Back contact cell, cell assembly and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system. The back contact battery comprises a silicon substrate and a plurality of fine grids arranged on the silicon substrate, the plurality of fine grids extend along a first direction and are arranged at intervals along a second direction, and the silicon substrate is provided with a first edge in the second direction; the silicon substrate comprises a first edge region, and the first edge region is an edge region close to the first edge; at least one fine grid located in the first edge area comprises a bent part, the maximum distance between the bent part and the first edge is larger than the distance between the fine grid and the first edge, and the bent part is located in the area, electrically connected with the welding strip, of the fine grid. According to the back contact battery, the battery assembly and the photovoltaic system provided by the invention, the welding tension of the fine grids in the first edge region can be improved, the current collection effect can also be improved, and the power generation efficiency of the battery is further improved.

Description

[0001] This application claims priority to patent application number 2024118350446 (the filing date of the prior application is December 12, 2024, and the name of the invention is back contact battery, battery module and photovoltaic system. Technical Field

[0002] The present application relates to the technical field of solar cells, and in particular to a back-contact cell, a cell assembly and a photovoltaic system. Background Art

[0003] At present, during the manufacturing process of battery modules, when placing the solder ribbon on the back contact battery, the position of the solder ribbon may be offset. The end of the solder ribbon may not be able to form an effective electrical connection with the fine grid at the edge of the silicon substrate, resulting in the current of this part of the fine grid being unable to be collected, which reduces the power generation efficiency of the back contact battery. Summary of the invention

[0004] The present application provides a back-contact cell, a cell assembly and a photovoltaic system, aiming to solve the technical problem in the prior art that the end of the welding strip may not be able to form an effective electrical connection with the fine grid in the edge area of ​​the silicon substrate.

[0005] The present application provides a back contact battery, comprising: a silicon substrate and a plurality of fine grids arranged on the silicon substrate; the plurality of fine grids extend along a first direction and are arranged at intervals in a second direction, the silicon substrate has a first edge in the second direction, and the first direction and the second direction intersect; the silicon substrate comprises a first edge region, and the first edge region is an edge region on the silicon substrate close to the first edge;

[0006] At least one fine grid located in the first edge area includes a bending portion, the maximum distance between the bending portion and the first edge is greater than the distance between the non-bending portion on the fine grid and the first edge, and the bending portion is located in the area on the fine grid electrically connected to the welding strip.

[0007] In some embodiments, the line width of the bending portion is greater than the line width of the gate line segments on the fine gate except the bending portion.

[0008] In some embodiments, the fine grid closest to the first edge among the plurality of fine grids is a first edge fine grid, the bending portion includes a first bending portion located at the first edge fine grid, and a first pad is disposed on the first bending portion.

[0009] In some embodiments, the back contact battery is provided with a second pad, the second pad is located above the first pad, and the second pad is integrally connected to the first pad.

[0010] In some embodiments, the fine grid adjacent to the first bending portion is a second edge fine grid, a second bending portion is provided on the second edge fine grid, and the midpoint of the second bending portion is on the same straight line as the midpoint of the first bending portion.

[0011] In some embodiments, the length of the second bending portion in the first direction is greater than the length of the first bending portion in the first direction.

[0012] In some embodiments, the distance between the first bending portion and the second bending portion is smaller than the distance between two adjacent fine grids.

[0013] In some embodiments, the first edge fine gate and the second edge fine gate have different polarities;

[0014] A third pad is provided on the second edge fine grid in an area electrically connected to the welding strip;

[0015] The third pad extends toward the first edge, and a disconnection portion is provided on the first edge gate line;

[0016] A length of the disconnected portion in the first direction is greater than a length of the third pad in the first direction.

[0017] In some embodiments, the fine gate closest to the first edge among the plurality of fine gates is a first edge fine gate, and the fine gate adjacent to the first edge fine gate is a second edge fine gate;

[0018] A fourth pad is disposed on the first edge fine grid, and the bending portion includes a fourth bending portion located on the second edge fine grid; the fourth pad is disposed opposite to the fourth bending portion and extends toward the fourth bending portion.

[0019] In some embodiments, a width of the fourth pad in the second direction is greater than a distance between two adjacent fine gates in an area of ​​the silicon substrate except the first edge area.

[0020] The present application also provides a battery assembly, which includes the back-contact battery described in any one of the above items.

