Busbarless back-contact cell, cell assembly, and photovoltaic system

Abstract

The present disclosure is applicable to the technical field of solar cells, and provides a busbarless back-contact cell, a cell assembly, and a photovoltaic system. The busbarless back-contact cell is sequentially provided with a first edge region and a middle region in a first direction. The first edge region is provided with a plurality of first fixing structures arranged on first fingers and / or second fingers. In the present disclosure, in a first edge region of the busbarless back-contact cell, the areas of first fixing structures are gradually increased in a direction opposite to a first direction, so that the soldering area is increased, and thus the soldering tension of a soldering strip and fingers is gradually increased toward the edge of the busbarless back-contact cell, so as to dissipate and counteract the stress and tension which are gradually increased toward the edge of the busbarless back-contact cell, thereby achieving the effects of improving the tension of the soldering strip at the edge portion, improving the soldering firmness of the soldering strip, stabilizing the soldering of the soldering strip, and reducing the risk of cold soldering of the soldering strip.

Description

Back contact cell without main grid, cell assembly and photovoltaic system

[0001] Cross-reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411098844.4, filed on August 9, 2024, entitled "Back contact cell without main grid, cell assembly and photovoltaic system", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of solar cells, in particular to a back contact cell without main grid, a cell assembly and a photovoltaic system. BACKGROUND

[0004] In a back contact solar cell, in order to reduce the use of paste, the back contact solar cell adopts a design without main grid, and a solder strip is directly welded on the fine grid.

[0005] However, in such a technical solution, the solder strip welded between the fine grid and the edge portion of the back contact solar cell is prone to false welding.

[0006] SUMMARY

[0007] The present disclosure provides a back contact cell without main grid, a cell assembly and a photovoltaic system, aiming to solve the technical problem of false welding of the solder strip welded on the edge portion of the back contact solar cell in the prior art.

[0008] The present disclosure is implemented in this way, a back contact cell without main grid, the back contact cell without main grid is sequentially provided with a first edge region and a middle region along a first direction; a plurality of first fine grids and a plurality of second fine grids are provided in the first edge region, the plurality of first fine grids and the plurality of second fine grids are alternately and spaced arranged, the first fine grid and the second fine grid are opposite in polarity; a plurality of first fixed structures provided on at least one of the first fine grid and the second fine grid are provided in the first edge region, each first fixed structure is spaced apart, the first fixed structure is used for welding with a solder strip; in the first edge region, along the opposite direction of the first direction, the area of the plurality of first fixed structures located on the fine grid of the same polarity gradually increases.

[0009] In some embodiments, the back contact cell without main grid further has a second edge region, the back contact cell without main grid is sequentially provided with the first edge region, the middle region and the second edge region along a first direction; a plurality of the first fine grids and a plurality of the second fine grids are provided in the second edge region, the plurality of the first fine grids and the plurality of the second fine grids are alternately and spacedly arranged in sequence; a plurality of second fixed structures provided on at least one of the first fine grids and the second fine grids are provided in the second edge region, each of the second fixed structures is spacedly arranged, and the second fixed structure is used for welding with a solder strip; in the second edge region, along the first direction, the area of the plurality of the second fixed structures on the fine grid of the same polarity gradually increases.

[0010] In some embodiments, a plurality of the first fine grids and a plurality of the second fine grids are provided in the middle region, the plurality of the first fine grids and the plurality of the second fine grids are alternately and spacedly arranged in sequence; a plurality of third fixed structures provided on at least one of the first fine grids and the second fine grids are provided in the middle region, each of the third fixed structures is spacedly arranged, and the third fixed structure is used for welding with a solder strip; in the middle region, along the first direction, the area of the third fixed structure is constant.

[0011] In some embodiments, the area of the first fixed structure is greater than or equal to the area of the third fixed structure.

[0012] In some embodiments, the area of the second fixed structure is greater than or equal to the area of the third fixed structure.

[0013] In some embodiments, the external contour of the plurality of the first fixed structures in combination is a trapezoid-like shape.

[0014] In some embodiments, the external contour of the first fixed structure is a trapezoid, a circle, a rectangle or an octagon.

[0015] In some embodiments, the external contour of the first fixed structure is a trapezoid with a short side close to the middle region and a long side away from the middle region.

[0016] In some embodiments, the external contour of the plurality of the second fixed structures in combination is a trapezoid-like shape.

[0017] In some embodiments, the external contour of the second fixed structure is a trapezoid, a circle, a rectangle or an octagon.

[0018] In some embodiments, the external contour of the second fixed structure is a trapezoid with a short side close to the middle region and a long side away from the middle region.

[0019] In some embodiments, the external outline of the third fixed structure group is rectangular.

[0020] In some embodiments, the external outline of the third fixed structure is trapezoidal, circular, rectangular or octagonal.

[0021] In some embodiments, the first fixed structure is further configured to set a first solder paste layer; along the opposite direction of the first direction, the area of the first solder paste layer corresponding to the same polarity fine grid gradually increases.

[0022] In some embodiments, the second fixed structure is further configured to set a second solder paste layer; along the first direction, the area of the second solder paste layer corresponding to the same polarity fine grid gradually increases.

[0023] In some embodiments, the third fixed structure is further configured to set a third solder paste layer; along the first direction, the area of the third solder paste layer is constant.

[0024] In some embodiments, in the first edge area, the first fixed structure corresponding to adjacent first fine grids is configured to set a first insulating glue, the first fixed structure corresponding to adjacent second fine grids is configured to set the first insulating glue, and along the opposite direction of the first direction, the area of the first insulating glue corresponding to the same polarity fine grid gradually increases.

[0025] In some embodiments, in the second edge area, the second fixed structure corresponding to adjacent first fine grids is configured to set a second insulating glue, the second fixed structure corresponding to adjacent second fine grids is configured to set the second insulating glue, and along the first direction, the area of the second insulating glue corresponding to the same polarity fine grid gradually increases.

[0026] In some embodiments, in the middle area, the third fixed structure corresponding to adjacent first fine grids is configured to set a third insulating glue, the third fixed structure corresponding to adjacent second fine grids is configured to set the third insulating glue, and along the first direction, the area of the third insulating glue is constant.

[0027] In some embodiments, the first edge area further comprises a plurality of doped layers, and the first fine grid or the second fine grid is correspondingly arranged on each doped layer; the first edge area has a first boundary along a second direction, and in the first edge area, the doping type of the doped layer closest to the first boundary is opposite to the doping type of the silicon substrate in the back contact cell without main grid.

[0028] In some embodiments, the first edge region further comprises a plurality of doped layers, and the first fine grid or the second fine grid is correspondingly arranged on each of the doped layers; the first edge region has a first boundary along a second direction, and the doped layer closest to the first boundary in the first edge region is a P-type doped layer, and the first direction is perpendicular to the second direction.

