Main-grid-free back contact solar cell, back contact solar cell string and photovoltaic module

Abstract

The invention relates to a main-grid-free back contact solar cell piece, a back contact solar cell string and a photovoltaic module. The main-grid-free back contact solar cell piece comprises a plurality of fine grid groups. The fine grid group comprises a first fine grid, a second fine grid and a third fine grid; the third fine grid comprises a plurality of first sub-fine grids and a plurality of second sub-fine grids, and the first sub-fine grids and the second sub-fine grids are alternately arranged at intervals in the second direction. A plurality of first conductive parts are arranged on the first fine grid at intervals, a plurality of second conductive parts are arranged on the second fine grid at intervals, a third conductive part is arranged on the first sub fine grid, and a fourth conductive part is arranged on the second sub fine grid; in the same fine grid group, the first conductive part and the second conductive part are staggered along a first direction, and the first conductive part and the third conductive part are oppositely arranged along the first direction; the second conductive part and the fourth conductive part are oppositely arranged in the first direction. According to the main-grid-free back contact solar cell, the photoelectric conversion efficiency of the solar cell can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a main grid-free back-contact solar cell sheet, a back-contact solar cell string and a photovoltaic module. Background Art

[0002] BC cell, which refers to the back contact cell, is an advanced design used to improve the efficiency of solar cells. Its core design concept is to place all the metal electrodes of the cell on the back of the cell, thereby ensuring that the front of the cell is not blocked by any metal grid, thereby maximizing the area of ​​the cell that absorbs sunlight, reducing optical losses and improving photoelectric conversion efficiency.

[0003] With the gradual popularization of busbar-free technology, back-contact solar cells have also begun to join this lineup. For back-contact cells that do not have any grid lines blocking the front, busbar-free technology mainly brings them gains in the direction of cost reduction. Since back-contact cells always need to be printed with insulating glue during the packaging process to prevent leakage, in related technologies, busbar-free back-contact solar cells eliminate the busbar and set insulating glue at the fine grid position corresponding to the original heterosexual busbar. The fine grid does not need to be disconnected at the heterosexual busbar, thereby improving the carrier collection capacity.

[0004] However, heterosexual pads need to be set on the heterosexual fine grids. In order to prevent the heterosexual pads from short-circuiting during the series connection process, the heterosexual pads need to be set at intervals. The distance between the pads and the ends of the fine grids is large, which affects the ability of the pads to collect carriers, resulting in low photoelectric conversion efficiency of the solar cell. Summary of the invention

[0005] Based on this, it is necessary to provide a main grid-free back-contact solar cell, a back-contact solar cell string and a photovoltaic module, aiming to solve the problem that the distance between the pad and the end of the fine grid is large, which affects the ability of the pad to collect carriers and leads to low photoelectric conversion efficiency of the solar cell.

[0006] In a first aspect, an embodiment of the present application provides a busbar-free back contact solar cell, comprising:

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

[0008] The fine gate group includes a first fine gate, a second fine gate and a third fine gate, wherein the first fine gate, the second fine gate and the third fine gate are arranged along the first direction and extend along the second direction;

[0009] The third fine gate includes a plurality of first sub-fine gates and a plurality of second sub-fine gates, and the first sub-fine gates and the second sub-fine gates are spaced and alternately arranged along the second direction;

[0010] A plurality of first conductive members are arranged at intervals on the first fine grid, a plurality of second conductive members are arranged at intervals on the second fine grid, a third conductive member is arranged on the first sub-fine grid, and a fourth conductive member is arranged 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 opposite to each other along the first direction; the second conductive member and the fourth conductive member are arranged opposite to each other along the first direction;

[0011] The electrical properties of the first fine gate and the second fine gate are opposite, the electrical properties of the first sub-fine gate and the first fine gate are the same, and the electrical properties of the second sub-fine gate and the second fine gate are the same;

[0012] The first direction intersects the second direction.

[0013] In some embodiments, 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.

[0014] In some embodiments, along the first direction, the third conductive element contacts the adjacent first conductive element, and the fourth conductive element contacts the adjacent second conductive element.

[0015] In a second aspect, an embodiment of the present application provides a back-contact solar cell string, comprising a plurality of interconnecting wires and a plurality of busbar-free back-contact solar cells in the first aspect, wherein each two adjacent busbar-free back-contact solar cells are connected in series via the interconnecting wires.