[0021] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0022] The back-contact cell, cell assembly and photovoltaic system provided by the present application provide a bending portion on at least one fine grid in the first edge region so that the area on the fine grid electrically connected to the welding strip is closer to the middle region of the silicon substrate, thereby reducing the distance between the fine grid in the first edge region and the end of the welding strip, and can reduce the accuracy requirements for the placement of the welding strip, ensuring that this part of the welding strip and the fine grid in the first edge region can be effectively electrically connected, thereby improving the current collection effect, and further improving the battery power generation efficiency and battery reliability; at the same time, the grid line segment corresponding to the bending portion can form a larger space to increase the printing area, thereby increasing the welding area, and then increasing the welding tension between the fine grid and the end of the welding strip.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is one of the structural schematic diagrams of the back contact battery provided in the embodiment of the present application;

[0025] Figure 2 This is the second structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0026] Figure 3 This is the third structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0027] Figure 4 This is the fourth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0028] Figure 5 This is the fifth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0029] Figure 6 This is the sixth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0030] Figure 7 This is the seventh structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0031] Figure 8 This is the eighth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0032] Fig. 9 This is the ninth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0033] Fig.10 This is the tenth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0034] Fig.11This is the eleventh structural diagram of the back contact battery provided in the embodiment of the present application;

[0035] Fig.12 This is the twelfth structural diagram of the back contact battery provided in the embodiment of the present application;

[0036] Fig.13 This is the thirteenth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0037] Fig.14 This is the fourteenth structural diagram of the back contact battery provided in the embodiment of the present application;

[0038] Fig.15 This is the fifteenth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0039] Fig.16 This is the sixteenth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0040] Fig.17 This is the seventeenth structural diagram of the back contact battery provided in the embodiment of the present application;

[0041] Fig.18 This is the eighteenth structural schematic diagram of the back contact battery provided in the embodiment of the present application;

[0042] Fig.19 This is the nineteenth structural schematic diagram of a back contact battery provided in an embodiment of the present application;

[0043] Fig. 20 is a schematic diagram of the structure of a battery assembly provided in an embodiment of the present application;

[0044] Fig.21 It is a schematic diagram of the structure of the photovoltaic system provided in the embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0046] In the description of the present application, it should be understood that the terms "upper", "lower", "back", "front", etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0047] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0048] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0049] Combine the following Figures 1 to 21 , the back-contact battery, battery assembly and photovoltaic system provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0050] Figure 1 This is one of the schematic diagrams of the structure of the back contact battery provided in the embodiment of the present application. Figure 1 As shown, the present application provides a back contact battery, comprising: a silicon substrate 10 and a plurality of fine grids 20 arranged on the silicon substrate 10; the plurality of fine grids 20 extend along a first direction and are arranged at intervals in a second direction, the silicon substrate 10 has a first edge 101 in the second direction, and the first direction and the second direction intersect; the silicon substrate 10 comprises a first edge region 102, and the first edge region 102 is an edge region on the silicon substrate 10 close to the first edge 101;

[0051] At least one fine grid 20 located in the first edge area 102 includes a bending portion 30, the maximum distance between the bending portion 30 and the first edge 101 is greater than the distance between the non-bending portion on the fine grid 20 and the first edge 101, and the bending portion 30 is located in the area on the fine grid 20 that is electrically connected to the welding strip.

[0052] In the embodiment of the present application, the back contact cell is a main grid-free back contact cell. The silicon substrate 10 included in the back contact cell can be a whole cell, or a half cell, a third cell, or a cell of other proportions divided from a whole cell. It should be noted that the drawings provided in the present application are schematic diagrams and do not limit the specific form of the back contact cell.

[0053] Furthermore, the silicon substrate 10 may include a front side and a back side opposite to each other, the front side faces the sun and mainly receives direct sunlight, and the back side faces the mounting surface of the battery assembly and mainly receives sunlight reflected by the mounting surface, and the mounting surface is, for example, the ground or a roof. A plurality of fine gates 20 are arranged on the back side of the silicon substrate 10, and a stacked doping layer and a passivation layer are also arranged on the back side of the silicon substrate 10, and the doping layer can be connected to the plurality of fine gates 20 to establish ohmic contact.

[0054] A plurality of fine gates 20 are disposed on the back of the silicon substrate 10. The fine gates 20 with opposite polarities extend along a first direction and are alternately arranged along a second direction, and the second direction intersects the first direction. The spacing between two adjacent fine gates 20 may be equal or unequal, which is not specifically limited here.

[0055] It should be noted that the first direction may be the length direction of the fine grid 20, that is, Figure 1 The second direction may be the width direction of the fine grid 20, that is, Figure 1 Of course, in other embodiments, the first direction and the second direction may also be other directions, such as diagonal directions, etc., which are not specifically limited here.