[0029] In some embodiments, the second edge region further comprises a plurality of doped layers, and the first fine grid or the second fine grid is correspondingly arranged on each of the doped layers; the second edge region has a second boundary along a second direction, and the doped layer closest to the second boundary in the second edge region is a P-type doped layer, and the first direction is perpendicular to the second direction.

[0030] In some embodiments, the second edge region further comprises a plurality of doped layers, and the first fine grid or the second fine grid is correspondingly arranged on each of the doped layers; the second edge region has a second boundary along a second direction, and the doped layer closest to the second boundary in the second edge region is a P-type doped layer, and the first direction is perpendicular to the second direction.

[0031] The present disclosure also provides a battery assembly comprising a plurality of the back contact cell without busbar as described in any one of the above.

[0032] The present disclosure also provides a photovoltaic system comprising the battery assembly as described above.

[0033] In the back contact cell without busbar, the battery assembly and the photovoltaic system of the embodiments of the present disclosure, the back contact cell without busbar is sequentially provided with a first edge region and a middle region along a first direction; a plurality of first fine grids and a plurality of second fine grids are provided in the first edge region, and the plurality of first fine grids and the plurality of second fine grids are alternately and spaced arranged; a plurality of first fixed structures provided on the first fine grid and / or the second fine grid are provided in the first edge region, each of the first fixed structures is spaced arranged, and the first fixed structure is used for welding with a solder strip; in the first edge region, the area of the first fixed structure gradually increases along the opposite direction of the first direction. The present disclosure gradually increases the area of the first fixed structure along the opposite direction of the first direction in the first edge region of the back contact cell without busbar, increases the welding area, gradually increases the welding tensile force of the solder strip and the fine grid of the back contact cell without busbar closer to the edge, disperses and resists the stress and tensile force gradually increasing of the back contact cell without busbar closer to the edge, achieves the effect of improving the tensile force of the solder strip of the edge part, improving the firmness of the solder strip welding, stabilizing the solder strip welding, and reducing the risk of virtual welding of the solder strip.

[0034] Additional aspects and advantages of the present disclosure will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0035] Fig. 1 is a schematic diagram of a module of a photovoltaic system according to an embodiment of the present disclosure;

[0036] Fig. 2 is a schematic diagram of a module of a battery assembly according to an embodiment of the present disclosure;

[0037] Fig. 3 is a schematic diagram of a planar structure of a back surface of a solar cell without busbars according to an embodiment of the present disclosure;

[0038] Fig. 4 is a schematic diagram of a planar structure of an external contour of a combination of a plurality of first fixed structures in the solar cell without busbars in Fig. 3;

[0039] Fig. 5 is a schematic diagram of a planar structure of an external contour of a combination of a plurality of second fixed structures in the solar cell without busbars in Fig. 3;

[0040] Fig. 6 is a schematic diagram of a planar structure of an external contour of a combination of a plurality of third fixed structures in the solar cell without busbars in Fig. 3;

[0041] Fig. 7 is a schematic diagram of a planar structure of a back surface of a solar cell without busbars according to an embodiment of the present disclosure, in which a fixed structure is composed of a plurality of solder points and a fixed structure is composed of a single solder point;

[0042] Fig. 8 is a schematic diagram of a planar structure of a back surface of a solar cell without busbars according to an embodiment of the present disclosure, in which the solar cell without busbars is provided with solder paste;

[0043] Fig. 9 is a schematic diagram of a planar structure of a back surface of a solar cell without busbars according to an embodiment of the present disclosure, in which the solar cell without busbars is provided with insulating glue;

[0044] Fig. 10 is a schematic diagram of a planar structure of a back surface of a solar cell without busbars according to an embodiment of the present disclosure, in which the solar cell without busbars is provided with insulating glue and solder paste;

[0045] Fig. 11 is a schematic diagram of an arrangement of doped layers in the solar cell without busbars in Fig. 3;

[0046] Fig. 12 is a schematic diagram of a partial enlargement of an arrangement of doped layers near a first boundary in the solar cell without busbars in Fig. 3;

[0047] Fig. 13 is a schematic diagram of a partial enlargement of another arrangement of doped layers near a first boundary in the solar cell without busbars in Fig. 3;

[0048] Fig. 14 is a schematic diagram of a partial enlargement of an arrangement of doped layers near a second boundary in the solar cell without busbars in Fig. 3;

[0049] Fig. 15 is a partial enlarged schematic view of another arrangement of the doped layer near the second border in the solar cell without busbars in Fig. 3;

[0050] Fig. 16 is a schematic view of one way of gradually increasing the area of the first fixed structure combination in the solar cell without busbars in Fig. 3;

[0051] Fig. 17 is a schematic view of another way of gradually increasing the area of the first fixed structure combination in the solar cell without busbars in Fig. 3;

[0052] Fig. 18 is a schematic view of one way of gradually increasing the area of the second fixed structure combination in the solar cell without busbars in Fig. 3;

[0053] Fig. 19 is a schematic view of another way of gradually increasing the area of the second fixed structure combination in the solar cell without busbars in Fig. 3.

[0054] Main element symbol explanation: 1000, photovoltaic system; 1001, cell assembly; 100, back contact cell without busbars; 200, first fine grid; 300, second fine grid; 400, doped layer; 410, P-type doped layer; 420, N-type doped layer; 10, first edge area; 11, first fixed structure; 12, first solder paste layer; 13, first insulating adhesive; 14, first border; 20, second edge area; 21, second fixed structure; 22, second solder paste layer; 23, second insulating adhesive; 24, second border; 30, middle area; 31, third fixed structure; 32, third solder paste layer; 33, third insulating adhesive. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the present disclosure clearer, the present disclosure will be further described in detail below in combination with the drawings and examples. The examples described below by referring to the drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as a limitation of the present disclosure. In addition, it should be understood that the specific examples described herein are only used to explain the present disclosure and do not limit the present disclosure.

[0056] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present disclosure.

[0057] In addition, the terms "first", "second", etc. are used herein only to describe different instances, and do not imply or suggest relative importance or a number of the indicated technical features. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0058] In the description of the present disclosure, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, can be fixed connection, can be detachable connection, or integrally connected; can be mechanical connection, or electrical connection or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0059] In the present disclosure, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0060] The following disclosure provides many different embodiments or examples for implementing different structures of the present disclosure. In order to simplify the disclosure of the present disclosure, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present disclosure. In addition, the present disclosure can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present disclosure provides various specific examples of processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0061] Referring to FIG. 1 and FIG. 2, the photovoltaic system 1000 in the embodiment of the present disclosure can include a cell assembly 1001 in the embodiment of the present disclosure, the cell assembly 1001 in the embodiment of the present disclosure can include a plurality of cell strings, and each cell string can include a plurality of back contact cells 100 without busbars in the embodiment of the present disclosure. In the present disclosure, the plurality of back contact cells 100 without busbars in the cell assembly 1001 can be sequentially connected in series by a solder strip to form a cell string. Each cell string in the cell assembly 1001 can be connected in series, in parallel, or in a combination of series and parallel to realize the current output, for example, the connection between each cell string can be realized by a bus bar.

