Master grid back contact solar cell, back contact solar cell string and photovoltaic module

Abstract

The present application relates to a busbar-free back-contact solar cell, a back-contact solar cell string, and a photovoltaic module. The busbar-free back-contact solar cell includes multiple fine grid groups. The fine grid group includes a first fine grid, a second fine grid, and a third fine grid; the third fine grid includes multiple first sub-fine grids and multiple second sub-fine grids, and the first sub-fine grids and the second sub-fine grids are spaced and alternately arranged along the second direction. Multiple first conductive members are spaced apart on the first fine grid, multiple second conductive members are spaced apart on the second fine grid, a third conductive member is provided on the first sub-fine grid, and a fourth conductive member is provided on the second sub-fine grid; in the same fine grid group, the first conductive member and the second conductive member are staggered along the first direction, the first conductive member and the third conductive member are arranged oppositely along the first direction; the second conductive member and the fourth conductive member are arranged oppositely along the first direction. The busbar-free back-contact solar cell of the present application can improve the photoelectric conversion efficiency of the solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a back contact solar cell without main grid, a back contact solar cell string and a photovoltaic module. BACKGROUND

[0002] BC cell refers to a back contact cell, which is an advanced design for improving the efficiency of solar cells. The core design concept is to place all metal electrodes of the cell on the back surface of the cell, so that the front surface of the cell is not blocked by any metal grid lines, thereby maximizing the area of the cell for absorbing sunlight, reducing optical loss and improving photoelectric conversion efficiency.

[0003] With the gradual popularization of the main grid-free technology, back contact solar cells have also joined this lineup. For back contact cells that are not blocked by any grid lines on the front surface, the main grid-free technology mainly brings cost reduction gains. Since the back contact cell always needs to print insulating glue during packaging to prevent electrical leakage, in the related technology, the main grid of the main grid-free back contact solar cell is cancelled, and insulating glue is arranged at the position of the fine grid corresponding to the original heterogeneous main grid. The fine grid does not need to be disconnected at the heterogeneous main grid, thereby improving the collection capacity of the carriers.

[0004] However, the heterogeneous solder pad needs to be arranged on the heterogeneous fine grid. In order to prevent the heterogeneous solder pad from short-circuiting during series connection, the heterogeneous solder pads need to be arranged at intervals. The distance between the solder pad and the end of the fine grid is large, which affects the ability of the solder pad to collect carriers, resulting in low photoelectric conversion efficiency of the solar cell. SUMMARY

[0005] Therefore, it is necessary to provide a back contact solar cell without main grid, a back contact solar cell string and a photovoltaic module, which aims to solve the problem that the distance between the solder pad and the end of the fine grid is large, which affects the ability of the solder pad to collect carriers, resulting in low photoelectric conversion efficiency of the solar cell.

[0006] In a first aspect, an embodiment of the present application provides a back contact solar cell without main grid, comprising:

[0007] A plurality of fine grid groups are arranged at intervals along a first direction;

[0008] The fine grid group comprises a first fine grid, a second fine grid and a third fine grid, the first fine grid, the second fine grid and the third fine grid are arranged along the first direction, and all extend along a second direction;

[0009] The third fine grid comprises a plurality of first fine grid sub-groups and a plurality of second fine grid sub-groups, the first fine grid sub-groups and the second fine grid sub-groups are arranged at intervals and alternately along the second direction;

[0010] The first fine grid is provided with a plurality of first conductive pieces at intervals, the second fine grid is provided with a plurality of second conductive pieces at intervals, the first sub-fine grid is provided with a third conductive piece, and the second sub-fine grid is provided with a fourth conductive piece; in the same fine grid group, the first conductive piece and the second conductive piece are arranged in a staggered manner along a first direction, and the first conductive piece and the third conductive piece are arranged in opposition along the first direction; and the second conductive piece and the fourth conductive piece are arranged in opposition along the first direction.

[0011] The first fine grid and the second fine grid are in opposite electrical properties, the first sub-fine grid has the same electrical property as the first fine grid, and the second sub-fine grid has the same electrical property as the second fine grid.

[0012] The first direction intersects the second direction.

[0013] In some embodiments, along the first direction, the third conductive piece has a gap with the second fine grid, and the fourth conductive piece has a gap with the first fine grid.

[0014] In some embodiments, along the first direction, the third conductive piece is in contact with the adjacent first conductive piece, and the fourth conductive piece is in contact with the adjacent second conductive piece.

[0015] In a second aspect, the embodiments of the present application provide a back contact solar cell string, which comprises a plurality of interconnection lines and a plurality of pieces of the back contact solar cell without bus bars in the first aspect, and each two adjacent pieces of the back contact solar cell without bus bars are connected in series by the interconnection line.