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

[0017] A plurality of first insulating members are arranged on the first fine grid at intervals; along the first direction, the first insulating members and the second conductive members are arranged opposite to each other;

[0018] A plurality of second insulating members are arranged on the second fine grid at intervals; along the first direction, the second insulating members and the first conductive members are arranged opposite to each other.

[0019] In some embodiments, 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;

[0020] 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.

[0021] In some embodiments, 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 all extend along the first direction; in any busbar-free back contact solar cell:

[0022] The first interconnection line connects all the first conductive members and all the third conductive members in the first direction, and the first interconnection line is located on a side of all the second insulating members arranged opposite to the first conductive members 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 the second interconnection line 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-free back-contact solar cell is collinear with the first interconnection line in an adjacent busbar-free back-contact solar cell;

[0025] The second interconnection line in any busbar-free back-contact solar cell is collinear with the second interconnection line in an adjacent busbar-free 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 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 away from the bottom plate.

[0030] The above-mentioned busbar-free back contact solar cell comprises a plurality of fine grid groups. The plurality of fine grid groups are arranged at intervals along the first direction; 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 the 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 arranged at intervals and alternately along the second direction. Wherein, a plurality of first conductive members are arranged at intervals on the first fine grid, a plurality of second conductive members are arranged at intervals on the second fine grid, a third conductive member is arranged on the first sub-fine grid, and a fourth conductive member is arranged on the second sub-fine grid; in the same fine grid group, the first conductive member and the second conductive member are arranged 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 electrical properties of the first fine grid and the second fine grid are opposite, the electrical properties of the first sub-fine grid and the first fine grid are the same, and the electrical properties of the second sub-fine grid and the second fine grid are the same; wherein the first direction intersects with the second direction.

[0031] In the busbar-free back-contact solar cell of the present 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 member and the end of the first sub-fine grid is smaller than the distance between the first conductive member and the end of the first fine grid, and at the same time, the distance between the fourth conductive member and the end of the second sub-fine grid is smaller than the distance between the second conductive member and the end of the second fine grid, and thus the ability of the third conductive member to collect carriers is stronger than the ability of the first conductive member to collect carriers, and at the same time, the ability of the fourth conductive member to collect carriers is stronger than the ability of the second conductive member 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, that is, along the first direction, there is a third fine grid in each fine grid group, and the third conductive member and the fourth conductive member in the third fine grid both have a high ability to collect carriers, thereby improving the photoelectric conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a solar cell without busbar back contact in one embodiment of the present application.

[0033] Figure 2 FIG. 4 is a schematic diagram of the structure of a fine grid group in an embodiment of the present application.

[0034] Figure 3 FIG. 1 is a schematic structural diagram of a back-contact solar cell string in an embodiment of the present application.

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

[0036] Figure 5 Another structural schematic diagram of a photovoltaic module in an embodiment of the present application.

[0037] Description of reference numerals:

[0038] 10. Busbar-free back-contact solar cell; 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, a first conductive member; 1121, a second conductive member;

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

[0043] 1133, a third conductive element; 1134, a fourth conductive element;

[0044] 21. interconnection line; 22. first insulating member; 23. second insulating member;

[0045] 211, a first interconnection line; 212, a second interconnection 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-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0048] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0049] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0051] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it 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. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0052] First, see Figure 1 and Figure 2 As shown, the embodiment of the present application provides a busbar-free back contact solar cell 10, comprising a plurality of fine grid groups 11. The plurality of fine grid groups 11 are arranged at intervals along the first direction; the fine grid group 11 comprises 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 along the first direction and all extend along the second direction; the third fine grid 113 comprises 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 arranged at intervals and alternately along the second direction. A plurality of first conductive elements 1111 are arranged at intervals on the first fine grid 111, a plurality of second conductive elements 1121 are arranged at intervals on the second fine grid 112, a third conductive element 1133 is arranged on the first sub-fine grid 1131, and a fourth conductive element 1134 is arranged on the second sub-fine grid 1132; in the same fine grid group 11, the first conductive element 1111 and the second conductive element 1121 are arranged staggered along the first direction, the first conductive element 1111 and the third conductive element 1133 are arranged oppositely along the first direction; the second conductive element 1121 and the fourth conductive element 1134 are arranged oppositely 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; wherein the first direction intersects with the second direction.

[0053] It should be noted that the first conductive member 1111, the second conductive member 1121, the third conductive member 1133 and the fourth conductive member 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, and are used to realize electrical connection between the fine grids, and further realize series connection between the plurality of fine grid groups 11. The first conductive member 1111, the second conductive member 1121, the third conductive member 1133 and the fourth conductive member 1134 may be pads or other conductive connection structures. In the present application, the first conductive member 1111, the second conductive member 1121, the third conductive member 1133 and the fourth conductive member 1134 are exemplarily set as pads.

