Back-contacted photovoltaic cell and photovoltaic module

Abstract

Back-contacted photovoltaic cell, comprising: a cell base (100) with a central area (110) and two peripheral areas (120) arranged on two opposite sides of the central area (110); a plurality of first fingers (210) and a plurality of second fingers (220), wherein the plurality of first fingers (210) is arranged in the central region (110) and the plurality of second fingers (220) is arranged in the two outer regions (120), wherein the plurality of first fingers (210) extends in a first direction (X) and is arranged at intervals in a second direction (Y) that intersects the first direction (X), wherein the two outer regions (120) are spaced apart from each other in the second direction (Y);wherein the plurality of second fingers (220) comprises a plurality of first sets and a plurality of second sets arranged alternately in the second direction (Y) at intervals, wherein the second fingers (220) in the same set of the plurality of first sets and the plurality of second sets extend along the same straight line in the first direction (X) and adjacent second fingers (220) in the same set are spaced apart from each other in the first direction (X); ; at least one central connecting line (310) and a pair of lateral connecting lines (320) arranged in each of the two boundary regions (120), wherein the at least one central connecting line (310) and the pair of lateral connecting lines (320) extend in the second direction (Y); wherein the pair of lateral connecting lines (320) is each arranged close to two opposite edges of the cell base (100) in the first direction (X), and the at least one central connecting line (310) is arranged between the pair of lateral connecting lines (320) in a common boundary region (120), wherein one connecting line of the at least one central connecting line (310) and one connecting line of the pair of lateral connecting lines (320) are each electrically connected to second fingers (220) having the same electrical polarity as the respective connecting line in the plurality of second fingers (220); and a pair of auxiliary connecting lines (340) which is located close to the two opposite edges, extends in the second direction (Y) through the central area (110) and is each electrically connected to the pair of lateral connecting lines (320); where in the first direction (X) the pair of lateral connecting lines (320) is wider than the pair of auxiliary connecting lines (340).

Description

TECHNICAL AREA

[0001] Various embodiments of the present disclosure relate to the field of photovoltaic cell technology, in particular to a back-contacted photovoltaic cell and a photovoltaic module. BACKGROUND

[0002] In solar photovoltaic technology, the most distinctive feature of back-contact cells is that both the PN junction and the contact metals are located on the back side of the cell. The front of the back-contact cell completely avoids shading by metal grid electrodes, thus maximizing the use of incident light, reducing optical losses, and achieving a higher short-circuit current.

[0003] In related technologies, back-end contact cells typically use busbars to connect fingers of the same electrical polarity, and then solder pads on the busbars are used to weld them to ribbons. However, the carriers on the fingers not connected to the solder pads must first be transferred to the busbars and then through the solder pads to the ribbons. This transport path is long, resulting in low carrier transport efficiency.

[0004] Therefore, the question of how to design a back-contacted photovoltaic cell with high transport efficiency is a problem that needs to be addressed by experts. SUMMARY

[0005] Embodiments of the present disclosure provide a back-contacted photovoltaic cell and a photovoltaic module which contribute at least to solving the problem of low carrier transport efficiency in the path between the fingers by means of busbars.

[0006] According to some embodiments of the present disclosure, a back-contacted photovoltaic cell is provided, which includes a cell base. The cell base has a central region and two edge regions arranged on two opposite sides of the central region.

