Photovoltaic cell, assembly, and system

Abstract

The present disclosure provides a photovoltaic cell, an assembly, and a system. First interconnection areas and second interconnection areas extend along a first direction, intersect with all first fingers and second fingers, and are alternately arranged at intervals in sequence along a second direction. First welded segments at the intersections of each first finger and the first interconnection areas are located in the first interconnection areas, and a pre-applied adhesive is provided between the first interconnection areas and second interconnection areas.

Description

Photovoltaic cells, modules and systems

[0001] Cross Reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411296006.8, filed on September 14, 2024, entitled "Back Contact Cell Without Main Grid, Cell String, Cell Module and Photovoltaic System", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure belongs to the technical field of solar cells, and particularly relates to a back contact cell without main grid, a cell string, a cell module and a photovoltaic system. BACKGROUND

[0004] In the related art, in a back contact solar cell without main grid, a tin paste pad is provided at a position on each fine grid for connection with a solder ribbon. In order to avoid the solder ribbon from deviating in the lamination welding, a pre-adhesive is provided at a position near the tin paste pad to pre-fix the solder ribbon. However, the pre-adhesive occupies the surface space of the cell sheet, affects the light receiving rate of the cell sheet, and the provision of the pre-adhesive also increases the cost of the cell. SUMMARY

[0005] The present disclosure provides a back contact cell without main grid, a cell string, a cell module and a photovoltaic system, which aims to solve the problem that the photovoltaic cell will block light and reduce the bifacial rate when using a pre-adhesive.

[0006] The present disclosure provides a back contact cell without main grid, which comprises:

[0007] A silicon substrate comprising a front surface and a back surface opposite to each other;

[0008] A plurality of first fine grids and a plurality of second fine grids are arranged on the back surface, the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spaced apart along a first direction, and both extend along a second direction, the second direction intersects the first direction, the back surface has a plurality of first string connection areas and a plurality of second string connection areas for arranging solder ribbons, the first string connection areas and the second string connection areas extend along the first direction and intersect all the first fine grids and all the second fine grids, and the plurality of first string connection areas and the plurality of second string connection areas are arranged alternately and spaced apart along the second direction;

[0009] Each first fine grid has a first welding section at the intersection position with the first string connection area, and all the first welding sections are located in the first string connection area, and each second fine grid has a second welding section at the intersection position with the second string connection area, and all the second welding sections are located in the second string connection area;

[0010] The pre-adhesive is arranged on the back surface, and is arranged between the first stringing area and the second stringing area and at least partially extends into the first stringing area and the second stringing area.

[0011] In the back contact cell without busbars in the embodiment of the present disclosure, the back contact cell includes a silicon substrate, a plurality of first fine grids and a plurality of second fine grids, and a pre-adhesive, the silicon substrate includes a front surface and a back surface opposite to each other; the plurality of first fine grids and the plurality of second fine grids are arranged on the back surface, the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spaced apart in sequence along a first direction and extend along a second direction intersecting the first direction, the back surface has a plurality of first stringing areas and second stringing areas for arranging solder strips, the first stringing areas and the second stringing areas extend along the first direction and cross all the first fine grids and the second fine grids, and the plurality of first stringing areas and the plurality of second stringing areas are arranged alternately and spaced apart in sequence along the second direction; each first fine grid has a first soldering segment at a crossing position with the first stringing area, and all the first soldering segments are located in the first stringing area; each second fine grid has a second soldering segment at a crossing position with the second stringing area, and all the second soldering segments are located in the second stringing area; and the pre-adhesive is arranged on the back surface, and is arranged between the first stringing area and the second stringing area and at least partially extends into the first stringing area and the second stringing area. In this way, the pre-adhesive is arranged between the first stringing area and the second stringing area, the solder strips arranged in the first stringing area and the second stringing area can be simultaneously pre-fixed, the use amount of the pre-adhesive is reduced, the influence on light is reduced, and the cost is reduced.

[0012] In some embodiments, at least one first soldering segment in the first stringing area is staggered with the remaining at least one first soldering segment in the first direction, and at least one second soldering segment in the second stringing area is staggered with the remaining at least one second soldering segment in the first direction.

[0013] In some embodiments, according to the arrangement sequence of the first soldering segments in the first direction, the center points of all the first soldering segments are sequentially connected to form a first line segment which is a non-straight line segment, and the first line segment has at least one first recessed segment.

[0014] In some embodiments, according to the arrangement sequence of the second soldering segments in the first direction, the center points of all the second soldering segments are sequentially connected to form a second line segment which is a non-straight line segment, and the second line segment has at least one second recessed segment.

[0015] In some embodiments, the opening of the first recessed segment is oppositely arranged with the opening of the second recessed segment.

[0016] In some embodiments, the pre-adhesive is arranged between the first recessed segment and the second recessed segment, and the openings of the first recessed segment and the second recessed segment are both directed to the pre-adhesive.

[0017] In some embodiments, the number of the first solder segments corresponding to the first recessed segments is multiple;

[0018] The number of the second solder segments corresponding to the second recessed segments is multiple.