[0054] It should also be noted that, taking the first conductive member 1111 as an example, the first conductive member 1111 is arranged on the first fine grid 111. When the internal current of the solar cell 10 is connected without a main grid back contact, a large number of carriers will move on the first fine grid 111. The closer the distance between the carriers and the first conductive member 1111 is, the easier it is for the first conductive member 1111 to collect active carriers. On the contrary, the farther the distance between the carriers and the first conductive member 1111 is, the worse the ability of the first conductive member 1111 to collect active carriers is.

[0055] It should be noted that the busbar-free back-contact solar cell 10 in the present application can be applied to solar cells. In the present application, solar cells are used as an example to refer to a cell structure that the busbar-free back-contact solar cell 10 can be applied to or formed by.

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

[0057] It is understandable that a plurality of first conductive members 1111 are spaced apart on the first fine gate 111 , that is, among any two first conductive members 1111 , the carrier farthest from one of the first conductive members 1111 is located at the midpoint of the connection line between the two first conductive members 1111 .

[0058] However, for the third conductive element 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 and alternately arranged along the second direction, the third conductive element 1133 is arranged on the first sub-fine grid 1131, and the fourth conductive element 1134 is arranged on the second sub-fine grid 1132, that is, there is a discontinuity between the third sub-fine grid and the fourth sub-fine grid, that is, the farthest distance between the third conductive element 1133 and the carrier is the distance between the third conductive element 1133 and the end of the first sub-fine grid 1131 far from the third conductive element 1133. For the convenience of description, the present application takes the example of the third conductive element 1133 being arranged at the midpoint of the first sub-fine grid 1131 for description, and at this time, the farthest distance between the third conductive element 1133 and the carrier is the distance between the third conductive element 1133 and any end of the first sub-fine grid 1131.

[0059] Since the arrangement of the second conductive member 1121 is similar to that of the first conductive member 1111 , and the arrangement of the fourth conductive member 1134 is similar to that of the third conductive member 1133 , this application will not further elaborate on the distance between the second conductive member 1121 and the carriers and the distance between the fourth conductive member 1134 and the carriers.

[0060] Further, it can be understood that, since a plurality of first conductive members 1111 are arranged at intervals on the first fine grid 111, the first sub-fine grid 1131 and the second sub-fine grid 1132 are arranged at intervals and alternately 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 from the second sub-fine grid 1132. At the same time, since the third conductive member 1133 is arranged on the first sub-fine grid 1131, the first conductive member 1111 and the second conductive member 1121 are arranged staggered along the first direction, and the first conductive member 1133 is arranged at intervals on the first fine grid 1131. 1111 and the third conductive element 1133 are arranged relatively along the first direction, that is, along the second direction, the length of the first sub-fine grid 1131 is smaller than the length of the first fine grid 111. At the same time, since two third conductive elements 1133 and two fourth conductive elements 1134 are correspondingly arranged in the area corresponding to any two first conductive elements 1111, if the first sub-fine grid 1131 and the second sub-fine grid 1132 corresponding to the third conductive element 1133 and the fourth conductive element 1134 are evenly divided, the length of the first sub-fine grid 1131 is one quarter of the length of the first fine grid 111.

[0061] Based on the distance between the first conductive member 1111 and the carriers in the first fine grid 111 and the distance between the third conductive member 1133 and the carriers in the first sub-fine grid 1131, it can be seen that the maximum distance between the third conductive member 1133 and the carriers is half of the maximum distance between the first conductive member 1111 and the carriers. Similarly, it can be seen that the maximum distance between the fourth conductive member 1134 and the carriers is half of the maximum distance between the second conductive member 1121 and the carriers.

[0062] Since the maximum distance between the third conductive member 1133 and the carriers is half of the maximum distance between the first conductive member 1111 and the carriers, and the maximum distance between the fourth conductive member 1134 and the carriers is half of the maximum distance between the second conductive member 1121 and the carriers, the ability to collect carriers can be improved by the third conductive member 1133 and the fourth conductive member 1134, thereby reducing the series resistance and further improving the photoelectric conversion efficiency of the solar cell.