[0016] In some embodiments, the back contact solar cell string further comprises:

[0017] A plurality of first insulating pieces are provided at intervals on the first fine grid; along the first direction, the first insulating piece and the second conductive piece are arranged in opposition.

[0018] A plurality of second insulating pieces are provided at intervals on the second fine grid; along the first direction, the second insulating piece and the first conductive piece are arranged in opposition.

[0019] In some embodiments, along the first direction, the orthographic projection of the second conductive piece is located within the orthographic projection of the adjacent first insulating piece; and the orthographic projection of the fourth conductive piece is located within the orthographic projection of the adjacent first insulating piece.

[0020] Along the first direction, the orthographic projection of the first conductive piece is located within the orthographic projection of the adjacent second insulating piece; and the orthographic projection of the third conductive piece is located within the orthographic projection of the adjacent second insulating piece.

[0021] In some embodiments, the interconnection line comprises a plurality of first interconnection lines and a plurality of second interconnection lines, the plurality of first interconnection lines and the plurality of second interconnection lines are arranged at intervals along a second direction and extend along the first direction; in any piece of the back contact solar cell without bus bars:

[0022] The first interconnection line connects all the first conductive elements and all the third conductive elements in the first direction, and the first interconnection line is located on a side of all the second insulating elements arranged opposite to the first conductive elements away from the second fine gate;

[0023] The second interconnection line connects all the second conductive elements and all the fourth conductive elements in the first direction, and is located on a side of all the first insulating elements arranged opposite to the second conductive elements away from the first fine gate.

[0024] In some embodiments, the first interconnection line in any busbar-less back-contact solar cell is collinear with the first interconnection line in an adjacent busbar-less back-contact solar cell;

[0025] The second interconnection line in any busbar-less back-contact solar cell is collinear with the second interconnection line in an adjacent busbar-less back-contact solar cell.

[0026] In a third aspect, an embodiment of the present application provides a photovoltaic module, comprising a base plate, a cover plate, and the back-contact solar cell string of the second aspect, wherein the back-contact solar cell string and the cover plate are stacked in sequence along a third direction and arranged on one side of the base plate;

[0027] The third direction intersects both the second direction and the first direction.

[0028] In some embodiments, the photovoltaic module further includes a first adhesive layer and a second adhesive layer;

[0029] Along the third direction, the first adhesive layer is connected to the bottom plate and the side of the back-contact solar cell string facing away from the cover plate; the second adhesive layer is connected to the side of the cover plate and the back-contact solar cell string facing away from the bottom plate.

[0030] The busbar-less back-contact solar cell comprises a plurality of fine grid groups. The plurality of fine grid groups are arranged at intervals along a first direction. The fine grid groups comprise a first fine grid, a second fine grid, and a third fine grid. The first, second, and third fine grids are arranged along the first direction and extend along a second direction. The third fine grid comprises a plurality of first sub-fine grids and a plurality of second sub-fine grids. The first sub-fine grids and the second sub-fine grids are spaced and alternately arranged along the second direction. A plurality of first conductive elements are spaced apart on the first fine grid, a plurality of second conductive elements are spaced apart on the second fine grid, a third conductive element is provided on the first sub-fine grid, and a fourth conductive element is provided on the second sub-fine grid. Within the same fine grid group, the first and second conductive elements are staggered along the first direction, the first and third conductive elements are arranged oppositely along the first direction, and the second and fourth conductive elements are arranged oppositely along the first direction. The first fine grid and the second fine grid have opposite electrical properties, the first sub-fine grid and the first fine grid have the same electrical properties, and the second sub-fine grid and the second fine grid have the same electrical properties. The first direction intersects the second direction.

[0031] The back contact solar cell without main grid in the application, since the third fine grid includes a plurality of first sub-fine grids and a plurality of second sub-fine grids, the first sub-fine grids and the second sub-fine grids are spaced and alternately arranged along the second direction, so that the distance between the third conductive part and the end of the first sub-fine grid is less than the distance between the first conductive part and the end of the first fine grid, and at the same time, the distance between the fourth conductive part and the end of the second sub-fine grid is less than the distance between the second conductive part and the end of the second fine grid, and then the ability of the third conductive part to collect carriers is stronger than the ability of the first conductive part to collect carriers, and at the same time, the ability of the fourth conductive part to collect carriers is stronger than the ability of the second conductive part to collect carriers. Since each fine grid group includes a third fine grid, and the third fine grid includes a plurality of first sub-fine grids and a plurality of second sub-fine grids, i.e. along the first direction, there will be a third fine grid in each fine grid group, and the third conductive part and the fourth conductive part in the third fine grid both have higher ability to collect carriers, so as to improve the photoelectric conversion efficiency of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structure schematic diagram of the back contact solar cell without main grid in an embodiment of the application.