[0062] Referring to FIG. 3, the back contact cell 100 without busbars in the embodiment of the present disclosure has opposite front and back surfaces, and the back surface of the back contact cell 100 without busbars has a first edge region 10 and a middle region 30 sequentially arranged in a first direction. Specifically, as shown in FIG. 3, the first direction can be a horizontal right direction, and of course, in other embodiments, the first direction can be other directions, for example, a horizontal left direction, a diagonal direction, etc., which are not limited specifically herein.

[0063] As shown in FIG. 3 and FIG. 4, the first edge region 10 has a plurality of first fine grids 200 and a plurality of second fine grids 300, and the plurality of first fine grids 200 and the plurality of second fine grids 300 are alternately and spaced arranged. Specifically, the first fine grid 200 can be a negative fine grid, and the second fine grid 300 can be a positive fine grid, or the first fine grid 200 can be a positive fine grid, and the second fine grid 300 can be a negative fine grid, which is not limited herein. That is, the first fine grid 200 and the second fine grid 300 have opposite polarities.

[0064] The first edge region 10 has a plurality of first fixed structures 11 arranged on the first fine grid 200 and / or the second fine grid 300, and each first fixed structure 11 is spaced apart. The first fixed structure 11 is used for welding with a solder strip, and the first fixed structure 11 is specifically used for welding the solder strip on the first fine grid 200 and / or the second fine grid 300 in the first edge region 10. In the first edge region 10, the area of the plurality of first fixed structures 11 on the fine grid with the same polarity gradually increases in the opposite direction of the first direction.

[0065] In the present disclosure, "the area of the plurality of first fixed structures 11 on the same polarity fine grid gradually increases in the opposite direction of the first direction within the first edge region 10" can be understood as the area of the first fixed structure 11 on the first fine grid 200 gradually increases in the opposite direction of the first direction within the first edge region 10; the area of the first fixed structure 11 on the second fine grid 300 gradually increases in the opposite direction of the first direction. In addition, for the gradually increasing manner of the area of the first fixed structure 11, there can be multiple cases, for example, there are 6 first fixed structures 11 arranged in order along the opposite direction of the first direction, and the area of each first fixed structure 11 is in order: X1, X2, X3, X4, X5, X6. As shown in FIG. 16, there can be X1 < X2 < X3 < X4 < X5 < X6 so that the area of the first fixed structure 11 gradually increases, or as shown in FIG. 17, there can also be X1 = X2 < X3 = X4 < X5 = X6 so that the area of the first fixed structure 11 gradually increases, which is not limited here.

[0066] Each first fixed structure 11 is specifically arranged on the first fine grid 200 and / or the second fine grid 300 at intervals, and the first fixed structure 11 is used to weld the solder strip on the first fine grid 200 and / or the second fine grid 300 provided with the first fixed structure 11. And as shown in the upper half of the back contact cell 100 without a main grid in FIG. 7, the first fixed structure 11 can specifically be composed of multiple solder points (also referred to as pad points), or as shown in the lower half of the back contact cell 100 without a main grid in FIG. 7, the first fixed structure 11 can also be composed of one larger solder point.

[0067] For example, as shown in the upper half of the back contact cell 100 without a main grid in FIG. 7, the first fixed structure 11 can specifically be composed of multiple solder points, the number of solder points included in the first fixed structure 11 away from the middle region 30 is A, and the number of solder points included in the first fixed structure 11 close to the middle region 30 is B, A is greater than B. And along the opposite direction of the first direction, the number of solder points in the first fixed structure 11 gradually increases.

[0068] Specifically, in the back contact cell 100 without a main grid, the stress tension is more concentrated in the edge part, so the solder strip in this part is not enough to be pulled, and is prone to false welding. And the closer to the edge of the back contact cell 100 without a main grid, the stronger the stress tension, the more difficult it is to stably weld the solder strip, and the more prone to false welding.

[0069] In the embodiments of the present disclosure, the back surface of the back contact cell without main grid 100 is sequentially provided with a first edge area 10 and an intermediate area 30 along a first direction. The first edge area 10 is an edge portion of the back contact cell without main grid 100. In the first edge area 10, the closer to the edge of the back contact cell without main grid 100, the stronger the stress tension, and the more difficult the stable welding of the solder strip, and the greater the risk of false welding.

[0070] Therefore, in the embodiments of the present disclosure, in the first edge area 10, the closer to the edge of the back contact cell without main grid 100, the larger the area of the first fixed structure 11, the welding area is increased to gradually increase the welding tension of the solder strip and the fine grid of the back contact cell without main grid 100 closer to the edge, so as to disperse and resist the gradually increasing stress and tension of the back contact cell without main grid 100 closer to the edge, thereby improving the solder strip tension of the edge portion, improving the stability of the solder strip welding, stabilizing the solder strip welding, and reducing the risk of false welding of the solder strip.

[0071] In addition, in the embodiments of the present disclosure, the area of the first fixed structure 11 is not uniformly matched with the stress tension of the edge portion of the back contact cell without main grid 100. Instead, the area of the first fixed structure 11 gradually increases in the first edge area 10 along the opposite direction of the first direction. This gradually increasing area of the first fixed structure 11 can optimize the use of materials and reduce costs while ensuring the strength of the solder strip welding.

[0072] Further, in a possible implementation, as shown in FIGS. 3 and 4, the external contour of the plurality of first fixed structures 11 is a trapezoidal shape.

[0073] Specifically, because the stress and tension of the edge portion (the first edge area 10) of the back contact cell without main grid 100 increase as the position approaches the edge. Therefore, in order to match the stress and tension of the first edge area 10, the area of the first fixed structure 11 in the present disclosure can be gradiently changed, that is, the closer to the edge (i.e., along the opposite direction of the first direction) of the back contact cell without main grid 100, the larger the area of the first fixed structure 11 is set to gradually increase from a smaller area close to the intermediate area 30 to a larger area close to the edge. Therefore, the external contour of the plurality of first fixed structures 11 is a trapezoidal shape. The embodiments of the present disclosure divide the first edge area 10 into a plurality of segments, and the area of the fixed structure in each segment gradually increases, thereby adapting to different stress requirements, effectively addressing the high stress and large tension problem of the edge portion of the back contact cell without main grid 100, and improving the stability of the solder strip welding and the overall reliability of the back contact cell without main grid 100.

[0074] Further, in a possible implementation, the external profile of the first fixed structure 11 can be trapezoidal, circular, rectangular, or octagonal. Specifically, the external profile of each first fixed structure 11 can be set to be trapezoidal, circular, rectangular, octagonal, or the like.

