Back contact cell, cell assembly and photovoltaic system

Abstract

The utility model provides a back contact battery, a battery assembly and a photovoltaic system. The back contact battery comprises a plurality of first polarity fine grids and a plurality of second polarity fine grids; the first polarity fine grid comprises a first fine grid and a second fine grid, and the distance between the first fine grid and the second fine grid is a first distance in the first direction; the first polarity fine grid further comprises a third fine grid and a fourth fine grid, the distance between the third fine grid and the fourth fine grid is a second distance in the first direction, and the second distance is larger than the first distance; the second polarity fine grid comprises a fifth fine grid, the fifth fine grid is located between the third fine grid and the fourth fine grid, the fifth fine grid comprises a first bending part, and the extending direction of the first bending part is crossed with the second direction. As the fifth fine grid is positioned between the third fine grid and the fourth fine grid which are relatively large in distance and have the same polarity, the current between the third fine grid and the fourth fine grid can be better collected through the first bend of which the direction is crossed with the second direction, so that the photoelectric conversion efficiency of the back contact battery is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic technology field especially relates to a back contact cell, battery assembly and photovoltaic system. BACKGROUND

[0002] In the back contact cell, two kinds of polarity fine grid alternate arrangement carries out the collection to the current. The back contact cell in the prior art, the interval of two adjacent fine grids of same polarity is too big, the effect of collecting current is poor, which leads to low photoelectric conversion efficiency of the back contact cell.

[0003] Therefore, how to improve the effect of collecting current of the back contact cell has become a problem to be solved. SUMMARY

[0004] The utility model provides a kind of back contact cell, battery assembly and photovoltaic system to solve the technical problem of how to improve the effect of collecting current of back contact cell.

[0005] The utility model provides a kind of back contact cell, battery assembly and photovoltaic system. Back contact cell includes multiple first polarity fine grid and multiple second polarity fine grid;The first polarity fine grid and the second polarity fine grid are alternately arranged along first direction, the first polarity fine grid and the second polarity fine grid extend along second direction, the second direction with the first direction intersection, the polarity of the first polarity fine grid with the second polarity fine grid is opposite;The first polarity fine grid includes first fine grid and second fine grid, the first fine grid and the second fine grid are adjacent, along the first direction, the interval of the first fine grid and the second fine grid is first interval;The first polarity fine grid further includes third fine grid and fourth fine grid, the third fine grid and the fourth fine grid are adjacent, along the first direction, the interval of the third fine grid and the fourth fine grid is second interval, and the second interval is greater than the first interval;The second polarity fine grid includes fifth fine grid, and the fifth fine grid is located between the third fine grid and the fourth fine grid, and the fifth fine grid includes first bending portion, and the extension direction of the first bending portion with the second direction intersection.

[0006] Further, the second interval is 900 microns to 1300 microns.

[0007] Further, the fifth fine grid includes first end point and second end point, the first end point is the point on the fifth fine grid closest to the third fine grid, the second end point is the point on the fifth fine grid closest to the fourth fine grid, and the interval of the first end point and the second end point in the first direction is 20 microns to 150 microns.

[0008] Further, the first bending part comprises a plurality of first bending segments, a plurality of second bending segments and a plurality of bending points, the bending points being located between adjacent first bending segments and second bending segments.

[0009] Further, in the second direction, the interval between two adjacent bending points is 40-300 microns.

[0010] Further, the number of first bending segments is a plurality, each of the first bending segments being parallel to each other; and / or, the number of second bending segments is a plurality, each of the second bending segments being parallel to each other.

[0011] Further, the first bending part is a straight segment or a curved segment.

[0012] Further, the fifth fine grid comprises a bending structure, the bending structure comprising a plurality of first bending parts.

[0013] Further, the bending structure is in the shape of a triangular wave.

[0014] Further, the bending structure is in the shape of a sine wave.

[0015] Further, the fifth fine grid further comprises a first non-bending part, the extension direction of the first non-bending part being parallel to the second direction.

[0016] Further, the back contact cell further comprises a plurality of positioning points, the positioning points being located between the third fine grid and the fourth fine grid.

[0017] Further, in the second direction, the interval between the fifth fine grid and the positioning points is 200-2000 microns.

[0018] Further, the second polarity fine grid comprises a sixth fine grid, the sixth fine grid being located between the third fine grid and the fourth fine grid, and the sixth fine grid, the positioning points and the fifth fine grid being sequentially distributed along the second direction; in the second direction, the interval between the sixth fine grid and the positioning points is 200-2000 microns.

[0019] Further, in the second direction, the interval between the sixth fine grid and the fifth fine grid is 400-4000 microns.

[0020] Further, the sixth fine grid is a non-bending grid line, the extension direction of the sixth fine grid being parallel to the second direction.