[0019] In some embodiments, the distance between the pre-adhesive and the first solder segment located on the first recessed segment is 100 μm-2 mm; or

[0020] The distance between the pre-adhesive and the second solder segment located on the second recessed segment is 100 μm-2 mm; or

[0021] The distance between the pre-adhesive and the first solder segment located on the first recessed segment is 100 μm-2 mm, and the distance between the pre-adhesive and the second solder segment located on the second recessed segment is 100 μm-2 mm.

[0022] In some embodiments, the length of the pre-adhesive in the second direction is 300 μm-2 mm.

[0023] In some embodiments, the distance between the first stringing area and the second stringing area in the first direction is 0.01 mm-2 mm.

[0024] The battery string provided by the embodiments of the present disclosure comprises the back contact battery without busbar of any of the above embodiments; and

[0025] The solder tape covering the first stringing area and the second stringing area, the solder tape on the first stringing area being bonded with the pre-adhesive and being in contact with the solder layer on the first solder segment, and the solder tape on the second stringing area being bonded with the pre-adhesive and being in contact with the solder layer on the second solder segment.

[0026] The battery assembly provided by the embodiments of the present disclosure comprises the battery string of the above embodiments.

[0027] The photovoltaic system provided by the embodiments of the present disclosure comprises the battery assembly of the above embodiments.

[0028] In the back contact cell without busbar, the cell string, the cell module and the photovoltaic system of the embodiments of the present disclosure, the back contact cell without busbar comprises a silicon substrate, a plurality of first fine grids and a plurality of second fine grids, and a pre-adhesive, the silicon substrate comprises a front surface and a back surface opposite to each other; the plurality of first fine grids and the plurality of second fine grids are arranged on the back surface, the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spaced apart in sequence along a first direction, and both extend along a second direction, the second direction intersects the first direction, the back surface has a plurality of first stringing areas and a plurality of second stringing areas for arranging solder strips, the first stringing areas and the second stringing areas extend along the first direction and cross all the first fine grids and the second fine grids, and the plurality of first stringing areas and the plurality of second stringing areas are arranged alternately and spaced apart in sequence along the second direction; each first fine grid has a first soldering section at the crossing position of the first fine grid and the first stringing area, and all the first soldering sections are located in the first stringing area; each second fine grid has a second soldering section at the crossing position of the second fine grid and the second stringing area, and all the second soldering sections are located in the second stringing area; the pre-adhesive is arranged on the back surface, and the pre-adhesive is arranged between the first stringing areas and the second stringing areas and at least partially extends into the first stringing areas and the second stringing areas. In this way, the pre-adhesive arranged between the first stringing areas and the second stringing areas can simultaneously pre-fix the solder strips arranged in the first stringing areas and the second stringing areas, the use amount of the pre-adhesive is reduced, the influence on the light is reduced, and the cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a schematic diagram of a planar structure of a back contact cell without busbar according to an embodiment of the present disclosure;

[0030] FIG. 2 is another schematic diagram of a planar structure of a back contact cell without busbar according to an embodiment of the present disclosure;

[0031] FIG. 3 is a schematic diagram of a partial structure of a back contact cell without busbar according to an embodiment of the present disclosure;

[0032] FIG. 4 is a schematic diagram of a module structure of a cell string according to an embodiment of the present disclosure;

[0033] FIG. 5 is a schematic diagram of a module structure of a cell module according to an embodiment of the present disclosure;

[0034] FIG. 6 is a schematic diagram of a module structure of a photovoltaic system according to an embodiment of the present disclosure.

[0035] Main element symbol explanation: back contact cell without main grid 100, silicon substrate 10, first fine grid 20, first solder section 21, second fine grid 30, second solder section 31, pre-adhesive 40, first stringing area 50, first line section 51, first recess section 511, first sub-straight section 5111, first inclined section 5112, first straight section 512, second stringing area 60, second line section 61, second recess section 611, second sub-straight section 6111, second inclined section 6112, second straight section 612, solder strip 70, first solder strip 71, second solder strip 72, cell string 200, cell assembly 300, photovoltaic system 400. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as a limitation on the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to explain the present disclosure and cannot be used to limit the present disclosure.

[0037] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present disclosure and simplifying the description, and do 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 on the present disclosure.

[0038] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, 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 "multiple" is two or more, unless otherwise explicitly specified and limited.

[0039] In the description of the present disclosure, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium; it can be 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.

[0040] In the present disclosure, unless specifically stated and limited otherwise, a first feature "on" or "under" a 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 first feature "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0041] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present disclosure. For the purpose of simplifying the present disclosure, certain examples of components and arrangements are described. Of course, they are only examples and are intended to be illustrative only and are not intended to be limiting of the present disclosure. Additionally, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art will appreciate that other processes and / or materials can be used.