[0007] The back-contacted photovoltaic cell further includes a plurality of first fingers and a plurality of second fingers. The plurality of first fingers is arranged in the central region, and the plurality of second fingers is arranged in the two peripheral regions. The plurality of first fingers extends in a first direction and is arranged at intervals in a second direction that intersects the first direction. The two peripheral regions are spaced apart in the second direction. The plurality of second fingers includes a plurality of first sets and a plurality of second sets that are arranged alternately at intervals in the second direction. The second fingers of the same set in the plurality of first sets and the plurality of second sets extend along the same straight line in the first direction, and adjacent second fingers of the same set are spaced apart in the first direction.The back-contacted photovoltaic cell further includes at least one central connection line and a pair of lateral connection lines, which are arranged in each of the two edge regions and electrically connected to the second fingers of the same electrical polarity, with the at least one central connection line and the pair of lateral connection lines extending in the second direction. The pair of lateral connection lines is each located near two opposite edges of the cell base in the first direction, and the at least one central connection line is located between the pair of lateral connection lines in an equal edge region.Each connecting line of the at least one central connecting line and of the pair of lateral connecting lines is electrically connected to second fingers that have the same electrical polarity as the respective connecting line in the plurality of second fingers. The back-contacted photovoltaic cell further includes a pair of auxiliary connecting lines located near the two opposite edges, extending secondarily through the central region, and each electrically connected to the pair of lateral connecting lines. In the first direction, the pair of lateral connecting lines is wider than the pair of auxiliary connecting lines.

[0008] According to some embodiments of the present disclosure, a back-contacted photovoltaic cell is provided. The back-contacted photovoltaic cell has a central region and two edge regions arranged on two opposite sides of the central region. The back-contacted photovoltaic cell includes at least one grid line structure, including a first grid line structure in the central region and two second grid line structures arranged in the two edge regions. The first grid line structure includes a plurality of first fingers, the plurality of first fingers extending continuously in a first direction and arranged at intervals in a second direction that intersects the first direction. The two edge regions are spaced apart from each other in the second direction.The second grid line structure includes at least one first set of second fingers and at least one second set of second fingers, arranged alternately at intervals in the second direction. The first set of second fingers and the second set of second fingers each include a plurality of second fingers extending along the same straight line in the first direction and spaced apart from one another. The back-contacted photovoltaic cell further includes two connection line structures, each located in the two edge regions. The two connection line structures each include at least one central connection line and a pair of lateral connection lines, the at least one central connection line and the pair of lateral connection lines extending in the second direction.The pair of lateral connection lines is arranged close to two opposite edges of the back-contacted photovoltaic cell in the first direction, and the at least one central connection line is located between the pair of lateral connection lines. Each connection line of the at least one central connection line and of the pair of lateral connection lines is electrically connected to second fingers that have the same electrical polarity as the respective connection line in the at least one first set of second fingers and the at least one second set of second fingers. A pair of auxiliary connection lines, arranged close to the two opposite edges, extends through the central region in the second direction and is electrically connected to each pair of lateral connection lines.In the first direction, the pair of lateral connecting lines is wider than the pair of auxiliary connecting lines.

[0009] In some embodiments, in the first direction at least one central connecting line has a greater width than the two lateral connecting lines.

[0010] In some embodiments, in the first direction, the at least one central connecting line has a first width W1, the pair of lateral connecting lines has a second width W2; in the second direction, the plurality of first fingers and the plurality of second fingers have a third width W3, where W1 > W2 > W3, 400 µm ≥ W1 ≥ 250 µm, 250 µm ≥ W2 ≥ 50 µm, 50 µm ≥ W3 ≥ 15 µm.

[0011] In some embodiments, the rear-contacted photovoltaic cell further includes a plurality of welded structures that are electrically connected to the plurality of first fingers, the at least one central connecting line, or the pair of lateral connecting lines.

[0012] The multitude of weld structures includes a multitude of first weld structures located in the two boundary regions near the central region, and a respective first weld structure from the multitude of first weld structures that is electrically connected to a connecting line having the same electrical polarity as the respective first weld structure in the at least one central connecting line and the pair of lateral connecting lines.

[0013] The multitude of weld structures further includes a multitude of second weld structures arranged in the central area, comprising a first group of second weld structures with first electrical polarity, electrically connected to first fingers exhibiting the first electrical polarity in the multitude of first fingers, and a second group of second weld structures with second electrical polarity, electrically connected to first fingers exhibiting the second electrical polarity in the multitude of first fingers.