[0056] The silicon substrate 10 has two opposite edges in the second direction, any one of which is a first edge 101. On the back side of the silicon substrate 10, near the first edge 101 is a first edge region 102. The length of the first edge region 102 in the first direction may include the length of the silicon substrate in the first direction, and the size of the first edge region 102 in the second direction may be determined based on the number of gate lines near the first edge 101 or the size of the middle region of the silicon substrate, which is not specifically limited herein.

[0057] There are also a number of regions on at least one fine grid 20 located in the first edge region 102 that are electrically connected to the welding strips for conducting current and transmitting current.

[0058] In actual implementation, a plurality of welding strips are provided on the back of the silicon substrate 10. The plurality of welding strips extend along the second direction and are alternately arranged along the first direction, and two adjacent welding strips collect the current of the fine grids 20 of opposite polarities. For example, the welding strip that collects the current of the positive fine grid can be a positive electrode welding strip, and the welding strip that collects the current of the negative fine grid can be a negative electrode welding strip, then the positive fine grid is electrically connected to the positive electrode welding strip, and the positive electrode welding strip is insulated from the negative fine grid, and the negative fine grid is electrically connected to the negative electrode welding strip, and the negative electrode welding strip is insulated from the positive fine grid.

[0059] In the embodiment of the present application, the area on the fine grid 20 within the first edge area 102 that is electrically connected to the welding strip is the position where the fine grid 20 is electrically connected to the end of the welding strip, and a bending portion 30 is provided at this position. The extension direction of the bending portion 30 is different from the extension direction of the fine grid 20, and the fine grid 20 adjacent to the bending portion 30 and the fine grid 20 corresponding to the bending portion 30 are kept apart to avoid a short circuit.

[0060] Among them, Figure 2 As shown, the bending portion 30 may be a sawtooth grid line segment, such as Figure 3 As shown, the bending portion 30 may be a wavy grid line segment, such as Figure 4 , Figure 5 and Figure 6 As shown, the bent portion 30 may also be a gate line segment that is recessed toward a side away from the first edge.

[0061] Depend on Figures 2 to 6 It can be seen that the maximum distance between the bending portion 30 and the first edge 101 in the second direction is greater than the distance between the fine grid 20 and the first edge 101. The maximum distance between the bending portion 30 and the first edge 101 is the distance between a point on the grid line segment corresponding to the bending portion 30 and the first edge 101, and the distance between the fine grid 20 and the first edge 101 is the distance between a point on the grid line segment corresponding to the non-bending portion of the fine grid 20 and the first edge 101.

[0062] It can be understood that, for the same fine gate 20, the gate line segment corresponding to the bend 30 is closer to the middle area of ​​the silicon substrate 10 than the gate line segment corresponding to the non-bend portion, so that the end of the solder strip is easier to contact the bend 30, and the bend 30 can form a larger space, thereby increasing the printing area. The printing area can directly print solder paste, or print the solder pad first and then print the solder paste. The gate line segment corresponding to the bend 30 has a larger printing area than the gate line segment without the bend 30, the solder pad or the solder paste.

[0063] The back-contact battery provided in the embodiment of the present application is provided with a bending portion on at least one fine grid in the first edge area, so that the area on the fine grid electrically connected to the welding strip is closer to the middle area of ​​the silicon substrate, and the distance between the grid line segment corresponding to the bending portion and the end of the welding strip is reduced, which can reduce the accuracy requirement for the placement of the welding strip, ensure that this part of the welding strip and the fine grid in the first edge area can be effectively electrically connected, improve the current collection effect, and further improve the battery power generation efficiency and battery reliability; at the same time, the grid line segment corresponding to the bending portion can form a larger space to increase the printing area, thereby increasing the welding area, and then increasing the welding tension between the fine grid and the end of the welding strip.

[0064] In some embodiments, the line width of the bending portion 30 is greater than the line width of the gate line segments on the fine gate 20 except the bending portion 30 .

[0065] In actual implementation, Figures 1 to 6 As shown, the line width of the bending portion 30 is greater than the line width of the gate line segments on the fine gate 20 except the bending portion 30. The line width of the bending portion 30 may be the line width of the gate line segment corresponding to the bending portion 30.

[0066] If the fine grid 20 is a positive fine grid, the line width of the grid line segment except the bending portion 30 is generally about 38μm, and the line width of the bending portion 30 on the positive fine grid can be 38μm to 50μm, or can be 39μm, 40μm, 42μm, 44μm, 46μm, 48μm, 50μm or a range value greater than 38μm, etc.