[0042] In the related art, a solar cell is a semiconductor device that directly converts the energy of sunlight into electricity. The solar cell utilizes the photovoltaic effect to excite electrons by absorbing photons, and to guide these electrons out to generate electric current by the built-in electric field. The back contact cell refers to a solar cell in which the light-receiving surface of the cell piece is free of electrodes, and the positive and negative electrodes are arranged on the back light side of the cell piece, so that the shading of the cell piece by the electrodes can be reduced, the short-circuit current of the cell piece can be increased, and the energy conversion efficiency of the cell piece can be improved. In the prior art, a tin paste pad is arranged at a position on each fine grid for connection with a solder strip. In order to avoid the offset of the solder strip in the laminated welding, a pre-adhesive is arranged near the tin paste pad to pre-fix the solder strip. However, the pre-adhesive occupies the surface space of the cell piece, affects the light receiving rate of the cell piece, and the arrangement of the pre-adhesive also increases the cost of the cell. In the embodiment of the present disclosure, the pre-adhesive is arranged between the first stringing area and the second stringing area, so that the solder strips arranged in the first stringing area and the second stringing area can be pre-fixed at the same time, the amount of pre-adhesive used is reduced, the influence on light is reduced, and the cost is reduced.

[0043] Embodiment one

[0044] Referring to FIGS. 1-4, the disclosed embodiment provides a back contact cell 100 without busbars, which includes a silicon substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30, and a pre-adhesive 40. The silicon substrate 10 includes a front surface and a back surface opposite to each other. The plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged on the back surface. The plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged alternately and spaced apart along a first direction, and extend along a second direction. The second direction intersects the first direction. The back surface has a plurality of first stringing areas 50 and a plurality of second stringing areas 60 for arranging solder ribbons 70. The first stringing areas 50 and the second stringing areas 60 extend along the first direction and intersect all of the first fine grids 20 and the second fine grids 30. The plurality of first stringing areas 50 and the plurality of second stringing areas 60 are arranged alternately and spaced apart along the second direction. Each of the first fine grids 20 has a first soldering section 21 at a position intersecting the first stringing area 50. All of the first soldering sections 21 are located within the first stringing area 50. Each of the second fine grids 30 has a second soldering section 31 at a position intersecting the second stringing area 60. All of the second soldering sections 31 are located within the second stringing area 60. The pre-adhesive 40 is arranged on the back surface. The pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60 and at least partially extends into the first stringing area 50 and the second stringing area 60.

[0045] In the back contact cell 100 without busbars of the disclosed embodiment, the back contact cell 100 includes a silicon substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30, and a pre-adhesive 40. The silicon substrate 10 includes a front surface and a back surface opposite to each other. The plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged on the back surface. The plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged alternately and spaced apart along a first direction, and extend along a second direction. The second direction intersects the first direction. The back surface has a plurality of first stringing areas 50 and a plurality of second stringing areas 60 for arranging solder ribbons 70. The first stringing areas 50 and the second stringing areas 60 extend along the first direction and intersect all of the first fine grids 20 and the second fine grids 30. The plurality of first stringing areas 50 and the plurality of second stringing areas 60 are arranged alternately and spaced apart along the second direction. Each of the first fine grids 20 has a first soldering section 21 at a position intersecting the first stringing area 50. All of the first soldering sections 21 are located within the first stringing area 50. Each of the second fine grids 30 has a second soldering section 31 at a position intersecting the second stringing area 60. All of the second soldering sections 31 are located within the second stringing area 60. The pre-adhesive 40 is arranged on the back surface. The pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60 and at least partially extends into the first stringing area 50 and the second stringing area 60. In this way, the pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60, so that the solder ribbons 70 arranged in the first stringing area 50 and the second stringing area 60 can be pre-fixed simultaneously, the use amount of the pre-adhesive 40 is reduced, the influence on light is reduced, and the cost is reduced.

[0046] In the embodiment, the front surface of the silicon substrate 10 is used to receive light, and the back surface of the silicon substrate 10 includes a plurality of first doped layers and second doped layers (not shown in the figure) arranged alternately, the first doped layers are provided with the first fine grids 20, and the second doped layers are provided with the second fine grids 30. The first fine grids 20 and the second fine grids 30 extend along the second direction and are arranged alternately along the first direction, and the first doped layers and the second doped layers also extend along the second direction and are arranged alternately along the first direction. In the embodiment, the back surface of the silicon substrate 10 is not provided with a main grid, and the first fine grids 20 and the second fine grids 30 can directly realize the convergence of current through the solder strip 70.

[0047] In the embodiment, the doping types of the first doped layers and the second doped layers are not limited, for example, the first doped layers and the second doped layers can be P-type doped layers and N-type doped layers respectively; or the first doped layers can be N-type doped layers, and the second doped layers can be P-type doped layers, as long as the polarities of the two are opposite to meet different requirements. In some embodiments, the first doped layers can be P-type polycrystalline silicon layers, P-type amorphous silicon layers, or P-type microcrystalline silicon layers, which are not limited here. Similarly, the second doped layers can be N-type polycrystalline silicon layers, N-type amorphous silicon layers, or N-type microcrystalline silicon layers, which are not limited here. When the first doped layers are P-type doped layers and the second doped layers are N-type doped layers, P-type grid lines can be further provided on the first doped layers, and N-type grid lines can be further provided on the second doped layers, which are not limited here.