[0075] When the first fixed structure 11 is specifically set to be trapezoidal, optionally, the external profile of the first fixed structure 11 can be trapezoidal with the short side close to the middle region 30 and the long side away from the middle region 30.

[0076] Moreover, the solder strip is usually welded by means of solder paste. Therefore, further, in a possible implementation, as shown in FIG. 3, FIG. 8, and FIG. 10, the first fixed structure 11 is further used to set the first solder paste layer 12, and the area of the plurality of first solder paste layers 12 corresponding to the same-polarity fine grids in the reverse direction of the first direction gradually increases. Of course, the manner in which the area of the first solder paste layer 12 gradually increases can be set with reference to the first fixed structure 11, and thus will not be described here.

[0077] In the present disclosure, “the area of the plurality of first solder paste layers 12 corresponding to the same-polarity fine grids in the reverse direction of the first direction gradually increases” can be understood as that the area of the first solder paste layer 12 corresponding to the first fine grid 200 gradually increases in the reverse direction of the first direction; and the area of the first solder paste layer 12 corresponding to the second fine grid 300 gradually increases in the reverse direction of the first direction. The first solder paste layer 12 specifically consists of solder paste, and the first solder paste layer 12 is used to weld the solder strip on the first fixed structure 11. Moreover, in order to cope with the stress and tension of the edge portion (the first edge region 10) of the main grid-free back contact battery 100 increasing as the position close to the edge, the area of the first solder paste layer 12 set in the present disclosure also gradually increases in the reverse direction of the first direction.

[0078] Wherein, before the solder strip is specifically welded, each first fixed structure 11 is correspondingly covered with the first solder paste layer 12. Optionally, in each first fixed structure 11, the coverage range of the first solder paste layer 12 does not exceed the area of the first fixed structure 11. Before the solder strip is welded, the external profile of the plurality of first solder paste layers 12 in combination can also be trapezoidal. The external profile of each first solder paste layer 12 can also be set to be trapezoidal, circular, rectangular, octagonal, or other irregular shapes, and the specific shape can be selected according to actual conditions, which is not limited here.

[0079] Further, in the first edge area 10, as shown in FIG. 3, FIG. 9 and FIG. 10, in addition to the first fixed structure 11. In a possible implementation, in the first edge area 10, the first insulating glue 13 is arranged between the first fixed structure 11 corresponding to the adjacent first fine grid 200, the first insulating glue 13 is arranged between the first fixed structure 11 corresponding to the adjacent second fine grid 300, and the area of the first insulating glue 13 corresponding to the fine grid with the same polarity gradually increases in the opposite direction of the first direction. Of course, the gradually increasing manner of the area of the first insulating glue 13 can be arranged by referring to the first fixed structure 11, which will not be described here.

[0080] In the present disclosure, the "area of the first insulating glue 13 corresponding to the fine grid with the same polarity gradually increases in the opposite direction of the first direction" can be understood as that the area of the first insulating glue 13 corresponding to the first fine grid 200 gradually increases in the opposite direction of the first direction; the area of the first insulating glue 13 corresponding to the second fine grid 300 gradually increases in the opposite direction of the first direction. Specifically, in addition to arranging the first fixed structure 11 on the first fine grid 200 and the second fine grid 300, the first insulating glue 13 can also be arranged on the first fine grid 200 and / or the second fine grid 300 in the first edge area 10. Specifically, the first insulating glue 13 is arranged between the adjacent first fixed structure 11, or the first fixed structure 11 is arranged between the adjacent first insulating glue 13.

[0081] In the first edge area 10, by arranging the first fixed structure 11 and the first insulating glue 13, the first fine grid 200 with the same polarity can be welded with the solder strip, and the second fine grid 300 with opposite polarity can be insulated from the solder strip; or the second fine grid 300 with the same polarity can be welded with the solder strip, and the first fine grid 200 with opposite polarity can be insulated from the solder strip. For example, when the solder strip to be welded has the same polarity as the first fine grid 200 and opposite polarity as the second fine grid 300, the solder strip is welded with the first fine grid 200 through the first fixed structure 11, and the solder strip is insulated from the second fine grid 300 through the first insulating glue 13; similarly, when the solder strip to be welded has the same polarity as the second fine grid 300 and opposite polarity as the first fine grid 200, the solder strip is welded with the second fine grid 300 through the first fixed structure 11, and the solder strip is insulated from the first fine grid 200 through the first insulating glue 13.

[0082] In addition, in the back contact cell 100 without main grid, as shown in FIGS. 3, 11, 12 and 13, the fine grid is arranged on the doped layer 400, and the first edge area 10 further comprises a plurality of doped layers 400, and the first fine grid 200 or the second fine grid 300 is arranged on each doped layer 400 correspondingly. The doped layer 400 can be a P-type doped layer 410 or an N-type doped layer 420, and the P-type doped layer 410 and the N-type doped layer 420 are arranged alternately. Specifically, the first fine grid 200 can be arranged on the P-type doped layer 410, and the second fine grid 300 can be arranged on the N-type doped layer 420; or the second fine grid 300 can be arranged on the P-type doped layer 410, and the first fine grid 200 can be arranged on the N-type doped layer 420, which can be selected according to actual conditions, and is not limited herein. The first edge area 10 has a first boundary 14 in a second direction, and the first direction and the second direction are perpendicular to each other. In the present disclosure, the second direction is a vertical direction, and the first boundary 14 is one of the boundaries of the first edge area 10, and the first boundary 14 is also one of the boundaries of the back contact cell 100 without main grid.

[0083] In a possible implementation, in the first edge area 10, the doped type of the doped layer 400 closest to the first boundary 14 is opposite to the doped type of the silicon substrate in the back contact cell 100 without main grid, so as to increase the emitter area of the back contact cell 100 without main grid and improve the cell efficiency of the back contact cell 100 without main grid.

[0084] In addition, for the electrons and the holes, the collection of the holes is more difficult. Therefore, in the first edge area 10, the doped type of the doped layer 400 closest to the first boundary 14 is opposite to the doped type of the silicon substrate in the back contact cell 100 without main grid, so as to enhance the hole collection capability of the back contact cell 100 without main grid in the edge part.

[0085] For example, the silicon substrate in the back contact cell 100 without main grid is P-type doped, as shown in FIG. 13, that is, the doped layer closest to the first boundary 14 is an N-type doped layer 420; or the silicon substrate in the back contact cell 100 without main grid is N-type doped, as shown in FIG. 12, that is, the doped layer closest to the first boundary 14 is a P-type doped layer 410.

[0086] Of course, as shown in FIG. 12, in a possible implementation, the doped layer 400 closest to the first boundary 14 in the first edge area 10 can be arranged as a P-type doped layer 410, so as to enhance the hole collection capability of the back contact cell 100 without main grid in the edge part.