[0067] If the fine grid 20 is a negative electrode fine grid, the line width of the grid line segment except the bending portion 30 is generally about 35μm, and the line width of the first bending portion 301 on the negative electrode fine grid can be 35μm to 50μm, or can be 36μm, 38μm, 40μm, 42μm, 44μm, 46μm, 48μm, 50μm or a range value greater than 35μm, etc.

[0068] Of course, in other embodiments, the line width of the fine grid 20 can be adjusted according to actual conditions, and the line width of the bending portion 30 can also be adjusted to a larger line width accordingly, which is not limited here.

[0069] It can be understood that the larger the line width of the bending portion 30, the closer the lower edge of the fine grid corresponding to the bending portion 30 in the second direction is to the middle area of ​​the silicon substrate, making it easier for the end of the welding strip to connect with the grid line segment corresponding to the bending portion 30, thereby increasing the chance of the end of the welding strip contacting the grid line segment corresponding to the bending portion 30.

[0070] The back-contact battery provided in the embodiment of the present application further reduces the distance between the grid line segment corresponding to the bending portion and the end of the welding strip by increasing the line width of the bending portion, thereby reducing the accuracy requirements for the placement of the welding strip and ensuring that this part of the welding strip and the fine grid in the first edge area can achieve effective electrical connection.

[0071] In some embodiments, the fine grid 20 closest to the first edge 101 among the plurality of fine grids is a first edge fine grid 201 , the bending portion 30 includes a first bending portion 301 located at the first edge fine grid 201 , and a first pad 40 is disposed on the first bending portion 301 .

[0072] like Figure 7 As shown, the first edge fine gate 201 is the fine gate 20 closest to the first edge 101 in the first edge region 102 , that is, compared with other fine gates in the first edge region 102 , the point on the first edge fine gate 201 is the shortest distance from the first edge 101 in the second direction.

[0073] A first bending portion 301 may be provided in an area of ​​the first edge fine grid 201 that is electrically connected to the welding strip.

[0074] A first pad 40 is disposed on the first bending portion 301 and connected to the first bending portion 301. The length of the first pad 40 in the first direction is less than or equal to the length of the first bending portion 301 in the first direction.

[0075] It is understandable that the solder paste can be printed on the first solder pad 40, and the solder strip is placed on the solder pad 50 coated with the solder paste. After the solder paste is melted, a solder joint is formed between the solder strip and the first solder pad 40, so that the first bent portion 301 and the first solder pad 40 can form a good solder connection. Alternatively, the solder paste can be directly printed on the first bent portion 301. Since the first bent portion 301 can form a larger printing area, the first solder pad 40 or the solder paste can cover more areas. The size of the area can be selected according to the required welding tension, and is not specifically limited here.

[0076] The back-contact battery provided in the embodiment of the present application can increase the welding area by setting a first welding pad on the first bending portion. When the welding strip is connected to the fine grid, the welding tension between the grid line segment corresponding to the first bending portion and the welding strip can be increased, and the first welding pad on the first bending portion is closer to the middle area of ​​the silicon substrate, which increases the probability of forming an effective electrical connection between the end of the welding strip and the fine grid in the first edge area, making it easier for the end of the welding strip to be connected to the first bending portion, thereby improving the current collection effect, and then the battery power generation efficiency and battery reliability can also be improved.

[0077] In some embodiments, the back-contact battery is provided with a second pad 50, which is located above the first pad 40 and integrally connected to the first pad 40. The length of the first pad 40 in the first direction is greater than or equal to the length of the second pad 50 in the first direction, and the length of the second pad 50 in the first direction does not exceed the length of the first bending portion 301 in the first direction.

[0078] As Figure 8 shown, a second pad 50 integrally connected to the first pad 40 is provided above the first pad 40, and the second pad 50 extends toward the first edge 101 or extends in the second direction.

[0079] Among them, the second pad 50 may be composed of one or more pads.

[0080] The integrally connected second pad 50 and first pad 40 may be in a "mountain" shape, as Figure 8 shown; or may also be in an "inverted π" shape, as Fig.10 shown; may also be in an "inverted T" shape, as Fig. 9 shown; or may also be in a comb shape or a zigzag shape, etc., which is not specifically limited herein.

[0081] It can be understood that the second pad 50 can further expand the welding area of the first pad 301 in the second direction, thereby increasing the solder joint area. The distribution of the second pad 50 in the first direction may be multiple dispersed pads or one pad, which is not specifically limited herein. Among them, multiple dispersed pads can also increase the probability of the solder tape being connected to the pad.

[0082] The back-contact battery provided by the embodiments of the present application can increase the welding area by providing an integrally connected second pad above the first pad, further improving the probability of effectively electrically connecting the end of the solder tape to the fine grid in the first edge area, thereby increasing the welding tension between the grid line segment corresponding to the first bending portion and the solder tape.