[0014] In some embodiments, the adjacent second fingers of the same set are separated from each other by a distance in the first direction.

[0015] The respective first weld structure has two ends, each electrically connected to second fingers having the same electrical polarity as the respective first weld structure in two adjacent sets closest to the central region in the plurality of first sets and the plurality of second sets, or wherein the respective first weld structure has one end electrically connected to second fingers having the same electrical polarity as the respective first weld structure in a first set closest to the central region in the plurality of first sets and the plurality of second sets, and the other end electrically connected to a first finger having the same electrical polarity as the respective first weld structure and closest to the edge regions in the plurality of first fingers.

[0016] The respective first weld structure extends in the second direction from one end to the other end through the gap between adjacent second fingers, which have a different electrical polarity than the respective first weld structure, in a second set that is closest to the central area in the multitude of first sets and the multitude of second sets.

[0017] In some embodiments, the plurality of first welded structures includes at least one central welded section and a pair of lateral welded sections, the at least one central welded section being electrically connected to the at least one central connecting line, and the pair of lateral welded sections being electrically connected to the pair of lateral connecting lines.

[0018] In some embodiments, the photovoltaic cell further comprises extension connection lines that electrically connect a respective lateral weld section of the pair of lateral weld sections to a corresponding lateral weld section of the pair of lateral connection lines.

[0019] The distance between each lateral weld section and a first edge closest to each lateral weld section is greater than the distance between the corresponding lateral connecting line and the first edge.

[0020] In some embodiments, the extension connecting line has a fourth width W4 in the second direction, the lateral connecting line has a second width W2 in the first direction, where W2 = W4.

[0021] In some embodiments, the plurality of first welded structures in the second direction has a first length L1 and the plurality of second welded structures has a second length L2, where L1 is greater than L2.

[0022] In some embodiments, the central weld section has a third length L3 in the second direction, and the lateral weld section has a fourth length L4, where L4 > L3.

[0023] In some embodiments, the lateral weld section in the second direction has a fourth length L4, wherein the distance dimension between adjacent first fingers or adjacent second fingers has a distance length G, where 4 × G > L4 > 2 × G.

[0024] In some embodiments, the lateral connecting line in the first direction has a second width W2 and the auxiliary connecting line has a fifth width W5, where 250 µm≥W2≥50 µm and 200 µm≥W5≥30 µm.

[0025] In some embodiments, the plurality of second fingers includes a first interrupted grid arranged on one side of the respective lateral weld section facing the first edge, and a first extension connecting finger extending in the second direction and arranged on the side of the respective lateral weld section facing the first edge, each electrically connected to the interrupted grid and a second finger having the same electrical polarity as the first extension connecting finger.

[0026] In some embodiments, the plurality of first fingers includes a second interrupted grid arranged on one side of the respective lateral weld section facing the first edge, and a second extension connecting finger extending in the second direction and arranged on the side of the respective lateral weld section facing the first edge, each electrically connected to the second interrupted grid and to a first finger having the same electrical polarity as the second extension connecting finger, which is adjacent to the respective lateral weld section in the second direction in the plurality of second fingers.

[0027] In some embodiments, the two end edges of the cell base that extend in the second direction are first edges, and the two end edges of the cell base that extend along the first direction are second edges.

[0028] A distance between a first end of the respective connecting line and a corresponding second edge that is closest to the first end in the second direction is smaller than a distance from the corresponding second edge to a second finger that is electrically connected to the respective connecting line and is closest to the corresponding second edge in the plurality of second fingers.

[0029] The distance between the second end of a second finger, which is electrically connected in the first direction to a corresponding lateral connecting line, and a corresponding first edge that is closest to the second end, is less than the distance between the lateral connecting line and the corresponding first edge.