[0048] In some embodiments, P-type doping refers to doping group III elements, including boron, aluminum, gallium, indium, thallium, and the like; and N-type doping refers to doping group V elements, including nitrogen, phosphorus, arsenic, antimony, bismuth, and the like, which are not limited here.

[0049] In addition, in some embodiments, the first doped layers and the second doped layers can also be composite doped, for example, N-type doping also includes a small amount of P-type doping elements. The content of the N-type doping elements of the second doped layers is higher than 20% of the content of the P-type doping elements, so as to ensure that the polarity of the first doped layers is opposite to that of the second doped layers.

[0050] Specifically, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back contact cell 100 without a main grid, respectively. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, the two can be diagonal directions of the silicon substrate 10, which are not limited here.

[0051] It is not difficult to understand that in the conventional technology, the dispensing adhesive points are usually arranged on the grid line segments of the fine grids for soldering, the solder paste pads are arranged on the soldering segments, and the dispensing adhesive points need to be as close as possible to the center points of the solder strips 70. Due to the close distance, the height of the dispensing adhesive points is greater than the height of the soldering positions, which easily causes the solder strips 70 to fail to contact the corresponding soldering points near the dispensing adhesive points, thereby easily causing a virtual soldering.

[0052] In the embodiment of the present disclosure, the pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60 and at least partially extends into the first stringing area 50 and the second stringing area 60. That is, the solder strip 70 connected with the positive fine grid and the solder strip 70 connected with the negative fine grid are close to each other, and a pre-adhesive 40 is used for pre-connection to realize the positioning of the two solder strips 70 and ensure the positioning accuracy. One pre-adhesive 40 can simultaneously pre-fix the solder strips 70 arranged in the first stringing area 50 and the second stringing area 60, thereby reducing the use amount of the pre-adhesive 40, reducing the influence on light, and reducing the cost.

[0053] In addition, in the embodiment of the present disclosure, the form and preparation method of the pre-adhesive 40 are not limited to meet different needs. In one embodiment, the pre-adhesive 40 is arranged at the corresponding position by a spraying process. In this way, the arrangement position of the pre-adhesive 40 is more accurate, the speed of arranging the pre-adhesive 40 is faster, and the spraying equipment does not need to be in direct contact with the battery piece, which can reduce the pollution and damage to the battery piece. Further, the pre-adhesive 40 can be at least one of light-cured and heat-cured.

[0054] Embodiment two

[0055] Please refer to FIGS. 1 to 3. In some optional embodiments, at least one first soldering segment 21 and the remaining at least one first soldering segment 21 are staggered with each other in the first direction within the first stringing area 50, and at least one second soldering segment 31 and the remaining at least one second soldering segment 31 are staggered with each other in the first direction within the second stringing area 60.

[0056] In the embodiment, the back surface has a plurality of first stringing areas 50 and a plurality of second stringing areas 60 for arranging the solder strips 70, the first stringing areas 50 and the second stringing areas 60 extend along the first direction and cross all the first fine grids 20 and the second fine grids 30, and the plurality of first stringing areas 50 and the plurality of second stringing areas 60 are sequentially and alternately arranged along the second direction. Each first fine grid 20 has a first soldering segment 21 at the crossing position with the first stringing area 50, and all the first soldering segments 21 are located within the first stringing area 50. Each second fine grid 30 has a second soldering segment 31 at the crossing position with the second stringing area 60, and all the second soldering segments 31 are located within the second stringing area 60.

[0057] In the embodiments of the present disclosure, in the first stringing area 50, at least one first welding section 21 is staggered with the rest of the at least one first welding section 21 in the first direction, that is, in the first direction, at least one first welding section 21 is not completely aligned (that is, not completely located on the same straight line parallel to the first direction) with the rest of the at least one first welding section 21. At the same time, in the second stringing area 60, at least one second welding section 31 is staggered with the rest of the at least one second welding section 31 in the first direction, that is, in the first direction, at least one second welding section 31 is not completely aligned (that is, not completely located on the same straight line parallel to the first direction) with the rest of the at least one second welding section 31. In this way, the first stringing area 50 and the second stringing area 60 can avoid the pre-adhesive 40 by staggering, leaving enough space for the pre-adhesive 40.

[0058] In some embodiments, the first welding section 21 and the second welding section 31 are both thick grid sections, that is, the first welding section 21 is thicker than other parts of the first fine grid 20, and the second welding section 31 is thicker than other parts of the second fine grid 30. In some embodiments, the length (that is, the length in the second direction) of the first welding section 21 and the second welding section 31 can be 250-350 μm, and the width (that is, the length in the second direction) can be 25-50 μm, so as to ensure the contact area of the first welding section 21 and the second welding section 31 with the solder strip 70 and improve the stability of welding.