[0083] In some embodiments, the fine grid adjacent to the first bending portion 301 is the second edge fine grid 202, and a second bending portion 60 is provided on the second edge fine grid 202. The midpoint of the second bending portion 60 and the first bending portion 301 is on the same straight line.

[0084] It can be understood that the second edge fine grid 202 and the first edge fine grid 201 are fine grids with opposite polarities. If the second bending portion 60 is not provided on the fine grid 202 adjacent to the first bending portion 301, the distance between the fine grid 202 adjacent to the first bending portion 301 and the first edge fine grid 201 is relatively close, increasing the risk of short circuit.

[0085] As Fig.11 and Fig.12As shown, a second bending portion 60 is provided on the fine grid 202, and the second bending portion 60 is insulated from the welding strip connected to the first bending portion 30. Specifically, insulating glue or other insulating materials can be printed on the second bending portion 60, which is not specifically limited here. The length of the insulating material printed on the second bending portion 60 in the first direction is greater than the width of the welding strip in the first direction.

[0086] Optionally, the welding strip electrically connected to the first bending portion 30 needs to be insulated from the second bending portion 60, and the line width of the second bending portion 60 can be the same as the line width of the non-bending portion on the fine grid 20 where the second bending portion 60 is located, that is, the second bending portion 60 does not need to be widened.

[0087] The second bending portion 60 and the first bending portion 301 may have the same or different shapes, and there is a gap between the second bending portion 60 and the first bending portion 301. Preferably, the second bending portion 60 and the first bending portion 301 are set to have the same shape, which is more conducive to keeping the second bending portion 60 and the first bending portion 301 spaced apart.

[0088] The midpoints of the second bending portion 60 and the first bending portion 301 in the first direction may be arranged on the same straight line. Of course, in other embodiments, the midpoints of the second bending portion 60 and the first bending portion 301 in the first direction may not be on the same straight line. In this case, the length of the second bending portion 60 in the first direction needs to be greater than the length of the first bending portion 301 in the first direction to prevent the second bending portion 60 and the first bending portion 301 from being too close in the second direction.

[0089] The back-contact battery provided in the embodiment of the present application increases the distance between two adjacent fine grids by providing a second bent portion on the fine grid adjacent to the first bent portion, thereby preventing the two adjacent fine grids from contacting each other and thus avoiding a short circuit.

[0090] In some embodiments, the length of the second bending portion 60 in the first direction is greater than the length of the first bending portion 301 in the first direction.

[0091] like Fig.11 and Fig.12 As shown, the length of the second bending portion 60 in the first direction is greater than the length of the first bending portion 301 in the first direction, and the midpoint of the second bending portion 60 in the first direction is on the same straight line as the midpoint of the first bending portion 301 in the first direction.

[0092] like Fig.13 As shown, among the two fine grids 20 adjacent to the fine grid 202, the fine grid 203 except the first edge fine grid 201 can also be provided with a third bending portion 70, and the length of the third bending portion 70 in the first direction is greater than the length of the second bending portion 60 in the first direction.

[0093] It can be understood that the line width of the third bending portion 70 is greater than the line width of the gate line segment on the fine gate where the third bending portion 70 is located except the third bending portion 70. Fig.15 As shown, the fine grid where the third bending portion 70 is located has the same polarity as the fine grid where the first bending portion 301 is located. The third bending portion 70 can also be provided with solder paste or a pad to increase the welding area, which is not specifically limited here.

[0094] It is understandable that, starting from the first bending portion 301 of the first edge fine grid 201 , the lengths of the bending portions arranged sequentially along the second direction may gradually increase in the first direction, which is more conducive to maintaining the spacing between the bending portions on adjacent fine grids 20 .

[0095] The back contact battery provided in the embodiment of the present application can further reduce the risk of short circuit by providing a second bent portion, and the length of the second bent portion in the first direction is greater than the length of the first bent portion in the first direction.

[0096] In some embodiments, the distance between the first bending portion 301 and the second bending portion 60 is smaller than the distance between two adjacent fine grids 20 .

[0097] like Fig.13 As shown, the maximum bending distance of the first bending portion 301 in the second direction relative to the first edge fine grid 201 is greater than the maximum bending distance of the second bending portion 60 in the second direction relative to the fine grid 202. Therefore, in the second direction, the distance d between the first bending portion 301 and the second bending portion 60 is less than the distance D between two adjacent fine grids 20.