[0030] In some embodiments, each auxiliary connecting line of the pair of auxiliary connecting lines is electrically connected to first fingers that have the same electrical polarity as the respective auxiliary connecting line in the plurality of first fingers.

[0031] In some embodiments, the two end edges of the cell base extending in the second direction are first edges, and the two end edges of the cell base extending in the first direction are second edges.

[0032] A distance between a third end of the first fingers that are electrically connected to the respective auxiliary connecting line and a corresponding first edge that is closest to the respective auxiliary connecting line in the second direction is smaller than the distance between the auxiliary connecting line and the corresponding first edge.

[0033] In some embodiments, the pair of auxiliary connecting lines and the multitude of first fingers are crosswise connected to each other.

[0034] In some embodiments, the second fingers are connected crosswise to each other at the points where they are connected to the at least one central connecting line or the pair of lateral connecting lines.

[0035] According to some embodiments of the present disclosure, a photovoltaic module is provided. The photovoltaic module includes at least one cell string formed by connecting a plurality of back-contacted photovoltaic cells, each of the plurality of back-contacted photovoltaic cells being the aforementioned; strips configured to connect adjacent back-contacted photovoltaic cells of the plurality of back-contacted photovoltaic cells; at least one encapsulation film configured to cover the surfaces of the plurality of back-contacted photovoltaic cells; and at least one cover plate arranged on a surface of the at least one encapsulation film facing away from the plurality of back-contacted photovoltaic cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] One or more embodiments are illustrated by way of example and in combination with the figures in the accompanying drawings. These exemplary descriptions do not constitute limitations of the embodiments. The figures in the accompanying drawings do not constitute a limitation relating to proportions unless otherwise indicated. For better illustration of the embodiments of the present disclosure or of the technical solutions in the prior art, the drawings used in the embodiments or the related prior art are briefly described below. Obviously, the drawings in the following description are only some of the embodiments of the present disclosure. For those skilled in the art, further drawings can be derived from these drawings without creative effort. Fig. Figure 1 is a schematic structural diagram of a back-contacted photovoltaic cell according to an embodiment of the present disclosure. Fig. Figure 2 is a schematic structural diagram of a back-contacted photovoltaic cell according to another embodiment of the present disclosure. Fig. Figure 3 is a schematic structural diagram of a finger of a back-contacted photovoltaic cell according to the embodiment of the present disclosure. Fig. Figure 4 is a schematic diagram of a photovoltaic module according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0037] As can be seen from the prior art, related technologies typically use busbars to connect grid line structures of the same electrical polarity, and then weld structures on the busbars are used to weld on ribbons, thus reducing the number of weld structures. However, in this structure, the carriers on the grid line structures not connected to the weld structures must first be transferred to the busbar and then pass through the weld structures to the ribbons. The carrier transport efficiency in this way is low, which impairs the photoelectric conversion efficiency of the back-contacted photovoltaic cell, and the provision of busbars increases the cost of the paste.The back-contacted photovoltaic cell described in the embodiments of the present disclosure may be an Interdigitated Back Contact (IBC) photovoltaic cell.

[0038] Some embodiments of the present disclosure provide a back-contacted photovoltaic cell in which the grid line structure in the central region of the cell base is configured as a collecting finger and the grid line structure in the edge region is configured as a converging finger. The collecting fingers are directly electrically connected to the weld structures, and the transmission path for the carriers collected by the collecting fingers to the weld structures is short, thereby improving the carrier transport efficiency. Converging fingers of the same electrical polarity are electrically connected to the weld structures via connecting lines. The width of a central connecting line, which connects more converging fingers, is greater than the width of a lateral connecting line, which is arranged on both sides and connects fewer converging fingers.The wider central connection line has a lower internal resistance, which improves the transport efficiency of the charge carriers within the central connection line and improves the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0039] In the description of embodiments of this disclosure, technical terms such as "first," "second," etc., are used only to distinguish between different objects and should not be interpreted as indicating or implying a relative importance or implicitly defining the quantity, specific sequence, or primary-secondary relationship of the specified technical features. In the description of embodiments of this disclosure, the term "a plurality of" means two or more unless expressly and specifically defined otherwise. Similarly, "a plurality of groups" means two or more groups (including two groups), and "a plurality of parts" means two or more parts (including two parts).

