Back-contact cell and photovoltaic module

Abstract

The present application relates to the technical field of photovoltaics, and provides a back-contact cell and a photovoltaic module. The back-contact cell provided in the present application comprises a cell body, and a plurality of first fingers and a plurality of second fingers extending in a first direction. The plurality of first fingers and the plurality of second fingers are sequentially and alternately arranged at intervals along a second direction on a first surface of the cell body. The first surface comprises a first region, and comprises a first edge and a second edge arranged opposite to each other in the second direction. Within the first region, a plurality of first pads and a plurality of second pads are arranged on both the first fingers and the second fingers, and the area of each first pad is smaller than the area of each second pad.

Description

Back contact batteries and photovoltaic modules

[0001] This application claims priority to two Chinese patent applications filed on January 23, 2025, entitled “Back Contact Battery and Photovoltaic Module”, and on March 25, 2025, entitled “Back Contact Solar Cell, Photovoltaic Module and Photovoltaic System”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photovoltaic technology, specifically to a back contact battery and a photovoltaic module. Background Technology

[0003] Back contact (BC) cells with a gridless design typically use solder strips for bonding on pads in a fine grid. Solder strip bonding is prone to incomplete soldering, resulting in poor welding stability and severely limiting the reliability of current collection.

[0004] Application content

[0005] This application provides a back-contact battery and a photovoltaic module, aiming to solve the problems of poor welding stability and severely limited reliability of current collection during the welding process of back-contact battery electrical connectors.

[0006] One aspect of this application provides a back-contact battery, including a battery body, a plurality of first fine grids and a plurality of second fine grids extending along a first direction; the plurality of first fine grids and the plurality of second fine grids are alternately and sequentially disposed on a first surface of the battery body along a second direction; the first surface includes a first region; in the first region, a plurality of first pads and a plurality of second pads are disposed on both the first fine grids and the second fine grids; the area of ​​the first pads is smaller than the area of ​​the second pads; wherein, in the first direction, the first fine grids and / or the second fine grids have a plurality of first repeating units; and / or, in the second direction, the plurality of first pads and the plurality of second pads on the plurality of first fine grids and the plurality of second fine grids are respectively arranged in columns, and each column has a plurality of second repeating units arranged along the second direction, wherein each of the first repeating unit and the second repeating unit includes at least one first pad and at least one second pad.

[0007] In some embodiments, the first repeating unit includes a first pad and a second pad; and / or, the second repeating unit includes a first pad and a second pad.

[0008] In some embodiments, the lengths of the first pad and the second pad are different in a first direction;

[0009] And / or, the widths of the first pad and the second pad are different in the second direction;

[0010] And / or, the first pad and the second pad have different shapes.

[0011] In some embodiments, the first pad and the second pad have the same length in the first direction and the same width in the second direction, but the first pad and the second pad have different shapes.

[0012] In some embodiments, the outer contour of the second pad is rectangular or racetrack-shaped; and / or,

[0013] The first pad includes a central portion and extensions on both sides of the central portion in a first direction. The outer contour of the central portion is rectangular or racetrack-shaped, and the outer contour of the extensions is trapezoidal, semi-elliptical, or triangular; and / or,

[0014] In the second direction, the width of the middle portion is greater than the width of the extension portion.

[0015] In some embodiments, the first surface further includes a first side and a second side disposed opposite to each other along the second direction, and a second region disposed between the first region and the first side and adjacent to the first region along the second direction; in the second region, a plurality of third pads are disposed on both the first fine gate and the second fine gate, which are spaced apart along the first direction, and the third pads on each first fine gate are staggered with the third pads on the adjacent second fine gate in the second direction, and the third pads on the adjacent first fine gate are arranged in a row in the second direction;

[0016] The area of ​​the second pad is smaller than the area of ​​the third pad.

[0017] In some embodiments, the lengths of the third pad and the second pad are different in the first direction;

[0018] And / or, the width of the third pad is different from that of the second pad in the second direction;

[0019] And / or, the third pad has a different shape than the second pad.

[0020] In some embodiments, the length of the third pad in the first direction is the same as that of the second pad, and the width of the third pad in the second direction is greater than that of the second pad.

[0021] In some embodiments, the first surface further includes a third region disposed between the second region and the first side and adjacent to the second region along a second direction; in the third region, a plurality of fourth pads are disposed on both the first fine gate and the second fine gate, which are spaced apart along the first direction, and the fourth pads on each of the first fine gates and the fourth pads on the adjacent second fine gates are staggered in the second direction, and are arranged in a row with the fourth pads on the adjacent first fine gates in the second direction; the area of ​​the third pad is smaller than the area of ​​the fourth pad.

[0022] In some embodiments, the fourth pad and the third pad have different lengths in the first direction;

[0023] And / or, the width of the fourth pad is different from that of the third pad in the second direction;

[0024] And / or, the fourth pad has a different shape than the third pad.

[0025] In some embodiments, the length of the fourth pad in the first direction is greater than that of the third pad, and the width of the fourth pad in the second direction is the same as that of the third pad.

[0026] In some embodiments, the first pad has a dimension of 0.9mm-1.1mm in the first direction and a dimension of 0.19mm-0.25mm in the second direction; and / or, the second pad has a dimension of 0.9mm-1.1mm in the first direction and a dimension of 0.19mm-0.3mm in the second direction; and / or, the third pad has a dimension of 0.9mm-1.3mm in the first direction and a dimension of 0.19mm-0.4mm in the second direction; and / or, the fourth pad has a dimension of 0.9mm-1.5mm in the first direction and a dimension of 0.19mm-0.5mm in the second direction.

[0027] In some embodiments, the back contact battery further includes a plurality of first doped layers and a plurality of second doped layers; the plurality of first doped layers and the plurality of second doped layers are arranged alternately and at intervals along a second direction, each first doped layer is disposed between a corresponding first grid and the battery body, and each second doped layer is disposed between a corresponding second grid and the battery body; wherein the doping types of the first doped layers and the second doped layers are different.

[0028] In some embodiments, within the second region and / or the third region, the first doped layer or the second doped layer protrudes at least partially along the second direction to form a receiving region to accommodate a corresponding third pad or fourth pad.

[0029] In some embodiments, the first surface further includes an edge region disposed between the third region and the first side, and the edge region is adjacent to the first side; within the edge region, a plurality of fifth pads are respectively spaced apart on the first fine grid and the second fine grid adjacent to the first side, and the area of ​​the fifth pad is larger than that of the fourth pad; an end line is also disposed between the fifth pad and the first side, and in the second direction, one end of the end line is connected to the corresponding fifth pad, and the other end is connected to the corresponding first fine grid or the second fine grid near the first side of the battery body edge.

[0030] In some embodiments, the fifth pad has the same length as the fourth pad in the first direction and a greater width in the second direction than the fourth pad; and / or the fifth pad has a dimension of 0.9mm-1.1mm in the first direction and a dimension of 1.1mm-1.8mm in the second direction.

[0031] In some embodiments, the first or second fine gate is a disconnected structure at the location where the first, second, third, fourth, or fifth pads are provided.

[0032] In some embodiments, one of the first fine grid and the second fine grid is an N-type fine grid and the other is a P-type fine grid, and the back contact battery further includes: an N-type pad array and a P-type pad array;

[0033] The N-type pad column and the P-type pad column are alternately distributed along the first direction; the N-type pad column includes a plurality of N-type pads arranged in a row along the second direction, and the N-type pads are electrically connected to the N-type fine gate; the P-type pad column includes a plurality of P-type pads arranged in a row along the second direction, and the P-type pads are electrically connected to the P-type fine gate.

[0034] Along the second direction, the first surface includes multiple regions, and the area of ​​the P-type pad in the same region is larger than the area of ​​the N-type pad.

[0035] In some embodiments, the total area of ​​the plurality of P-type pads in the P-type pad column is greater than the total area of ​​the plurality of N-type pads in the N-type pad column.

[0036] In some embodiments, in the second direction, the first surface includes: two edge regions that are distributed opposite to each other, and an intermediate region located between the two edge regions;

[0037] In the edge region, the total area of ​​the plurality of P-type pads in a P-type pad column is greater than the total area of ​​the plurality of N-type pads in an N-type pad column.

[0038] And / or, in the intermediate region, the total area of ​​the plurality of P-type pads in a P-type pad column is greater than the total area of ​​the plurality of N-type pads in an N-type pad column.

[0039] In some embodiments, the first surface further includes: a transition region located between the edge region and the intermediate region; the area of ​​the P-type pad in the transition region is smaller than the area of ​​the P-type pad in the edge region and larger than the area of ​​the P-type pad in the intermediate region; the area of ​​the N-type pad in the transition region is smaller than the area of ​​the N-type pad in the edge region and larger than the area of ​​the N-type pad in the intermediate region.

[0040] In the transition region: the total area of ​​a plurality of P-type pads in a P-type pad row is greater than the total area of ​​a plurality of N-type pads in an N-type pad row.

[0041] In some embodiments, in the same region of the first surface, along the first direction, the total area of ​​multiple pads in the first pad column and the total area of ​​multiple pads in the last pad column are both greater than the total area of ​​multiple pads in the middle pad column.

[0042] In some embodiments, an N-type gate has two N-type pads of the same material but different areas; and / or,

[0043] On a P-type fine gate, there are two P-type pads with the same material but different areas.

[0044] In some embodiments, the N-type pads are made of the same material as the P-type pads; and / or,

[0045] The N-type pad and the N-type fine gate overlap, and the width ratio of the two parts of an N-type pad on both sides of the N-type fine gate is M; the P-type pad and the P-type fine gate overlap, and the width ratio of the two parts of a P-type pad on both sides of the P-type fine gate is Q; M is not equal to Q.

[0046] In some embodiments, the aspect ratio of the P-type pad is E in the edge region and F in the middle region;

[0047] The number of P-type pads in the middle region is more than 9 times the number of P-type pads in the edge region, and F is greater than 3E.

[0048] In some embodiments, the battery body includes an N-type doped substrate, and / or the surfaces of the battery body covered by N-type pads and P-type pads are both polished surfaces;

[0049] And / or, the length-to-width ratio of an N-type pad and / or a P-type pad is between 3 and 8; the length of the pad is in the direction parallel to the first direction, and the width of the pad is in the direction parallel to the second direction.

[0050] In some embodiments, the overlap area between the P-type fine gate and the P-type pad is greater than the overlap area between the N-type fine gate and the N-type pad.

[0051] Another aspect of this application provides a photovoltaic module, including a back contact cell and an electrical connector as described above. The electrical connector is electrically connected to a first grid of the same polarity via a first pad, and the electrical connector is connected to a second grid of the same polarity via a second pad. An insulating block is provided between the electrical connector and the first or second grid of opposite polarity.

[0052] The back-contact solar cell and photovoltaic module provided in this application have at least the following advantages compared to the prior art:

[0053] By optimizing the pad layout on the back contact battery, multiple first pads and multiple second pads are provided on both the first and second grids in the first region. Since the first pads are smaller in area than the second pads, they help to reduce the area occupied on the battery body surface and reduce metal recombination loss. The second pads are larger in area than the first pads, and the probability of forming cold solder joints after welding is lower, which helps to improve the stability of electrical connector welding and improve the reliability of current collection.

[0054] In some embodiments, when multiple first pads and multiple second pads on the first and / or second fine gates have multiple first repeating units including at least one first pad and at least one second pad in the first direction, the amount of metal paste used can be minimized, reducing production costs. Furthermore, even if a smaller area of ​​the first pad experiences a cold solder joint, the larger area of ​​the second pad in the first direction can still ensure soldering reliability. Current at the cold solder joint location of the first pad is collected, thereby preventing current loss due to excessive current path transmission. In the second direction, when the first and second pads on the first and second fine gates are arranged in columns, and each column has multiple second repeating units including at least one first pad and at least one second pad, the amount of metal paste used can also be minimized, reducing production costs. Additionally, it helps to increase the end contact area of ​​the electrical connector in the first region along the second direction, thereby increasing the welding pull force, ensuring welding stability, and preventing electrical connector misalignment.

[0055] Therefore, through the above-mentioned back-contact battery design, the use of metal paste and the loss of metal composite on the surface of the battery body can be minimized, while the stability of electrical connector welding can be significantly improved, the occurrence of incomplete welding can be reduced, and the reliability of current collection can be ensured.

[0056] In some embodiments, on an electrical connector, the total area of ​​the N-type pads fixed thereto is smaller than the total area of ​​the P-type pads fixed thereto.

[0057] In some embodiments, the photovoltaic module includes multiple battery strings, each battery string including multiple back-contact batteries connected in series; the total area of ​​the P-type pads in the P-type pad column of the back-contact battery A1 in battery string 1 is greater than the total area of ​​the N-type pads in the N-type pad column of the back-contact battery B1 in battery string 2.

[0058] In some embodiments, the first pad includes a central portion and extensions located on both sides of the central portion in the first direction; the length of the central portion is 0.9 to 1.1 times the width of the electrical connector, and the length of the extensions is 0.4 to 0.6 times the width of the electrical connector; the directions in which the length of the central portion, the width of the electrical connector, and the length of the extensions lie are all parallel to the first direction; and / or,

[0059] The electrical connector includes: a first portion disposed on an N-type pad array and a second portion disposed on a P-type pad array; along the first direction, the width of the second portion is greater than the width of the first portion.