[0021] Further, the sixth fine grid comprises a second bending part, the extension direction of the second bending part being crossed with the second direction.

[0022] Further, the back contact cell further comprises a plurality of first polarity doped regions and a plurality of second polarity doped regions; the first polarity doped regions and the second polarity doped regions are arranged alternately along the first direction, the first polarity doped regions and the second polarity doped regions extend along the second direction, positions of the first polarity doped regions correspond to positions of the first polarity fine grids, positions of the second polarity doped regions correspond to positions of the second polarity fine grids, and the first polarity doped regions and the second polarity doped regions are opposite in doping polarity.

[0023] Further, the second polarity fine grid comprises a seventh fine grid located between the first fine grid and the second fine grid; a second polarity doped region corresponding to a position of the fifth fine grid is a first doped region, and a size of the first doped region in the first direction is a first size; a second polarity doped region corresponding to a position of the seventh fine grid is a second doped region, and a size of the second doped region in the first direction is a second size; and the first size is greater than the second size.

[0024] Further, the first polarity doped region comprises a third doped region and a fourth doped region, the third doped region and the fourth doped region are adjacent, and the first doped region is located between the third doped region and the fourth doped region; along the first direction, a spacing between the third doped region and the fourth doped region is a third spacing; the first polarity doped region further comprises a fifth doped region and a sixth doped region, the fifth doped region and the sixth doped region are adjacent, and the second doped region is located between the fifth doped region and the sixth doped region; along the first direction, a spacing between the fifth doped region and the sixth doped region is a fourth spacing; and in the first direction, the fourth spacing is less than the third spacing.

[0025] The utility model embodiment further provides a battery assembly, the battery assembly includes the back contact cell that any preceding description is had.

[0026] The utility model embodiment further provides a photovoltaic system, the photovoltaic system includes the battery assembly that any preceding description is had.

[0027] The back contact cell in the utility model, because the fifth fine grid is located between the third fine grid and the fourth fine grid with larger spacing and same polarity, the fifth fine grid comprises a first bending part with a cross direction intersecting with the second direction, so that the current between the third fine grid and the fourth fine grid can be better collected, thereby improving the photoelectric conversion efficiency of the back contact cell. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0029] Figure 1 is a module schematic diagram of a photovoltaic system provided by an embodiment of the present application;

[0030] Figure 2 is a partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0031] Figure 3 is another partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0032] Figure 4 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0033] Figure 5 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0034] Figure 6 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0035] Figure 7 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application;

[0036] Figure 8 is a partial structure schematic diagram of a fifth fine grid provided by an embodiment of the present application;

[0037] Figure 9 is another partial structure schematic diagram of a fifth fine grid provided by an embodiment of the present application;

[0038] Figure 10 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application.

[0039] Figure 11 is still another partial structure schematic diagram of a solar cell provided by an embodiment of the present application.

[0040] Main element symbol explanation: 1000, photovoltaic system; 1001, battery assembly; 100, back contact cell; 10, first polarity fine grid; 20, second polarity fine grid; 30, positioning point; 40, first polarity doped region; 50, second polarity doped region; 11, first fine grid; 12, second fine grid; 13, third fine grid; 14, fourth fine grid; 21, fifth fine grid; 22, sixth fine grid; 23, seventh fine grid; 41, third doped region; 42, fourth doped region; 43, fifth doped region; 44, sixth doped region; 51, first doped region; 52, second doped region; 211, first end point; 212, second end point; 710, bending structure; 711, first bending part; 712, first non-bending part; 713, second bending part; 7111, first bending segment; 7112, second bending segment; 7113, bending point. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following will be further described in detail 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 utility model, and cannot be understood as the limitation of the utility model. In addition, it should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model.

[0042] In the description of the utility model, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "transverse", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as the limitation of the utility model.

[0043] In addition, the terms "first", "second" are only used for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0044] In the description of the utility model, it is necessary to explain that, unless there is definite stipulation and limitation, the term "mounting", "connection" should be broad sense understanding, for example, it can be fixed connection, also can be detachable connection, or integrally connected, it can be mechanical connection, also can be electrical connection or can communicate with each other, it can be directly connected, also can be indirectly connected through intermediate medium, it can be the communication of two elements or the interaction of two elements. For ordinary skilled in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to specific circumstances.

[0045] The following disclosure provides many different embodiments or examples for implementing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the utility model. In addition, the utility model can refer to the same reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which does not indicate the relationship between the various embodiments and / or settings discussed per se. In addition, the utility model provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0046] Please refer to Figure 1 The photovoltaic system 1000 in the embodiment of the utility model can include the battery assembly 1001 in the embodiment of the utility model, and the battery assembly 1001 in the embodiment of the utility model can include a plurality of back contact cells 100. The plurality of back contact cells 100 can be sequentially connected in series by welding strips to form a battery string. Each battery string in the battery assembly 1001 can be connected in series, parallel, or a combination of series and parallel to realize the current output of the bus, for example, the connection between each battery string can be realized by bus bars.