[0040] In this document, the reference to "embodiment" means that a particular feature, structure, or property described in connection with the embodiment may be included in at least one embodiment of the present disclosure. The occurrence of this term in different places in the patent specification does not necessarily refer to the same embodiment, nor to an independent or alternative embodiment that is mutually exclusive with other embodiments. Persons skilled in the art will understand, explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

[0041] In the description of the embodiments of the present disclosure, the term "and / or" merely describes an associative relationship between related objects, indicating that three relationships are possible. For example, "A and / or B" can indicate the following three cases: the presence of only A; the presence of both A and B; and the presence of only B. Additionally, the symbol " / " in this patent specification generally indicates an "or" relationship between the preceding and subsequent related objects.

[0042] In the description of the embodiments of this disclosure, technical terms indicating orientation or position relationships, such as "center," "longitudinal," "transverse," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "above," "below," "inside," "outside," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like, are based on the orientation or position relationships illustrated in the accompanying drawings. These terms are used only to describe the embodiments of this disclosure and to simplify the description, rather than indicating or suggesting that the device or element in question must have a specific orientation or be designed and operated in a specific orientation. Therefore, these terms should not be interpreted as limiting the embodiments of this disclosure.For example, if the fixture or element in the diagram is reversed, then an element described as "under," "below," "below," or "at the bottom" of another element or feature would then be oriented "above" or "on top" of that other element or feature. The term "below" can therefore encompass both an orientation from above and from below, depending on the context, which should be obvious to a professional in this field. Materials can also be oriented in other ways (e.g., rotated 90 degrees, inverted, mirrored), and the spatially relative descriptors used here should be interpreted accordingly.

[0043] In the description of the embodiments of this disclosure, technical terms such as "install," "connect," "couple," "fasten," and the like are to be interpreted broadly unless expressly stated and defined otherwise. For example, the technical term may refer to a permanent connection, a detachable connection, or an integral connection. The technical term may refer to a mechanical connection, an electrical connection, or both. The technical term may refer to a direct connection, an indirect connection via an intermediate part, internal communication between two elements, or an interaction relationship between two elements. A person skilled in the art will be able to understand the specific meanings of the foregoing terms in the embodiments of this disclosure based on the specific context.

[0044] In the drawings corresponding to the embodiments of the present disclosure, the thicknesses and areas of layers are exaggerated for clarity and ease of description. Furthermore, when a component is described as being formed "substantially" on another component, this means that the component is formed neither on the entire surface (or front face) of the other component, nor on any part of the edge of the entire surface.

[0045] When, in the description of embodiments of the present disclosure, a component is described as "comprising" or "including" another component, this does not preclude the presence of other components unless otherwise specified, and other components may also be included. Forming or providing a second component on or above a first component, or forming or providing a second component on a surface of a first component, or forming or providing a second component on a side of a first component may include embodiments in which the first component and the second component are in direct contact, and may also include embodiments in which additional components are present between the first and the second component, such that these components are not in direct contact.For simplification and clarity, various components may be arbitrarily represented at different scales. Some layers / components may have been omitted from the drawings for clarity. Unless otherwise specified, forming or providing a second component on the surface of a first component means that the first and second components are in direct contact. In this context, the aforementioned "component" may refer to a layer, film, region, section, structure, etc.

[0046] The terminology used in the description of the various embodiments serves only to describe specific embodiments and is not intended to be restrictive. As used in the description of the various embodiments and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Herein, a component includes components such as a layer, a film, an area, a plate, etc.