[0059] Please refer to FIG. 1 and FIG. 3, the pre-adhesive 40 is at least partially disposed in the second stringing area 60, the solder strip 70 is covered on the first stringing area 50, the solder strip 70 on the first stringing area 50 is bonded with the left end of the pre-adhesive 40 and contacts the solder layer on the first welding section 21, and the solder strip 70 on the second stringing area 60 is bonded with the right end of the pre-adhesive 40 and contacts the solder layer on the second welding section 31.

[0060] Embodiment three

[0061] Please refer to FIG. 1 to FIG. 3, in some optional embodiments, according to the arrangement order of the first welding section 21 in the first direction, the first line segment 51 formed by sequentially connecting the center points of all the first welding sections 21 is a non-straight line segment, and the first line segment 51 has at least one first recessed segment 511.

[0062] Please refer to FIG. 1 to FIG. 3, in some optional embodiments, according to the arrangement order of the second welding section 31 in the first direction, the second line segment 61 formed by sequentially connecting the center points of all the second welding sections 31 is a non-straight line segment, and the second line segment 61 has at least one second recessed segment 611.

[0063] Thus, in the welding process, the welding layer can be arranged on the first welding section 21 and the second welding section 31, and when the pre-adhesive 40 is used to pre-fix the solder strip 70, the pre-adhesive 40 can be arranged at a position where the openings of the first recess section 511 and the second recess section 611 face, so that the distance between the welding sections corresponding to the first recess section 511 and the second recess section 611 of the pre-adhesive 40 is far, which can effectively avoid the occurrence of virtual welding in the subsequent welding process, and at the same time, the adhesion of the pre-adhesive 40 to the solder strip 70 can be ensured.

[0064] In the embodiments of the present disclosure, the specific forms of the first recess section 511 and the second recess section 611 are not limited to meet different needs. For example, in some embodiments, the first recess section 511 and the second recess section 611 can also be arc-shaped sections, that is, the first line section 51 can be composed of the first straight line section 512 and an arc-shaped section, and the second line section 61 can be composed of the second straight line section 612 and an arc-shaped section. For another example, the first line section 51 can be a wavy line, that is, in the up-down direction of the first direction, the arrangement profile of the first welding section 21 is wavy, and the first line section 51 is an arc-shaped curve as a whole. In the embodiments of the present disclosure, the first recess section 511 and the second recess section 611 can also have other forms, which will be described below by taking the first recess section 511 as an example.

[0065] In some embodiments, the first line section 51 has at least one first straight line section 512, the first straight line section 512 is arranged in parallel to the first direction, and the first recess section 511 is offset in the second direction compared to the first straight line section 512. In this way, by arranging the first straight line section 512, the first welding sections 21 on the first straight line section 512 are located on the same straight line parallel to the first direction, which can improve the welding efficiency in the welding process (such as laser welding), and at the same time, the same straight line of the solder strip 70 having a plurality of welding points can improve the reliability and stability of the welding.

[0066] In other embodiments, the first recess section 511 can include a first sub-straight line section 5111 parallel to the first straight line section 512 and a first inclined section 5112 connecting the first sub-straight line section 5111 and the first straight line section 512. In this way, the first sub-straight line section 5111 and the first inclined section 5112 constitute the first recess section 511, and the first welding sections 21 on the first sub-straight line section 5111 are located on the same straight line parallel to the first direction, which can increase the same straight line of the solder strip 70 having a plurality of welding points to improve the reliability and stability of the welding. Of course, the second recess section 611 can include a second sub-straight line section 6111 parallel to the second straight line section 612 and a second inclined section 6112 connecting the second sub-straight line section 6111 and the second straight line section 612, which is not limited in detail.

[0067] In some embodiments, the first linear segment 512 and the first recessed segment 511 are arranged alternately and sequentially. In this way, by arranging a plurality of first linear segments 512 and first recessed segments 511, at least one pre-adhesive 40 can be arranged at the position corresponding to each first recessed segment 511, thereby arranging a plurality of pre-adhesives 40 while effectively avoiding false welding, and improving the stability and adhesion of the pre-fixing of the solder tape 70.

[0068] It should be noted that the first stringing area 50 and the second stringing area 60 of the present disclosure refer to the area covered by the solder tape 70 on the back surface and the area covered by the solder tape 70 on the back surface, which is not strictly divided on the back surface by physical marking, but a virtual defined area.

[0069] In addition, it should be noted that the first linear segment 51 in the present disclosure is not a physical linear segment existing on the battery piece, but a virtual line. The first linear segment 51 can be a smooth curve, a combination of curves and straight lines, or a combination of curves and polylines. The specific form is not limited herein, for example, if the center point of the first welding segment 21 in the area corresponding to the first recessed segment 511 is a curve profile, then the first recessed segment 511 can be a polyline segment formed by connecting straight lines sequentially, or a smooth curve segment.