[0033] Figure 2 It is a structure schematic diagram of the fine grid group in an embodiment of the application.

[0034] Figure 3 It is a structure schematic diagram of the back contact solar cell string in an embodiment of the application.

[0035] Figure 4 It is a structure schematic diagram of the photovoltaic module in an embodiment of the application.

[0036] Figure 5 It is another structure schematic diagram of the photovoltaic module in an embodiment of the application.

[0037] BRIEF DESCRIPTION OF DRAWINGS:

[0038] 10, back contact solar cell without main grid; 20, back contact solar cell string; 30, photovoltaic module;

[0039] 11, fine grid group;

[0040] 111, first fine grid; 112, second fine grid; 113, third fine grid;

[0041] 1111, first conductive part; 1121, second conductive part;

[0042] 1131, first sub-fine grid; 1132, second sub-fine grid;

[0043] 1133, third conductive part; 1134, fourth conductive part;

[0044] 21, interconnect line; 22, first insulating member; 23, second insulating member;

[0045] 211, first interconnect line; 212, second interconnect line;

[0046] 31, bottom plate; 32, cover plate; 33, first adhesive layer; 34, second adhesive layer. DETAILED DESCRIPTION

[0047] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the spirit of the present application, and that the present application is therefore not limited to the specific embodiments set forth below.

[0048] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms 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 application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0049] In addition, if the terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features referred to. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0050] In the present application, unless otherwise specifically defined and limited, if the terms "mounting", "connection", "connection", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0052] First, see Figure 1 and Figure 2 As shown, an embodiment of the present application provides a busbar-less back-contact solar cell 10, comprising a plurality of fine grid groups 11. The plurality of fine grid groups 11 are arranged in a first direction at intervals. The fine grid groups 11 include a first fine grid 111, a second fine grid 112, and a third fine grid 113. The first fine grid 111, the second fine grid 112, and the third fine grid 113 are arranged in the first direction and extend in a second direction. The third fine grid 113 includes a plurality of first sub-fine grids 1131 and a plurality of second sub-fine grids 1132. The first sub-fine grids 1131 and the second sub-fine grids 1132 are spaced and alternately arranged in the second direction. A plurality of first conductive elements 1111 are spaced apart on the first fine grid 111, a plurality of second conductive elements 1121 are spaced apart on the second fine grid 112, a third conductive element 1133 is disposed on the first sub-fine grid 1131, and a fourth conductive element 1134 is disposed on the second sub-fine grid 1132. Within the same fine grid group 11, the first conductive elements 1111 and the second conductive elements 1121 are staggered along a first direction, the first conductive elements 1111 and the third conductive elements 1133 are disposed opposite each other along the first direction, and the second conductive elements 1121 and the fourth conductive elements 1134 are disposed opposite each other along the first direction. The first fine grid 111 and the second fine grid 112 have opposite electrical properties, the first sub-fine grid 1131 and the first fine grid 111 have the same electrical properties, and the second sub-fine grid 1132 and the second fine grid 112 have the same electrical properties. The first direction intersects the second direction.

[0053] It should be noted that the first conductive part 1111, the second conductive part 1121, the third conductive part 1133 and the fourth conductive part 1134 are conductive structures provided on the first fine grid 111, the second fine grid 112, the first sub-fine grid 1131 and the second sub-fine grid 1132, respectively, for realizing the electrical connection between the fine grids, and further realizing the series connection between the plurality of fine grid groups 11. The first conductive part 1111, the second conductive part 1121, the third conductive part 1133 and the fourth conductive part 1134 can be pads or other conductive connection structures. In this application, the first conductive part 1111, the second conductive part 1121, the third conductive part 1133 and the fourth conductive part 1134 are exemplarily provided as pads.

[0054] In addition, it should be noted that the first conductive part 1111 is provided on the first fine grid 111. In the case that there is no main grid back contact inside the solar cell sheet 10, there will be a large number of carriers moving on the first fine grid 111. The closer the distance between the carriers and the first conductive part 1111, the easier it is for the first conductive part 1111 to collect the active carriers. Conversely, the farther the distance between the carriers and the first conductive part 1111, the worse the ability of the first conductive part 1111 to collect the active carriers.

[0055] It should also be noted that the solar cell sheet 10 without a main grid back contact in this application can be applied to a solar cell. In this application, the solar cell exemplarily refers to the cell structure to which the solar cell sheet 10 without a main grid back contact can be applied or formed.