[0060] Other features and advantages of the back contact battery and photovoltaic module provided in this application will be further described in the following detailed embodiments. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 is a schematic diagram of the structure of a back contact battery according to one embodiment of this application;

[0063] Figure 2 is a partial structural diagram of a back contact battery along the second direction according to one embodiment of this application;

[0064] Figure 3 is a partial structural diagram of a back contact battery along a first direction according to one embodiment of this application;

[0065] Figure 4 is a schematic diagram of the structure of a first pad according to one embodiment of this application;

[0066] Figure 5 is a schematic diagram of a first doped layer and a second doped layer according to one embodiment of this application;

[0067] Figure 6a is a schematic diagram of the connection between the second pad and the first fine gate according to one embodiment of this application;

[0068] Figure 6b is a schematic diagram of the connection between the second pad and the first fine gate according to one embodiment of this application;

[0069] Figure 7 is a schematic diagram of the structure of a back contact battery according to one embodiment of this application;

[0070] Figures 8 to 13 show partial structural schematic diagrams of several back contact batteries in the embodiments of this application;

[0071] Figure 14 shows a partial structural schematic diagram of a photovoltaic module according to an embodiment of this application;

[0072] Figure 15 shows a partial structural schematic diagram of a first doped layer in an embodiment of this application;

[0073] Figures 16 to 18 show partial structural schematic diagrams of several first doped layers and second doped layers in embodiments of this application;

[0074] Figure 19 shows a partial structural schematic diagram of a fine gate and pad in an embodiment of this application;

[0075] Figure 20 shows a partial structural schematic diagram of the first surface of a back contact battery according to an embodiment of this application.

[0076] The attached diagram is labeled as follows: 100, back contact battery; 10. Battery body; 11. First doped layer; 12. Second doped layer; 20. First fine grid; 30. Second fine grid; 40. First pad; 41. Middle portion; 42. Extension portion; 50. Second pad; 60. Third pad; 70. Fourth pad; 80. Fifth pad; 81. End line; 1. N-type fine grid; 2. P-type fine grid; 13. N-type pad; 131. Edge N-type pad; 132. Middle N-type pad; 133. Transition N-type pad; 14. P-type pad; 141. Edge P-type pad; 142. Middle P-type pad; 143. Transition P-type pad; 15. N-type doped layer; 16. P-type doped layer; 17. Interface dielectric layer; 18. Isolation region; 19. Silicon substrate; 22. Electrical connector; 221. First part; 222. Second part; 23. Insulating block. A. First region; B. Second region; C. Third region; D. Edge region; X. First direction; Y. Second direction. Specific Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0078] Those skilled in the art should understand that, in the disclosure of this application, the terms "first," "second," "third," "fourth," "fifth," etc., are only used to distinguish different structures and do not limit the number of specific structures, connection relationships, etc.; in addition, the orientation or positional relationship indicated by "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this application.

[0079] It should be noted that in the embodiments of this application, the first direction X and the second direction Y are perpendicular to each other and both are perpendicular to the thickness direction of the battery body 10. It should also be noted that the first fine grid 20, the second fine grid 30, the first pad (also called the first sub-pad) 40, the second pad (also called the second sub-pad) 50, the third pad (also called the third sub-pad) 60, the fourth pad (also called the fourth sub-pad) 70, and the fifth pad (also called the fifth sub-pad) 80 in the embodiments of this application can all be made using metal paste through a printing process. For example, at least one of silver paste, copper paste, and silver-coated copper paste can be used, and the structures can be formed using a printing process. Of course, other processes such as electroplating, or a combination of electroplating and printing, can also be used. This application does not limit the formation method of the above structures. In this application, at least one of the first fine grid, the second fine grid, and various pads can be formed using a high-temperature paste, such as high-temperature silver paste; or a low-temperature paste, such as at least one of copper paste, silver-coated copper paste, and nickel-coated copper paste. At least one of the first and second fine gates can be a two-layer or multi-layer structure. For example, at least one of the first and second fine gates can be a two-layer structure, wherein the layer closer to the doped layer is a discontinuous structure and can be formed by high-temperature paste, and the layer farther from the doped layer is a continuous structure and can be formed by low-temperature paste. In some embodiments, various pads can be formed using low-temperature paste.

[0080] It should be noted that the first fine grid, the second fine grid, and various pads in this application are all electrode structures. In this back-contact battery, the electrode structures are located on the back side of the battery body 10, and the electrode structures are used to collect and conduct current. The battery body contains a PN junction, which can separate charge carriers. During normal operation of the back-contact battery, the side of the battery body that mainly receives light is the light-facing side, and the back-light side is opposite to the light-facing side.

[0081] As mentioned above, in order to improve battery conversion efficiency and reduce the use of metal paste, existing back-contact batteries generally adopt a gridless electrode design. At the same time, in order to achieve effective interconnection welding in the subsequent photovoltaic module manufacturing process, pads (pad points) are formed on the battery for welding electrical connectors (also known as interconnects or solder strips). However, electrical connectors are prone to partial cold solder joints, which makes it impossible to guarantee the reliability of photovoltaic modules in subsequent use.

[0082] In this regard, the inventive concept of this application is to design two types of solder pads with different areas. The solder pad with a larger area has a lower probability of forming a cold solder joint after welding, which is beneficial to improving the stability of electrical connector welding and the reliability of current collection. The solder pad with a smaller area is beneficial to reduce the occupation of the battery body surface area, reduce metal composite loss, and reduce the use of metal paste, thereby reducing battery cost.

[0083] Based on the above-described inventive concept, the advantages of this application will be described in detail below with reference to specific embodiments. It should be understood that the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0084] Based on the general inventive concept of the embodiments of this application, one embodiment of this application provides a back contact battery 100, the back contact battery 100 includes a battery body 10, a plurality of first fine grids 20 and a plurality of second fine grids 30 extending along a first direction X; the first fine grids 20 and the second fine grids 30 are alternately and sequentially disposed on a first surface of the battery body 10 along a second direction Y; the first surface includes a first region A and a first side and a second side disposed opposite to each other along the second direction Y; in the first region A, a plurality of first pads 40 and a plurality of second pads 50 are disposed on both the first fine grids 20 and the second fine grids 30; the area of ​​the first pads 40 is smaller than the area of ​​the second pads 50.

[0085] It should be noted that in the description of the pads on the fine gate in the embodiments of this application, the term "on" does not represent a positional relationship, but only means that the fine gate and the pads are connected, and should not be construed as a limitation of this application. Specifically, regarding the positional relationship between the fine gate and the pads, the position of the pads and the fine gate can be interchanged; that is, the fine gate can be located above the pads or below the pads, and optionally, the pads can be located below and closer to the battery body 10. For example, in the first region A, multiple first pads 40 and multiple second pads 50 are provided on both the first fine gate 20 and the second fine gate 30, and the multiple first pads 40 and multiple second pads 50 can be located above or below the corresponding first fine gate 20 or second fine gate 30, respectively.

[0086] The battery body 10 in this embodiment can be sheet-shaped, and the battery body 10 has two opposing surfaces along its thickness direction. Either of these two surfaces can be used as the first surface. The first fine grid 20 and the second fine grid 30 have opposite polarities. For example, the first fine grid 20 can be a positive electrode fine grid (e.g., it can be called a P-type fine grid), and the second fine grid 30 can be a negative electrode fine grid (e.g., it can be called an N-type fine grid), or the first fine grid 20 can be a negative electrode fine grid, and the second fine grid 30 can be a positive electrode fine grid.

[0087] Therefore, the first surface of the battery body 10 includes a first region A and a first side and a second side disposed opposite to each other along the second direction Y. The first region A is located between the first side and the second side along the second direction Y. The first pad 40 and the second pad 50 are both arranged in the first region A. Since the area of ​​the first pad 40 is smaller than the area of ​​the second pad 50, the smaller area of ​​the first pad 40 is beneficial to reducing the area occupied by the pad on the surface of the battery body 10, and can reduce the consumption of metal paste during the manufacturing process, so as to reduce metal composite loss, improve the photoelectric collection efficiency, and reduce production costs. The second pad 50 has a larger area, which is more conducive to improving welding stability, reducing the occurrence of cold solder joints, and further improving the reliability of current collection.

[0088] Referring to Figures 1 to 3, Figure 1 is a schematic diagram of the structure of the back contact battery 100 provided in an embodiment of this application; Figure 2 is a partial schematic diagram of the structure of the back contact battery 100 provided in an embodiment of this application; and Figure 3 is a partial schematic diagram of the structure of the back contact battery 100 provided in an embodiment of this application.

[0089] Please refer to Figures 1 and 3. In one possible embodiment of this application, in the first direction X, a plurality of first pads 40 and a plurality of second pads 50 on the first fine gate 20 have a plurality of first repeating units, and / or, a plurality of first pads 40 and a plurality of second pads 50 on the second fine gate 30 have a plurality of first repeating units, wherein the first repeating unit includes at least one first pad 40 and at least one second pad 50.

[0090] It should be noted that in this embodiment, in the second direction Y, the plurality of first pads 40 and the plurality of second pads 50 on the plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged in a row, but it is not necessary to have a plurality of second repeating units as described below.

[0091] Since the area of ​​the first pad 40 is smaller than that of the second pad 50, this design allows the first pad 40 and the second pad 50 to be arranged in a periodic repeating pattern in the first direction X for a first fine gate 20 or a second fine gate 30. This can minimize the amount of metal paste used, reduce production costs, and ensure that even if a cold solder joint occurs when the smaller area of ​​the first pad 40 is soldered to an electrical connector, the larger area of ​​the second pad 50 in the first direction X can still ensure soldering reliability. The current at the cold solder joint location of the first pad 40 is collected, thereby preventing current loss caused by excessive current path transmission.

[0092] It should be noted that in the embodiments of this application, a single first repeating unit is composed of a first pad 40 and a second pad 50, and the number of the first pad 40 and the second pad 50 constituting a single first repeating unit can be one or more.

[0093] In some embodiments, referring to FIG1, the first repeating unit in this application embodiment may optionally include a first pad 40 and a second pad 50; that is, in the first direction X, the first pad 40 and the second pad 50 in the plurality of first repeating units are repeatedly arranged with the feature of first pad 40, second pad 50, first pad 40, second pad 50...; of course, in some embodiments not shown, the first repeating unit may also include two first pads 40 and one second pad 50, that is, the first pads 40 and the second pad 50 in the plurality of first repeating units are arranged with the feature of first pad 40, second pad 50, second pad 50... The first pad 40, the second pad 50, the second pad 50... are arranged in a repeating pattern; or, the first repeating unit may also include two first pads 40 and two second pads 50, that is, the first pads 40 and the second pads 50 in multiple first repeating units are arranged in a repeating pattern; both can minimize the amount of metal paste used, reduce production costs, ensure welding reliability, and prevent current loss caused by excessive current path transmission. Further details are not provided here.

[0094] In some embodiments, to ensure that the area of ​​the first pad 40 is smaller than the area of ​​the second pad 50, for example, the lengths of the first pad 40 and the second pad 50 in the first direction X can be different; the widths of the first pad 40 and the second pad 50 in the second direction Y can be different; or the shapes of the first pad 40 and the second pad 50 can be different. That is, the lengths of the first pad 40 and the second pad 50 in the first direction X can be different, their widths in the second direction Y can be different, and their shapes can be different (i.e., their outer contours are different). Based on satisfying that the area of ​​the first pad 40 is smaller than the area of ​​the second pad 50, the design can be flexible to minimize the amount of metal paste used, reduce production costs, and ensure welding reliability to the greatest extent possible, while preventing current loss caused by excessive current path transmission.

[0095] In one optional embodiment of this application, the first pad 40 and the second pad 50 have the same length (which can refer to the maximum length in the first direction X) and width (which can refer to the maximum width in the second direction Y), but the shapes of the first pad 40 and the second pad 50 are different. As shown in Figure 3, the second pad 50 is rectangular, and the first pad 40 is a combination of two trapezoids and a rectangle. Although the first pad 40 and the second pad 50 have the same length in the first direction X and width in the second direction Y, their different shapes result in the first pad 40 having a smaller area than the second pad 50.

[0096] Regarding the shape design of the first pad 40 and the second pad 50, in some embodiments, the outer contour of the second pad 50 may be rectangular or racetrack-shaped. The racetrack shape mentioned in this application can refer to a shape formed by adding a semicircle to each opposite side of a rectangle. In some embodiments, the first pad 40 includes a central portion 41 and extension portions 42 located on both sides of the central portion 41 in the first direction X. The outer contour of the central portion 41 may be rectangular or racetrack-shaped, and the outer contour of the extension portions 42 may be trapezoidal, semi-elliptical, or triangular.

[0097] For example, the second pad 50 can adopt a rectangular design to better match the shape of the electrical connector and increase the contact area; the first pad 40 is shown in Figure 4, which is a structural schematic diagram of the first pad 40 in an optional embodiment of this application. The outer contour of the middle part 41 of the first pad 40 is rectangular, and the extensions 42 on both sides of the middle part 41 in the first direction X are trapezoidal, so as to ensure that when the length of the first pad 40 and the second pad 50 in the first direction X and the width in the second direction Y are the same, the area of ​​the first pad 40 is smaller than that of the second pad 50.

[0098] In another possible embodiment of this application, based on the area design concept of the first pad 40 and the second pad 50 of the above embodiment, as shown in Figures 1 and 2, the area of ​​the first pad 40 is smaller than the area of ​​the second pad 50; in the second direction Y, the multiple first pads 40 and multiple second pads 50 on the multiple first fine gates 20 and the multiple second fine gates 30 are arranged in columns (i.e., the first pads 40 and the second pads 50 on the first fine gates 20 are arranged in columns, and the first pads 40 and the second pads 50 on the second fine gates 30 are arranged in columns), and each column has multiple second repeating units, the second repeating unit including at least one first pad 40 and at least one second pad 50.