[0047] The drawings provided by the utility model are schematic drawings, and some elements are not shown in the drawings. The purpose is to clearly describe the technical scheme and highlight the key points of the utility model. It is not intended to limit the technical scheme and not to include these unshown elements. That is to say, the drawings are only examples and do not represent the specific form of the battery assembly 1001.

[0048] As Figures 2 to 11 shown, the utility model embodiment back contact cell 100 multiple first polarity fine grid 10 and multiple second polarity fine grid 20. Back contact cell 100 can be back contact cell 100 with main grid, also can be back contact cell 100 without main grid can. In the case of main grid, fine grid and main grid are electrically connected.

[0049] The first polarity fine grid 10 and the second polarity fine grid 20 are alternately arranged along a first direction, and the first polarity fine grid 10 and the second polarity fine grid 20 extend along a second direction intersecting the first direction, and the polarity of the first polarity fine grid 10 is opposite to that of the second polarity fine grid 20.

[0050] The first polarity fine grid 10 comprises a first fine grid 11 and a second fine grid 12 adjacent to each other along the first direction, and the interval between the first fine grid 11 and the second fine grid 12 is a first interval D1; the first polarity fine grid 10 further comprises a third fine grid 13 and a fourth fine grid 14 adjacent to each other along the first direction, and the interval between the third fine grid 13 and the fourth fine grid 14 is a second interval D2, and the second interval D2 is greater than the first interval D1. The second polarity fine grid 20 comprises a fifth fine grid 21 located between the third fine grid 13 and the fourth fine grid 14, and the fifth fine grid 21 comprises a first bending part 711, and the extension direction of the first bending part 711 intersects the second direction.

[0051] Therefore, in the back contact battery 100 in the embodiment of the utility model, the fifth fine grid 21 is located between the third fine grid 13 and the fourth fine grid 14 with a larger interval and the same polarity, and the fifth fine grid 21 comprises the first bending part 711 with the extension direction intersecting the second direction, so that the fifth fine grid 21 can better collect the current between the third fine grid 13 and the fourth fine grid 14 through the first bending part 711, thereby improving the photoelectric conversion efficiency of the back contact battery 100.

[0052] As shown in Figure 2 and Figure 3 Specifically, the first fine grid 11 and the second fine grid 12 and the third fine grid 13 and the fourth fine grid 14 are respectively two groups of adjacent first polarity fine grids 10. Along the first direction, the second interval D2 is greater than the first interval D1, and the third fine grid 13 and the fourth fine grid 14 are a group of adjacent first polarity fine grids 10 with a larger interval.

[0053] If the interval between the third fine grid 13 and the fourth fine grid 14 is large, it is difficult for the conventional grid line to collect the current between the third fine grid 13 and the fourth fine grid 14. Therefore, in the embodiment of the utility model, the fifth fine grid 21 is arranged between the third fine grid 13 and the fourth fine grid 14. The fifth fine grid 21 comprises the first bending part 711, and the extension direction of the first bending part 711 intersects the second direction. In this way, through the first bending part 711 intersecting the second direction, the current collection area of the fifth fine grid 21 can be expanded to better collect the current between the third fine grid 13 and the fourth fine grid 14, thereby improving the photoelectric conversion efficiency of the back contact battery 100.

[0054] In a possible implementation, the third fine grid 13, the fifth fine grid 21 and the fourth fine grid 14 are three fine grids arranged in sequence along the first direction. The third fine grid 13 and the fourth fine grid 14 have the same polarity, and the third fine grid 13 and the fifth fine grid 21 have opposite polarities.

[0055] Of course, in other embodiments, in order to better collect the current between the third fine grid 13 and the fourth fine grid 14, the number of the fifth fine grid 21 can be set to be multiple. That is, multiple fifth fine grids 21 with the first bending part 711 are arranged between the third fine grid 13 and the fourth fine grid 14, so as to better collect the current between the third fine grid 13 and the fourth fine grid 14, thereby improving the photoelectric conversion efficiency of the back contact battery 100.

[0056] In addition, in other embodiments, in order to better collect the current between the third fine grid 13 and the fourth fine grid 14, the number of fine grids between the third fine grid 13 and the fourth fine grid 14 can be set to be multiple. For example, a number of fifth fine grids 21 or a number of fine grids without the first bending part 711 are arranged between the third fine grid 13 and the fourth fine grid 14, which is not limited here.