[0056] In addition, the first direction is the X direction in the above formula, and the second direction is the Y direction in the above formula. Figure 1 Figure 1

[0057] It can be understood that a plurality of first conductive parts 1111 are provided on the first fine grid 111 at intervals, that is, in any two first conductive parts 1111, the carrier with the farthest distance from one of the first conductive parts 1111 is located at the midpoint of the connecting line of the two first conductive parts 1111.

[0058] ​​However, for the third conductive piece 1133, since the third fine grid 113 includes a plurality of first sub-fine grids 1131 and a plurality of second sub-fine grids 1132, the first sub-fine grids 1131 and the second sub-fine grids 1132 are spaced apart and alternately arranged along the second direction, the third conductive piece 1133 is arranged on the first sub-fine grid 1131, and the fourth conductive piece 1134 is arranged on the second sub-fine grid 1132, that is, the third sub-fine grid and the fourth sub-fine grid are interrupted, that is, the farthest distance between the third conductive piece 1133 and the carrier is the distance between the third conductive piece 1133 and one end of the first sub-fine grid 1131 away from the third conductive piece 1133. For the convenience of description, the third conductive piece 1133 is arranged at the midpoint of the first sub-fine grid 1131 in this application, and at this time, the farthest distance between the third conductive piece 1133 and the carrier is the distance between the third conductive piece 1133 and any one end of the first sub-fine grid 1131.

[0059] Since the arrangement of the second conductive piece 1121 and the first conductive piece 1111 is similar, and the arrangement of the fourth conductive piece 1134 and the third conductive piece 1133 is similar, this application will not repeat the distance between the second conductive piece 1121 and the carrier and the distance between the fourth conductive piece 1134 and the carrier.

[0060] Further, it can be understood that since a plurality of first conductive pieces 1111 are spaced apart on the first fine grid 111, the first sub-fine grid 1131 and the second sub-fine grid 1132 are spaced apart and alternately arranged along the second direction, that is, along the second direction, the first fine grid 111 is always a continuous fine line, and the first sub-fine grid 1131 is a fine line interrupted by the second sub-fine grid 1132, and since the third conductive piece 1133 is arranged on the first sub-fine grid 1131, the first conductive piece 1111 and the second conductive piece 1121 are arranged staggered along the first direction, and the first conductive piece 1111 and the third conductive piece 1133 are arranged opposite along the first direction, that is, along the second direction, the length of the first sub-fine grid 1131 is less than the length of the first fine grid 111, and since two third conductive pieces 1133 and two fourth conductive pieces 1134 are arranged in the region corresponding to any two first conductive pieces 1111, if the first sub-fine grid 1131 and the second sub-fine grid 1132 corresponding to the third conductive piece 1133 and the fourth conductive piece 1134 are equally divided, that is, the length of the first sub-fine grid 1131 is one fourth of the length of the first fine grid 111.

[0061] Based on the above distance between the first conductive piece 1111 and the carrier in the first fine grid 111 and the distance between the third conductive piece 1133 and the carrier in the first sub-fine grid 1131, it can be known that the farthest distance between the third conductive piece 1133 and the carrier is half of the farthest distance between the first conductive piece 1111 and the carrier. Similarly, it can be known that the farthest distance between the fourth conductive piece 1134 and the carrier is half of the farthest distance between the second conductive piece 1121 and the carrier.

[0062] Since the farthest distance of the third conductive member 1133 from the carriers is half of the farthest distance of the first conductive member 1111 from the carriers, and the farthest distance of the fourth conductive member 1134 from the carriers is half of the farthest distance of the second conductive member 1121 from the carriers, the ability to collect carriers can be improved through the third conductive member 1133 and the fourth conductive member 1134, so that the series resistance can be reduced, and the photoelectric conversion efficiency of the solar cell can be improved.

[0063] It should be noted that in the related art, the main grid back contact solar cell cancels the main grid, and the insulating glue is arranged at the position of the fine grid corresponding to the original heterogeneous main grid, so the fine grid does not need to be disconnected at the heterogeneous main grid, but the heterogeneous solder pad needs to be arranged on the heterogeneous fine grid. In order to prevent the short circuit of the heterogeneous solder pad in the series process, the heterogeneous solder pads need to be arranged at intervals. That is, the fine grids in the main grid back contact solar cell in the related art are alternately arranged between the fine grids, that is, the fine grids are grouped as two groups of fine grids with different electrical properties, and the farthest distance of the solder pad from the carriers in any fine grid is the same. In the present application, three fine grids are grouped as one group, and the distance of the solder pad in one fine grid from the carriers is half of the distance of the solder pad in any other fine grid from the carriers. Further, in order to facilitate understanding, if a multiple of 6 fine grids are arranged in the related art and in the present application, the farthest distance of the solder pad in each fine grid from the carriers is the same, and in the present application, the farthest distance of the solder pad in a multiple of 2 fine grids from the carriers is half of the farthest distance of the solder pad in the remaining fine grids from the carriers, so that the ability of the solder pad to collect carriers can be further improved, so that the series resistance can be further reduced, and the photoelectric conversion efficiency of the solar cell can be further improved.