[0098] It should be noted that if Figures 2 to 6 As shown, the maximum bending distance a refers to the distance between the lower edge of the bending portion 30 in the second direction and the non-bending portion of the first edge fine grid 201 .

[0099] It can be understood that, starting from the first bending portion 30 of the first edge fine grid 201, along the second direction, the maximum bending distance of the bending portions arranged sequentially can be gradually reduced until the maximum bending distance is reduced to 0, at which time there will be no bending area on the fine grid 20.

[0100] The back-contact battery provided in the embodiment of the present application can gradually reduce the bending distance of the bending portion by setting the distance between the first bending portion and the second bending portion to be smaller than the distance between two adjacent fine grids. Therefore, in the two fine grids adjacent to the fine grid corresponding to the bending portion, the distance between the fine grid closer to the bending portion and the fine grid where the bending portion is located can be increased, thereby reducing the risk of adjacent fine grids contacting each other, thereby avoiding short circuit.

[0101] In some embodiments, the first edge fine gate 201 and the second edge fine gate 202 have different polarities;

[0102] A third pad 80 is provided in the area of ​​the second edge fine grid 202 where current is derived;

[0103] The third pad 70 extends toward the first edge 101 . A disconnection portion 90 is disposed on the first edge gate line 201 . The length of the disconnection portion 90 in the first direction is greater than the length of the third pad 80 in the first direction.

[0104] like Fig.14 As shown, the second edge fine grid 202 is a fine grid 20 with opposite polarity to the first edge fine grid 201. The area where the current is derived on the second edge fine grid 202 is the area where the solder strip is connected, and the third solder pad 80 can be arranged in this area, and the third solder pad 80 extends toward the first edge 101 and along the second direction.

[0105] The shape of the third solder pad 80 can be the same as or different from the shape of the second solder pad 50 and the first solder pad 40 connected as a whole. For example, the shape of the third solder pad 80 can be an "inverted T" shape, a "mountain" shape, an "inverted π" shape, or a comb shape, which is not specifically limited here.

[0106] The disconnected portion 90 disposed on the first edge gate line 201 is convenient for increasing the coverage area of ​​the third pad 80 , that is, it can increase the welding area and improve the welding tension.

[0107] It can be understood that the provision of the disconnection portion 90 increases the extension distance of the third pad 80 in the second direction, and thus the third pad 80 can further expand the welding area, and the distribution of the third pad 80 in the first direction can be a plurality of dispersed pads or a single pad, which is not specifically limited here. Among them, the dispersed plurality of pads can also increase the probability of the soldering ribbon being connected to the pad.

[0108] The back-contact battery provided in the embodiment of the present application has a disconnected portion set on the first edge grid line, and a third pad is set in the area where the current is extracted on the second edge fine grid, so that the coverage area of ​​the third pad can be increased, and then the welding area can be increased, thereby increasing the welding tension.

[0109] In some embodiments, Fig.16 As shown, the fine grid 20 closest to the first edge 101 among the plurality of fine grids is the first edge fine grid 201, the fine grid adjacent to the first edge fine grid 201 is the second edge fine grid 202, the first edge fine grid 201 is provided with a fourth pad 91, and the bending portion 30 includes a fourth bending portion 92 located at the second edge fine grid 202;

[0110] The fourth pad 91 is disposed opposite to the fourth bending portion 92 and extends toward the fourth bending portion 92 .

[0111] It can be understood that, unlike the above-mentioned embodiment, a fourth bending portion 92 is provided on the second edge fine grid 202, and the distance from the lower edge of the fourth bending portion 92 in the second direction to the first edge fine grid 201 is greater than the distance from the non-bending area of ​​the second edge fine grid 202 to the first edge fine grid 201, so that a larger space can be formed between the first edge fine grid 201 and the fourth bending portion 92, and more silver paste or solder paste can be arranged at the position of the first edge fine grid 201 opposite to the fourth bending portion 92. Therefore, in this embodiment, a fourth soldering pad 91 can be provided at a position of the first edge fine grid 201 opposite to the fourth bending portion 92, and the fourth soldering pad 91 extends toward the area where the fourth bending portion 92 is bent, and the fourth soldering pad 91 maintains a spacing toward the fourth bending portion 92. The width of the fourth soldering pad 91 in the second direction in this embodiment is greater than the line width of the first edge fine grid 201, which facilitates welding and enhances component reliability.

[0112] like Fig.16 As shown, the fourth solder pad 91 is rectangular, and the length of the fourth solder pad 91 in the first direction is smaller than the length of the fourth bending portion 92 in the first direction, so that when the fourth solder pad 91 extends toward the fourth bending portion 92, the extended portion of the solder pad can extend into the space formed by the fourth bending portion 92 and maintain a distance from the fourth bending portion 92.