[0057] In a possible implementation, the second interval D2 is 900 microns to 1300 microns. For example, 900 microns, 950 microns, 1000 microns, 1050 microns, 1100 microns, 1150 microns, 1200 microns, 1250 microns, 1300 microns. In this way, the fifth fine grid 21 is located between the third fine grid 13 and the fourth fine grid 14 with a larger interval, so as to better collect the current between the third fine grid 13 and the fourth fine grid 14, thereby improving the photoelectric conversion efficiency of the back contact battery 100.

[0058] Further, for the structure of the first bending part 711, the first bending part 711 intersects with the extension direction of the fine grid. The angle between the first bending part 711 and the second direction can be selected according to actual conditions, which is not limited here. In the fifth fine grid 21, the number of the first bending part 711 can be set to one or more. In a possible implementation, all of the fifth fine grids 21 can be set to the first bending part 711, so as to better collect the current between the third fine grid 13 and the fourth fine grid 14, thereby improving the photoelectric conversion efficiency of the back contact battery 100.

[0059] As Figure 2 and Figure 3As shown, in one possible implementation, the fifth fine gate 21 includes a first endpoint 211 and a second endpoint 212. The first endpoint 211 is the point on the fifth fine gate 21 that is closest to the third fine gate 13, and the second endpoint 212 is the point on the fifth fine gate 21 that is closest to the fourth fine gate 14. The distance D3 between the first endpoint 211 and the second endpoint 212 in a first direction is 20 micrometers to 150 micrometers. For example, it is 20 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 80 micrometers, 100 micrometers, 120 micrometers, 140 micrometers, or 150 micrometers.

[0060] Specifically, if the distance D3 between the first endpoint 211 and the second endpoint 212 in the first direction is too close, the fifth fine gate 21 may be unable to effectively collect the current between the third fine gate 13 and the fourth fine gate 14, affecting the photoelectric conversion efficiency of the back contact cell 100. If the distance D3 between the first endpoint 211 and the second endpoint 212 in the first direction is too far, the fifth fine gate 21 may be too close to the fourth fine gate 14 and / or the third fine gate 13, causing electrical contact between the fifth fine gate 21 and the fourth fine gate 14 and / or the third fine gate 13, thereby leading to a short circuit.

[0061] Therefore, the distance D3 between the first endpoint 211 and the second endpoint 212 in the first direction is 20 micrometers to 150 micrometers. This allows for sufficient collection of the current between the third fine gate 13 and the fourth fine gate 14 while preventing the fifth fine gate 21 from being too close to the third fine gate 13 or the fourth fine gate 14, which could lead to a short circuit.

[0062] Furthermore, depending on the specific structure of the different fifth fine gate 21, there may be one or more first endpoints 211 and second endpoints 212.

[0063] like Figure 2 and Figure 4 As shown, in one possible implementation, the first bending portion 711 includes a plurality of first bending segments 7111, a plurality of second bending segments 7112 and a plurality of bending points 7113, wherein the bending points 7113 are located between adjacent first bending segments 7111 and second bending segments 7112.

[0064] Specifically, the first bending portion 711 includes a first bending segment 7111 and a second bending segment 7112, the extending directions of the first bending segment 7111 and the second bending segment 7112 intersect. The first bending segment 7111 and the second bending segment 7112 are connected at the bending point 7113.

[0065] The number of the first bending segment 7111, the second bending segment 7112 and the bending point 7113 in the first bending portion 711 can be one or multiple, which is not limited herein. In addition, the number of the first bending segment 7111, the second bending segment 7112 and the bending point 7113 can be set to be the same.

[0066] Specifically, in the second direction, the interval D4 between two adjacent bending points 7113 is 40-300 microns. For example, 40 microns, 60 microns, 80 microns, 100 microns, 120 microns, 150 microns, 180 microns, 200 microns, 220 microns, 250 microns, 270 microns, 300 microns.

[0067] It can be understood that the bending point 7113 is located between the adjacent first bending segment 7111 and the second bending segment 7112, and by setting the interval D4 between two adjacent bending points 7113 to be 40-300 microns, the specific position and angle of the first bending portion 711 can be controlled. In the second direction, if the interval D4 between two adjacent bending points 7113 is too large, the fifth fine grid 21 cannot fully collect the current between the third fine grid 13 and the fourth fine grid 14; if the interval D4 between two adjacent bending points 7113 is too small, the manufacturing difficulty of the fifth fine grid 21 is increased, and the manufacturing cost is increased.

[0068] Therefore, in the second direction, the interval D4 between two adjacent bending points 7113 is 40-300 microns. The manufacturing cost of the fifth fine grid 21 can be reduced while fully collecting the current between the third fine grid 13 and the fourth fine grid 14.