[0087] Further, in a possible implementation, as shown in FIG. 3 and FIG. 5, the back surface of the back contact cell 100 further has a second edge area 20, and the back surface of the back contact cell 100 sequentially has the first edge area 10, the middle area 30 and the second edge area 20 along the first direction.

[0088] Likewise, the second edge area 20 has a plurality of first fine grids 200 and a plurality of second fine grids 300, and the plurality of first fine grids 200 and the plurality of second fine grids 300 are alternately and spacedly arranged. Specifically, the first fine grids 200 can be negative fine grids, and the second fine grids 300 can be positive fine grids; or the first fine grids 200 can be positive fine grids, and the second fine grids 300 can be negative fine grids, which are not limited herein.

[0089] The second edge area 20 has a plurality of second fixed structures 21 arranged on the first fine grids 200 and / or the second fine grids 300, and each second fixed structure 21 is spacedly arranged. The second fixed structure 21 is used for welding with a solder strip, and the second fixed structure 21 is specifically used for welding the solder strip on the first fine grid 200 and / or the second fine grid 300 in the second edge area 20. In the second edge area 20, along the first direction, the area of the plurality of second fixed structures 21 located on the fine grid of the same polarity gradually increases.

[0090] In the present disclosure, “in the second edge area 20, along the first direction, the area of the plurality of second fixed structures 21 located on the fine grid of the same polarity gradually increases” can be understood as that, in the second edge area 20, the area of the second fixed structure 21 located on the first fine grid 200 gradually increases along the first direction; and the area of the second fixed structure 21 located on the second fine grid 300 gradually increases along the first direction. In addition, for the gradually increasing manner of the area of the second fixed structure 21, there can be multiple cases, for example, along the first direction, there are six second fixed structures 21 arranged in sequence, and the area of each second fixed structure 21 is Y1, Y2, Y3, Y4, Y5 and Y6 in sequence. As shown in FIG. 18, Y1<Y2<Y3<Y4<Y5<Y6 can be used to make the area of the second fixed structure 21 gradually increase, or as shown in FIG. 19, Y1=Y2<Y3=Y4<Y5=Y6 can also be used to make the area of the second fixed structure 21 gradually increase, which are not limited herein.

[0091] As shown in FIG. 7, each second fixed structure 21 is specifically arranged on the first fine grid 200 and / or the second fine grid 300 at intervals, and the second fixed structure 21 is used to weld the solder strip on the first fine grid 200 and / or the second fine grid 300 provided with the second fixed structure 21. As shown in the upper half of the back contact cell 100 without busbar in FIG. 7, the second fixed structure 21 can specifically be composed of multiple solder points; or as shown in the lower half of the back contact cell 100 without busbar in FIG. 7, the second fixed structure 21 can also be composed of a larger solder point.

[0092] For example, as shown in the upper half of the back contact cell 100 without busbar in FIG. 7, the second fixed structure 21 can specifically be composed of multiple solder points, the number of solder points included in the second fixed structure 21 away from the middle area 30 is C, the number of solder points included in the second fixed structure 21 close to the middle area 30 is D, C is greater than D. And along the first direction, the number of solder points in the second fixed structure 21 gradually increases.

[0093] In the embodiment of the present disclosure, the first edge area 10, the middle area 30 and the second edge area 20 are sequentially arranged along the first direction on the back of the back contact cell 100 without busbar. The second edge area 20 is also an edge part of the back contact cell 100 without busbar. In the second edge area 20, the closer to the edge of the back contact cell 100 without busbar, the stronger the stress tension, and the more difficult the stable welding of the solder strip, and the greater the risk of virtual welding.

[0094] Therefore, in the embodiment of the present disclosure, in the second edge area 20, the closer to the edge of the back contact cell 100 without busbar, the larger the area of the second fixed structure 21, the welding area is increased to gradually increase the welding tension of the solder strip and the fine grid of the back contact cell 100 without busbar close to the edge, so as to disperse and resist the gradually increasing stress and tension of the back contact cell 100 without busbar close to the edge, so as to improve the solder strip tension of the edge part, improve the stability of the solder strip welding, stabilize the solder strip welding, and reduce the risk of virtual soldering of the solder strip.

[0095] In addition, in the embodiment of the present disclosure, the area of the second fixed structure 21 is not uniformly matched with the stress tension of the most edge part of the back contact cell 100 without busbar. Instead, it gradually increases along the first direction in the second edge area 20. This gradually decreasing area of the second fixed structure 21 can optimize the use of materials and reduce costs while ensuring the strength of the solder strip welding.

[0096] Further, in a possible implementation, as shown in FIGS. 3 and 5, the external contour of the combination of multiple second fixed structures 21 is a trapezoidal shape.

[0097] Specifically, because the stress and tension of the edge portion (the second edge region 20) of the back contact cell without busbar 100 increases as the position approaches the edge. Therefore, in order to match the stress and tension of the second edge region 20, the area of the second fixed structure 21 in the present disclosure can specifically be gradiently changed, that is, along the first direction, the area of the second fixed structure 21 corresponding to the setting gradually increases from a smaller area close to the middle region 30 to a larger area close to the edge, so that the external contour of the combination of the plurality of second fixed structures 21 is set to be similar to a trapezoid. The embodiment of the present disclosure divides the second edge region 20 into a plurality of segments, and the area of the fixed structure in each segment gradually increases, thereby adapting to different stress requirements, which can effectively cope with the high stress and large tension of the edge portion of the back contact cell without busbar 100, and improve the stability of the solder strip welding and the overall reliability of the back contact cell without busbar 100.

[0098] Further, in a possible implementation, the external contour of the second fixed structure 21 can be trapezoidal, circular, rectangular, or octagonal. Specifically, the external contour of each second fixed structure 21 can be set to be trapezoidal, circular, rectangular, or octagonal, etc.

[0099] When the second fixed structure 21 is specifically set to be trapezoidal, optionally, the external contour of the second fixed structure 21 can be a trapezoid with the short side close to the middle region 30 and the long side away from the middle region 30.

[0100] Moreover, the solder strip is usually welded by solder paste. Therefore, further, as shown in FIGS. 3, 5, 8 and 10, in a possible implementation, the second fixed structure 21 is further used to set a second solder paste layer 22, and along the first direction, the area of the second solder paste layer 22 gradually increases. Of course, the way in which the area of the second solder paste layer 22 gradually increases can be set by referring to the second fixed structure 21, which will not be described here.

[0101] The second solder paste layer 22 specifically consists of solder paste, and the second solder paste layer 22 is used to weld the solder strip on the second fixed structure 21. And in order to cope with the stress and tension of the edge portion (the second edge region 20) of the back contact cell without busbar 100 increasing as the position approaches the edge, along the first direction, the area of the second solder paste layer 22 set by the present disclosure also gradually increases.

