service life of the battery in high-temperature environments. Specifically, only one fine grid 3 may have a honeycomb structure 305, or multiple fine grids 3 may have a honeycomb structure 305; only one main grid 4 may have a honeycomb structure 305, or multiple main grids 4 may have a honeycomb structure 305, or multiple fine grids 3 and multiple main grids 4 may have a honeycomb structure 305. Of course, the connecting grid lines 5 can also be provided with a honeycomb structure 305, that is, all back grid lines of the back contact solar cell can be provided with a honeycomb structure 305. Figure 11 The illustration only shows the case where the main gate 4 located at the edge of the silicon substrate 1 is provided with a honeycomb structure 305.

[0139] As an embodiment of the present invention, the honeycomb structure 305 is disposed near the edge of the silicon substrate 1.

[0140] In this embodiment, the honeycomb structure 305 is located on the fine grid 3 or main grid 4 disposed near the edge of the silicon substrate 1, thus better improving the heat dissipation performance of the cell by the honeycomb structure 305. Of course, the honeycomb structure 305 can also be located on the fine grid 3 or main grid 4 in the middle of the silicon substrate 1.

[0141] In some embodiments, the ratio of the projected area of ​​the honeycomb structure 305 on the back surface 11 to the total area of ​​the back surface 11 is less than 0.5%. This allows the honeycomb structure 305 to improve the heat dissipation performance of the solar cells while ensuring good current collection. Furthermore, the ratio of the projected area of ​​the honeycomb structure 305 on the back surface 11 to the total area of ​​the back surface 11 can be 0.001 to 0.5%, achieving a balance between good heat dissipation performance and good current collection of the solar cells.

[0142] As an embodiment of the present invention, the honeycomb structure 305 is composed of a plurality of honeycomb holes arranged in a circle, quadrilateral, pentagon, hexagon, octagon and triangle cross-section.

[0143] In this embodiment, the honeycomb cells of the honeycomb structure 305 can be at least one of the following shapes: circular, quadrilateral, pentagonal, hexagonal, octagonal, and triangular. This increases the surface area of ​​the honeycomb structure 305, significantly increasing its heat dissipation contact area and effectively reducing the operating temperature of the solar cell.

[0144] Please refer to Figure 12 As an embodiment of the present invention, the main gate 4 includes two edge main gates 41, which are respectively close to two opposite edges of the silicon substrate 1 along the first direction X. At least one fine gate 3 penetrates the connected edge main gate 41 along the first direction X. The fine gate 3 forms an extension 306 between the edge main gate 41 and the edge of the silicon substrate 1.

[0145] In this embodiment, the back surface 11 is provided with connecting grid lines 5 extending along the first direction X and connected to the corresponding edge main grids 41. The connecting grid lines 5 extend to the serial connection area 13 where the same polarity solder strips 200 are located, so that each edge main grid 41 is soldered to the same polarity solder strips 200 through the corresponding connecting grid lines 5. Insulating adhesive can be provided on the connecting grid lines 5 in the serial connection area 13 where the non-different polarity solder strips 200 are located to prevent the connecting grid lines 5 from contacting the non-different polarity solder strips 200.

[0146] In this embodiment, there are two edge main gates 41, and the polarities of the two edge main gates 41 are opposite. One edge main gate 41 is located near the third edge 103, and the other edge main gate 41 is located near the fourth edge 104. One edge main gate 41 is connected to a fine gate 3 of the same polarity, and the other edge main gate 41 is connected to another fine gate 3 of the same polarity.

[0147] In this embodiment, at least one fine gate 3 penetrates the connected edge main gate 41 along the first direction X. The fine gate 3 forms an extension 306 between the edge main gate 41 and the edge of the silicon substrate 1. That is, under the premise that the fine gate 3 overlaps with the corresponding edge main gate 41, the fine gate 3 extends beyond the edge main gate 41 to form an extension 306. Due to the existence of the extension 306, the carrier collection effect of the fine gate 3 can be better improved, and good contact between the fine gate 3 and the edge main gate 41 can be guaranteed.