[0047] The embodiments of the present disclosure are described in detail with reference to the accompanying drawings. However, those skilled in the field will understand that many technical details are presented in the various embodiments of the present disclosure to facilitate readers' understanding. Nevertheless, the technical solutions claimed in the disclosure can also be implemented without these technical details and based on various changes and modifications of the following embodiments.

[0048] Fig. 1 and Fig. Figure 2 are schematic structural diagrams of back-contacted photovoltaic cells according to embodiments of the present disclosure.

[0049] With reference to Fig. 1 The rear-contacted photovoltaic cell includes a cell base 100, at least one grid line structure 200 and at least one connection line structure 300.

[0050] The cell base 100 encloses a central region 110 and two boundary regions 120, which are arranged on two opposite sides of the central region 110. For illustration, see Fig. 1 a first direction X and a second direction Y that intersects with the first direction X, where the second direction Y is a direction in which the two boundary regions are spaced 120 apart.

[0051] The at least one grid line structure 200 includes a plurality of first fingers arranged in the central region 110 and a plurality of second fingers, each arranged in the two boundary regions 120. In the embodiments of the present disclosure, the first fingers are configured as collecting fingers 210 in the central region 110 and the second fingers are configured as converging fingers 220 in the boundary regions 120, as shown in Fig. 1 is shown.

[0052] The collecting fingers 210 arranged in the central region 110 extend continuously in the first direction X and are arranged at intervals in the second direction Y. The plurality of second fingers includes at least one first set of converging fingers 220 and at least one second set of converging fingers 220, which are arranged alternately at intervals in the second direction Y. Each of the first and second sets of converging fingers 220 includes a plurality of converging fingers 220 that extend along the same straight line in the first direction and are spaced apart from each other in the first direction.

[0053] The at least one connecting line structure 300 is arranged in the edge regions 120. The connecting line structure 300 is electrically connected to the converging fingers 220 of the same electrical polarity. The connecting line structure 300 includes at least one central connecting line 310 and at least one pair of lateral connecting lines 320 in edge regions 120. Each of the at least one central connecting line 310 and the lateral connecting lines 320 extends in the second direction Y. Each pair of lateral connecting lines 320 in the same edge region 120 is arranged in the first direction X near two opposite edges of the cell base 100. The at least one central connecting line 310 is arranged between the two lateral connecting lines 320.

[0054] In the first direction X, the width of the middle connecting line 310 is greater than the width of the lateral connecting line 320.

[0055] In some embodiments, a rear-contacted photovoltaic cell is provided, which has a central area 110 and two edge areas 120 that are arranged on two opposite sides of the central area 120.

[0056] The back-contacted photovoltaic cell includes at least one grid structure, comprising a first grid structure in the central region and two second grid structures arranged in the two edge regions. The first grid structure includes a plurality of first fingers 210, the plurality of first fingers extending continuously in a first direction X and arranged at intervals in a second direction Y that intersects the first direction. The two edge regions 120 are spaced apart in the second direction Y. The second grid structure includes at least one first set of second fingers and at least one second set of second fingers arranged alternately at intervals in the second direction.The first set of second fingers and the second set of second fingers each include a plurality of second fingers 220 that extend in the first direction along the same straight line and are spaced apart from each other.

[0057] The back-contacted photovoltaic cell further includes two connection line structures, each arranged in the two edge regions. Each of the two connection line structures includes at least one central connection line 310 and a pair of lateral connection lines 320, the at least one central connection line and the pair of lateral connection lines extending in the second direction. The pair of lateral connection lines 320 is arranged close to two opposite edges of the back-contacted photovoltaic cell in the first direction, and the at least one central connection line 310 is arranged between the pair of lateral connection lines.Each connecting line of the at least one middle connecting line 310 and of the pair of lateral connecting lines 320 is electrically connected to second fingers 220, which have the same electrical polarity as the respective connecting line in the at least one first set of second fingers and the at least one second set of second fingers.