[0099] It should be noted that, in this embodiment, in the first direction X, the plurality of first pads 40 and the plurality of second pads 50 on the first fine gate 20 and / or the second fine gate 30 do not necessarily have a plurality of second repeating units. Here, taking the first fine gate 20 as a P-type fine gate and the second fine gate 30 as an N-type fine gate as an example, the first pads 40 and the second pads 50 electrically connected to the first fine gate can be called P-type pads, and the first pads 40 and the second pads 50 electrically connected to the second fine gate can be called N-type pads.

[0100] It is understood that in the second direction Y, the first pads 40 and second pads 50 on the first fine gate 20 and the second fine gate 30 are arranged in columns, and each column has multiple second repeating units. When the second repeating unit includes at least one first pad 40 and at least one second pad 50, the first pads 40 and second pads 50 in the multiple second repeating units can be welded in the first region A along the second direction Y during electrical connector welding. The first pad 40 can minimize the amount of metal paste used and reduce production costs; the second pad 50 can increase the contact area between the electrical connector and the second pad, thereby improving the welding pull force, ensuring welding stability, and preventing the electrical connector from shifting.

[0101] It should be noted that in the embodiments of this application, a single second repeating unit is composed of a first pad 40 and a second pad 50, and the number of the first pad 40 and the second pad 50 constituting a single second repeating unit can be one or more.

[0102] Further, referring to FIG2, the second repeating unit in the embodiment of this application may include a first pad 40 and a second pad 50; that is, in the second direction Y, the first pad 40 and the second pad 50 in the plurality of second repeating units are repeatedly arranged with the features of first pad 40, second pad 50, first pad 40, second pad 50...; of course, other examples can refer to the above-mentioned first repeating unit, which will not be listed in detail here.

[0103] In some embodiments, as shown in FIG1, the first surface in this embodiment further includes a second region B disposed between the first region A and the first side along the second direction Y and adjacent to the first region A; in the second region B, a plurality of third pads 60 are disposed on the first fine gate 20 and the second fine gate 30 at intervals along the first direction X, and the third pads 60 on each first fine gate 20 are staggered with the third pads 60 on the adjacent second fine gate 30 in the second direction Y, and the third pads 60 on the adjacent first fine gate 20 are arranged in a row in the second direction Y; the area of ​​the second pad 50 is smaller than the area of ​​the third pad 60.

[0104] It should be noted that the second region B can also be located along the second direction Y between the first region A and the second side, and adjacent to the first region A. Alternatively, as shown in Figure 2, two second regions B can be designed, with each second region B located along the second direction Y between the first region A and the first side, and between the first region A and the second side, respectively. Both second regions B are adjacent to the first region A on their respective sides. Thus, the first region A can specifically be the middle region of the first surface. Similarly, the third pad 60 electrically connected to the P-type fine gate is a P-type pad, and the third pad 60 electrically connected to the N-type fine gate is an N-type pad.

[0105] After welding, the connection points of multiple electrical connectors to the back contact battery 100 can be arranged intersectingly along the first direction X and the second direction Y within the second region B, which effectively avoids stress concentration and improves the welding reliability of the electrical connectors. Since the second region B is closer to the edge of the back contact battery, the electrical connectors in this region will bear greater stress after welding. Therefore, a third pad 60 with a larger area than the second pad 50 is used as the connection point for welding the electrical connectors, so as to increase the connection area of ​​the electrical connectors in the second region B and further improve the connection stability of the electrical connectors in the second region B.

[0106] In some embodiments, the third pad 60 and the second pad 50 in this application embodiment have different lengths in the first direction X; alternatively, the third pad 60 and the second pad 50 have different widths in the second direction Y; and of course, the third pad 60 and the second pad 50 have different shapes. That is, the third pad 60 and the second pad 50 can have different lengths in the first direction X, different widths in the second direction Y, and different shapes (i.e., different outer contours). Based on the premise that the area of ​​the second pad 50 is smaller than that of the third pad 60, the design can be flexible to minimize the amount of metal paste used, reduce production costs, and increase the connection area of ​​the electrical connectors in the second region B, thereby further improving the connection stability of the electrical connectors in the second region B.

[0107] In some embodiments, the length of the third pad 60 in the first direction X is the same as that of the second pad 50, and the width of the third pad 60 in the second direction Y is greater than that of the second pad 50.

[0108] Since the electrical connector has width and cannot be offset from the pad in order to minimize the obstruction of the battery surface, the length of the third pad 60 in the first direction X should not be less than that of the second pad 50. However, the width of the third pad 60 in the second direction Y can be greater than that of the second pad 50 to ensure that the area of ​​the third pad 60 is greater than that of the second pad 50, thereby improving the welding reliability between the third pad 60 and the electrical connector.

[0109] Referring to Figures 1 and 2, in some embodiments, the first surface in this application embodiment further includes a third region C disposed between the second region B and the first side along the second direction Y and adjacent to the second region B; within the third region C, a plurality of fourth pads 70 are disposed on the first fine gate 20 and the second fine gate 30 at intervals along the first direction X, and the fourth pads 70 on each first fine gate 20 and the fourth pads 70 on the adjacent second fine gate 30 are staggered in the second direction Y, and are opposite to the fourth pads 70 on the adjacent first fine gate 20 in the second direction Y; the area of ​​the third pad 60 is smaller than the area of ​​the fourth pad 70.

[0110] It should be noted that the third region C can also be located along the second direction Y between the second region B and the second side, and adjacent to the second region B. Alternatively, as shown in Figure 2, two third regions C can be designed, with the two third regions C located along the second direction Y between the second region B and the first side, and between the second region B and the second side, respectively. Both third regions C are adjacent to the second region B on their respective sides. Thus, the second region B can specifically be a sub-edge region of the first surface. Similarly, the fourth pad 70 electrically connected to the P-type fine gate is a P-type pad, and the fourth pad 70 electrically connected to the N-type fine gate is an N-type pad.

[0111] Thus, after welding multiple electrical connectors, the connection points to the back contact battery can be arranged intersecting along the first direction X and the second direction Y within the third region C, effectively avoiding stress concentration and improving the welding reliability of the electrical connectors. Furthermore, since the third region C is closer to the edge of the back contact battery 100 than the second region B, the electrical connectors in this region will bear greater stress after welding. Therefore, using the fourth pad 70, which has a larger area than the third pad 60, as the connection point for welding the electrical connectors can increase the connection area of ​​the electrical connectors within the third region C, further improving the connection stability of the electrical connectors within the third region C.

[0112] It should be understood that during the photovoltaic module stringing process, the closer to the edge of the back contact cell 100, the stronger the tensile force on the electrical connector, making it more difficult to securely weld the electrical connector and increasing the risk of poor soldering. In this embodiment, in the second direction Y, the areas of the first pad 40, the second pad 50, the third pad 60, and the fourth pad 70 increase sequentially. Multiple first pads 40 and multiple second pads 50 form multiple second repeating units distributed along the second direction Y within the first region A located at the center of the back contact cell 100, to ensure the welding stability of the central region of the back contact cell 100. The third pad 60 is alternately distributed along the first direction X and the second direction Y in the second region B of the secondary edge area. Multiple fourth pads 70 are alternately distributed along the first direction X and the second direction Y in the third region C near the edge. Thus, the pad area gradually increases along the directions closer to the first and second edges. This matches the welding pull force between the electrical connectors and the grid near the edge of the back contact cell 100 during photovoltaic module stringing, thereby increasing the pull force of the electrical connectors at the edge, improving the weld strength of the electrical connectors, stabilizing the weld, and reducing the risk of cold solder joints. In summary, by setting pads of different areas and arrangements in different regions of the back contact cell 100, it is possible to ensure strong weld strength at the edge of the back contact cell 100, effectively achieve effective welding contact between the electrical connectors and the pads in the middle to collect photocurrent, and minimize the use of metal paste to reduce production costs.

[0113] In some embodiments, the fourth pad 70 and the third pad 60 in this application embodiment have different lengths in the first direction X; alternatively, the fourth pad 70 and the third pad 60 have different widths in the second direction Y; and of course, the fourth pad 70 and the third pad 60 have different shapes. That is, the fourth pad 70 and the third pad 60 can have different lengths in the first direction X, different widths in the second direction Y, and different shapes (i.e., different outer contours). Based on the premise that the area of ​​the third pad 60 is smaller than that of the fourth pad 70, the design can be flexible to reduce the amount of metal paste used, reduce production costs, and increase the connection area of ​​the electrical connectors in the third region C, thereby further improving the connection stability of the electrical connectors in the third region C.

[0114] In some embodiments, the third pad 60 and the fourth pad 70 may have the same shape, and their outer contours may be rectangular or racetrack-shaped; for example, as shown in FIG2, the outer contours of the third pad 60 and the fourth pad 70 are both rectangular. In addition, the shape of each pad may also be trapezoidal, octagonal, or a combination of different shapes.

[0115] In some embodiments, the centers of a row of first pads, second pads, third pads, and fourth pads electrically connected to the first gate are located on the same straight line extending along the second direction along the first direction. Similarly, the centers of a row of first pads, second pads, third pads, and fourth pads electrically connected to the second gate are located on the same straight line extending along the second direction along the first direction.

[0116] In some embodiments, referring to Figures 1 and 2, the length of the fourth pad 70 in the first direction X is greater than that of the third pad 60, and the width of the fourth pad 70 in the second direction Y is the same as that of the third pad 60.

[0117] Because the third region C is closer to the edge of the battery, the electrical connectors in this region experience greater tensile force, making them more prone to pull-out and displacement. The design of the fourth pad 70, which is longer than the third pad 60 in the first direction X and has the same width as the third pad 60 in the second direction Y, allows the pads closer to the battery edge to have a larger area. This helps to further offset and disperse the greater stress and tensile force generated by the electrical connectors due to their proximity to the edge of the back contact battery 100, thus significantly improving the stability of the electrical connector welding in the third region C and preventing pull-out. Furthermore, the fourth pad 70 is longer along the first direction X, which helps prevent the electrical connectors from shifting and failing to weld to the pads in the third region C (i.e., the fourth pad 70).

[0118] In the above embodiments, the size of the first pad 40 in the first direction X can be 0.9mm-1.1mm, and the size in the second direction Y can be 0.19mm-0.25mm. For example, the size of the first pad 40 in the first direction X can be any value within the range of 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, or 0.9mm-1.1mm, and the size of the first pad 40 in the second direction Y can be any value within the range of 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, or 0.19mm-0.25mm.

[0119] In the embodiment shown in Figure 4, the size of the middle portion 41 of the first pad 40 in the first direction X can be 0.5mm-1mm, and the size of the extension portion 42 in the first direction X can be 0.1mm-0.4mm.

[0120] In the above embodiments, the size of the second pad 50 in the first direction X can be 0.9mm-1.1mm, and the size in the second direction Y can be 0.19mm-0.3mm. For example, the size of the second pad 50 in the first direction X can be any value within the range of 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, or 0.9mm-1.1mm, and the size of the second pad 50 in the second direction Y can be any value within the range of 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, or 0.19mm-0.3mm.

[0121] In the above embodiments, the dimension of the third pad 60 in the first direction X can be 0.9mm-1.3mm, and the dimension in the second direction Y can be 0.19mm-0.4mm; for example, the dimension of the third pad 60 in the first direction X can be any value within the range of 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, 1.2mm, 1.3mm, or 0.9mm-1.3mm, and the dimension of the third pad 60 in the second direction Y can be... The dimension value is any value within the range of 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, or 0.19mm-0.4mm.

[0122] In the above embodiments, the dimension of the fourth pad 70 in the first direction X can be 0.9mm-1.5mm, and the dimension in the second direction Y can be 0.19mm-0.5mm. For example, the dimension of the fourth pad 70 in the first direction X can be any value within the range of 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, or 0.9mm-1.5mm, and the dimension of the fourth pad 70 in the second direction Y can be 0.19mm, 0.2mm, 0.21mm, 0.22mm, or 0. Any dimension value within the range of 23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.5mm, or 0.19mm-0.5mm.

[0123] In some embodiments, the first surface further includes an edge region D (also referred to as a fourth region D), which is located between the first region A, the second region B, or the third region C and the first side, and is adjacent to the first side. Within the edge region D, a plurality of fifth pads 80 are spaced apart on the first fine gate 20 and the second fine gate 30 near the first side. For a column of pads along the second direction Y, each column may have one or more fifth pads 80. The area of ​​the fifth pad 80 is larger than that of the fourth pad 70. An end line (also referred to as a bus line) 81 is also provided between the fifth pad 80 and the first side, and in the second direction Y, one end of the end line 81 connects to the corresponding fifth pad 80, and the other end connects to the corresponding first fine gate 20 or second fine gate 30 near the first side. Similarly, the fifth pad 80 electrically connected to the P-type fine gate is a P-type pad, and the fifth pad 80 electrically connected to the N-type fine gate is an N-type pad.

[0124] It should be understood that when there are two edge regions D, they can also be adjacent to the second side. Referring to Figure 7, which is a schematic diagram of the structure of a back contact battery 100 according to one embodiment of this application, in Figure 7, the two edge regions D are respectively disposed between a third region C and the first side, and the other third region C and the second side, and the two edge regions D are respectively adjacent to the first side or the second side.