[0064] In some embodiments, along the first direction, the third conductive member 1133 has a gap with the second fine grid 112, and the fourth conductive member 1134 has a gap with the first fine grid 111.

[0065] Thus, since the third conductive member 1133 has a gap with the second fine grid 112, the fourth conductive member 1134 has a gap with the first fine grid 111, and since the first fine grid 111 and the second fine grid 112 have opposite electric properties, the first sub-fine grid 1131 has the same electric property as the first fine grid 111, and the second sub-fine grid 1132 has the same electric property as the second fine grid 112, the third conductive member 1133 can avoid contacting the second fine grid 112, and thus can avoid short circuiting with the second fine grid 112. Similarly, the fourth conductive member 1134 can avoid contacting the first fine grid 111, and thus can avoid short circuiting with the first fine grid 111, so as to ensure normal operation of the back contact solar cell 10 without main grid, and to improve the service life of the back contact solar cell 10 without main grid.

[0066] In some embodiments, along the first direction, the third conductive member 1133 contacts the adjacent first conductive member 1111, and the fourth conductive member 1134 contacts the adjacent second conductive member 1121.

[0067] It should be noted that since the first fine grid 111 and the second fine grid 112 have opposite electric properties, the first sub-fine grid 1131 has the same electric property as the first fine grid 111, and the second sub-fine grid 1132 has the same electric property as the second fine grid 112, so that when the third conductive member 1133 contacts the adjacent first conductive member 1111, the third conductive member 1133 and the first conductive member 1111 will not short circuit, and similarly, when the fourth conductive member 1134 contacts the adjacent second conductive member 1121, the fourth conductive member 1134 and the second conductive member 1121 will not short circuit.

[0068] Since along the first direction, the third conductive member 1133 contacts the adjacent first conductive member 1111, and the fourth conductive member 1134 contacts the adjacent second conductive member 1121, so that no gap region is provided between the third conductive member 1133 and the adjacent first conductive member 1111, and no gap region is provided between the fourth conductive member 1134 and the adjacent second conductive member 1121, so as to increase the area of the cell doping part, improve the carrier concentration, and thus improve the cell utilization and current density of the solar cell. Similarly, no gap region is provided between the fourth conductive member 1134 and the adjacent second conductive member 1121, so as to increase the area of the cell doping part, improve the carrier concentration, and thus improve the cell utilization and current density of the solar cell.

[0069] In a second aspect, referring to Figure 3 As shown in the drawings, the embodiments of the present application provide a back contact solar cell string 20, which comprises a plurality of interconnection lines 21 and a plurality of back contact solar cell pieces 10 without main grid in the first aspect, and each two adjacent back contact solar cell pieces 10 without main grid are connected in series by the interconnection line 21.

[0070] In this way, a plurality of back contact solar cell pieces 10 can be connected in series through a plurality of interconnection lines 21, on the one hand, the voltage of the back contact solar cell string 20 can be increased. Under the irradiation of the sun, each back contact solar cell piece 10 will generate a certain voltage and current. When a plurality of back contact solar cell pieces 10 are connected in series, their voltages will be added to form a total voltage, thereby meeting the needs of some specific applications. On the other hand, connecting a plurality of back contact solar cell pieces 10 in series can increase the output voltage of the back contact solar cell string 20, thereby improving the efficiency of the back contact solar cell string 20. In addition, connecting back contact solar cell pieces 10 in series can also reduce the internal resistance of the back contact solar cell string 20 and improve the output power of the back contact solar cell string 20.

[0071] In some embodiments, the back contact solar cell string 20 further comprises a plurality of first insulating pieces 22 and a plurality of second insulating pieces 23. The plurality of first insulating pieces 22 are arranged on the first fine grid 111 in a spaced manner; along the first direction, the first insulating piece 22 and the second conductive piece 1121 are arranged opposite to each other; the plurality of second insulating pieces 23 are arranged on the second fine grid 112 in a spaced manner; along the first direction, the second insulating piece 23 and the first conductive piece 1111 are arranged opposite to each other.