[0058] The rear-contacted photovoltaic cell further includes a pair of auxiliary connection lines located close to the two opposite edges, extending in a second direction through the central area, and each electrically connected to the pair of lateral connection lines.

[0059] In the first direction, the pair of lateral connecting lines is wider than the pair of auxiliary connecting lines.

[0060] In the embodiments of the present disclosure, the grid line structure 200 of the cell base 100 is subdivided into a plurality of collecting fingers 210, which are arranged in the central region 110, and a plurality of converging fingers 220, which are arranged in the peripheral regions 120. The collecting fingers 210 are directly electrically connected to the welded structures 400, resulting in a shorter transmission path for the carriers collected by the collecting fingers 210 to the welded structures 400 and thus improving the carrier transport efficiency. The converging fingers 220 of the same electrical polarity are electrically connected to the welded structures 400 via the connecting line 300. The central connecting line 310, which is connected to more converging fingers 220, has a greater width than the lateral connecting lines 320, which are arranged on both sides and are connected to fewer converging fingers 220.The wider central connection line 310 exhibits lower internal resistance, thereby improving the transport efficiency of the carriers within the central connection line 310 and increasing the photoelectric conversion efficiency of the back-contacted photovoltaic cell. By arranging the connection line structure 300 in the edge regions 120, the number of weld structures 400 in the edge regions 120 is reduced, thus avoiding problems such as cracking of the cell base 100 due to stress concentrations during welding of the weld structures 400 and strips, as well as deformation of the cell base 100 due to differing coefficients of thermal expansion between the cell base 100 and the strips. This improves the production yield of the back-contacted photovoltaic cell and extends its service life.

[0061] The embodiments of the present disclosure are described in more detail below with reference to the accompanying drawings.

[0062] Fig. Figure 1 is a schematic structure diagram of a back-contacted photovoltaic cell according to an embodiment of the present disclosure. For illustrative purposes, it shows Fig. 1. A first direction X and a second direction Y, which intersect. In the embodiments of the present disclosure, both the positive and the negative electrode of the back-contacted photovoltaic cell are arranged on the back side of the cell base 100. The back-contacted photovoltaic cell includes a cell base 100, at least one grid line structure 200, at least one connection line structure 300, and a plurality of weld structures 400.

[0063] The cell base 100 is a rectangular, sheet-like structure and exhibits a photoelectric effect. The cell base 100 has a first surface and a second surface that are opposite each other in a third direction. The third direction is the thickness direction of the cell base 100 and intersects both the first direction X and the second direction Y. In the embodiments of the present disclosure, the first surface of the cell base 100 is the light-receiving surface of the back-contacted photovoltaic cell, and the second surface is the back side. The at least one grid line structure 200, the at least one connection line structure 300, and the weld structures 400 are all arranged on the second surface of the cell base 100. In the first direction X, the cell base 100 has two opposite first edges 101. In the second direction Y, the cell base 100 has two opposite second edges 102.The cell base 100 includes the central region 110 and two boundary regions 120, which are arranged on two opposite sides of the central region 110 in the second direction Y, i.e. the two boundary regions 120 are each close to the opposite second edges 102 of the cell base 100.

[0064] In some embodiments, the at least one grid line structure 200, the at least one connecting line structure 300 and the weld structures 400 on the second surface of the cell base 100 are formed by a screen printing process.

[0065] In some embodiments, the cell base 100 can be obtained by cutting an entire cell into 1 / N pieces, i.e., the cell base 100 is an N-segmented cell, where N is a positive integer greater than 1. In other embodiments, the cell base 100 can be an entire cell, i.e., the cell base 100 is a full-size cell.

[0066] In some embodiments, the cell base 100 is obtained by cutting an entire cell into two segments, i.e., the cell base 100 is a cell cut in two (i.e., a halved cell).