[0125] Edge region D is the area closest to the edge on the battery body 10. The electrical connectors in this area bear the greatest stress and tensile force after welding. In edge region D, the area of ​​the fifth pad 80 is larger than that of the fourth pad 70 to increase the connection area of ​​the electrical connectors in edge region D, thereby further improving the connection stability of the electrical connectors in edge region D and reducing the risk of poor soldering of electrical connectors.

[0126] In the above embodiments, the first region A is required, while the second region B, the third region C, and the edge region D can be at least one of them or none of them can be absent. When the second region B, the third region C, and the edge region D can be selected, it can ensure that the pull-out force of the electrical connector is good. When the second region B, the third region C, and the edge region D can be selected for two or three of them, the pull-out force of the electrical connector has a sufficient buffer, which can ensure sufficient pull-out force while reducing costs.

[0127] In some embodiments, the back contact battery further includes a plurality of first doped layers 11 and a plurality of second doped layers 12; referring to FIG5, FIG5 is a schematic diagram of the first doped layer 11 and the second doped layer 12 provided according to one embodiment of the present application, the plurality of first doped layers 11 and the plurality of second doped layers 12 are arranged alternately along the second direction Y, each first doped layer 11 is disposed between a corresponding first fine grid 20 and the battery body 10, and each second doped layer 12 is disposed between a corresponding second fine grid 30 and the battery body 10; wherein, the doping types of the first doped layer 11 and the second doped layer 12 are different.

[0128] Specifically, the first doped layer 11 can be a P-type doped layer, and the second doped layer 12 can be an N-type doped layer, or the first doped layer 11 can be an N-type doped layer and the second doped layer 12 can be a P-type doped layer. The choice can be made based on actual conditions and is not limited here. The materials of the N-type and P-type doped layers are not specifically limited, and for example, include at least one of doped polycrystalline silicon, doped amorphous silicon, and doped microcrystalline silicon. In some optional embodiments, the doping type of the doped layer corresponding to the first fine gate 20 and / or the second fine gate 30 closest to the edge of the back contact cell 100 is opposite to the doping type of the silicon substrate in the back contact cell 100, in order to increase the emitter area of ​​the back contact cell 100, enhance the carrier collection capability of the edge portion of the back contact cell 100, and optimize the cell efficiency.

[0129] To accommodate larger pad sizes, in some embodiments, within the second region B and / or the third region C, the first doped layer 11 or the second doped layer 12 at least partially protrudes along the second direction Y to form a receiving region. That is, as shown in Figures 5 and 12, the P-type doped layer and / or the N-type doped layer can be of non-uniform width, or the first doped layer 11 and / or the second doped layer 12 can be of non-uniform width. The P-type doped layer and / or the N-type doped layer of the battery body have a first width and a second width, where the first width is greater than the second width. The first width can correspond to the design of the pads, and the second width can correspond to the design of the fine grid, thereby reserving more space for the pad design to accommodate the corresponding third pad 60 or fourth pad 70. In this application, the width at the corresponding position of at least one of the first, second, third, fourth, and fifth pads in the first doped layer 11 and / or the second doped layer 12 can be the first width. For example, the width at the corresponding positions of the third, fourth, and fifth pads in the first doped layer 11 and / or the second doped layer 12 is the first width. In some examples, the N-type doped layer is a non-uniform width design, that is, the N-type doped layer has a first width and a second width, while the P-type doped layer is a uniform width design.

[0130] In some embodiments, by designing the first doped layer 11 and / or the second doped layer 12 with non-uniform widths to match the size of larger pads, as shown in Figures 15 to 18, for locations in the doped layer where a larger pad area needs to be provided, one side of the doped layer along the second direction Y can protrude away from the other side, thereby increasing the width of the location in the doped layer where the pad needs to be provided, while the other side of the doped layer along the second direction Y extends in a straight line without protrusion. Alternatively, as shown in Figures 5 and 12, for locations in the doped layer where a larger pad area needs to be provided, both sides of the doped layer along the second direction Y can protrude away from the other side, thereby increasing the width of the location in the doped layer where the pad needs to be provided.

[0131] In the case where both the first doped layer 11 and the second doped layer 12 are such that one side protrudes away from the other side along the second direction Y, while the other side along the second direction Y extends in a straight line without protrusion, as shown in FIG16, the protruding sides of adjacent first doped layers 11 and second doped layers 12 in the second direction Y are opposite to each other, and the protruding sides are located on different sides of the first doped layer and the second doped layer; or, as shown in FIG18, the protruding sides of adjacent first doped layers 11 and second doped layers 12 in the second direction Y are close to each other; or, as shown in FIG17, the protruding sides of adjacent first doped layers 11 and second doped layers 12 in the second direction Y are all located on the same side of the first doped layer and the second doped layer.

[0132] Furthermore, for adjacent first doped layers 11 and second doped layers 12, taking the first doped layer as an example, when the first doped layer protrudes from one side away from the other side along the second direction Y, the side of the second doped layer corresponding to the protruding position of the side of the first doped layer can extend along a straight line as shown in Figure 5, or it can be as shown in Figure 12, where the side of the second doped layer corresponding to the protruding position of the side of the first doped layer is recessed to further increase the width of the first doped layer at the protruding position, thereby increasing the area of ​​the pads provided at the protruding position; the design of the second doped layer can refer to the design of the first doped layer described above, and will not be repeated here.

[0133] The aforementioned methods for pads with a large area in a doped layer and for doped layers with two different doping types can be used in combination or individually, and are all within the scope of protection of this application.

[0134] It should be noted that Figure 15 only illustrates the widening method of the first doped layer 11 at the larger area pad position using the first doped layer 11 as an example. The widening method at each larger area pad position electrically connected to the first doped layer 11 in this application is similar. The widening method at each larger area pad position electrically connected to the second doped layer 12 in this application is also similar. To avoid repetition, it will not be described again.

[0135] Referring again to Figure 5, within the second region B and the third region C, the first doped layer 11 or the second doped layer 12 protrudes at least partially along the second direction Y to form a receiving region. The explanation of the receiving region can be found above, with the third pad 60 and the fourth pad 70 accommodated within their respective receiving regions. Of course, in some embodiments not shown, the first doped layer 11 or the second doped layer 12 may only be designed to protrude at least partially along the second direction Y within the third region C to form a receiving region, in order to accommodate the larger area of ​​the fourth pad 70. More specifically, in the second direction Y: because the size of the third pad 60 and / or the size of the fourth pad 70 may be larger than the size of the portion of the first doped layer 11 or the second doped layer 12 outside the receiving region, the width of the first doped layer 11 or the second doped layer 12 in the second direction Y is appropriately increased at the location of the third pad 60 and / or the fourth pad 70, thereby accommodating the larger third pad 60 and / or the fourth pad 70 in the second direction Y.

[0136] To collect the current at the edge of the back contact battery 100, referring to FIG7, an end line 81 is provided between the fifth pad 80 and the first side. In the second direction Y, one end of the end line 81 is connected to the corresponding fifth pad 80, and the other end is connected to the corresponding first fine gate 20 or second fine gate 30 near the first side, so that the current at the edge of the back contact battery 100 can be collected and converged.

[0137] In some embodiments, the fifth pad 80 in this application embodiment has the same length as the fourth pad 70 in the first direction X, and a wider width in the second direction Y than the fourth pad 70; thus, the area of ​​the fifth pad 80 can be larger than that of the fourth pad 70. The fifth pad 80 is arranged in the edge region D closest to the edge of the battery, which helps to offset and disperse the stress and tension generated by the electrical connector due to its proximity to the edge of the back contact battery 100, thereby effectively improving the stability of the electrical connector welding in the edge region D.

[0138] In the above embodiments, the size of the fifth pad 80 in the first direction X can be 0.9mm-1.1mm, and the size in the second direction Y can be 1.1mm-1.8mm. For example, the size of the fifth pad 80 in the first direction X can be any value within the range of 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, or 0.9mm-1.1mm, and the size of the fifth pad 80 in the second direction Y can be any value within the range of 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, or 1.1mm-1.8mm.

[0139] In some embodiments, the first fine gate 20 or the second fine gate 30 has a broken or continuous structure at the location where the first pad 40, second pad 50, third pad 60, fourth pad 70, or fifth pad 80 is located. Taking the structural design of the first fine gate 20 at the location where the second pad 50 is located as an example, as shown in FIG6a, which is a schematic diagram of the connection between the second pad 50 and the first fine gate 20 according to one embodiment of this application, the first fine gate 20 has a broken structure at the location where the second pad 50 is located, which helps to reduce the overall thickness of the fine gate and the pad at that location and avoid waste of metal paste; or as shown in FIG6b, which is a schematic diagram of the connection between the second pad 50 and the first fine gate 20 according to one embodiment of this application, the first fine gate 20 has a continuous structure at the location where the second pad 50 is located. The pad is printed first, and then the fine gate is printed on the pad. In this way, the fine gate can be stacked on the pad, ensuring that the test probe can contact the fine gate during IV testing, thereby improving the accuracy of the test. Optionally, to avoid affecting the soldering effect of pads and electrical connectors, for smaller pads (e.g., first pad 40, second pad 50), the fine gate can be set to break at the smaller pad; for larger pads, the fine gate can be set continuously or intermittently. Furthermore, when the size of the pad in the first direction is less than 1.1 mm, the fine gate can be broken at that pad.

[0140] Since the pads on the fine gate are mainly used to power the connectors and make electrical connections with the fine gates of the same polarity, in some embodiments, each pad on the first fine gate 20 and the second fine gate 30 is used to load the solder paste layer. The area of ​​the solder paste layer is equal to or smaller than the area of ​​the corresponding pad. The outer contour of the solder paste layer can be set as trapezoidal, circular, rectangular, octagonal or other irregular shapes to ensure the electrical connection between the connectors and the fine gate.

[0141] In addition, considering the insulation between the electrical connector and the non-circular fine grid, an insulating block is arranged between the electrical connector and the non-circular fine grid to ensure an insulated connection between the electrical connector and the non-circular fine grid.

[0142] Please refer to Figures 1-3. Based on the design concept of at least one of the above embodiments, in other embodiments of this application, the back contact battery 100 includes a battery body 10, a plurality of first fine grids 20 extending along a first direction X, and a plurality of second fine grids 30; the first fine grids 20 and the second fine grids 30 are alternately and sequentially disposed on a first surface of the battery body 10 along a second direction Y; the first surface includes a first region A and a first side and a second side disposed opposite to each other along the second direction Y; within the first region A, a plurality of first pads 40 and a plurality of second pads 50 are disposed on both the first fine grids 20 and the second fine grids 30; the area of ​​the first pads 40 is smaller than that of the first pads 50. The area of ​​the second pad 50; in the first direction X, the plurality of first pads 40 and the plurality of second pads 50 on the first fine gate 20 have a plurality of first repeating units, and / or, the plurality of first pads 40 and the plurality of second pads 50 on the second fine gate 30 have a plurality of first repeating units, the first repeating unit including at least one first pad 40 and at least one second pad 50; in the second direction Y, the first pads 40 and the second pads 50 on the plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged in columns, and each column has a plurality of second repeating units, the second repeating unit including at least one first pad 40 and at least one second pad 50.

[0143] As shown in Figure 1, in the first direction X, each first repeating unit includes a first pad 40 and a second pad 50, such that the first pad 40 and the second pad 50 on a single first fine gate 20 and a second fine gate 30 in the first region A are alternately arranged along the first direction X; and as shown in Figure 3, the first pad 40 on each first fine gate 20 and the second pad 50 on its adjacent second fine gate 30 are staggered in the second direction Y, and each first fine gate 20 and the second pad 50 on its adjacent first fine gate 20 are opposite to each other in the second direction Y; as shown in Figure 2, in the second direction Y, each second repeating unit includes a first pad 40 and a second pad 50, such that when the electrical connector is soldered, the first pad 40 and the second pad 50 can be alternately soldered sequentially along the second direction Y in the first region A.

[0144] This design minimizes the amount of metal paste used, reducing production costs. Even when a smaller area of ​​the first pad 40 experiences a cold solder joint, the larger area of ​​the second pad 50 in the first direction X can still ensure welding reliability. Current at the cold solder joint location of the first pad 40 is collected, preventing current loss due to excessive current path transmission. Furthermore, in the second direction Y, the first pads 40 and 50 on the first and second fine grids 20 and 30 are arranged in columns, with each column having multiple second repeating units including at least one first pad 40 and at least one second pad 50. The first pads reduce metal paste usage and production costs, while the second pads increase the contact area of ​​the electrical connectors in the first region A, thereby increasing welding pull, ensuring welding stability, and preventing electrical connector misalignment. In addition, the connection points of the multiple electrical connectors to the back contact battery 100 after welding are arranged crosswise in the first direction X and the second direction Y, facilitating uniform stress distribution after welding and effectively reducing cold solder joints, thus significantly improving welding reliability.

[0145] Based on the general inventive concept of the embodiments of this application, in another embodiment of this application, referring to Figures 8 to 14, the main feature is that the area of ​​the P-type pad is designed to be larger than that of the N-type pad in the same area, so as to increase the attachment area of ​​the P-type pad to the battery body and the bonding area with the electrical connector, thereby enhancing the bonding force between the battery and the electrical connector, making the two firmly bonded, with virtually no risk of pull-out, and the electrical connection more reliable.