[0072] In this way, when a plurality of back contact solar cell pieces 10 are connected in series, the first conductive piece 1111 and the second conductive piece 1121 or the fourth conductive piece 1134 can be prevented from short-circuiting through the first insulating piece 22, and the second conductive piece 1121 and the first conductive piece 1111 or the third conductive piece 1133 can be prevented from short-circuiting through the second insulating piece 23, thereby improving the use stability and safety of the back contact solar cell string 20.

[0073] In some embodiments, along the first direction, the orthographic projection of the second conductive piece 1121 is located within the orthographic projection of the adjacent first insulating piece 22; the orthographic projection of the fourth conductive piece 1134 is located within the orthographic projection of the adjacent first insulating piece 22; along the first direction, the orthographic projection of the first conductive piece 1111 is located within the orthographic projection of the adjacent second insulating piece 23; the orthographic projection of the third conductive piece 1133 is located within the orthographic projection of the adjacent second insulating piece 23.

[0074] Thus, on one hand, if the back contact solar cell string 20 is affected by external factors, the positions of the first fine grid 111, the second fine grid 112 and the third fine grid 113 in the fine grid group 11 are affected and changed, since along the first direction, the orthographic projection of the second conductive member 1121 is located within the orthographic projection of the adjacent first insulating member 22, and the orthographic projection of the fourth conductive member 1134 is located within the orthographic projection of the adjacent first insulating member 22, thus further avoiding the second conductive member 1121 or the fourth conductive member 1134 from contacting the adjacent first fine grid 111, thus further avoiding the second conductive member 1121 or the fourth conductive member 1134 from short-circuiting with the first fine grid 111, likewise, further avoiding the first conductive member 1111 or the third conductive member 1133 from short-circuiting with the second fine grid 112, thus further improving the stability and safety of the back contact solar cell string 20.

[0075] In addition, since along the first direction, the orthographic projection of the second conductive member 1121 is located within the orthographic projection of the adjacent first insulating member 22, and the orthographic projection of the fourth conductive member 1134 is located within the orthographic projection of the adjacent first insulating member 22, when connecting each two adjacent back contact solar cell pieces 10 without main grid in series through the interconnection line 21, the first insulating member 22 can provide sufficient contact area for the interconnection line 21, thus avoiding the misalignment between the interconnection line 21 and the first insulating layer connection and the communication with the fine grid of opposite gender, thus further avoiding the short-circuiting during the series connection. Likewise, since along the first direction, the orthographic projection of the first conductive member 1111 is located within the orthographic projection of the adjacent second insulating member 23, and the orthographic projection of the third conductive member 1133 is located within the orthographic projection of the adjacent second insulating member 23, thus when connecting each two adjacent back contact solar cell pieces 10 without main grid in series through the interconnection line 21, the second insulating member 23 can provide sufficient contact area for the interconnection line 21, thus avoiding the misalignment between the interconnection line 21 and the second insulating layer connection and the communication with the fine grid of opposite gender, thus further avoiding the short-circuiting during the series connection.

[0076] In some embodiments, the interconnection line 21 includes a plurality of first interconnection lines 211 and a plurality of second interconnection lines 212, the plurality of first interconnection lines 211 and the plurality of second interconnection lines 212 are arranged at intervals along the second direction and extend along the first direction; in any back contact solar cell piece 10 without main grid: the first interconnection line 211 connects all the first conductive members 1111 and all the third conductive members 1133 in the first direction, and the first interconnection line 211 is located on the side of all the second insulating members 23 opposite to the first conductive members 1111 and away from the second fine grid 112; the second interconnection line 212 connects all the second conductive members 1121 and all the fourth conductive members 1134 in the first direction, and the second interconnection line 212 is located on the side of all the first insulating members 22 opposite to the second conductive members 1121 and away from the first fine grid 111.

[0077] Thus, all the first conductive members 1111 and all the third conductive members 1133 in the first direction can be connected by the first interconnection line 211, and all the second conductive members 1121 and all the fourth conductive members 1134 in the first direction can be connected by the second interconnection line 212, so that the two adjacent back contact solar cell pieces 10 without main grid can be connected in series, and the voltage and output power of the back contact solar cell string 20 can be improved.

[0078] In addition, since the first interconnection line 211 is located on the side of all the second insulating members 23 opposite to the first conductive members 1111 and facing away from the second fine grid 112, and the second interconnection line 212 is located on the side of all the first insulating members 22 opposite to the second conductive members 1121 and facing away from the first fine grid 111, the first interconnection line 211 and the second interconnection line 212 can avoid contacting the fine grid of different polarity respectively, so that the short circuit can be avoided during the series connection, and the use stability and safety of the back contact solar cell string 20 can be improved.