[0102] In particular, before the soldering of the soldering ribbon, each second fixed structure 21 is covered with a second layer of tin paste 22. Of course, in each second fixed structure 21, the second layer of tin paste 22 can optionally cover no more than the area of the second fixed structure 21. Before the soldering of the soldering ribbon, the external contour of the combination of the plurality of second layers of tin paste 22 can also be trapezoidal. The external contour of each second layer of tin paste 22 can also be trapezoidal, circular, rectangular, octagonal or other irregular shape, which can be selected according to actual conditions and is not limited herein.

[0103] Further, in the second edge area 20, in addition to the second fixed structure 21. In one possible implementation, as shown in FIGS. 3, 5, 9 and 10, in the second edge area 20, the second fixed structure 21 corresponding to the adjacent first fine grid 200 is provided with the second insulating glue 23, the second fixed structure 21 corresponding to the adjacent second fine grid 300 is provided with the second insulating glue 23, and the area of the plurality of second insulating glues 23 corresponding to the fine grid of the same polarity gradually increases along the first direction. Of course, the gradually increasing manner of the area of the second insulating glue 23 can be set by referring to the second fixed structure 21, which will not be described herein.

[0104] In the present disclosure, the "area of the plurality of second insulating glues 23 corresponding to the fine grid of the same polarity gradually increases along the first direction" can be understood as the area of the second insulating glue 23 corresponding to the first fine grid 200 gradually increases along the first direction; the area of the second insulating glue 23 corresponding to the second fine grid 300 gradually increases along the first direction. Specifically, in addition to setting the second fixed structure 21 on the first fine grid 200 and / or the second fine grid 300, the second insulating glue 23 can also be set on the first fine grid 200 and / or the second fine grid 300 in the first edge area 10. Specifically, the second insulating glue 23 is set between adjacent second fixed structures 21, or the second fixed structure 21 is set between adjacent second insulating glues 23.

[0105] In the second edge area 20, by means of the arrangement of each second fixing structure 21 and each second insulating glue 23, the first fine grid 200 with the same polarity and the solder strip can be welded, and the second fine grid 300 with the opposite polarity and the solder strip can be insulated; or the second fine grid 300 with the same polarity and the solder strip can be welded, and the first fine grid 200 with the opposite polarity and the solder strip can be insulated. For example, when the solder strip to be welded has the same polarity as the first fine grid 200 and the opposite polarity as the second fine grid 300, the solder strip is welded to the first fine grid 200 through the second fixing structure 21, and the solder strip is insulated from the second fine grid 300 through the second insulating glue 23; similarly, when the solder strip to be welded has the same polarity as the second fine grid 300 and the opposite polarity as the first fine grid 200, the solder strip is welded to the second fine grid 300 through the second fixing structure 21, and the solder strip is insulated from the first fine grid 200 through the second insulating glue 23.

[0106] In addition, as shown in FIGS. 3, 5, 11, 14 and 15, in the back contact cell without busbars 100, the fine grid is arranged on the doped layer 400, and in a possible implementation, the second edge area 20 further comprises a plurality of doped layers 400, and each doped layer 400 is correspondingly provided with the first fine grid 200 or the second fine grid 300. The doped layer 400 can be a P-type doped layer 410 or an N-type doped layer 420, and the P-type doped layer 410 and the N-type doped layer 420 are alternately arranged. Specifically, the first fine grid 200 can be arranged on the P-type doped layer 410, and the second fine grid 300 can be arranged on the N-type doped layer 420; or the second fine grid 300 can be arranged on the P-type doped layer 410, and the first fine grid 200 can be arranged on the N-type doped layer 420, which can be selected according to actual conditions and is not limited herein. The second edge area 20 has a second boundary 24 in a second direction, and the first direction and the second direction are perpendicular, and in the present disclosure, the second direction is specifically a vertical direction, and the second boundary 24 is one of the boundaries of the second edge area 20, and the second boundary 24 is also one of the boundaries of the entire back contact cell without busbars 100.

[0107] In a possible implementation, in the second edge area 20, the doped type of the doped layer closest to the second boundary 24 is opposite to the doped type of the silicon substrate in the back contact cell without busbars 100, so as to increase the emitter area of the back contact cell without busbars 100 and improve the cell efficiency of the back contact cell without busbars 100.

[0108] In addition, for electrons and holes, the collection of holes is more difficult, so in the second edge area 20, the doped type of the doped layer 400 closest to the second boundary 24 is opposite to the doped type of the silicon substrate in the back contact cell without busbars 100, which can also enhance the hole collection capability of the back contact cell without busbars 100 in the edge part.

[0109] For example, the silicon substrate in the back contact cell 100 without busbars is P-type doped, as shown in FIG. 14, i.e. the doped layer closest to the second boundary 24 is an N-type doped layer 420; or the silicon substrate in the back contact cell 100 without busbars is N-type doped, as shown in FIG. 15, i.e. the doped layer closest to the second boundary 24 is a P-type doped layer 410.

[0110] Of course, as shown in FIG. 15, in a possible implementation, the doped layer 400 closest to the second boundary 24 in the second edge region 20 can be optionally set as a P-type doped layer 410. To achieve the effect of enhancing the hole collection capability of the edge part of the back contact cell 100 without busbars.

[0111] Optionally, in the embodiments of the present disclosure, the doped layer closest to the first boundary 14 can be set as an N-type doped layer 420, and / or the doped layer closest to the second boundary 24 can also be set as an N-type doped layer 420.

[0112] Further, for the arrangement of the fixed structures in the middle part of the back contact cell 100 without busbars. As shown in FIG. 3 and FIG. 6, further, in a possible implementation, the middle region 30 also has a plurality of first fine busbars 200 and a plurality of second fine busbars 300, which are arranged in turn and alternately. Specifically, the first fine busbar 200 can be a negative fine busbar, and the second fine busbar 300 can be a positive fine busbar; or the first fine busbar 200 can be a positive fine busbar, and the second fine busbar 300 can be a negative fine busbar, which is not limited herein.

[0113] The middle region 30 has a plurality of third fixed structures 31 arranged on the first fine busbar 200 and / or the second fine busbar 300, and each third fixed structure 31 is arranged in a spaced manner. The third fixed structure 31 is used for welding with a solder strip, and specifically used for welding the solder strip on the first fine busbar 200 and / or the second fine busbar 300 in the middle region 30. In the middle region 30, the area of the third fixed structure 31 is constant along the first direction.

[0114] Optionally, in a possible implementation, the area of the first fixed structure 11 in the first edge region 10 is greater than or equal to the area of the third fixed structure 31 in the middle region 30; and the area of the second fixed structure 21 in the second edge region 20 is greater than or equal to the area of the third fixed structure 31 in the middle region 30.