[0146] In another embodiment, in the electrode structure of the back contact battery, one of the aforementioned first and second fine grids is an N-type fine grid 1, and the other is a P-type fine grid 2. The back contact battery also includes an N-type pad array (also referred to as a first electrode array) and a P-type pad array (also referred to as a second electrode array). The N-type fine grid 1 refers to an N-type current collector line, and the P-type fine grid 2 refers to a P-type current collector line, used to collect charge carriers in the battery body. Both the N-type fine grid 1 and the P-type fine grid 2 extend along a first direction X and are alternately distributed along a second direction Y. For example, in the second direction Y, an N-type fine grid 1 can be followed by a P-type fine grid 2, and then another N-type fine grid 1. The N-type pad array and the P-type pad array extend along the second direction Y and can be alternately distributed along the first direction X. For example, in the first direction X, an N-type pad array can be followed by a P-type pad array, and then another N-type pad array. The N-type pad array includes several N-type pads 13 arranged in a row along the second direction Y. The number of N-type pads 13 in the N-type pad array is not limited. The N-type pads 13 are electrically connected to the N-type fine gate 1 to realize the collection and conduction of current or charge carriers. The P-type pad array includes several P-type pads 14 arranged in a row along the second direction Y. The number of P-type pads 14 in the P-type pad array is not limited. The P-type pads 14 are electrically connected to the P-type fine gate 2 to realize the collection and conduction of current or charge carriers. Along the second direction Y, the battery body or the first surface of the battery body includes multiple regions. Each region can cover the total size of the battery body or the first surface in the first direction X. In other words, the size of each region in the first direction X can be equal. The relative size of each region is not limited. The size covered by each region in the second direction Y is not limited. The number of regions included in a battery body or the first surface is not limited. The area of ​​a P-type pad in the same region refers to the area of ​​a single P-type pad 14 in the same region. The area of ​​an N-type pad in the same region refers to the area of ​​one N-type pad 13 in that region. The pad area mentioned in this application refers to the area of ​​the surface of the pad facing away from the battery body, or the area of ​​the projection of the pad onto the first surface.

[0147] Due to differences in doping types, thickness, doping concentration, and width between the N-type and P-type doped layers, N-type pads 13 and P-type pads 14 exhibit different bonding pull forces during the conductive interconnection process of photovoltaic modules. Data analysis reveals that N-type pad 13 exhibits higher bonding pull forces, while P-type pad 14 exhibits lower bonding pull forces. This imbalance in bonding forces between the N-type and P-type pads can lead to pull-out risks at the P-type pad 14 location. Therefore, to address these issues, based on the inventive concept of this application, the area of ​​the P-type pad in the same region is larger than the area of ​​the N-type pad. By setting a larger area for the P-type pad in the same region, the adhesion area between the P-type pad and the battery body, and the bonding area with the electrical connector, can be increased. This enhances the bonding force between the battery and the electrical connector, resulting in a stronger bond with virtually no risk of pull-out and a more reliable electrical connection.

[0148] In this application, when comparing the areas of N-type pads and P-type pads, if both N-type and P-type pads in the same area include only one type of pad from the first, second, third, fourth, and fifth pads mentioned above, it means that all N-type pads and all P-type pads in the same area have the same area. This refers to comparing the area of ​​any P-type pad and any N-type pad in the same area. When comparing the areas of N-type and P-type pads, if both N-type and P-type pads in the same area include at least two types of pads from the first, second, third, fourth, and fifth pads mentioned above, this refers to comparing the areas of P-type and N-type pads of the same type in the same area. For example, in the same region where both P-type pads and N-type pads contain a first pad and a second pad, this refers to comparing the areas of the first pad of the P-type pad and the first pad of the N-type pad in the same region; or, comparing the areas of the second pad of the P-type pad and the second pad of the N-type pad in the same region.

[0149] It should be noted that the "same region" here can be one of the aforementioned first region, second region, third region, and edge region. Within the same region, the areas or one-dimensional dimensions of the P-type pads are all the same, and the areas or one-dimensional dimensions of the N-type pads are all the same, or the P-type pads have the same arrangement pattern, and the N-type pads have the same arrangement pattern. For example, the P-type pads are arranged along the first direction in an alternating pattern of first and second pads, or along the second direction in an alternating pattern of first and second pads. The total area of ​​the P-type pads 14 in a P-type pad column is the sum of the areas of all P-type pads 14 on the surface away from the battery body in a P-type pad column, or the sum of the projected areas of all P-type pads 14 on the first surface in a P-type pad column. The total area of ​​all N-type pads 13 in an N-type pad column can be referenced from the P-type pad column, and will not be elaborated here. The projection of the P-type pad 14 (or N-type pad) on the first surface mentioned in this application can refer to the area of ​​the orthographic projection of the P-type pad 14 onto the first surface when illuminated by light rays parallel to the thickness direction Z of the back contact battery. All projections mentioned in this application can refer to orthographic projections.

[0150] In some embodiments, the total area of ​​multiple P-type pads in a P-type pad column is greater than the total area of ​​multiple N-type pads in an N-type pad column. By increasing the total area of ​​the P-type pads in the P-type pad column, the overall bonding area and bonding force between the electrical connector and the battery body can be increased, thereby making the two bond firmly and virtually eliminating the risk of pull-out, resulting in a more reliable electrical connection.

[0151] For example, referring to Figure 8, along the first direction X, there is an N-type pad column on the left, a P-type pad column in the middle, and an N-type pad column on the right. The total area of ​​the multiple P-type pads 14 in the middle P-type pad column is greater than the total area of ​​the multiple N-type pads 13 in the left N-type pad column. The total area of ​​the multiple P-type pads 14 in the middle P-type pad column is also greater than the total area of ​​the multiple N-type pads 13 in the right N-type pad column.

[0152] It should be noted that the total area of ​​the P-type pads in the P-type pad column in this application can be the total area of ​​multiple P-type pads in any P-type pad column in the back contact battery. The method for determining the total area of ​​the N-type pads in the N-type pad column in this application is the same, and will not be repeated here to avoid repetition.

[0153] In some embodiments, in the second direction Y, the battery body includes: two relatively distributed edge regions and an intermediate region located between the two edge regions, wherein the relative sizes of the edge regions and the intermediate region are not limited. In the second direction Y, the battery body includes: two relatively distributed edges, which may refer to the aforementioned first edge and second edge. The edge region may refer to a region close to the aforementioned first edge or second edge. The intermediate region may overlap with at least one of the aforementioned first region, second region, and third region. For example, in FIG8, the N-type pads located in the edge regions of the N-type pad column are edge N-type pads 131, and the N-type pads located in the intermediate regions are intermediate N-type pads 132. The area of ​​the edge N-type pads 131 is larger than the area of ​​the intermediate N-type pads 132. Specifically, the edge region in the second direction Y is the location where the back contact battery begins to connect with the electrical connector. The reliability of the connection in the aforementioned edge region has a significant impact on the connection effect. In this application, the area of ​​the edge N-type pad 131 in the edge region of the N-type pad row is larger. By increasing the contact area, the bonding force in the edge region can be improved, ensuring a reliable connection in the edge region. In addition, the middle region is the central location in the back contact battery where the electrical connector is connected. The reliability of the connection in the middle region has a relatively smaller impact on the connection effect. In this application, by appropriately reducing the area of ​​the middle N-type pad 132 in the middle region of the N-type pad row, the bonding force in the middle region can still be guaranteed, while also avoiding material waste and reducing costs.

[0154] It should be noted that in some embodiments, there may be one or more regions, and within the same region, the area of ​​a P-type pad may be equal to the area of ​​an N-type pad. When comparing the areas of N-type and P-type pads, if both N-type and P-type pads in the same region include only one type of pad (the first, second, third, fourth, and fifth pads), it means that all N-type pads and all P-type pads in the same region have the same area; this refers to the area of ​​any P-type pad and any N-type pad in the same region being approximately the same. When comparing the areas of N-type and P-type pads, if both N-type and P-type pads in the same region include at least two types of pads (the first, second, third, fourth, and fifth pads), this refers to the comparison of the areas of P-type and N-type pads of the same type in the same region. For example, if both P-type and N-type pads in the same area contain a first pad and a second pad, this means that the first pad of type P and the first pad of type N in the same area have the same area, and at the same time, the second pad of type P and the second pad of type N in the same area have the same area.

[0155] In some embodiments, the P-type pads located in the edge region of the P-type pad row are edge P-type pads 141, and the P-type pads located in the middle region are middle P-type pads 142. The area of ​​the edge P-type pads 141 is larger than the area of ​​the middle P-type pads 142. The effect here is as described above and will not be repeated here.

[0156] It should be noted that the area of ​​the edge N-type pad 131 in this application can be the area of ​​the surface of any edge N-type pad 131 facing away from the battery body in the back contact battery, or the area of ​​the orthographic projection of any edge N-type pad 131 onto the first surface of the battery body. In this application, the methods for determining the area of ​​the middle N-type pad 132, the area of ​​the edge P-type pad 141, and the area of ​​the middle P-type pad 142 are similar or the same, and will not be repeated here to avoid repetition. In this application, the methods for determining the area are similar or the same unless otherwise specified, and will not be repeated here to avoid repetition.

[0157] In some embodiments, in the edge region, the total area of ​​all P-type pads in a P-type pad row is greater than or equal to the total area of ​​all N-type pads in an N-type pad row. By increasing the total area of ​​the edge P-type pads 141 in the P-type pad row, the contact area between the edge P-type pads 141 and the electrical connector and battery body is increased in the edge region, thereby improving the difference in bonding force between the edge P-type pads 141 and the edge N-type pads in the edge region, and enhancing the connection reliability of the electrical connector. Optionally, in the edge region, the area of ​​any P-type pad is greater than the area of ​​any N-type pad.

[0158] In some embodiments, the area of ​​an edge P-type pad 141 is greater than or equal to the area of ​​an edge N-type pad 131. The effect is described above and will not be repeated here.

[0159] In some embodiments, in the intermediate region, the total area of ​​all P-type pads in a P-type pad row is greater than the total area of ​​all N-type pads in an N-type pad row. Increasing the total area of ​​all intermediate P-type pads 142 in the P-type pad row in the intermediate region increases the contact area between the intermediate P-type pads 142 and the electrical connectors and battery body, thereby improving the difference in bonding force between the intermediate P-type pads 142 and the intermediate N-type pads in the intermediate region, and enhancing the connection reliability of the electrical connectors. Optionally, in the intermediate region, the area of ​​any P-type pad is greater than the area of ​​any N-type pad.

[0160] In some embodiments, in the intermediate region, the total area of ​​all P-type pads in a P-type pad column can also be equal to the total area of ​​all N-type pads in an N-type pad column.

[0161] In some embodiments, the length-to-width ratio of the edge P-type pads 141 is E, and the length-to-width ratio of the middle P-type pads 142 is F. In this application, the length and width of the pads refer to the length and width of the pads away from the battery body surface. The length can be greater than or equal to the width. The direction of the length of any pad is parallel to the first direction X, and the direction of the width of any pad is parallel to the second direction Y. The number of middle P-type pads 142 is more than 9 times the number of edge P-type pads 141, E is less than F, and F is greater than 3E. In other words, the aspect ratio E of the edge P-type pad 141 is smaller, and the aspect ratio of the edge P-type pad 141 is more likely to be roughly equal. The aspect ratio F of the middle P-type pad 142 is larger, and the shape of the middle P-type pad 142 is more likely to be elongated. Furthermore, F is greater than 3E. The edge region in the second direction Y is the position where the electrical connector and the back contact battery begin to connect. The connection reliability in the aforementioned edge region has a greater impact on the connection effect. The middle region is the central position where the electrical connector and the back contact battery are connected. The requirement for current transmission function is greater than the requirement for connection reliability. The edge P-pad 141 has a smaller aspect ratio (E), resulting in a larger contact area with the electrical connector in all directions, leading to more reliable connections in the edge region. Conversely, when F is less than or equal to 3E, the width of the middle P-pad 142 may be excessive. In the middle region, an overly large contact area between the electrical connector and the P-pad could be wasteful, increasing costs and causing more light shading. When F is greater than 3E, the width of the middle P-pad 142 is appropriate, providing a suitable contact area and bonding strength between the electrical connector and the electrical connector, while also ensuring good current transmission. The number of middle P-pads is more than nine times that of the edge P-pads. In the middle region, there are more contact points between the electrical connector and the P-pads, resulting in more current convergence points and improved current transmission efficiency.

[0162] For example, the aspect ratio of the edge P-type pad 141 is E, and the aspect ratio of the middle P-type pad 142 is F; E is less than F, and F can be 3.1E, 3.3E, 3.5E, 3.8E, 3.9E, 4E, 4.1E, 4.2E, 4.4E, 4.5E, 4.7E, 4.8E, 5E, 5.5E, or 6E; for example, the number of middle P-type pads 142 is 9 times, 9.5 times, 10 times, 10.5 times, 11 times, 11.5 times, or 12 times the number of edge P-type pads 141.