[0063] It should be noted that in the related art, the main grid-free back contact solar cell eliminates the main grid, and an insulating glue is set at the position of the fine grid corresponding to the original heterosexual main grid, so the fine grid does not need to be disconnected at the heterosexual main grid. However, heterosexual pads need to be set on the heterosexual fine grid. In order to prevent the heterosexual pads from short-circuiting during the series connection, the heterosexual pads need to be set at intervals. That is, the fine grids in the main grid-free back contact solar cell in the related art are alternately set, that is, the fine grids are grouped in two groups of fine grids with different electrical properties, and the maximum distance between the pad and the carrier in any fine grid is the same. In the present application, three fine grids are grouped in one group, and the distance between the pad and the carrier in one of the fine grids is half the distance between the pad and the carrier in any of the other fine grids. Further, for ease of understanding, if multiples of 6 fine grids are set in the related art and in the present application, the maximum distance between the pad and the carrier in each of the related art is the same, while in the present application, the maximum distance between the pad and the carrier in multiples of 2 fine grids is half of the maximum distance between the pad and the carrier in the remaining fine grids, thereby further improving the ability of the pad to collect carriers, thereby further reducing the series resistance, and further improving the photoelectric conversion efficiency of the solar cell.

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

[0065] In this way, since there is a gap between the third conductive member 1133 and the second fine grid 112, and there is a gap between the fourth conductive member 1134 and the first fine grid 111, and since the electrical properties of the first fine grid 111 and the second fine grid 112 are opposite, the electrical properties of the first sub-fine grid 1131 and the first fine grid 111 are the same, and the electrical properties of the second sub-fine grid 1132 and the second fine grid 112 are the same, it is possible to avoid contact between the third conductive member 1133 and the second fine grid 112, and further avoid short circuit between the third conductive member 1133 and the second fine grid 112. Similarly, it is possible to avoid contact between the fourth conductive member 1134 and the first fine grid 111, and thus avoid short circuit between the fourth conductive member 1134 and the first fine grid 111, so that the normal operation of the busbar-free back contact solar cell 10 can be guaranteed, and the service life of the busbar-free back contact solar cell 10 can be improved.

[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 electrical properties of the first fine gate 111 and the second fine gate 112 are opposite, the electrical properties of the first sub-fine gate 1131 and the first fine gate 111 are the same, and the electrical properties of the second sub-fine gate 1132 and the second fine gate 112 are the same, 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 be short-circuited. 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 be short-circuited.

[0068] Since 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 along the first direction, no gap region may be provided between the third conductive member 1133 and the adjacent first conductive member 1111, which may increase the area of ​​the cell doping portion, improve the carrier concentration, and further improve the cell utilization rate and current density of the solar cell. Similarly, no gap region may be provided between the fourth conductive member 1134 and the adjacent second conductive member 1121, which may increase the area of ​​the cell doping portion, improve the carrier concentration, and further improve the cell utilization rate and current density of the solar cell.

[0069] Second, see Figure 3 As shown, an embodiment of the present application provides a back-contact solar cell string 20, comprising a plurality of interconnecting wires 21 and a plurality of busbar-free back-contact solar cells 10 in the first aspect, wherein each two adjacent busbar-free back-contact solar cells 10 are connected in series via the interconnecting wires 21.

[0070] In this way, multiple busbar-free back-contact solar cells 10 can be connected in series through multiple interconnection lines 21. On the one hand, the voltage of the back-contact solar cell string 20 can be increased. Under sunlight, each busbar-free back-contact solar cell 10 will generate a certain voltage and current. When multiple busbar-free back-contact solar cells 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 multiple busbar-free back-contact solar cells 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 the busbar-free back-contact solar cells 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 includes a plurality of first insulating members 22 and a plurality of second insulating members 23. The plurality of first insulating members 22 are arranged on the first fine grid 111 at intervals; along the first direction, the first insulating members 22 and the second conductive member 1121 are arranged opposite to each other; the plurality of second insulating members 23 are arranged on the second fine grid 112 at intervals; along the first direction, the second insulating members 23 and the first conductive member 1111 are arranged opposite to each other.

[0072] In this way, when multiple main grid-free back-contact solar cells 10 are connected in series, the first insulating member 22 can be used to prevent a short circuit between the first conductive member 1111 and the second conductive member 1121 or the fourth conductive member 1134, and the second insulating member 23 can be used to prevent a short circuit between the second conductive member 1121 and the first conductive member 1111 or the third conductive member 1133, 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 member 1121 is located within the orthographic projection of the adjacent first insulating member 22; the orthographic projection of the fourth conductive member 1134 is located within the orthographic projection of the adjacent first insulating member 22; 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; the orthographic projection of the third conductive member 1133 is located within the orthographic projection of the adjacent second insulating member 23.