[0113] like Fig.17 As shown, the length of the fourth solder pad 91 in the first direction can be greater than the length of the fourth bending portion 92 in the first direction. When the fourth solder pad 91 extends toward the fourth bending portion 92, the length of the extended portion of the fourth solder pad 91 in the first direction is less than the length of the fourth bending portion 92 in the first direction, so that the extended portion of the solder pad can extend into the space formed by the fourth bending portion 92 and maintain a distance from the fourth bending portion 92.

[0114] like Fig.18 As shown, the fourth pad 91 can extend toward the first edge 101 and the fourth bent portion 92 at the same time. The length of the portion of the pad extending toward the fourth bent portion 92 in the first direction is less than the length of the fourth bent portion 92 in the first direction; the length of the portion of the pad extending toward the first edge 101 in the first direction can be greater than or equal to the length of the fourth bent portion 92 in the first direction, or can be less than the length of the fourth bent portion 92 in the first direction.

[0115] It is understandable that if Figures 2 to 6As shown, the space formed by the fourth bend portion 92 can be determined based on the shape of the fourth bend portion 92. Among the part of the fourth pad 91 extending toward the fourth bend portion 92, the shape of the end portion close to the fourth bend portion 92 can also be adjusted according to the space formed by the fourth bend portion 92, which is not specifically limited here.

[0116] In some embodiments, the width of the fourth pad 91 in the second direction is greater than the distance between two adjacent fine gates 20 in the region of the silicon substrate 10 except the first edge region 102 .

[0117] It is understandable that if Fig.17 and Fig.18 As shown, the fourth pad 91 may extend toward the fourth bend 92, or may extend toward the first edge 101 and the fourth bend 92 at the same time, and may extend into the space formed by the fourth bend 92. Therefore, the width of the fourth pad 91 in the second direction may be greater than the spacing between two adjacent fine gates 20 in the region other than the first edge region 102 on the silicon substrate 10.

[0118] like Fig.19 As shown, the first edge fine grid 201 is provided with a fourth pad 91, the second edge fine grid 202 is provided with a third pad 80, and the first edge fine grid 201 and the second edge fine grid 202 are fine grids 20 with opposite polarities. Since the first edge fine grid 201 is provided with a disconnection portion 90 at a position opposite to the third pad 80, and the second edge fine grid 202 is provided with a fourth bending portion 91 at a position opposite to the fourth pad 91, a larger space can be formed to increase the printing area, so that pads with a larger width can be provided in the second direction on both the first edge fine grid 201 and the second edge fine grid 202, thereby providing a larger welding tension.

[0119] Fig. 20 Schematic diagram of the structure of the battery assembly provided in the embodiment of the present application. Fig. 20 As shown, the present application provides a battery assembly 2000, including: a back contact battery 1000 in any of the above embodiments.

[0120] It should be noted that the back contact cell 1000 has been described in detail in the above embodiments and is not specifically limited here.

[0121] In this embodiment, the back-contact cells 1000 in the battery assembly 2000 can be connected in series in sequence to form a battery string, thereby realizing the series bus output of the current. For example, the series connection of the battery cells can be realized by setting welding strips (bus bars, interconnecting strips), conductive back plates, etc.

[0122] It is understandable that in such an embodiment, the battery assembly may also include a metal frame, a back plate, photovoltaic glass and an adhesive film. The adhesive film may be filled between the front and back of the solar cell and the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0123] Photovoltaic glass can cover the adhesive film on the front of the solar cell. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the solar cell without affecting the efficiency of the solar cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the solar cell together. The presence of the adhesive film can seal and insulate the solar cell and make it waterproof and moisture-proof.

[0124] The backplane can be attached to the adhesive film on the back of the solar cell. The backplane can protect and support the solar cell and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to the specific situation and is not limited here. The whole composed of the backplane, solar cell, adhesive film and photovoltaic glass can be set on a metal frame. The metal frame serves as the main external support structure of the entire battery assembly and can stably support and install the battery assembly. For example, the battery assembly can be installed at the required location through the metal frame.

[0125] The embodiment of the present application provides a battery assembly, which provides a bending portion on at least one fine grid in the first edge area so that the area on the fine grid that is electrically connected to the welding strip is closer to the middle area of ​​the silicon substrate, thereby reducing the distance between the fine grid in the first edge area and the end of the welding strip, and can reduce the accuracy requirements for the placement of the welding strip, ensuring that this part of the welding strip and the fine grid in the first edge area can be effectively electrically connected, thereby improving the current collection effect, and further improving the battery power generation efficiency and battery reliability, thereby improving the photoelectric conversion efficiency of the assembly; at the same time, the grid line segment corresponding to the bending portion can form a larger space to increase the printing area, thereby increasing the welding area, and then increasing the welding tension between the fine grid and the end of the welding strip.