[0069] In a possible implementation, the number of the first bending segment 7111 is multiple, and each first bending segment 7111 is parallel to each other; and / or, the number of the second bending segment 7112 is multiple, and each second bending segment 7112 is parallel to each other. In this way, by setting the first bending portion or the second bending portion parallel to each other, the manufacturing difficulty of the fifth fine grid 21 can be reduced, and the manufacturing process of the fifth fine grid 21 is simplified.

[0070] Preferably, the adjacent first bending segment 7111 and the second bending segment 7112 are symmetrical along the first direction. In this way, the current collection of the bending portion is more uniform, avoiding insufficient or overload current collection on one side. The symmetrical first bending segment 7111 and the second bending segment 7112 can make the current collection of the fifth fine grid 21 more balanced.

[0071] As Figure 2 , Figure 4 , Figure 8 and Figure 9As shown, in one possible embodiment, the first bend 711 is a straight segment or a curved segment. When the first bend 711 is a straight segment, it is easier to manufacture, reducing the manufacturing cost of the fifth fine grid 21. When the first bend 711 is a curved segment, the current collecting area of ​​the fifth fine grid 21 can be further increased to better collect the current between the third fine grid 13 and the fourth fine grid 14, thereby improving the photoelectric conversion efficiency of the back contact cell 100.

[0072] In one possible implementation, the fifth fine grid 21 includes a bent structure 710, which comprises a plurality of first bends 711. The bent structure 710 is triangular or sinusoidal. Specifically, the fifth fine grid 21 may include a triangular-wave bent structure 710 or a sinusoidal-wave bent structure 710. Thus, the structure of the fifth fine grid 21 can be adjusted by adjusting the period or amplitude of the bent structure 710 to accommodate different second spacing D2.

[0073] like Figure 2 and Figure 5 As shown, in one possible implementation, the fifth fine grid 21 may further include a first non-bent portion 712, the extension direction of which is parallel to the second direction. Thus, by combining the first non-bent portion 712 and the first bent portion 711, the flexibility of the fifth fine grid 21 can be improved, and the manufacturing difficulty of the fifth fine grid 21 can be reduced.

[0074] Specifically, the first non-bending portion 712 may be connected to the first bending portion 711. The fifth fine grid 21 may specifically include one or more first non-bending portions 712 and first bending portions 711, which is not limited here.

[0075] like Figure 2 , Figure 6 and Figure 7 As shown, in one possible embodiment, the back contact cell 100 further includes a plurality of positioning points 30 located between the third fine grid 13 and the fourth fine grid 14. Specifically, the back contact cell 100 includes a plurality of positioning points 30, which can be used to position the grid lines of the solar cell. By setting the positioning points 30, the grid lines can be better positioned and aligned during grid line arrangement.

[0076] Meanwhile, in the second direction, because the spacing between the third fine grid 13 and the fourth fine grid 14 is relatively large, there is sufficient space between the third fine grid 13 and the fourth fine grid 14 to place the positioning point 30, so the positioning point 30 can be set larger, improving the recognizability of the positioning point 30.

[0077] Specifically, the positioning point 30 is located between the third fine grid 13 and the fourth fine grid 14. That is, the fifth fine grid 21 and the positioning point 30 are both located between the third fine grid 13 and the fourth fine grid 14, and thus the current of the region corresponding to the positioning point 30 can be better collected.

[0078] Specifically, in the second direction, the interval D5 between the fifth fine grid 21 and the positioning point 30 is 200 microns to 2000 microns. For example, 200 microns, 400 microns, 500 microns, 600 microns, 700 microns, 800 microns, 900 microns, 1000 microns, 1200 microns, 1500 microns, 1700 microns, 1800 microns, 2000 microns.

[0079] As shown in Figure 2 , Figure 6 and Figure 7 , in a possible implementation, the second polarity fine grid 20 includes a sixth fine grid 22, the sixth fine grid 22 is located between the third fine grid 13 and the fourth fine grid 14, and the sixth fine grid 22, the positioning point 30, and the fifth fine grid 21 are sequentially distributed along the second direction. In the second direction, the interval D6 between the sixth fine grid 22 and the positioning point 30 is 200 microns to 2000 microns. For example, 200 microns, 400 microns, 500 microns, 600 microns, 700 microns, 800 microns, 900 microns, 1000 microns, 1200 microns, 1500 microns, 1700 microns, 1800 microns, 2000 microns.