[0115] Specifically, because the first edge region 10 and the second edge region 20 are respectively arranged on both sides of the middle region 30, by setting the area of the first fixed structure 11 in the first edge region 10 to be greater than or equal to the area of the third fixed structure 31 in the middle region 30, the problem of high stress and large tension in the edge part of the back contact cell 100 without main grid can be effectively solved, and the stability of the solder strip welding and the overall reliability of the back contact cell 100 without main grid can be further improved. Similarly, by setting the area of the second fixed structure 21 in the second edge region 20 to be greater than or equal to the area of the third fixed structure 31 in the middle region 30, the problem of high stress and large tension in the edge part of the back contact cell 100 without main grid can be effectively solved, and the stability of the solder strip welding and the overall reliability of the back contact cell 100 without main grid can be further improved.

[0116] As shown in FIG. 7, each third fixed structure 31 is specifically arranged on the first fine grid 200 and the second fine grid 300 at intervals, and the third fixed structure 31 is used to weld the solder strip on the first fine grid 200 or the second fine grid 300 provided with the third fixed structure 31. And as shown in the upper half of the back contact cell 100 without main grid in FIG. 7, the third fixed structure 31 can specifically be composed of multiple solder points; or as shown in the lower half of the back contact cell 100 without main grid in FIG. 7, the third fixed structure 31 can also be composed of one larger solder point.

[0117] For example, as shown in the upper half of the back contact cell 100 without main grid in FIG. 7, the third fixed structure 31 can be composed of multiple solder points, and the number of solder points included in the third fixed structure 31 is E, and the number of solder points in the third fixed structure 31 does not change along the first direction.

[0118] Specifically, in the back contact cell 100 without main grid, the middle region 30 is arranged between the two edge regions, and in the middle region 30, by setting the area of the third fixed structure 31 to be constant, a stable welding area is provided for the middle region 30 of the back contact cell 100 without main grid, ensuring that the welding part of the middle region 30 has uniform mechanical strength and stability, and also achieving the effect of optimizing the use of materials and reducing costs. Among them, the external contour of the combination of multiple third fixed structures 31 is rectangular, and the external contour of each third fixed structure 31 can be trapezoidal, circular, rectangular or octagonal.

[0119] Moreover, the solder strip is usually welded by solder paste. Therefore, further, in a possible implementation, as shown in FIGS. 3, 6, 8 and 10, the third fixed structure 31 is also used to set a third solder paste layer 32, and the area of the third solder paste layer 32 does not change along the first direction.

[0120] The third solder paste layer 32 is specifically composed of a solder paste, and the third solder paste layer 32 can be used to weld the solder strip on the third fixed structure 31. By setting the area of the third solder paste layer 32 unchanged, a stable welding area is provided for the middle area 30 of the no-main-grid back contact battery 100, so as to ensure that the welding part of the middle area 30 has uniform mechanical strength and stability, and also achieves the effect of optimizing the use of materials and reducing costs.

[0121] In particular, before welding the solder strip, the third solder paste layer 32 is correspondingly covered on each third fixed structure 31. Of course, in each third fixed structure 31, the coverage range of the third solder paste layer 32 does not exceed the area of the third fixed structure 31. Before welding the solder strip, the external contour of the combination of the plurality of third solder paste layers 32 can also be a quasi-rectangle. The external contour of each third solder paste layer 32 can also be set as a trapezoid, a circle, a rectangle, an octagon or other irregular shapes, which can be selected according to actual conditions and is not limited herein.

[0122] Further, in the second edge area 20, in addition to the third fixed structure 31. In one possible implementation, as shown in FIGS. 3, 6, 9 and 10, in the middle area 30, the third fixed structure 31 corresponding to the adjacent first fine grid 200 is used to set the third insulating glue 33, and the third fixed structure 31 corresponding to the adjacent second fine grid 300 is used to set the third insulating glue 33, and the area of the third insulating glue 33 is unchanged along the first direction.

[0123] Specifically, in addition to setting the third fixed structure 31 on the first fine grid 200 and the second fine grid 300, the third insulating glue 33 can also be set on the first fine grid 200 and / or the second fine grid 300 in the second edge area 20. Specifically, the third insulating glue 33 is set between adjacent third fixed structures 31, or the third fixed structure 31 is set between adjacent third insulating glues 33.

[0124] In the middle region 30, by the setting of each third fixed structure 31 and each third insulating glue 33, the first fine grid 200 with the same polarity and the solder strip can be welded, and the second fine grid 300 with opposite polarity and the solder strip can be insulated; or the second fine grid 300 with the same polarity and the solder strip can be welded, and the first fine grid 200 with opposite polarity and the solder strip can be insulated. For example, when the solder strip to be welded has the same polarity as the first fine grid 200 and opposite polarity as the second fine grid 300, the solder strip is welded to the first fine grid 200 through the third fixed structure 31, and the solder strip is insulated from the second fine grid 300 through the third insulating glue 33; similarly, when the solder strip to be welded has the same polarity as the second fine grid 300 and opposite polarity as the first fine grid 200, the solder strip is welded to the second fine grid 300 through the third fixed structure 31, and the solder strip is insulated from the first fine grid 200 through the third insulating glue 33.

[0125] In addition, similarly, as shown in FIGS. 3, 6 and 11, in the no main grid back contact cell 100, the fine grid is arranged on the doped layer 400, and in a possible implementation, the middle further includes a plurality of doped layers 400, and the first fine grid 200 or the second fine grid 300 is arranged on each doped layer 400. The doped layer 400 is specifically a P-type doped layer 410 or an N-type doped layer 420, and the P-type doped layer 410 and the N-type doped layer 420 are also arranged alternately. Specifically, the first fine grid 200 can be arranged on the P-type doped layer 410, and the second fine grid 300 can be arranged on the N-type doped layer 420; or the second fine grid 300 can be arranged on the P-type doped layer 410, and the first fine grid 200 can be arranged on the N-type doped layer 420, which can be selected according to actual conditions, and is not limited herein.

[0126] Therefore, in the no main grid back contact cell 100 of the present disclosure, by arranging the fixed structure gradually increasing in the opposite direction along the first direction in the edge region of the no main grid back contact cell 100, i.e. the first edge region 10, and arranging the fixed structure gradually increasing along the first direction in the second edge region 20, the problem of gradually increasing stress and tension in the no main grid back contact cell 100 closer to the edge can be effectively solved, and the effect of improving the stability of the solder strip welding and the overall reliability of the no main grid back contact cell 100 can be achieved; and in the middle region 30 between the first edge region 10 and the second edge region 20, the third fixed structure 31 with unchanged area is arranged, so as to ensure that the middle region 30 has uniform mechanical strength and stability, and the effect of reducing cost can be achieved.