[0126] Fig.21 Schematic diagram of the structure of the photovoltaic system provided in the embodiment of the present application. Fig.21 As shown, the present application provides a photovoltaic system 3000, including: the battery assembly 2000 in the above embodiment.

[0127] It should be noted that the battery assembly 2000 has been described in the above embodiments and is not specifically limited here.

[0128] In this embodiment, the photovoltaic system 3000 can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system 3000 are not limited to this, that is, the photovoltaic system 3000 can be applied in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system 3000 may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple battery components. For example, multiple battery components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0129] The photovoltaic system provided in the embodiment of the present application, by setting a bending portion on at least one fine grid in the first edge area, makes the area on the fine grid electrically connected to the welding strip closer to the middle area of ​​the silicon substrate, thereby reducing the distance between the fine grid in the first edge area and the end of the welding strip, and can reduce the accuracy requirements for the placement of the welding strip, ensuring that this part of the welding strip and the fine grid in the first edge area can be effectively electrically connected, thereby improving the current collection effect, and further improving the battery power generation efficiency and battery reliability, thereby improving the photoelectric conversion efficiency of the component and the power generation efficiency of the system; at the same time, the grid line segment corresponding to the bending portion can form a larger space to increase the printing area, thereby increasing the welding area, and then increasing the welding tension between the fine grid and the end of the welding strip.

[0130] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0131] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: include: A silicon substrate and a plurality of fine gates arranged on the silicon substrate; the plurality of fine gates extend along a first direction and are arranged at intervals in a second direction, the silicon substrate has a first edge in the second direction, and the first direction and the second direction intersect; the silicon substrate includes a first edge region, and the first edge region is an edge region on the silicon substrate close to the first edge; At least one fine grid located in the first edge area includes a bending portion, the maximum distance between the bending portion and the first edge is greater than the distance between the non-bending portion on the fine grid and the first edge, and the bending portion is located in the area on the fine grid electrically connected to the welding strip.

2. The back contact cell according to claim 1, characterized in that: The bending portion is a concave bending portion, and the distance from the bottom edge of the concave bending portion to the first edge is greater than the distance between the non-bending portion on the fine grid and the first edge.

3. The back contact cell according to claim 1, characterized in that: The line width of the bending portion is greater than the line width of the gate line segment on the fine gate except the bending portion.

4. The back contact cell according to claim 1, characterized in that: The fine grid closest to the first edge among the plurality of fine grids is a first edge fine grid, the bending portion includes a first bending portion located at the first edge fine grid, and a first pad is disposed on the first bending portion.

5. The back contact cell according to claim 4, characterized in that: The back contact battery is provided with a second pad, the second pad is located above the first pad, and the second pad is integrally connected to the first pad.

6. The back contact cell according to claim 4, characterized in that: The fine grid adjacent to the first bending portion is a second edge fine grid, a second bending portion is provided on the second edge fine grid, and the midpoint of the second bending portion and the first bending portion are on the same straight line.

7. The back contact cell according to claim 6, characterized in that: The length of the second bending portion in the first direction is greater than the length of the first bending portion in the first direction.

8. The back contact cell according to claim 6, characterized in that: The distance between the first bending portion and the second bending portion is smaller than the distance between two adjacent fine grids.

9. The back contact cell according to claim 4, characterized in that: The first edge fine grid and the second edge fine grid have different polarities; A third pad is provided on the second edge fine grid in an area electrically connected to the welding strip; The third pad extends toward the first edge, and a disconnection portion is provided on the first edge gate line; A length of the disconnected portion in the first direction is greater than a length of the third pad in the first direction.

10. The back contact cell according to claim 1, characterized in that: The fine grid closest to the first edge among the plurality of fine grids is a first edge fine grid, and the fine grid adjacent to the first edge fine grid is a second edge fine grid; A fourth pad is disposed on the first edge fine grid, and the bending portion includes a fourth bending portion located on the second edge fine grid; the fourth pad is disposed opposite to the fourth bending portion and extends toward the fourth bending portion.

11. The back contact cell according to claim 10, characterized in that: The width of the fourth pad in the second direction is greater than a distance between two adjacent fine gates in an area on the silicon substrate except the first edge area.

12. A battery assembly, characterized in that: A back contact battery comprising any one of claims 1-11.

13. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 12.

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