[0074] In this way, on the one hand, if the back-contact solar cell string 20 is affected by external factors and 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, it is possible to further avoid the second conductive member 1121 or the fourth conductive member 1134 from contacting the adjacent first fine grid 111, thereby further avoiding the second conductive member 1121 or the fourth conductive member 1134 from short-circuiting the first fine grid 111, and similarly, it is possible to further avoid the first conductive member 1111 or the third conductive member 1133 from short-circuiting the second fine grid 112, thereby further improving the use 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; the orthographic projection of the fourth conductive member 1134 is located within the orthographic projection of the adjacent first insulating member 22, when each two adjacent solar cells 10 without main grid back contact are connected in series through the interconnection line 21, the first insulating member 22 can provide a sufficient contact area for the interconnection line 21, thereby avoiding the interconnection line 21 from being misaligned with the first insulating layer and connected to the opposite-sex fine grid, thereby further avoiding a short circuit during the series connection process. Similarly, 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; the orthographic projection of the third conductive member 1133 is located within the orthographic projection of the adjacent second insulating member 23, when each adjacent two solar cells 10 without main grid back contact are connected in series through the interconnection line 21, the second insulating member 23 can provide a sufficient contact area for the interconnection line 21, thereby avoiding the interconnection line 21 from being misaligned with the second insulating layer and connected to the opposite-sex fine grid, thereby further avoiding a short circuit during the series connection process.

[0076] In some embodiments, the interconnection lines 21 include 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 all extend along the first direction; in any busbar-free back-contact solar cell 10: the first interconnection lines 211 connect all first conductive elements 1111 and all third conductive elements 1133 in the first direction, and the first interconnection lines 211 are located on a side of all second insulating elements 23 arranged opposite to the first conductive element 1111, away from the second fine grid 112; the second interconnection lines 212 connect all second conductive elements 1121 and all fourth conductive elements 1134 in the first direction, and the second interconnection lines 212 are located on a side of all first insulating elements 22 arranged opposite to the second conductive element 1121, away from the first fine grid 111.

[0077] In this way, all the first conductive elements 1111 and all the third conductive elements 1133 in the first direction can be connected through the first interconnection line 211, and all the second conductive elements 1121 and all the fourth conductive elements 1134 in the first direction can be connected through the second interconnection line 212, so that two adjacent main grid-free back-contact solar cells 10 can be connected in series, which can improve the voltage and output power of the back-contact solar cell string 20.

[0078] In addition, since the first interconnection line 211 is located on the side of all the second insulating members 23 arranged opposite to the first conductive member 1111 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 arranged opposite to the second conductive member 1121 away from the first fine grid 111, the first interconnection line 211 and the second interconnection line 212 can be prevented from contacting with the fine grids of opposite sex respectively, thereby preventing a short circuit from occurring during the series connection process, and further improving the use stability and safety of the back-contact solar cell string 20.

[0079] In some embodiments, the first interconnection line 211 in any busbar-free back-contact solar cell 10 is collinear with the first interconnection line 211 in an adjacent busbar-free back-contact solar cell 10; the second interconnection line 212 in any busbar-free back-contact solar cell 10 is collinear with the second interconnection line 212 in an adjacent busbar-free back-contact solar cell 10.

[0080] In this way, it can be ensured that the first interconnection line 211 and the second interconnection line 212 are not bent. On the one hand, it can facilitate the operation of connecting the first interconnection line 211 and the second interconnection line 212 in series with the main grid-free back-contact solar cell 10; on the other hand, the line arrangement of the back-contact solar cell string 20 after series connection can be regular, thereby avoiding the occurrence of wiring errors during the series connection process, thereby improving the safety of the back-contact solar cell string 20.

[0081] Optionally, the first interconnection line 211 connects all the first conductive elements 1111 and all the third conductive elements 1133 of the first busbar-free back-contact solar cell 10 along the first direction, and the first interconnection line 211 extends to connect all the first conductive elements 1111 and all the third conductive elements 1133 of the adjacent second busbar-free back-contact solar cell 10 along the first direction, the second interconnection line 212 connects all the second conductive elements 1121 and all the fourth conductive elements 1134 of the second busbar-free back-contact solar cell 10 along the first direction, and the second interconnection line 212 extends to connect all the second conductive elements 1121 and all the fourth conductive elements 1134 of the adjacent third busbar-free back-contact solar cell 10 along the first direction, and then all the first conductive elements 1111 and all the third conductive elements 1133 of the third busbar-free back-contact solar cell 10 along the first direction are connected to all the first conductive elements 1111 and all the third conductive elements 1133 of the adjacent fourth busbar-free back-contact solar cell 10 along the first direction through another first interconnection line 211. In this way, taking three adjacent busbar-free back-contact solar cells 10 as one cycle, it is possible to realize that the first interconnection line 211 in any busbar-free back-contact solar cell 10 is collinear with the first interconnection line 211 in the adjacent busbar-free back-contact solar cell 10; and the second interconnection line 212 in any busbar-free back-contact solar cell 10 is collinear with the second interconnection line 212 in the adjacent busbar-free back-contact solar cell 10.