[0127] In the description of the disclosure, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the disclosure. In the description of the disclosure, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0128] Although the embodiments of the disclosure have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the disclosure, and the scope of the disclosure is defined by the claims and their equivalents.

Claims

1. A back contact cell with no busbars, characterized in that, The main-free back contact cell is sequentially provided with a first edge region and a middle region along a first direction; A plurality of first fine grids and a plurality of second fine grids are arranged in the first edge region, and the plurality of first fine grids and the plurality of second fine grids are alternately and spacedly arranged; A plurality of first fixed structures arranged on at least one of the first fine grids and the second fine grids are arranged in the first edge region, and each of the first fixed structures is spacedly arranged, and the first fixed structure is used for welding with a solder strip; In the first edge region, the area of the plurality of first fixed structures on the fine grid of the same polarity gradually increases in the opposite direction of the first direction.

2. The no-lead back-contact cell of claim 1, wherein, The main-free back contact cell further has a second edge region, and the main-free back contact cell is sequentially provided with the first edge region, the middle region and the second edge region along the first direction; A plurality of first fine grids and a plurality of second fine grids are arranged in the second edge region, and the plurality of first fine grids and the plurality of second fine grids are alternately and spacedly arranged; A plurality of second fixed structures arranged on at least one of the first fine grids and the second fine grids are arranged in the second edge region, and each of the second fixed structures is spacedly arranged, and the second fixed structure is used for welding with a solder strip; In the second edge region, the area of the plurality of second fixed structures on the fine grid of the same polarity gradually increases along the first direction.

3. The eni -main grid back contact cell of claim 2, wherein, A plurality of first fine grids and a plurality of second fine grids are arranged in the middle region, and the plurality of first fine grids and the plurality of second fine grids are alternately and spacedly arranged; A plurality of third fixed structures arranged on at least one of the first fine grids and the second fine grids are arranged in the middle region, and each of the third fixed structures is spacedly arranged, and the third fixed structure is used for welding with a solder strip; In the middle region, the area of the third fixed structure is constant along the first direction.

4. The eni -main grid back contact cell of claim 3, wherein, The area of the first fixed structure is greater than or equal to the area of the third fixed structure.

5. The eni -main grid back contact cell of claim 3, wherein, The area of the second fixed structure is greater than or equal to the area of the third fixed structure.

6. The eni -main grid back contact cell of claim 1, wherein, The external contour of the plurality of first fixed structures in combination is a trapezoidal shape.

7. The gridless back contact cell of claim 1 wherein, The external contour of the first fixed structure is a trapezoidal shape, a circular shape, a rectangular shape or an octagonal shape.

8. The eni -main grid back contact cell of claim 7, wherein, The external contour of the first fixed structure is a trapezoidal shape with a short side close to the middle region and a long side away from the middle region.

9. The gridless back contact cell of claim 2, wherein, The external contour of the plurality of second fixed structures in combination is a trapezoidal shape.

10. The eni -main grid back contact cell of claim 2, wherein, The external contour of the second fixed structure is a trapezoidal shape, a circular shape, a rectangular shape or an octagonal shape.

11. The eni -main grid back contact cell of claim 10, wherein, The external contour of the second fixed structure is a trapezoidal shape with a short side close to the middle region and a long side away from the middle region.

12. The gridless back-contact cell of claim 3, wherein, The external contour of the plurality of third fixed structures in combination is a rectangular shape.

13. The gridless back contact cell of claim 3, wherein, The external contour of the third fixed structure is a trapezoidal shape, a circular shape, a rectangular shape or an octagonal shape.

14. The gridless back contact cell of claim 1, wherein, The first fixed structure is further used for arranging a first solder paste layer; In the opposite direction of the first direction, the area of the plurality of first solder paste layers corresponding to the fine grid of the same polarity gradually increases.

15. The gridless back contact cell of claim 2, wherein, The second fixed structure is further used for arranging a second solder paste layer; Along the first direction, the areas of the second solder paste layers corresponding to the fine grids of the same polarity gradually increase.

16. The gridless back contact cell of claim 3, wherein, The third fixed structure is further configured to arrange a third solder paste layer. Along the first direction, the area of the third solder paste layer is constant.

17. The gridless back contact cell of claim 1, wherein, In the first edge region, the first fixed structures corresponding to adjacent first fine grids are arranged with a first insulating adhesive, and the first fixed structures corresponding to adjacent second fine grids are arranged with the first insulating adhesive, along the opposite direction of the first direction, the areas of the first insulating adhesives corresponding to the fine grids of the same polarity gradually increase.

18. The gridless back contact cell of claim 2, wherein, In the second edge region, the second fixed structures corresponding to adjacent first fine grids are arranged with a second insulating adhesive, and the second fixed structures corresponding to adjacent second fine grids are arranged with the second insulating adhesive, along the first direction, the areas of the second insulating adhesives corresponding to the fine grids of the same polarity gradually increase.

19. The gridless back contact cell of claim 3, wherein, In the middle region, the third fixed structures corresponding to adjacent first fine grids are arranged with a third insulating adhesive, and the third fixed structures corresponding to adjacent second fine grids are arranged with the third insulating adhesive, along the first direction, the area of the third insulating adhesive is constant.

20. The gridless back contact solar cell of claim 1 wherein, The first edge region further includes a plurality of doped layers, and the first fine grids or the second fine grids are arranged on each of the doped layers correspondingly; The first edge region has a first boundary along a second direction, and in the first edge region, the doped type of the doped layer closest to the first boundary is opposite to the doped type of the silicon substrate in the back contact cell without main grid, and the first direction is perpendicular to the second direction.

21. The gridless back contact cell of claim 1, wherein, The first edge region further includes a plurality of doped layers, and the first fine grids or the second fine grids are arranged on each of the doped layers correspondingly; The first edge region has a first boundary along a second direction, and in the first edge region, the doped layer closest to the first boundary is a P-type doped layer, and the first direction is perpendicular to the second direction.

22. The gridless back contact cell of claim 2, wherein, The second edge region further includes a plurality of doped layers, and the first fine grids or the second fine grids are arranged on each of the doped layers correspondingly; The second edge region has a second boundary along a second direction, and in the second edge region, the doped type of the doped layer closest to the second boundary is opposite to the doped type of the silicon substrate in the back contact cell without main grid, and the first direction is perpendicular to the second direction.

23. The gridless back contact cell of claim 2, wherein, The second edge region further includes a plurality of doped layers, and the first fine grids or the second fine grids are arranged on each of the doped layers correspondingly; The second edge region has a second boundary along a second direction, and in the second edge region, the doped layer closest to the second boundary is a P-type doped layer, and the first direction is perpendicular to the second direction.

24. A battery assembly comprising: The battery assembly includes a plurality of back contact cells without main grid as claimed in any one of claims 1 to 23.

25. A photovoltaic system characterized by, The battery assembly includes the battery assembly as claimed in claim 24.

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