[0148] As an embodiment of the present invention, the ratio of the dimension L9 of the extension portion 306 along the first direction X to the width L10 of the edge main gate 4 is 0.1 to 0.5.

[0149] In this embodiment, the ratio of the dimension of the extension 306 along the first direction X to the width of the edge main gate 4 is 0.1 to 0.5, which can further improve the carrier collection effect of the fine gate 3 and further improve the contact reliability between the fine gate 3 and the edge main gate 4.

[0150] For example, the ratio of the dimension of the extension 306 along the first direction X to the width of the edge main gate 4 can be any value among 0.1, 0.12, 0.15, 0.19, 0.2, 0.25, 0.3, 0.36, 0.4, 0.45, and 0.5.

[0151] Please refer to Figure 13As an embodiment of the present invention, the surface of the doped layer 2 away from the silicon substrate 1 includes a first region 208 located on one side of the fine gate 3 and a second region 209 located on the other side of the fine gate 3, and the surface roughness of the first region 208 is greater than the surface roughness of the second region 209.

[0152] In this embodiment, the surface roughness on both sides of the fine gate 3 of a partial number of doped layers may differ, or the surface roughness on both sides of the fine gate 3 of all doped layers may differ. Here, "surface roughness" refers to the arithmetic mean deviation (Ra) of the surface micro-profile, which can be used to compare the degree of undulation of the surface of the first region 208 and the surface of the second region 209.

[0153] In this embodiment, the surface of the doped layer 2 facing away from the silicon substrate 1 is divided into two regions by a fine gate 3: a first region 208 located on one side of the fine gate 3 and a second region 209 located on the other side of the fine gate 3. The surface roughness of the first region 208 is set to be greater than that of the second region 209. This increases the surface roughness of the first region 208 and the adhesion between the surface of the first region 208 and the passivation film layer covering it, thereby improving the structural stability of the back contact solar cell 100. Moreover, it facilitates the reflection of sunlight transmitted through the silicon substrate 1 from the front side back into the silicon substrate 1 by the first region 208, which helps to improve the utilization rate of sunlight and thus improve the photoelectric conversion efficiency of the back contact solar cell 100.

[0154] As an embodiment of the present invention, the ratio of the surface roughness of the first region 208 to the surface roughness of the second region 209 can be 1.5 to 5. This can increase the bonding force between the first region 208 and the passivation film layer covering it, improve the structural stability of the back contact solar cell 100, and make it easier for the first region 208 to reflect sunlight that has passed through the silicon substrate 1 back into the silicon substrate 1, thereby improving the utilization rate of sunlight.

[0155] This invention also provides a battery assembly, which includes the back-contact solar cell 100 described in the above embodiments. It should be noted that this battery assembly has the same or similar beneficial effects as the back-contact solar cell 100, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0156] In this embodiment, multiple back-contact solar cells 100 in the battery module are connected in series by solder ribbons to form a battery string, thereby achieving series current collection and output.

[0157] 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 sides 11 of the back-contact solar cell 100, 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.

[0158] Photovoltaic glass can be applied to the encapsulating film on the front side of the back-contact solar cell 100. The photovoltaic glass can be ultra-clear glass, which has 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 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back-contact solar cell 100 together, providing sealing, insulation, waterproofing, and moisture protection for the back-contact solar cell 100.

[0159] The backsheet can be attached to the adhesive film on the back side 11 of the back-contact solar cell 100. The backsheet provides protection and support for the back-contact solar cell 100, and has reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, back-contact solar cell 100, 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 battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0160] This invention also provides a photovoltaic system, which includes the battery module described in the above embodiments. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back-contact solar cell 100 described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0161] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0162] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the invention. 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.