[0082] Thirdly, see Figure 4 As shown, an embodiment of the present application provides a photovoltaic assembly 30, comprising a base plate 31, a cover plate 32 and the back-contact solar cell string 20 in the second aspect, wherein the back-contact solar cell string 20 and the cover plate 32 are stacked in sequence on one side of the base plate 31 along a third direction; the third direction intersects with both the second direction and the first direction.

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

[0084] Specifically, a number of the above-mentioned back-contact solar cell strings 20 with the same number of interconnection cycles are selected for horizontal arrangement, and the adjacent back-contact solar cell strings 20 are connected first to form an array of back-contact solar cell strings 20. Along the third direction, the back-contact solar cell strings 20 and the cover plate 32 are stacked in sequence on one side of the base plate 31, so as to form a photovoltaic module 30.

[0085] Thus, on the one hand, a plurality of back-contact solar cell strings 20 are connected in series to form a photovoltaic module 30, which can reduce the resistance loss inside 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, a plurality of back-contact solar cell strings 20 make it easier to absorb light, especially in weak light conditions, and its power generation stability is better, which can improve the light absorption capacity of the photovoltaic module 30.

[0086] In addition, in a single busbar-free back-contact solar cell 10, since the maximum distance between the third conductive member 1133 and the carriers is half of the maximum distance between the first conductive member 1111 and the carriers, and the maximum distance between the fourth conductive member 1134 and the carriers is half of the maximum distance between the second conductive member 1121 and the carriers, the ability to collect carriers can be improved by the third conductive member 1133 and the fourth conductive member 1134, thereby reducing the series resistance. After multiple busbar-free back-contact solar cells 10 are connected in series to form a back-contact solar cell string 20, they are further connected in series to form a photovoltaic module 30, thereby further improving the photoelectric conversion efficiency of the photovoltaic module 30.

[0087] In some embodiments, see Figure 5 As shown, the photovoltaic module 30 also 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 side of the base plate 31 and the back contact solar cell string 20 away from the cover plate 32; the second adhesive layer 34 is connected to the side of the cover plate 32 and the back contact solar cell string 20 away from the base plate 31.

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

[0089] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A busbar-free back contact solar cell, characterized in that: include: A plurality of fine grid groups are arranged at intervals along a first direction; The fine gate group includes a first fine gate, a second fine gate and a third fine gate, wherein the first fine gate, the second fine gate and the third fine gate 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 members are arranged at intervals on the first fine grid, a plurality of second conductive members are arranged at intervals on the second fine grid, a third conductive member is arranged on the first sub-fine grid, and a fourth conductive member is arranged 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 opposite to each other along the first direction; the second conductive member and the fourth conductive member 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-free back contact solar cell according to claim 1, characterized in that: Along the first direction, the third conductive element contacts the adjacent first conductive element, and the fourth conductive element contacts the adjacent second conductive element.

4. A back contact solar cell string, characterized in that: The invention comprises a plurality of interconnecting wires 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 through the interconnecting wires.

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 arranged at intervals 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 arranged on the second fine grid at intervals; 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 both extend along the first direction; in any of the busbar-free back contact solar cells: The first interconnection line connects all the first conductive members and all the third conductive members in the first direction, and the first interconnection line is located on a side of all the second insulating members arranged opposite to the first conductive members 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 the second interconnection line is located on a side of all the first insulating elements arranged 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 of the solar cells without busbar back contact is collinear with the first interconnection line in an adjacent solar cell without busbar back contact; The second interconnection line in any one of the busbar-free back-contact solar cells is collinear with the second interconnection line in an adjacent one of the busbar-free 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 also includes a first adhesive layer and a second adhesive layer; Along the third direction, the first adhesive layer is connected to the bottom plate and the side of the back-contact solar cell string 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 away from the bottom plate.

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