[0163] In some embodiments, the battery body further includes: a transition region located between an edge region and a middle region in the second direction Y; for pads of the same polarity, the area of ​​a pad in the transition region is between the area of ​​a pad in the edge region and the area of ​​a pad in the middle region. For example, the N-type pad located in the transition region in an N-type pad array is a transition N-type pad 133, and the area of ​​the transition N-type pad 133 is between the area of ​​the edge N-type pad 131 and the area of ​​the middle N-type pad 132, that is, the area of ​​a transition N-type pad 133 is smaller than the area of ​​an edge N-type pad 131 and larger than the area of ​​a middle N-type pad 132. In this application, by setting a transition N-type pad 133 with an area between the area of ​​the edge N-type pad 131 and the area of ​​the middle N-type pad 132 in the transition region between the middle region and the edge region, a slow transition of the N-type pad bonding force can be ensured, and the flexibility of the interconnect design can be increased, providing effective current collection capability. For example, the P-type pad located in the transition region in the P-type pad row is the transition P-type pad 143 (shown as the wireframe corresponding to the transition P-type pad 143 in Figures 8 to 10). The area of ​​the transition P-type pad 143 is between the area of ​​the edge P-type pad 141 and the area of ​​the middle P-type pad 142. This can also ensure a reasonable and slow transition of the bonding force between the P-type pad and the electrical connector and the battery body, increase the flexibility of the interconnect design and provide effective current collection capability, and reduce costs.

[0164] Understandably, for a row of pads, taking a P-type pad row as an example, in addition to the main tension between the pads and electrical connectors in the edge region, the pads in the region near the edge region (e.g., the transition region, or the third region) also have a large tension with the electrical connectors. Therefore, in some examples, in the region near the edge region (e.g., the transition region, or the third region), the total area of ​​multiple P-type pads is greater than the total area of ​​multiple N-type pads, or the area of ​​one P-type pad is greater than the area of ​​one N-type pad. In other regions, such as the edge region, the middle region, the second region, and the first region, the areas of P-type pads and N-type pads can be equal.

[0165] It should be noted that the transition region in this application may overlap with at least one of the aforementioned second and third regions. Alternatively, the transition region in this application may be relatively independent of the aforementioned second and third regions, both of which are within the scope of protection of this application.

[0166] In some examples, the middle region corresponds to the first and second regions, and the transition region corresponds to the third region.

[0167] In other examples, the middle region corresponds to the first region, and the transition region corresponds to the second and third regions.

[0168] In some other examples, the middle region corresponds to the second region, and the transition region corresponds to the third region.

[0169] For example, in Figure 9, in the second direction Y, the area above dashed line L1 and below dashed line L4 can be considered as an edge region, the area between dashed lines L2 and L3 can be considered as an intermediate region, and the areas between dashed lines L2 and L1, and between dashed lines L3 and L4 can be considered as two transition regions. The dashed lines L1 to L4 here are only for illustrating different regions; there is no such clear division on the battery body or the first surface of the battery body.

[0170] The dimensions of N-type pad 13 and P-type pad 14 are not limited. For example, along the second direction Y, the width of N-type pad 13 and P-type pad 14 can be selected from 130μm, 150μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 270μm, and 300μm, and along the first direction X, the length of N-type pad 13 and P-type pad 14 can be selected from 500μm, 600μm, 800μm, 900μm, 1000μm, 1050μm, 1100μm, 1200μm, 1300μm, 1400μm, and 1500μm.

[0171] In the second direction Y, the spacing between adjacent N-type pads 13 or adjacent P-type pads 14 can be 800μm, 810μm, 830μm, 850μm, 860μm, 900μm, 910μm, 940μm, 950μm, 990μm, 1000μm, 1000μm, 1100μm, 1200μm, 1300μm, 1400μm, or 1500μm.

[0172] In some embodiments, the length of a transition N-type pad 133 can be from 0.8 mm to 1.2 mm, such as 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, or 1.2 mm, and the width of a transition N-type pad 133 can be selected from 0.2 mm to 0.3 mm, such as 0.2 mm, 0.22 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, or 0.3 mm. For example, the dimensions of a transition N-type pad 133 include at least one of the following: 1 mm × 0.25 mm, 0.9 mm × 0.21 mm, 1 mm × 0.21 mm, 1 mm × 0.3 mm, or 0.9 mm × 0.21 mm. Transition N-type pads 133 of the above dimensions have good electrical connection effects and are easy to manufacture.

[0173] In some embodiments, in the transition region: the total area of ​​all P-type pads in a row of P-type pads is greater than the total area of ​​all N-type pads in a row of N-type pads. Optionally, in the transition region, the area of ​​any transition P-type pad 143 is greater than the area of ​​any transition N-type pad 133. Increasing the contact area between the transition P-type pad 143 and the electrical connector and battery body in the transition region improves the bonding strength of the transition P-type pad 143, reduces the difference in bonding strength between the transition P-type pad 143 and the N-type pads in the transition region, and improves the overall bonding strength difference between the P-region and the N-region, thereby improving the connection reliability of the electrical connectors on the battery cell.

[0174] It should be noted that in an N-type pad row, the number of edge N-type pads 131, transition N-type pads 133, and middle N-type pads 132 is not specifically limited, nor is the size relationship between the numbers specified.

[0175] In some embodiments, in an N-type pad row, the number of transition N-type pads 133 is between the number of edge N-type pads 131 and the number of middle N-type pads 132, and the number of middle N-type pads 132 is greater than the number of edge N-type pads 131. The number of middle N-type pads 132 with the smallest area is the largest, which can save materials and reduce costs. At the same time, by transitioning with an appropriate number of transition N-type pads 133, the uniformity of bonding force can be further ensured, the flexibility of interconnect design can be increased, and the effective current collection capability can be provided.

[0176] For example, in Figures 8 to 10, in an N-type pad row, there are 2 edge N-type pads 131, 8 transition N-type pads 133, and 11 middle N-type pads 132.

[0177] It should be noted that in a row of P-type pads, the number of edge P-type pads 141, transition P-type pads 143, and middle P-type pads 142 is not specifically limited, nor is the size relationship between the numbers.

[0178] In some embodiments, in a row of P-type pads, the number of transition P-type pads 143 is between the number of edge P-type pads 141 and the number of intermediate P-type pads 142, and the number of intermediate P-type pads 142 is greater than the number of edge P-type pads 141. This can also save materials and reduce costs. At the same time, by transitioning with an appropriate number of transition P-type pads 143, the bonding force can be further ensured to be uniform and consistent, and the flexibility of the interconnect design can be increased and the effective current collection capability can be provided.

[0179] When the size of a P-type pad is larger than the size of an N-type pad in at least one of the three regions—edge region, middle region, and transition region—the bonding force of the electrical connector corresponding to the P-region can be improved. This reduces the difference in bonding force between the P-region and N-region segments of the electrical connector, thereby improving the reliability of the photovoltaic module's electrical connection. For example, in the transition region, the area of ​​any P-type pad is larger than the area of ​​any N-type pad; that is, the total area of ​​multiple P-type pads is greater than the total area of ​​multiple N-type pads. In the edge region and middle region, the area of ​​the P-type pad is equal to the area of ​​the N-type pad.

[0180] In some embodiments, referring to Figures 8 to 10, an N-type pad array is an axisymmetric figure, and the direction of the axis of symmetry is parallel to the second direction. In the first direction, the distance from the current or charge carrier at each position to the N-type pad 13 in the N-type pad array is approximately equal, the transmission loss is small, and the collection effect of the current or charge carrier at each position is relatively balanced.

[0181] The P-type pad array is an axisymmetric pattern, with the axis of symmetry parallel to the second direction. This results in lower transmission loss and more balanced collection of current or charge carriers at various locations.

[0182] In some embodiments, referring to FIG8, the area or size of each intermediate N-type pad 132 in an N-type pad column is the same. The fabrication processes of each intermediate N-type pad 132 in an N-type pad column can be compatible, resulting in lower production costs.

[0183] In other embodiments, a plurality of intermediate N-type pads 132 in an N-type pad column include the aforementioned second repeating units. For example, in FIG9, all intermediate N-type pads 132 in the leftmost N-type pad column include the aforementioned three second repeating units, each second repeating unit including a first pad and a second pad, wherein the area of ​​the first pad is smaller than the area of ​​the second pad.

[0184] In some embodiments, referring to Figures 8 to 10, the area or size of each intermediate P-type pad 142 in a P-type pad column is the same (for example, the wireframe corresponding to the intermediate P-type pad 142 in Figure 8). The fabrication processes of each intermediate P-type pad 142 in a P-type pad column can be compatible, resulting in lower production costs.

[0185] It should be noted that, in the middle region, when all the middle P-type pads 142 have the same area or size, and all the middle N-type pads 132 have the same area or size, the relationship between the area or size of one middle P-type pad 142 and the area or size of one middle N-type pad 132 is not limited. For example, the area or size of one middle P-type pad 142 can be greater than or equal to the area or size of one middle N-type pad 132.

[0186] In other embodiments, referring to Figures 8 to 10, a plurality of intermediate P-type pads 142 in a P-type pad column include the aforementioned second repeating units. For example, in Figure 9, all intermediate P-type pads 142 in the middle P-type pad column include three second repeating units (shown as three wireframes between dashed lines L2 and L3 in Figure 9), each second repeating unit including a first pad and a second pad, the area of ​​the first pad being smaller than the area of ​​the second pad.

[0187] It should be noted that, in the intermediate region, when both the intermediate N-type pad 132 and the intermediate P-type pad 142 include the aforementioned second repeating unit, the area of ​​the second pad in the second repeating unit of the intermediate P-type pad 142 can be greater than or equal to the area of ​​the second pad in the second repeating unit of the intermediate N-type pad 132, and the area of ​​the first pad in the second repeating unit of the intermediate P-type pad 142 can be greater than or equal to the area of ​​the first pad in the second repeating unit of the intermediate N-type pad 132.

[0188] In some embodiments, the length-to-width ratio of any pad in this application (in this application, any undefined pad appearing at any position can refer to at least one or any one of P-type pads, N-type pads, first pads, second pads, third pads, fourth pads, and subsequently fifth pads) is between 3 and 8. In this case, the pad length is relatively large, allowing the entire width range of the electrical connector to be fixed. Simultaneously, the pad width is not too small relative to its length, allowing the electrical connector to be fixed along its maximum length; furthermore, while maintaining a large contact area between the electrical connector and the pad, the production cost of the pad is reduced.

[0189] For example, the length-to-width ratio of any pad can be: 3, 3.2, 3.5, 3.8, 4, 4.1, 4.5, 4.8, 5, 5.2, 5.5, 5.9, 6, 6.3, 6.5, 6.9, 7, 7.2, 7.5, 7.8, 8.

[0190] In some embodiments, as shown in Figures 9 to 11, at least one N-type pad 13 and / or at least one P-type pad 14 includes: a middle portion 41 (also referred to as a main connection segment) and extension portions 42 (also referred to as auxiliary connection segments) located at both ends of the middle portion 41 in a first direction X, wherein the width of the extension portion is smaller than the width of the middle portion, the direction in which the width is located is parallel to the second direction Y, the length of the middle portion is 0.9-1.1 times the width of the electrical connector, and the length of the extension portion is 0.4-0.6 times the width of the electrical connector. Compared to rectangular or square designs, in this design, the central portion 41 of the pad along the first direction X is typically the main location for electrical connection between the pad and the electrical connector. The central portion 41 has a relatively large width, and its length is approximately equal to the width of the electrical connector, ensuring a large contact area between the pad and the connector, which helps reduce current loss. The extension portion at the end of the pad along the first direction X is mainly used to accommodate any possible offset of the electrical connector in that direction. This ensures a good electrical connection even with potential offsets. The extension portion has a smaller width, and its length is well-matched to the potential offset of the electrical connector along the first direction X. This not only accommodates potential offsets but also avoids wasted space and reduces pad cost. For example, the shapes of the central P-type pad 142 and the central N-type pad 132 include spindle shapes. The directions of the extension length, the central portion length, and the width of the electrical connector are all parallel to the first direction X.

[0191] For example, the length of the middle section is 0.9 times, 0.92 times, 0.93 times, 0.95 times, 0.96 times, 0.97 times, 0.99 times, 1 time, 1.02 times, 1.05 times, 1.08 times, 1.09 times, or 1.1 times the width of the electrical connector, and the length of the extension section is 0.4 times, 0.42 times, 0.45 times, 0.46 times, 0.48 times, 0.49 times, 0.5 times, 0.52 times, 0.53 times, 0.55 times, 0.57 times, 0.58 times, 0.59 times, or 0.6 times the width of the electrical connector.

[0192] For example, the length of the middle portion of a pad can be approximately 0.9 mm, with the length parallel to the first direction X. Referring to Figure 11, in the first direction X, at least one central N-shaped pad 132 is narrow at both ends and wide in the middle, forming an overall elongated ellipse (also known as a spindle shape). The length of the wide middle portion 41 can be approximately 0.6 mm, and the length of the narrow extensions 42 at both ends can be approximately 0.15 mm. Therefore, the length of the central N-shaped pad 132 is approximately 0.9 mm. The dimensions of the spindle-shaped central P-shaped pad 142 can be the same as this, or slightly larger; no specific limitation is made.

[0193] In some embodiments, referring to Figures 9 to 11, an N-type fine gate has two N-type pads of the same material but different areas, such as the first and second pads described above. Similarly, a P-type fine gate has two P-type pads of the same material but different areas, such as the first and second pads described above. For example, the area of ​​the first P-type pad may be greater than or equal to the area of ​​the first N-type pad, and / or the area of ​​the second P-type pad may be greater than or equal to the area of ​​the second N-type pad. The effects are as described above and will not be repeated here.

[0194] In some embodiments, referring to Figures 9 to 12, on an N-type grid, two N-type pads of the same material but different areas are arranged adjacently. Among the adjacent N-type pads, the larger N-type pad can improve the welding reliability with electrical connectors, while the smaller N-type pad helps reduce the area occupied on the battery body surface, reducing composite material usage and lowering costs. Referring to Figures 9 to 12, on a P-type grid, two P-type pads of the same material but different areas are arranged adjacently, and the beneficial effects are similar to those of the aforementioned N-type pads.