[0080] It can be understood that “the sixth fine grid 22, the positioning point 30, and the fifth fine grid 21 are sequentially distributed along the second direction”. This means that in the second direction, the sixth fine grid 22, the positioning point 30, and the fifth fine grid 21 are arranged and distributed along the second direction. For example, the sixth fine grid 22, the positioning point 30, and the fifth fine grid 21 can be arranged and distributed along the left direction in sequence; or the sixth fine grid 22, the positioning point 30, and the fifth fine grid 21 can be arranged and distributed along the right direction in sequence.

[0081] Specifically, in the second direction, the interval D7 between the sixth fine grid 22 and the fifth fine grid 21 is 400 microns to 4000 microns. For example, 400 microns, 500 microns, 800 microns, 1000 microns, 1500 microns, 2000 microns, 3000 microns, 4000 microns.

[0082] In a possible implementation, as shown in Figure 6 , the sixth fine grid 22 is a non-bent grid line, and the extension direction of the sixth fine grid 22 is parallel to the second direction. In this way, the manufacturing difficulty of the sixth fine grid 22 can be reduced, thereby reducing the manufacturing cost of the back contact battery 100.

[0083] In a possible implementation, as shown inFigure 7 As shown, the sixth fine grid 22 includes a second bending part 713, and the extension direction of the second bending part 713 is crossed with the second direction. In this way, the sixth fine grid 22 can better collect the current between the third fine grid 13 and the fourth fine grid 14, and improve the photoelectric conversion efficiency of the back contact cell 100.

[0084] As shown in FIG. 1, Figure 2 , Figure 10 and Figure 11 As shown in a possible implementation, the back contact cell 100 further includes a plurality of first polarity doped regions 40 and a plurality of second polarity doped regions 50; the first polarity doped regions 40 and the second polarity doped regions 50 are arranged alternately along the first direction, the first polarity doped regions 40 and the second polarity doped regions 50 extend along the second direction, the positions of the first polarity doped regions 40 correspond to the positions of the first polarity fine grids 10, the positions of the second polarity doped regions 50 correspond to the positions of the second polarity fine grids 20, and the doping polarities of the first polarity doped regions 40 and the second polarity doped regions 50 are opposite.

[0085] Specifically, the positions of the first polarity doped regions 40 correspond to the positions of the first polarity fine grids 10 means that one first polarity doped region 40 is arranged correspondingly to one first polarity fine grid 10. Alternatively, in the thickness direction of the back contact cell 100, the projection of the first polarity fine grid 10 on the back contact cell 100 is located at the first polarity doped region 40.

[0086] Specifically, the positions of the second polarity doped regions 50 correspond to the positions of the second polarity fine grids 20 means that one second polarity doped region 50 is arranged correspondingly to one second polarity fine grid 20. Alternatively, in the thickness direction of the back contact cell 100, the projection of the second polarity fine grid 20 on the back contact cell 100 is located at the second polarity doped region 50.

[0087] Meanwhile, the first polarity fine grid 10 is electrically connected with the first polarity doped region 40, so that the first polarity fine grid 10 can collect the current in the first polarity doped region 40. And the second polarity fine grid 20 is electrically connected with the second polarity doped region 50, so that the second polarity fine grid 20 can collect the current in the second polarity doped region 50.

[0088] Further, the second polarity fine grid 20 includes a seventh fine grid 23, the seventh fine grid 23 is located between the first fine grid 11 and the second fine grid 12; the second polarity doped region 50 corresponding to the position of the fifth fine grid 21 is a first doped region 51, the size of the first doped region 51 in the first direction is a first size D8; the second polarity doped region 50 corresponding to the position of the seventh fine grid 23 is a second doped region 52, the size of the first doped region 51 in the first direction is a second size D9; the first size D8 is greater than the second size D9.

[0089] In this way, the fifth fine grid 21 is arranged to correspond to the position of the first doped region 51 with a large size. The fifth fine grid 21 can better collect the current of the first doped region 51 with a large size through the first bending part 711, thereby improving the photoelectric conversion efficiency of the back contact cell 100.

[0090] It is worth noting that the "first size D8" refers to the interval of two boundaries of the first doped region 51 in the first direction. The "second size D9" refers to the interval of two boundaries of the second doped region 52 in the first direction.

[0091] Specifically, in the first direction, the first size D8 is 900 microns to 1300 microns. For example, 900 microns, 950 microns, 1000 microns, 1050 microns, 1100 microns, 1150 microns, 1200 microns.

[0092] As shown in Figure 2 , Figure 10 and Figure 11 Further, the first polarity doped region 40 includes a third doped region 41 and a fourth doped region 42, the third doped region 41 and the fourth doped region 42 are adjacent, and the first doped region 51 is located between the third doped region 41 and the fourth doped region 42; along the first direction, the interval of the third doped region 41 and the fourth doped region 42 is a third interval D10; the first polarity doped region 40 further includes a fifth doped region 43 and a sixth doped region 44, the fifth doped region 43 and the sixth doped region 44 are adjacent, and the first doped region 51 is located between the fifth doped region 43 and the sixth doped region 44; along the first direction, the interval of the fifth doped region 43 and the sixth doped region 44 is a fourth interval D11; in the first direction, the fourth interval D11 is smaller than the third interval D10.