[0070] Further, in the embodiments of the present disclosure, the center point of the first welding segment 21 refers to a point that divides the first welding segment 21 into two symmetrical halves in the second direction, i.e., the midpoint of the first welding segment 21 in the second direction. It is not difficult to understand that in the present disclosure, the lengths of all first welding segments 21 are substantially the same.

[0071] In addition, it should be noted that in some embodiments, in the first stringing area 50, an insulating layer is arranged at the position where the first stringing area 50 intersects with the second fine grid 30, i.e., an insulating layer can be arranged at the position where each second fine grid 30 intersects with the solder tape 70, thereby preventing the solder tape 70 from contacting fine grids of different polarities. Meanwhile, in the second stringing area 60, an insulating layer is arranged at the position where the second stringing area 60 intersects with the first fine grid 20, i.e., an insulating layer can be arranged at the position where each first fine grid 20 intersects with the solder tape 70, thereby preventing the solder tape 70 from contacting fine grids of different polarities. In the embodiments of the present disclosure, the form and preparation method of the insulating layer are not limited to meet different needs.

[0072] Embodiment Four

[0073] Please refer to FIGS. 1-3. In some optional embodiments, the opening of the first recessed segment 511 is arranged opposite to the opening of the second recessed segment 611.

[0074] Please refer to FIG. 1 to FIG. 3, in some optional embodiments, the pre-adhesive 40 is arranged between the first recessed section 511 and the second recessed section 611, and the opening of the first recessed section 511 and the opening of the second recessed section 611 both face the pre-adhesive 40.

[0075] In the embodiments of the present disclosure, by arranging the first welding section 21 and the second welding section 31 corresponding to the pre-adhesive 40 in a recessed profile arrangement, the opening corresponding to the recess of the pre-adhesive 40 is arranged, so that the distance between the pre-adhesive 40 and the first welding section 21 and the second welding section 31 corresponding thereto is increased, and the phenomenon of false welding in the welding process can be effectively avoided.

[0076] Embodiment five

[0077] Please refer to FIG. 1 to FIG. 3, in some optional embodiments, the number of the first welding section 21 corresponding to the first recessed section 511 is multiple;

[0078] The number of the second welding section 31 corresponding to the second recessed section 611 is multiple.

[0079] Specifically, the number and position of the first recessed section 511 and the second recessed section 611 are arranged correspondingly, and the opening of each first recessed section 511 corresponds to the opening of the second recessed section 611. At this time, the pre-adhesive 40 can be arranged between the first recessed section 511 and the second recessed section 611, so that the welding sections of the first recessed section 511 and the second recessed section 611 are simultaneously away from the pre-adhesive 40, and the phenomenon of false welding in the welding process can be effectively avoided.

[0080] Of course, in some embodiments, the first recessed section 511 can also correspond to only a single first welding section 21, which is not limited in particular herein. The second recessed section 611 can also correspond to only a single second welding section 31, which is not limited in particular herein.

[0081] Please refer to FIG. 1 to FIG. 3, in some embodiments, at least one pre-adhesive 40 is arranged between each first recessed section 511 and the corresponding second recessed section 611, that is, at least one pre-adhesive 40 is arranged in the range corresponding to the first recessed section 511 and the second recessed section 611 in the second direction.

[0082] Embodiment six

[0083] Please refer to FIG. 1 to FIG. 3, in some optional embodiments, the distance between the pre-adhesive 40 and the first welding section 21 located on the first recessed section 511 is 100 μm-2 mm; or

[0084] The distance between the pre-adhesive 40 and the second welding section 31 located on the second recessed section 611 is 100 μm-2 mm;

[0085] The distance between the pre-adhesive 40 and the first welding section 21 located on the first recess section 511 is 100 μm-2 mm, and the distance between the pre-adhesive 40 and the second welding section 31 located on the second recess section 611 is 100 μm-2 mm.

[0086] For example, the distance between the pre-adhesive 40 and the first welding section 21 located on the first recess section 511 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm; and the distance between the pre-adhesive 40 and the second welding section 31 located on the second recess section 611 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm.

[0087] For example, the distance between the pre-adhesive 40 and the first welding section 21 located on the first recess section 511 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm; and the distance between the pre-adhesive 40 and the second welding section 31 located on the second recess section 611 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm.

[0088] Embodiment Seven

[0089] For example, the distance between the pre-adhesive 40 and the first welding section 21 located on the first recess section 511 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm; and the distance between the pre-adhesive 40 and the second welding section 31 located on the second recess section 611 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm.

[0090] Embodiment Eight

[0091] For example, the distance between the pre-adhesive 40 and the first welding section 21 located on the first recess section 511 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm; and the distance between the pre-adhesive 40 and the second welding section 31 located on the second recess section 611 can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm.

[0092] In this way, the distance of the solder strips 70 arranged on the first and second series connection areas 50 and 60 is also within this range, which ensures that both solder strips 70 can be pre-fixed by one pre-adhesive 40, and avoids short circuit caused by too close distance between the two solder strips 70.