[0195] In some embodiments, along the second direction Y, the battery body includes multiple regions. Within the same region of the battery body, along the first direction X, the total area of ​​the multiple pads in the first pad column and the total area of ​​the multiple pads in the last pad column are both greater than the total area of ​​the multiple pads in the middle pad column. Here, the first pad column and the last pad column are opposite each other in the first direction. In the first direction X, the first and last pad columns, being located near the edge of the battery, have higher requirements for welding reliability; therefore, the areas of the first and last pad columns can be increased to meet welding quality requirements.

[0196] It should be noted that, along the first direction X, the first pad column or the last pad column can be an N-type pad column or a P-type pad column.

[0197] In the embodiments of this application, the N-type pad, P-type pad, first pad, second pad, third pad, fourth pad and fifth pad are made of the same material, which facilitates the simultaneous printing of different pads and improves process efficiency.

[0198] In some embodiments, referring to FIG19, the N-type pad 13 overlaps with the N-type fine gate 1, and along the second direction Y, the width ratio of the two portions of the N-type pad 13 on both sides of the N-type fine gate 1 is M; the P-type pad 14 overlaps with the P-type fine gate 2, and along the second direction Y, the width ratio of the two portions of the P-type pad 14 on both sides of the P-type fine gate 2 is Q; M is not equal to Q. That is, along the second direction Y, the N-type pad 13 is divided into two parts by the N-type fine gate 1, and the P-type pad 14 is divided into two parts by the P-type fine gate 2. The division ratio of the two parts of the N-type pad 13 is different from that of the two parts of the P-type pad 14. Consequently, at least in the positions between a portion of the N-type fine gate 1 and the P-type fine gate 2, adjacent N-type pads 13 and P-type pads 14 along the second direction Y exhibit mutual avoidance, resulting in a larger spacing between adjacent N-type pads 13 and P-type pads 14 along the second direction Y, which is beneficial for insulation between pads of different polarities. Here, the relationship between Q and M can be M > Q, or Q > M. The determination of M here can be the ratio of the dimension w1 of the upper portion of the N-type pad 13 on the surface near the battery body, along the second direction Y, located on the upper side of the N-type fine grid 1, to the dimension w2 of the lower portion of the N-type pad 13 on the surface near the battery body, along the second direction Y, located on the lower side of the N-type fine grid 1, i.e., w1 / w2 = M. The determination of Q is the same as M, i.e., Q = w3 / w4, and will not be elaborated further to avoid repetition.

[0199] Based on the general inventive concept of the embodiments of this application, referring to FIG20, another embodiment of this application provides a back contact battery 100. The back contact battery 100 includes a battery body 10, a plurality of first fine grids 20 and a plurality of second fine grids 30 extending along a first direction X; the first fine grids 20 and the second fine grids 30 are alternately and sequentially disposed on a first surface of the battery body 10 along a second direction Y; the first surface includes a first region A and a first side and a second side disposed opposite to each other along the second direction Y; in the first region A, a plurality of first pads 40 and a plurality of second pads 50 are disposed on both the first fine grids 20 and the second fine grids 30; the area of ​​the first pads 40 is smaller than the area of ​​the second pads 50. In the first direction X, the plurality of first pads 40 and the plurality of second pads 50 on the first fine gate 20 have a plurality of first repeating units, and / or, the plurality of first pads 40 and the plurality of second pads 50 on the second fine gate 30 have a plurality of first repeating units, and / or, in the second direction Y, the plurality of first pads 40 and the plurality of second pads 50 on the plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged in columns, and each column has a plurality of second repeating units arranged along the second direction Y. Each first repeating unit and each second repeating unit includes at least one first pad 40 and at least one second pad 50. The first surface of the back contact battery 100 also includes at least one region (taking the third region C as an example in FIG. 20), which is the same as or different from the first region A (exemplified in FIG. 20 as a region different from the first region A), in which the area of ​​the P-type pad 14 is larger than the area of ​​the N-type pad 13. Furthermore, in this embodiment, both the first pad 40 and the second pad 50 are arranged within the first region A. Since the area of ​​the first pad 40 is smaller than that of the second pad 50, the smaller area of ​​the first pad 40 helps reduce the area occupied by the pad on the surface of the battery body 10, and also reduces the consumption of metal paste during manufacturing, thereby reducing metal composite loss, improving photoelectric collection efficiency, and reducing production costs. The second pad 50, with its larger area, is more conducive to improving welding stability, reducing the occurrence of cold solder joints, and further improving the reliability of current collection. Additionally, by setting a larger area for the P-type pad 14 in the same region, the adhesion area between the P-type pad 14 and the battery body, and the bonding area with the electrical connector, can be increased, thereby enhancing the bonding force between the battery and the electrical connector, making the bond between them firm, virtually eliminating the risk of pull-out, and making the electrical connection more reliable.

[0200] In Figure 20, the first surface of the back contact battery 100 further includes a second region B located between the first region A and the third region C, and an edge region D located between the third region C and the first edge. All pads in the second region B are third pads, and the area of ​​any third pad is greater than the area of ​​any second pad. In the third region C, the area of ​​the P-type pad 14 is greater than or equal to the area of ​​the N-type pad 13. In the first region A, the area of ​​the first pad 40 of the P-type pad 14 is greater than or equal to the area of ​​the first pad 40 of the N-type pad 13, and the area of ​​the second pad 50 of the P-type pad 14 is greater than or equal to the area of ​​the second pad 50 of the N-type pad 13. In the second region B and the edge region D, the area of ​​the P-type pad 14 is greater than or equal to the area of ​​the N-type pad 13. Optionally, in the third region C, the area of ​​one P-type pad 14 is greater than the area of ​​one N-type pad 13. In the first region A, the area of ​​a first pad 40 of a P-type pad 14 is equal to the area of ​​a first pad 40 of an N-type pad 13, and the area of ​​a second pad 50 of a P-type pad 14 is equal to the area of ​​a second pad 50 of an N-type pad 13. In the second region B and the edge region D, the area of ​​a P-type pad 14 is equal to the area of ​​an N-type pad 13.

[0201] Referring to Figure 20, in the first surface of the back contact battery 100, both the third region C and the second region B typically have one or more but less than or equal to ten fine grids of the same polarity, for example, one to six fine grids of the same polarity. For the fine grids of the same polarity, the number of such fine grids in the third region C is greater than or equal to the number of such fine grids in the second region B.

[0202] In this embodiment, other related content can be referred to the foregoing relevant records. To avoid repetition, it will not be repeated here.

[0203] Figure 11 is a partially enlarged schematic diagram of the portion outlined by the largest dashed box in Figure 10. This application also provides a photovoltaic module, including any of the aforementioned back contact cells and electrical connectors connecting adjacent back contact cells. The electrical connectors are fixed to the previous cell body via N-type pads and to the next cell body via P-type pads, forming a cell string. The cell strings in the photovoltaic module can be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, busbars can be used to connect the cell strings. The number of back contact cells in this photovoltaic module is not limited. The photovoltaic module may also include encapsulating films located on opposite sides of the back contact cells; other structures in the photovoltaic module are not specifically limited.

[0204] In photovoltaic modules, on an electrical connector, the total area of ​​the N-type pads fixed to it is smaller than the total area of ​​the P-type pads fixed to it. By increasing the total area of ​​the P-type pads fixed to the electrical connector, the bonding force between the electrical connector and the P-type pads is increased, making the bonding force between the electrical connector and the P-type pads more balanced and improving the reliability of the electrical connector.

[0205] On an electrical connector, the height of the N-type pad it is fixed to is less than the height of the P-type pad it is fixed to. Therefore, without considering the height difference between the P and N regions of the solar cell, the top surface of the N-type pad fixed to the connector is lower than the top surface of the P-type pad it is fixed to. The top surface of the pad refers to the surface of the pad facing away from the solar cell body. For a given electrical connector, the P-type pad it is fixed to is taller, and its top surface is higher. Under the same pressure, the distance between the top surface of the P-type pad and the connector is closer, resulting in a stronger bond. This increases the contact area and the bonding force between the connector and the P-type pad, making the connection more secure and virtually eliminating the risk of pull-out.

[0206] In some embodiments, the photovoltaic module further includes multiple cell strings, each containing multiple back-contact cells connected in series. The total area of ​​the P-type pads in the P-type pad column of the back-contact cell A1 in cell string A is greater than the total area of ​​the N-type pads in the N-type pad column of the back-contact cell B1 in cell string B. Since the total area of ​​the P-type pad columns in different cell strings of the photovoltaic module is still greater than the total area of ​​the N-type pad columns, this ensures that the total area of ​​the P-type pad columns in the module is always greater than the total area of ​​the N-type pad columns, thereby improving the overall series reliability of the module.

[0207] In some embodiments, the material of the N-type pad 13 includes a first metal paste, such as a first high-temperature paste or a first low-temperature paste; the material of the P-type pad 14 includes a second metal paste, such as a second high-temperature paste or a second low-temperature paste. The high-temperature paste and low-temperature paste mentioned here can be referred to the aforementioned relevant descriptions and will not be repeated here. The bonding force between the second metal paste and the electrical connector is greater than the bonding force between the first metal paste and the electrical connector. The second metal paste, with its greater bonding force with the electrical connector, also enhances the bonding pull force, such as welding pull force, between the P-type pad and the electrical connector, resulting in a strong bond with virtually no risk of pull-out, and a more reliable electrical connection. For example, the second metal paste of the P-type pad 14 may contain a larger proportion of organic components by mass to improve its bonding force; however, this is not specifically limited.

[0208] In some embodiments, the surfaces of the battery body covered by N-type pads, P-type pads, the first pad, the second pad, the third pad, the fourth pad, and the fifth pad are all smooth surfaces or polished surfaces (e.g., they can be a tower-like textured structure), which can increase the contact area between the N-type pads or P-type pads and the electrical connectors.

[0209] In some embodiments, the overlap area of ​​the P-type fine gate with one (e.g., only one or each) P-type pad overlapping with the P-type fine gate is greater than or equal to the overlap area of ​​the N-type fine gate with one (e.g., only one or each) N-type pad overlapping with the N-type fine gate. Alternatively, the total overlap area of ​​the P-type fine gate with all P-type pads overlapping with the P-type fine gate is greater than or equal to the total overlap area of ​​the N-type fine gate with all N-type pads overlapping with the N-type fine gate. A larger overlap area between the P-type fine gate and the P-type pad results in a larger electrical connection area between the P-type fine gate and the P-type pad, enhancing the bonding force between the P-type fine gate and the P-type pad. This indirectly enhances the bonding pull force between the P-type fine gate and the electrical connector, making the connection strong and virtually eliminating the risk of pull-out, thus ensuring a more reliable electrical connection.

[0210] Referring to Figures 12 and 13, the battery body includes: an N-type doped layer 15 and a P-type doped layer 16, with an N-type fine grid 1 and an N-type pad 13 disposed on the N-type doped layer, and a P-type fine grid 2 and a P-type pad 14 disposed on the P-type doped layer.

[0211] Referring to Figure 12, the P-type doped layer and the N-type doped layer can be of non-equal width design. This can be referred to the aforementioned description of non-equal width design, and will not be repeated here. Referring to Figure 13, the back contact cell may also include an interface dielectric layer 17, which can be a tunneling oxide layer, etc., without specific limitations. An isolation region 18 is also provided between adjacent N-type doped layers 15 and P-type doped layers 16. The isolation region 18 is mainly used for electrical isolation to prevent short circuits. In some embodiments, the silicon substrate 19 may include an N-type doped substrate, which has advantages such as high minority carrier lifetime, no light decay, and good performance in weak light. In the first direction X, the width of a P-type doped layer 16 can be approximately 420 μm, the width of an N-type doped layer 15 can be approximately 250 μm, the width of an isolation region 18 can be approximately 240 μm, the linewidth of the N-type fine gate 1 can be approximately 25 μm, and the linewidth of the P-type fine gate 2 can be approximately 35 μm.

[0212] In this application, the electrode structure may not contain busbars, or may contain very few busbars, or may contain a large number of busbars; no specific limitation is made. N-type pad 13 may be part of N-type fine gate 1, or may be provided separately. When N-type pad 13 is part of N-type fine gate 1, the width of N-type pad 13 is greater than the linewidth of the remaining portion of N-type fine gate 1. P-type pad 14 may be part of P-type fine gate 2, or may be provided separately. When P-type pad 14 is part of P-type fine gate 2, the width of P-type pad 14 is greater than the linewidth of the remaining portion of P-type fine gate 2. In this application, when the electrode structure contains busbars, the busbars and pads can be formed in the same process to simplify the process. All pads can be formed in the same process, or formed in batches according to their shape and area.

[0213] Figure 14 shows a partial structural schematic diagram of a photovoltaic module according to this application. The photovoltaic module includes an electrical connector 22 and any of the aforementioned back contact cells. The electrical connector 22 electrically connects each N-type pad 13 in the N-type pad row of one back contact cell to each P-type pad 14 in the P-type pad row of the other back contact cell. The electrical connector 22 serves as a conductive interconnect. The electrical connector can be directly or indirectly connected to the aforementioned pads; neither is limited. For example, solder paste can be applied to the N-type and P-type pads to form a solder paste layer, and then the solder paste layer can be used to achieve the electrical connection between the N-type and P-type pads and the electrical connector.