[0079] In some embodiments, the first interconnection line 211 in any back contact solar cell piece 10 without main grid is collinear with the first interconnection line 211 in the adjacent back contact solar cell piece 10 without main grid, and the second interconnection line 212 in any back contact solar cell piece 10 without main grid is collinear with the second interconnection line 212 in the adjacent back contact solar cell piece 10 without main grid.

[0080] Thus, it can be ensured that the first interconnection line 211 and the second interconnection line 212 do not bend, on the one hand, the operation of connecting the back contact solar cell pieces 10 without main grid in series by the first interconnection line 211 and the second interconnection line 212 can be facilitated, and on the other hand, the line arrangement of the back contact solar cell string 20 after series connection can be regular, so that the situation of wrong connection during the series connection can be avoided, and the use safety of the back contact solar cell string 20 can be improved.

[0081] Optionally, the first interconnection line 211 connects all the first conductive members 1111 and all the third conductive members 1133 of the first back contact solar cell 10 along the first direction, and the first interconnection line 211 extends to connect all the first conductive members 1111 and all the third conductive members 1133 of the adjacent second back contact solar cell 10 along the first direction, the second interconnection line 212 connects all the second conductive members 1121 and all the fourth conductive members 1134 of the second back contact solar cell 10 along the first direction, and the second interconnection line 212 extends to connect all the second conductive members 1121 and all the fourth conductive members 1134 of the adjacent third back contact solar cell 10 along the first direction, and all the first conductive members 1111 and all the third conductive members 1133 of the third back contact solar cell 10 along the first direction are connected to all the first conductive members 1111 and all the third conductive members 1133 of the adjacent fourth back contact solar cell 10 along the first direction through another first interconnection line 211. In this way, three adjacent back contact solar cells 10 form a cycle, so that the first interconnection line 211 in any back contact solar cell 10 is collinear with the first interconnection line 211 in the adjacent back contact solar cell 10, and the second interconnection line 212 in any back contact solar cell 10 is collinear with the second interconnection line 212 in the adjacent back contact solar cell 10.

[0082] In a third aspect, referring to Figure 4 As shown in the drawings, the embodiments of the present application provide a photovoltaic module 30, which comprises a bottom plate 31, a cover plate 32 and the back contact solar cell string 20 in the second aspect, and the back contact solar cell string 20 and the cover plate 32 are stacked in sequence on one side of the bottom plate 31 along a third direction, and the third direction intersects with the second direction and the first direction.

[0083] It should be noted that the third direction is Figure 4 the Z direction in the above.

[0084] Specifically, a plurality of back contact solar cell strings 20 with the same number of interconnection cycles are selected and arranged laterally, and the adjacent back contact solar cell strings 20 are connected in sequence to form a back contact solar cell string 20 array, and the back contact solar cell string 20 and the cover plate 32 are stacked in sequence on one side of the bottom plate 31 along the third direction, so that the photovoltaic module 30 can be formed.

[0085] In this way, on the one hand, the plurality of back contact solar cell strings 20 are connected in series to form the photovoltaic module 30, which can reduce the internal resistance loss of the back contact solar cell string 20, thereby improving the working efficiency of the back contact solar cell string 20, and further improving the photoelectric conversion efficiency of the photovoltaic module 30. On the other hand, the plurality of back contact solar cell strings 20 make it easier for light to be absorbed, especially in weak light conditions, and have better power generation stability, which can improve the light absorption capacity of the photovoltaic module 30.

[0086] In addition, in the single back contact solar cell piece 10 without busbars, the farthest distance between the third conductive part 1133 and the carrier is half of the farthest distance between the first conductive part 1111 and the carrier, and the farthest distance between the fourth conductive part 1134 and the carrier is half of the farthest distance between the second conductive part 1121 and the carrier, so that the ability to collect carriers can be improved through the third conductive part 1133 and the fourth conductive part 1134, thereby reducing the series resistance. After the plurality of back contact solar cell pieces 10 without busbars are connected in series to form the back contact solar cell string 20, and the back contact solar cell string 20 is connected in series to form the photovoltaic module 30, the photoelectric conversion efficiency of the photovoltaic module 30 can be further improved.

[0087] In some embodiments, referring to Figure 5 As shown, the photovoltaic module 30 further includes a first adhesive layer 33 and a second adhesive layer 34; along the third direction, the first adhesive layer 33 is connected to the bottom plate 31 and the side of the back contact solar cell string 20 away from the cover plate 32; and the second adhesive layer 34 is connected to the cover plate 32 and the side of the back contact solar cell string 20 away from the bottom plate 31.

[0088] In this way, the first adhesive layer 33 can be used to connect the back contact solar cell string 20 and the bottom plate 31, thereby improving the tightness of the connection between the back contact solar cell string 20 and the bottom plate 31. Similarly, the second adhesive layer 34 can be used to connect the back contact solar cell string 20 and the cover plate 32, thereby improving the tightness of the connection between the back contact solar cell string 20 and the cover plate 32, and further improving the stability and safety of the photovoltaic module 30 as a whole.