[0093] Embodiment Nine

[0094] Referring to FIG. 4, the battery string 200 provided by the embodiment of the present disclosure includes the back contact cell 100 of any of the above embodiments; and

[0095] The solder strips 70 are arranged on the first and second series connection areas 50 and 60, the solder strip 70 on the first series connection area 50 is bonded with the pre-adhesive 40 and in contact with the solder layer on the first solder section 21, and the solder strip 70 on the second series connection area 60 is bonded with the pre-adhesive 40 and in contact with the solder layer on the second solder section 31, as shown in FIGS. 1-3.

[0096] It can be understood that in the battery string 200, the battery string 200 can include two cells in series, three cells in series, or more cells in series, and the number of cells to be connected in series can be determined according to actual use. In addition, in the embodiment of the present disclosure, the size and type of the cell are not limited, and the specifications and sizes of adjacent cells can be the same or different to meet different needs.

[0097] Specifically, the solder strip 70 includes a first solder strip 71 and a second solder strip 72, the first solder strip 71 can be arranged to connect the first fine grid 20 at the first series connection area 50, and the second solder strip 72 can be arranged to connect the second fine grid 30 at the second series connection area 60. At this time, an insulating layer is arranged between the first solder strip 71 and the second fine grid 30 to achieve insulation, and an insulating layer is arranged between the second solder strip 72 and the first fine grid 20 to achieve insulation.

[0098] Embodiment Ten

[0099] Referring to FIG. 5, the battery assembly 300 provided by the embodiment of the present disclosure includes the battery string 200 of the above embodiments.

[0100] Specifically, as shown in FIGS. 1-5, in the process of forming the battery assembly 300, the battery string 200 can be welded first, and then laminated to form the assembly, or the back contact cell 100 without busbars can be placed on the front plate and the adhesive film according to the assembly version first, and then the solder strip 70 is bonded and pre-fixed, and finally laminated and welded to directly form the battery assembly 300. In the process of lamination, each back contact cell 100 without busbars naturally forms a battery string 200.

[0101] It can be understood that in such embodiments, the ownerless grid back contact cell 100 can further include a frame, a back plate, photovoltaic glass and a film. The film can be filled between the front and back of the cell piece, photovoltaic glass, adjacent cell pieces, etc. as a filler, which can be a transparent gel with good light transmission performance and aging resistance, for example, the film can use EVA film or POE film, which can be selected according to actual conditions, and is not limited here.

[0102] The photovoltaic glass can be covered on the film on the front of the cell piece. The photovoltaic glass can be super white glass, which has high light transmittance, high transparency, and has superior physical, mechanical and optical properties. For example, the light transmittance of super white glass can be more than 92%, which can protect the cell piece as much as possible without affecting the efficiency of the cell piece. At the same time, the film can bond the photovoltaic glass and the cell piece together, and the presence of the film can seal and insulate the cell piece and prevent water and moisture.

[0103] The back plate can be attached to the film on the back of the cell piece. The back plate can protect and support the cell piece, has reliable insulation, water resistance and aging resistance, and can have multiple choices, which can be tempered glass, organic glass, aluminum alloy TPT composite film, etc. The specific setting can be made according to the specific situation, and is not limited here. The whole composed of the back plate, the cell piece, the film and the photovoltaic glass can be set on the frame. The frame is the main external support structure of the entire ownerless grid back contact cell 100, and can stably support and install the ownerless grid back contact cell 100, for example, the ownerless grid back contact cell 100 can be installed at the position required to be installed through the frame.

[0104] Embodiment eleven

[0105] Please refer to FIG. 6, the photovoltaic system 400 provided by the embodiment of the present disclosure includes the cell assembly 300 of the above-mentioned embodiment.

[0106] As shown in FIGS. 1-6, in the back contact cell 100, the cell string 200, the cell assembly 300 and the photovoltaic system 400 of the embodiments of the present disclosure, the back contact cell 100 includes a silicon substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30, and a pre-adhesive 40, the silicon substrate 10 includes a front surface and a back surface opposite to each other; the plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged on the back surface, the plurality of first fine grids 20 and the plurality of second fine grids 30 are arranged alternately and spaced apart in sequence along a first direction, and both extend along a second direction, the second direction intersects the first direction, the back surface has a plurality of first stringing areas 50 and a plurality of second stringing areas 60 for arranging the solder strips 70, the first stringing areas 50 and the second stringing areas 60 extend along the first direction and intersect all the first fine grids 20 and the second fine grids 30, and the plurality of first stringing areas 50 and the plurality of second stringing areas 60 are arranged alternately and spaced apart in sequence along the second direction; each first fine grid 20 has a first soldering section 21 at the intersection position with the first stringing area 50, and all the first soldering sections 21 are located within the first stringing area 50; each second fine grid 30 has a second soldering section 31 at the intersection position with the second stringing area 60, and all the second soldering sections 31 are located within the second stringing area 60; the pre-adhesive 40 is arranged on the back surface, and the pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60 and at least partially extends into the first stringing area 50 and the second stringing area 60. In this way, the pre-adhesive 40 is arranged between the first stringing area 50 and the second stringing area 60, the solder strips 70 arranged in the first stringing area 50 and the second stringing area 60 can be simultaneously pre-fixed, the use amount of the pre-adhesive 40 is reduced, the influence on the light is reduced, and the cost is reduced.