[0214] In some embodiments, referring to FIG14, the electrical connector 22 includes: a first portion 221 disposed on an N-type pad row, and a second portion 222 disposed on a P-type pad row; the width of the second portion 222 is greater than the width of the first portion 221. The first portion 221 and the second portion 222 of the aforementioned electrical connector 22 refer to the same electrical connector; in FIG14, the first portion 221 and the second portion 222 shown refer to two electrical connectors. Here, the main improvement is to increase the width of the second electrical connector 222 disposed on the P-type pad row, thereby increasing the contact area between the P-type pad row and the electrical connector, and thus enhancing the bonding force between the P-type pad row and the electrical connector, making the connection firm and virtually eliminating the risk of pull-out, resulting in a more reliable electrical connection. It should be noted that the direction in which the width of the second electrical connector 222 is located, and the direction in which the width of the first electrical connector 221 is located, are both parallel to the first direction X.

[0215] In some embodiments, the width of the N-type pad 13 and the width of the P-type pad 14 in the second direction Y are both smaller than the width of the electrical connector 22 in the first direction X.

[0216] In some embodiments, the length of the N-type pad 13 and the length of the P-type pad 14 in the first direction X can be 1 to 2 times the width of the electrical connector 22 in the first direction X, so that even if there are process deviations, it can be ensured that the N-type pad and the P-type pad 14 have a large contact area with the electrical connector.

[0217] For example, the length of the pad in the first direction X is 1, 1.1, 1.2, 1.25, 1.3, 1.4, 1.5, 1.6, 1.65, 1.7, 1.8, 1.9, or 2 times the width of the electrical connector 22 in the first direction X.

[0218] It should be noted that, at the intersection of the electrical connector and the non-polar grid line, referring to Figures 8 to 11 and Figure 14, a design with interrupted non-polar grid lines can be used; referring to Figures 1, 2, 7, 19, and 20, a continuous non-polar grid line design (without interruption) can also be used. In either the interrupted or continuous design, an insulating block 23 can be placed between the non-polar grid line and the electrical connector to ensure that the electrical connector is insulated from the non-polar grid line while electrically connecting to the same-polar fine grid. Specifically, for continuously designed non-polar grid lines, an insulating block 23 is placed at the intersection of the non-polar grid line and the electrical connector; for interrupted non-polar grid lines, an insulating block 23 is placed at the intersection of the extension line of the non-polar grid line and the electrical connector.

[0219] This application also provides a photovoltaic system comprising: a plurality of any of the aforementioned photovoltaic modules. The photovoltaic modules can be arrayed in the photovoltaic system, and the photovoltaic system can be installed on a building or in an outdoor environment, without limitation.

[0220] It should be noted that the related aspects between photovoltaic modules and photovoltaic systems in this application can be referenced, but to avoid repetition, they will not be repeated here.

[0221] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A back-contact battery, wherein, It includes a battery body, a plurality of first fine grids extending along a first direction, and a plurality of second fine grids; The first fine grid and the second fine grid are alternately spaced along a second direction on the first surface of the battery body; The first surface includes a first region; Within the first region, both the first fine gate and the second fine gate are provided with a plurality of first pads and a plurality of second pads; the area of ​​the first pad is smaller than the area of ​​the second pad; Wherein, in the first direction, the first fine gate and / or the second fine gate have a plurality of first repeating units; and / or, in the second direction, a plurality of first pads and a plurality of second pads on the plurality of first fine gates and the plurality of second fine gates are respectively arranged in columns, and each column has a plurality of second repeating units arranged along the second direction, wherein the first repeating unit and the second repeating unit each include at least one first pad and at least one second pad.

2. The back contact battery according to claim 1, wherein, The first repeating unit includes a first pad and a second pad; and / or, the second repeating unit includes a first pad and a second pad.

3. The back contact battery according to claim 1, wherein, The first pad and the second pad have different lengths in the first direction; And / or, the width of the first pad and the second pad are different in the second direction; And / or, the first pad and the second pad have different shapes.

4. The back contact battery according to claim 1, wherein, The first pad and the second pad have the same length in the first direction and the same width in the second direction, but the first pad and the second pad have different shapes.

5. The back contact battery according to claim 1, wherein, The outer contour of the second pad is rectangular or racetrack-shaped; and / or, The first pad includes a central portion and extensions located on both sides of the central portion in the first direction. The outer contour of the central portion is rectangular or racetrack-shaped, and the outer contour of the extensions is trapezoidal, semi-elliptical, or triangular; and / or, In the second direction, the width of the middle portion is greater than the width of the extension portion.

6. The back contact battery according to claim 1, wherein, The first surface further includes a first side and a second side disposed opposite to each other along the second direction, and a second region disposed between the first region and the first side and adjacent to the first region along the second direction; in the second region, a plurality of third pads are disposed on both the first fine gate and the second fine gate, which are spaced apart along the first direction, and the third pads on each of the first fine gates are staggered with the third pads on the adjacent second fine gates in the second direction, and the third pads on the adjacent first fine gates are arranged in a row in the second direction; The area of ​​the second pad is smaller than the area of ​​the third pad.

7. The back contact battery according to claim 6, wherein, The third pad has a different length from the second pad in the first direction; And / or, the width of the third pad is different from that of the second pad in the second direction; And / or, the third pad has a different shape than the second pad.

8. The back contact battery according to claim 7, wherein, The length of the third pad in the first direction is the same as that of the second pad, and the width of the third pad in the second direction is greater than that of the second pad.

9. The back contact battery according to claim 6, wherein, The first surface further includes a third region disposed along the second direction between the second region and the first edge and adjacent to the second region; In the third region, both the first fine gate and the second fine gate are provided with a plurality of fourth pads arranged at intervals along the first direction, and the fourth pads on each of the first fine gates and the fourth pads on the adjacent second fine gates are staggered in the second direction, and the fourth pads on each of the first fine gates and the adjacent first fine gates are arranged in a row in the second direction. The area of ​​the third pad is smaller than the area of ​​the fourth pad.

10. The back contact battery according to claim 9, wherein, The fourth pad has a different length from the third pad in the first direction; And / or, the width of the fourth pad is different from that of the third pad in the second direction; And / or, the fourth pad has a different shape than the third pad.

11. The back contact battery according to claim 10, wherein, The fourth pad is longer than the third pad in the first direction, and the width of the fourth pad is the same as that of the third pad in the second direction.

12. The back contact battery according to any one of claims 9-11, wherein, The first pad has a dimension of 0.9mm-1.1mm in the first direction and a dimension of 0.19mm-0.25mm in the second direction; and / or, The second pad has a dimension of 0.9mm-1.1mm in the first direction and a dimension of 0.19mm-0.3mm in the second direction; and / or, The third pad has a dimension of 0.9mm-1.3mm in the first direction and a dimension of 0.19mm-0.4mm in the second direction; and / or, The fourth pad has a dimension of 0.9mm-1.5mm in the first direction and a dimension of 0.19mm-0.5mm in the second direction.

13. The back contact battery according to claim 9, wherein, The back contact battery also includes multiple first doped layers and multiple second doped layers; The first doped layer and the second doped layer are arranged alternately along the second direction, with each first doped layer disposed between a corresponding first fine grid and the battery body, and each second doped layer disposed between a corresponding second fine grid and the battery body; The first doped layer and the second doped layer have different doping types; In the second and / or third region, the first or second doped layer protrudes at least partially along the second direction to form a receiving region to accommodate the corresponding third or fourth pad.

14. The back contact battery according to any one of claims 9-11, wherein, The first surface further includes an edge region, which is disposed between the third region and the first edge, and the edge region is adjacent to the first edge; Within the edge region F, a plurality of fifth pads are respectively provided on the first fine gate and the second fine gate adjacent to the first edge, and the area of ​​the fifth pad is larger than that of the fourth pad. An end line is also provided between the fifth pad and the first side, and in the second direction, one end of the end line is connected to the corresponding fifth pad, and the other end is connected to the corresponding first fine gate or second fine gate near the first side.

15. The back contact battery according to claim 14, wherein, The fifth pad has the same length as the fourth pad in the first direction, and its width in the second direction is greater than that of the fourth pad; and / or, The fifth pad has a size of 0.9mm-1.1mm in the first direction and a size of 1.1mm-1.8mm in the second direction.

16. The back contact battery according to claim 14, wherein, The first fine gate or the second fine gate is a disconnected structure at the location where the first pad, the second pad, the third pad, the fourth pad, or the fifth pad is provided.

17. The back contact battery according to claim 1, wherein, One of the first fine grid and the second fine grid is an N-type fine grid, and the other is a P-type fine grid. The back contact battery also includes: an N-type pad array and a P-type pad array. The N-type pad column and the P-type pad column are alternately distributed along the first direction; the N-type pad column includes a plurality of N-type pads arranged in a row along the second direction, and the N-type pads are electrically connected to the N-type fine gate; the P-type pad column includes a plurality of P-type pads arranged in a row along the second direction, and the P-type pads are electrically connected to the P-type fine gate. Along the second direction, the first surface includes multiple regions, and the area of ​​the P-type pad in the same region is larger than the area of ​​the N-type pad.

18. The back contact battery according to claim 17, wherein, The total area of ​​the multiple P-type pads in the P-type pad column is greater than the total area of ​​the multiple N-type pads in the N-type pad column.

19. The back contact battery according to claim 17, wherein, In the second direction, the first surface includes: two edge regions that are distributed opposite to each other, and an intermediate region located between the two edge regions; In the edge region, the total area of ​​the plurality of P-type pads in a P-type pad column is greater than the total area of ​​the plurality of N-type pads in an N-type pad column. And / or, in the intermediate region, the total area of ​​the plurality of P-type pads in a P-type pad column is greater than the total area of ​​the plurality of N-type pads in an N-type pad column.

20. The back contact battery according to claim 19, wherein, The first surface further includes: a transition region located between the edge region and the middle region; the area of ​​the P-type pad in the transition region is smaller than the area of ​​the P-type pad in the edge region and larger than the area of ​​the P-type pad in the middle region; the area of ​​the N-type pad in the transition region is smaller than the area of ​​the N-type pad in the edge region and larger than the area of ​​the N-type pad in the middle region. In the transition region: the total area of ​​the plurality of P-type pads in a P-type pad column is greater than the total area of ​​the plurality of N-type pads in an N-type pad column.

21. The back contact battery according to claim 17, wherein, In the same region of the first surface, along the first direction, the total area of ​​multiple pads in the first pad column and the total area of ​​multiple pads in the last pad column are both greater than the total area of ​​multiple pads in the middle pad column.

22. The back contact battery according to claim 1, wherein, On an N-type fine gate, there are two N-type pads of the same material but different areas; and / or, On a P-type fine gate, there are two P-type pads with the same material but different areas.

23. The back contact battery according to claim 17, wherein, N-type pads are made of the same material as P-type pads; and / or, The N-type pad and the N-type fine gate overlap, and the width ratio of the two parts of an N-type pad on both sides of the N-type fine gate is M; the P-type pad and the P-type fine gate overlap, and the width ratio of the two parts of a P-type pad on both sides of the P-type fine gate is Q; M is not equal to Q.

24. The back contact battery according to claim 19, wherein, In the edge region, the aspect ratio of the P-type pad is E; In the middle region, the aspect ratio of the P-type pad is F; The number of P-type pads located in the middle region is more than 9 times the number of P-type pads located in the edge region, and F is greater than 3E.

25. The back contact battery according to any one of claims 17 to 24, wherein, The battery body includes an N-type doped substrate, and / or the surfaces of the battery body covered by N-type pads and P-type pads are polished surfaces; And / or, the length-to-width ratio of an N-type pad and / or a P-type pad is between 3 and 8; the length of the pad is in the direction parallel to the first direction, and the width of the pad is in the direction parallel to the second direction.

26. The back contact battery according to any one of claims 17 to 25, wherein, The overlap area between the P-type fine gate and the P-type pad is greater than the overlap area between the N-type fine gate and the N-type pad.

27. A photovoltaic module, wherein, Includes a back contact battery and an electrical connector as described in any one of claims 1 to 26, wherein the electrical connector connects to an adjacent back contact battery, the electrical connector is electrically connected to the same type of first fine grid through the first pad, the electrical connector is connected to the same type of second fine grid through the second pad, and an insulating block is provided between the electrical connector and the opposite type of first fine grid or second fine grid.

28. The photovoltaic module according to claim 27, wherein, On an electrical connector, the total area of ​​the N-type pads fixed to it is smaller than the total area of ​​the P-type pads fixed to it.

29. The photovoltaic module according to claim 27 or 28, wherein, The photovoltaic module includes multiple battery strings, each battery string including multiple back-contact batteries connected in series; the total area of ​​the P-type pads in the P-type pad column of the back-contact battery A1 in battery string 1 is greater than the total area of ​​the N-type pads in the N-type pad column of the back-contact battery B1 in battery string 2.

30. The photovoltaic module according to claim 27 or 28, wherein, The first pad includes a central portion and extensions located on both sides of the central portion in the first direction; the length of the central portion is 0.9 to 1.1 times the width of the electrical connector, and the length of the extensions is 0.4 to 0.6 times the width of the electrical connector; the direction in which the length of the central portion, the direction in which the width of the electrical connector, and the direction in which the length of the extensions are located are all parallel to the first direction; And / or, The electrical connector includes: a first portion disposed on an N-type pad column, and a second portion disposed on a P-type pad column; Along the first direction, the width of the second part is greater than the width of the first part.

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