[0093] In this way, the fourth interval D11 is arranged to be smaller than the third interval D10. The fifth fine grid 21 can better collect the current between the third doped region 41 and the fourth doped region 42 with a large interval through the first bending part 711, thereby improving the photoelectric conversion efficiency of the back contact cell 100.

[0094] It is worth noting that the "third interval D10" refers to the distance between the boundary of the third doped region 41 closest to the first doped region 51 in the first direction and the boundary of the fourth doped region 42 closest to the first doped region 51 in the first direction. The "fourth interval D11" refers to the distance between the boundary of the fifth doped region 43 closest to the second doped region 52 in the first direction and the boundary of the sixth doped region 44 closest to the second doped region 52 in the first direction.

[0095] Specifically, the third doped region 41 and the fourth doped region 42 and the fifth doped region 43 and the sixth doped region 44 are respectively two groups of two adjacent first-polarity doped regions 40. In the first direction, the fourth spacing D11 is smaller than the third spacing D10, that is, the third doped region 41 and the fourth doped region 42 are a group of adjacent first-polarity doped regions 40 with a larger spacing.

[0096] In addition, in the first direction, the third spacing D10 is greater than or equal to the first size D8. When the third spacing D10 is greater than the first size D8, an isolation region is arranged between the third doped region 41 and the first doped region 51, and / or, between the first doped region 51 and the fourth doped region 42.

[0097] It can be understood that the isolation region refers to that there is a spacing between two doped regions, forming an isolation region. Specifically, there is a spacing between the third doped region 41 and the first doped region 51, and / or, between the first doped region 51 and the fourth doped region 42.

[0098] When the third spacing D10 is equal to the first size D8, no isolation region is arranged between the third doped region 41 and the first doped region 51, and, between the first doped region 51 and the fourth doped region 42.

[0099] Similarly, in the first direction, the fourth spacing D11 is greater than or equal to the second size D9. When the fourth spacing D11 is greater than the second size D9, an isolation region is arranged between the fifth doped region 43 and the second doped region 52, and / or, between the sixth doped region 44 and the second doped region 52.

[0100] It can be understood that there is a spacing between the fifth doped region 43 and the second doped region 52, and / or, between the sixth doped region 44 and the second doped region 52.

[0101] When the fourth spacing D11 is equal to the second size D9, no isolation region is arranged between the fifth doped region 43 and the second doped region 52, and, between the sixth doped region 44 and the second doped region 52.

[0102] It can be understood that the battery assembly 1001 in such an embodiment can further include a frame, a back plate, photovoltaic glass, and a film. The film can be filled between the front and back surfaces of the cell sheet, photovoltaic glass, adjacent cell sheets, etc., as a filler, which can be a transparent adhesive 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, which is not limited here.

[0103] The photovoltaic glass can be covered on the adhesive film on the front surface 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 the super white glass can reach 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 adhesive film can bond the photovoltaic glass and the cell piece together, and the presence of the adhesive film can seal and insulate the cell piece and prevent water and moisture.

[0104] The back plate can be attached to the adhesive film on the back surface of the cell piece, and the back plate can protect and support the cell piece, has reliable insulation, water resistance and aging resistance, and the back plate can have multiple choices, which can be tempered glass, organic glass, aluminum alloy composite adhesive film, etc., which can be set according to specific conditions, which is not limited here. The whole composed of the back plate, the cell piece, the adhesive film and the photovoltaic glass can be arranged on the frame, and the frame serves as the main external support structure of the entire cell assembly 1001, and can stably support and install the cell assembly 1001, for example, the cell assembly 1001 can be installed at the required installation position through the frame.

[0105] In the description of the present specification, the description of the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0106] In addition, the above only describes the preferred embodiments of the present application, and does not limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back contact cell, characterized in that, The first polarity fine grids and the second polarity fine grids are arranged alternately along a first direction, and the first polarity fine grids and the second polarity fine grids extend along a second direction intersecting the first direction, and the first polarity fine grids and the second polarity fine grids are opposite in polarity. The first polarity fine grids include a first fine grid and a second fine grid, and the first fine grid and the second fine grid are adjacent along the first direction, and a spacing between the first fine grid and the second fine grid is a first spacing. The first polarity fine grids further include a third fine grid and a fourth fine grid, and the third fine grid and the fourth fine grid are adjacent along the first direction, and a spacing between the third fine grid and the fourth fine grid is a second spacing, and the second spacing is greater than the first spacing. The second polarity fine grids include a fifth fine grid, and the fifth fine grid is located between the third fine grid and the fourth fine grid, and the fifth fine grid includes a first bending part, and an extending direction of the first bending part intersects the second direction. The second spacing is 900 microns to 1300 microns.