[0107] In the present embodiment, the photovoltaic system 400 can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus that utilizes solar energy to generate electricity, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system 400 are not limited to this, that is, the photovoltaic system 400 can be applied in all fields that need to utilize solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system 400 can include a photovoltaic array, a combiner box and an inverter, the photovoltaic array can be an array combination of a plurality of cell assemblies 300, for example, a plurality of cell assemblies 300 can constitute a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the combiner box, the combiner box can combine the currents generated by the photovoltaic arrays, the combined current flows through the inverter to convert into an alternating current required by a power grid, and then is connected to a power network to realize solar power supply.

[0108] In the description of the specification, the description of the terms "some embodiments", "exemplary embodiments", "example", "specific example", or "some examples" and the like means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the disclosure. Exemplary representations of the above terms do not necessarily refer to the same embodiment or example in this specification. Moreover, the described particular feature, structure, material or characteristic can be combined in any suitable manner in one or more embodiments or examples.

[0109] In addition, the above is only a preferred embodiment of the disclosure, and is not used to limit the disclosure, and any modification, equivalent replacement and improvement made within the spirit and principle of the disclosure shall be included in the protection scope of the disclosure.

Claims

1. A back contact cell without main grid, comprising: a silicon substrate comprising a front side and a back side opposite to each other; a plurality of first fine grids and a plurality of second fine grids arranged on the back side, the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spacedly in a first direction, and each extends in a second direction intersecting the first direction, the back side has a plurality of first stringing areas and a plurality of second stringing areas for arranging solder ribbons, the first stringing areas and the second stringing areas extend in the first direction and intersect all the first fine grids and all the second fine grids, the plurality of first stringing areas and the plurality of second stringing areas are arranged alternately and spacedly in the second direction; each of the first fine grids has a first soldering section at the intersection position with the first stringing area, all the first soldering sections are located in the first stringing area, each of the second fine grids has a second soldering section at the intersection position with the second stringing area, all the second soldering sections are located in the second stringing area; a pre-adhesive arranged on the back side, the pre-adhesive is arranged between the first stringing area and the second stringing area and at least partially extends into the first stringing area and the second stringing area.

2. The eni -grid back-contact cell according to claim 1, wherein, At least one of the first soldering sections is staggered with the rest of the first soldering sections in the first direction in the first stringing area, and at least one of the second soldering sections is staggered with the rest of the second soldering sections in the first direction in the second stringing area.

3. The enegy cell of claim 2, wherein, According to the arrangement sequence of the first soldering sections in the first direction, the center points of all the first soldering sections are connected in sequence to form a first line segment which is a non-linear line segment, and the first line segment has at least one first recessed segment.

4. The enegy cell of claim 3, wherein, According to the arrangement sequence of the second soldering sections in the first direction, the center points of all the second soldering sections are connected in sequence to form a second line segment which is a non-linear line segment, and the second line segment has at least one second recessed segment.

5. The enegy cell of claim 4, wherein, The opening of the first recessed segment is opposite to the opening of the second recessed segment.

6. The enegy cell of claim 5, wherein, The pre-adhesive is arranged between the first recessed segment and the second recessed segment, and the opening of the first recessed segment and the opening of the second recessed segment are both towards the pre-adhesive.

7. The enegy cell of claim 4, wherein, The number of the first soldering sections corresponding to the first recessed segment is multiple; The number of the second soldering sections corresponding to the second recessed segment is multiple.

8. The enegy cell of claim 4, wherein, The distance between the pre-adhesive and the first soldering section located on the first recessed segment is 100 μm-2 mm; or The distance between the pre-adhesive and the second soldering section located on the second recessed segment is 100 μm-2 mm; or The distance between the pre-adhesive and the first soldering section located on the first recessed segment is 100 μm-2 mm, and the distance between the pre-adhesive and the second soldering section located on the second recessed segment is 100 μm-2 mm.

9. The enegy cell of claim 8, wherein, The length of the pre-adhesive in the second direction is 300 μm-2 mm.

10. The enegy cell of claim 1, wherein, The distance between the first stringing area and the second stringing area in the first direction is 0.01 mm-2 mm.

11. A battery string comprising the back contact battery of any of claims 1-10; and a solder ribbon overlying the first stringing region and the second stringing region, the solder ribbon overlying the first stringing region being bonded to the pre-stick adhesive and in contact with the solder layer overlying the first solder segment, the solder ribbon overlying the second stringing region being bonded to the pre-stick adhesive and in contact with the solder layer overlying the second solder segment.

12. A battery assembly comprising the battery string of claim 11.

13. A photovoltaic system comprising the battery assembly of claim 12.

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