[0163] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A back-contact solar cell, characterized in that, include: Silicon substrate, the silicon substrate including a back side; A doped layer is disposed on the back side, the doped layer including a first doped portion and a second doped portion, the first doped portion extending along a first direction; the first doped portion and the second doped portion are spaced apart in the first direction to form a first marking region; and A first identification structure is located in the first identification area, and the first identification structure is spaced apart from the first doped portion and the second doped portion.

2. The back-contact solar cell according to claim 1, characterized in that, The doped layer includes a first doped layer and a second doped layer with opposite doping types, and the first doped layer and the second doped layer are spaced apart; the second doped layer includes the first doped portion and the second doped portion; or, the first doped layer includes the first doped portion and the second doped portion includes the second doped portion.

3. The back-contact solar cell according to claim 2, characterized in that, The first doped layer and the second doped layer are respectively extended along the first direction, and at least a portion of the first doped layer and at least a portion of the second doped layer are alternately spaced along the second direction, which intersects with the first direction.

4. The back-contact solar cell according to claim 3, characterized in that, Also includes: A plurality of fine gates are disposed on the back side, each fine gate being disposed on a corresponding doped layer, the fine gates extending along the first direction, and the plurality of fine gates being alternately spaced along the second direction.

5. The back-contact solar cell according to claim 4, characterized in that, The fine gate is respectively provided on the first doped portion and the second doped portion, and the fine gate on the first doped portion and the fine gate on the second doped portion are spaced apart in the first marking area; The spacing between two adjacent fine gates in the second direction is d, and the ratio of the distance from the center of the first marking structure along the second direction to the center line of the fine gate on the first doped portion to d is 0 to 0.2; and / or, the ratio of the distance from the center of the first marking structure along the second direction to the center line of the fine gate on the second doped portion to d is 0 to 0.

2.

6. The back-contact solar cell according to claim 3, characterized in that, The first identification structure is spaced apart from the adjacent doped layer in the second direction.

7. The back-contact solar cell according to claim 4, characterized in that, The first identification structure includes a first identification base disposed on the back side and a first marking point disposed on the first identification base; The first identification substrate has the opposite or the same doping type as the first doped portion, and the first identification substrate has the opposite or the same doping type as the second doped portion.

8. The back-contact solar cell according to claim 7, characterized in that, The doped layer further includes a third doped portion and a fourth doped portion, the third doped portion extending along the first direction, and the third doped portion and the fourth doped portion being spaced apart in the first direction to form a second marking region; The back-contact solar cell includes: The second identification structure is located in the second identification area, and the second identification structure is spaced apart from the third doped portion and the fourth doped portion.

9. The back-contact solar cell according to claim 8, characterized in that, The second identification structure is connected to the adjacent doped layer in the second direction.

10. The back-contact solar cell according to claim 8 or 9, characterized in that, The second identification structure includes a second identification substrate disposed on the back side and a second marking point disposed on the second identification substrate. The doping type of the second identification substrate is opposite to or the same as that of the third doped portion, and the doping type of the second identification substrate is opposite to or the same as that of the fourth doped portion.

11. The back-contact solar cell according to claim 10, characterized in that, The second identification substrate has the opposite doping type to the first identification substrate.

12. The back-contact solar cell according to claim 8, characterized in that, The doped layer further includes a fifth doped portion and a sixth doped portion, the fifth doped portion extending along the first direction, and the fifth doped portion and the sixth doped portion being spaced apart in the first direction to form a third marking region; The back-contact solar cell includes: A third identification structure is located in the third identification region, and the third identification structure is spaced apart from the fifth doped portion and the sixth doped portion.

13. The back-contact solar cell according to claim 12, characterized in that, The third identification structure is spaced apart from the adjacent doped layer in the second direction.

14. The back-contact solar cell according to claim 12, characterized in that, The third identification structure includes a third identification substrate disposed on the back side, a fourth identification substrate stacked on the third identification substrate, and a third marking point disposed on the fourth identification substrate, wherein the doping types of the third identification substrate and the fourth identification substrate are opposite.