[0089] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as within the scope of the present disclosure.

[0090] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A busbar-less back contact solar cell, characterized in that: include: A plurality of fine grid groups are arranged at intervals along a first direction; The fine grid group includes a first fine grid, a second fine grid and a third fine grid, wherein the first fine grid, the second fine grid and the third fine grid are arranged along the first direction and extend along the second direction; The third fine gate includes a plurality of first sub-fine gates and a plurality of second sub-fine gates, wherein the first sub-fine gates and the second sub-fine gates are spaced and alternately arranged along the second direction; A plurality of first conductive elements are provided at intervals on the first fine grid, a plurality of second conductive elements are provided at intervals on the second fine grid, a third conductive element is provided on the first sub-fine grid, and a fourth conductive element is provided on the second sub-fine grid; in the same fine grid group, the first conductive elements and the second conductive elements are staggered along the first direction, the first conductive element and the third conductive element are arranged opposite to each other along the first direction; and the second conductive element and the fourth conductive element are arranged opposite to each other along the first direction; The first fine gate and the second fine gate have opposite electrical properties, the first sub-fine gate and the first fine gate have the same electrical property, and the second sub-fine gate and the second fine gate have the same electrical property; The first direction intersects with the second direction.

2. The busbar-free back contact solar cell according to claim 1, characterized in that: Along the first direction, there is a gap between the third conductive member and the second fine grid, and there is a gap between the fourth conductive member and the first fine grid.

3. The busbar-less back contact solar cell according to claim 1, characterized in that: Along the first direction, the third conductive member contacts the adjacent first conductive member, and the fourth conductive member contacts the adjacent second conductive member.

4. A back contact solar cell string, characterized in that: The invention comprises a plurality of interconnecting lines and a plurality of busbar-free back-contact solar cells according to any one of claims 1 to 3, wherein every two adjacent busbar-free back-contact solar cells are connected in series via the interconnecting lines.

5. The back contact solar cell string according to claim 4, characterized in that: The back contact solar cell string further comprises: A plurality of first insulating members are spaced apart and arranged on the first fine grid; along the first direction, the first insulating members and the second conductive members are arranged opposite to each other; A plurality of second insulating members are spaced apart and arranged on the second fine grid; along the first direction, the second insulating members and the first conductive members are arranged opposite to each other.

6. The back contact solar cell string according to claim 5, characterized in that: Along the first direction, the orthographic projection of the second conductive member is located within the orthographic projection of the adjacent first insulating member; the orthographic projection of the fourth conductive member is located within the orthographic projection of the adjacent first insulating member; Along the first direction, the orthographic projection of the first conductive member is located within the orthographic projection of the adjacent second insulating member; and the orthographic projection of the third conductive member is located within the orthographic projection of the adjacent second insulating member.

7. The back contact solar cell string according to claim 5, characterized in that: The interconnection lines include a plurality of first interconnection lines and a plurality of second interconnection lines, the plurality of first interconnection lines and the plurality of second interconnection lines are arranged at intervals along the second direction and extend along the first direction; in any of the busbar-free back contact solar cells: The first interconnection line connects all the first conductive elements and all the third conductive elements in the first direction, and the first interconnection line is located on a side of all the second insulating elements arranged opposite to the first conductive elements away from the second fine gate; The second interconnection line connects all the second conductive elements and all the fourth conductive elements in the first direction, and is located on a side of all the first insulating elements opposite to the second conductive elements away from the first fine gate.

8. The back contact solar cell string according to claim 7, characterized in that: The first interconnection line in any one of the busbar-free back-contact solar cells is collinear with the first interconnection line in an adjacent one of the busbar-free back-contact solar cells; The second interconnection line in any one of the busbar-less back-contact solar cells is collinear with the second interconnection line in an adjacent one of the busbar-less back-contact solar cells.

9. A photovoltaic module comprising a base plate, a cover plate, and the back-contact solar cell string according to claim 4, wherein the back-contact solar cell string and the cover plate are stacked in sequence and arranged on one side of the base plate along a third direction; The third direction intersects both the second direction and the first direction.

10. The photovoltaic module according to claim 9, characterized in that: The photovoltaic module further includes a first adhesive layer and a second adhesive layer; Along the third direction, the first adhesive layer is connected to the side of the bottom plate and the back-contact solar cell string facing away from the cover plate; the second adhesive layer is connected to the side of the cover plate and the back-contact solar cell string facing away from the bottom plate.

Images