2. The back contact cell of claim 1, wherein, The fifth fine grid includes a first end point and a second end point, the first end point is a point on the fifth fine grid closest to the third fine grid, and the second end point is a point on the fifth fine grid closest to the fourth fine grid, and a spacing between the first end point and the second end point in the first direction is 20 microns to 150 microns.

3. The back contact cell of claim 1, wherein, The first bending part includes a plurality of first bending segments, a plurality of second bending segments, and a plurality of bending points, and the bending points are located between adjacent first bending segments and second bending segments.

4. The back contact cell of claim 1, wherein, In the second direction, a spacing between two adjacent bending points is 40 microns to 300 microns.

5. The back contact cell of claim 4, wherein, The number of first bending segments is a plurality, and each first bending segment is parallel to each other; and / or, the number of second bending segments is a plurality, and each second bending segment is parallel to each other.

6. The back contact cell of claim 4, wherein, The first bending part is a straight line segment or a curved line segment.

7. The back contact cell of claim 1, wherein, The fifth fine grid includes a bending structure, and the bending structure includes a plurality of first bending parts.

8. The back contact cell of claim 1, wherein, The bending structure is in a triangular wave shape.

9. The back contact cell of claim 8, wherein, The bending structure is in a sine wave shape.

10. The back contact cell of claim 8, wherein, The fifth fine grid further includes a first non-bending part, and an extending direction of the first non-bending part is parallel to the second direction.

11. The back contact cell of claim 1, wherein, The back contact cell further includes a plurality of positioning points, and the positioning points are located between the third fine grid and the fourth fine grid.

12. The back contact cell of claim 1, wherein, In the second direction, a spacing between the fifth fine grid and the positioning points is 200 microns to 2000 microns.

13. The back contact cell of claim 12, wherein, The second polarity fine grids include a sixth fine grid, and the sixth fine grid is located between the third fine grid and the fourth fine grid, and the sixth fine grid, the positioning points, and the fifth fine grid are sequentially distributed along the second direction.

14. The back contact cell of claim 12, wherein, In the second direction, a spacing between the sixth fine grid and the positioning points is 200 microns to 2000 microns. In the second direction, a spacing between the sixth fine grid and the fifth fine grid is 400 microns to 4000 microns.

15. The back contact cell of claim 14, wherein, The sixth fine grid is a non-bending grid line, and an extending direction of the sixth fine grid is parallel to the second direction.

16. The back contact cell of claim 14, wherein, ​ 17. The back contact cell of claim 14, wherein, The sixth fine grid comprises a second bending part, and an extension direction of the second bending part intersects the second direction.

18. The back contact cell of claim 1, wherein, The back contact cell further comprises a plurality of first polarity doped regions and a plurality of second polarity doped regions. The first polarity doped regions and the second polarity doped regions are alternately arranged along the first direction, and the first polarity doped regions and the second polarity doped regions extend along the second direction, positions of the first polarity doped regions correspond to positions of the first polarity fine grids, positions of the second polarity doped regions correspond to positions of the second polarity fine grids, and the first polarity doped regions and the second polarity doped regions have opposite doping polarities.

19. The back contact cell of claim 18, wherein, The second polarity fine grid comprises a seventh fine grid, and the seventh fine grid is located between the first fine grid and the second fine grid. The second polarity doped region corresponding to the position of the fifth fine grid is a first doped region, and a size of the first doped region in the first direction is a first size. The second polarity doped region corresponding to the position of the seventh fine grid is a second doped region, and a size of the second doped region in the first direction is a second size. The first size is greater than the second size.

20. The back contact cell of claim 19, wherein, The first polarity doped region comprises a third doped region and a fourth doped region, the third doped region and the fourth doped region are adjacent, and the first doped region is located between the third doped region and the fourth doped region. Along the first direction, a spacing between the third doped region and the fourth doped region is a third spacing. The first polarity doped region further comprises a fifth doped region and a sixth doped region, the fifth doped region and the sixth doped region are adjacent, and the second doped region is located between the fifth doped region and the sixth doped region. Along the first direction, a spacing between the fifth doped region and the sixth doped region is a fourth spacing. In the first direction, the fourth spacing is less than the third spacing.

21. A battery assembly comprising: The back contact cell comprises the back contact cell as claimed in any one of claims 1 to 20.

22. A photovoltaic system characterized by, The battery assembly comprises the battery assembly as claimed in claim 21.

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