15. The back-contact solar cell according to claim 7, characterized in that, The first marking base is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the first marking point is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

16. The back-contact solar cell according to claim 10, characterized in that, The second marking base is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon; and / or, the second marking point is one of a circle, quadrilateral, triangle, trapezoid, pentagon, hexagon, or octagon.

17. The back-contact solar cell according to claim 14, characterized in that, The third and fourth identification bases are respectively one of a circle, a quadrilateral, a triangle, a trapezoid, a pentagon, a hexagon, and an octagon; and / or, the third marking point is one of a circle, a quadrilateral, a triangle, a trapezoid, a pentagon, a hexagon, and an octagon.

18. The back-contact solar cell according to claim 12, characterized in that, The first and second identification structures are located on one side of the centerline of the silicon substrate, and the third identification structure is located on the other side of the centerline of the silicon substrate.

19. The back-contact solar cell according to claim 18, characterized in that, The total number of the first and second identifier structures is different from the number of the third identifier structure.

20. The back-contact solar cell according to claim 8, characterized in that, Each of the first identifier structures is arranged adjacent to a corresponding second identifier structure to form a marker group.

21. The back-contact solar cell according to claim 20, characterized in that, The spacing between two adjacent fine grids in the second direction is d, and the spacing between the first identification structure and the second identification structure of each mark group is D1, satisfying 2d < D1 < 10d.

22. The back-contact solar cell according to claim 20, characterized in that, The number of the marker groups is at least two, and at least two of the marker groups are spaced apart along the first direction.

23. The back-contact solar cell according to claim 22, characterized in that, The ratio of the spacing between the first marking structures of two adjacent marking groups to the dimension of the silicon substrate along the first direction is 0.25 to 0.8; and or, the ratio of the spacing between the second marking structures of two adjacent marking groups to the dimension of the silicon substrate along the first direction is 0.25 to 0.

8.

24. The back-contact solar cell according to claim 4, characterized in that, The back side includes a plurality of serial connection areas for setting solder strips, the plurality of serial connection areas being alternately spaced along the first direction and the serial connection areas extending along the second direction; the solder strips of two adjacent serial connection areas have opposite polarities, and the solder strips of each serial connection area are used to electrically connect the fine grids of the same polarity; The fine grid includes a widened portion located at the serial connection area of ​​the same polarity solder strip, and a non-widened portion located outside the serial connection area of ​​the same polarity solder strip, wherein the dimension of the widened portion along the second direction is greater than the dimension of the non-widened portion along the second direction.

25. The back-contact solar cell according to claim 24, characterized in that, The ratio of the dimension of the widened portion along the second direction to the dimension of the non-widened portion along the second direction is 1.2 to 6.

26. The back-contact solar cell according to claim 24, characterized in that, The fine grid also includes protruding structures formed at the corners of the widened portion.

27. The back-contact solar cell according to claim 26, characterized in that, The ratio of the dimension of the protruding structure along the second direction to the dimension of the non-widened portion along the second direction is 1.1 to 3.

28. The back-contact solar cell according to claim 24, characterized in that, The width of the widened portion along the first direction is greater than the width of the solder strip.

29. The back-contact solar cell according to claim 24, characterized in that, The ratio of the dimension of the widened portion along the first direction to the width of the welding strip is 1.1 to 2.

30. The back-contact solar cell according to claim 4, characterized in that, Also includes: A main grid is disposed on the back side, the main grid extending along the second direction, and each main grid is connected to at least a portion of the fine grids of the same polarity.

31. The back-contact solar cell according to claim 30, characterized in that, At least one of the fine grids has a honeycomb structure; and / or, at least one of the main grids has a honeycomb structure.

32. A battery assembly, characterized in that, Including the back-contact solar cell as described in any one of claims 1 to 31.

33. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 32.

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