[0067] In some embodiments, where the cell base 100 is obtained by cutting an entire cell into N segments, the grid line structure 200, the at least one connection line structure 300, and the weld structures 400 are first formed on the surface of the entire cell by a screen printing process, and then the entire cell is cut into the N-segmented cell base 100 of the embodiments of the present disclosure to form the back-contacted photovoltaic cell of the embodiments of the present disclosure. In other embodiments, the cell base 100 is an entire cell, and the grid line structure 200, the at least one connection line structure 300, and the weld structures 400 are formed on the surface of the cell base 100 by a screen printing process to directly form the back-contacted photovoltaic cell of the embodiment of the present disclosure.

[0068] The at least one grid line structure 200 is arranged on the second surface of the cell base 100 to collect and transport photogenerated carriers, thus enabling the conversion of electrical energy by the back-contacted photovoltaic cell. Since both the positive and negative electrodes of the back-contacted photovoltaic cell are arranged on the back of the cell base 100 in the embodiments of the present disclosure, the electrical polarity of the at least one grid line structure 200 can be either positive or negative. The at least one grid line structure 200 includes a plurality of collecting fingers 210 and a plurality of converging fingers 220. Each of the collecting fingers 210 and the converging fingers 220 extends in the first direction X.The plurality of collecting fingers 210 and the plurality of converging fingers 220, each with a different electrical polarity, are arranged at intervals in the second direction Y. In the embodiments of the present disclosure, the collecting fingers 210 are arranged in the central region 110. Each collecting finger 210 is arranged in a continuous linear pattern in the first direction X. Adjacent collecting fingers 210 in the second direction Y have different electrical polarities. The converging fingers 220 are arranged in the boundary regions 120. A set of converging fingers is formed by a plurality of converging fingers extending along the same straight line in the first direction and spaced apart from one another. In each boundary region 120, a plurality of sets are arranged at intervals in the second direction Y.That is, in each set of converging fingers, there is a gap 2201 between adjacent converging fingers 220 that extend in the same straight line of the first direction X. In each set of converging fingers, the converging fingers 220 that extend in the same straight line of the first direction X have the same electrical polarity. The converging fingers 220 of each set have a different electrical polarity than the converging fingers 220 of adjacent sets in the second direction Y. In the region bordering the central region 110 and the boundary regions 120, adjacent collecting fingers 210 and converging fingers 220 in the second direction Y have different electrical polarities.

[0069] The at least one connection line structure 300 is arranged in the boundary regions 120 to collect the carriers transported by the converging fingers 220. The at least one connection line structure 300 in each boundary region 120 includes at least one central connection line 310 and a pair of lateral connection lines 320. The at least one central connection line 310 and the pair of lateral connection lines 320 extend in the second direction Y. The electrical polarity of the at least one connection line structure 300 can be either positive or negative, and each connection line structure 300 is electrically connected to the converging fingers 220 of the same electrical polarity. In the same boundary region 120, two lateral connection lines 320 are arranged symmetrically on two opposite edges of the boundary region 120 in the first direction X.Two lateral connecting lines 320 on both sides are located near the opposite first edges 101 of the cell base 100. The converging fingers 220 and the at least one central connecting line 310 are arranged between the symmetrical lateral connecting lines 320. The at least one central connecting line 310 extends in the second direction Y and is arranged in the columns 2201 between converging fingers 220 of opposite electrical polarity. The at least one central connecting line 310 is electrically connected to the converging fingers 220 of the same electrical polarity, which are arranged in the second direction Y on both sides of the central connecting line 310.Each lateral connecting line 320 extends in the second direction Y and is electrically connected to the converging fingers 220 of the same electrical polarity, which are arranged on one side of the lateral connecting line 320.

[0070] The lateral connecting lines 320 and the at least one central connecting line 310 are arranged at intervals and uniformly spaced in the first direction X, such that the lengths of the converging fingers 220 connected to each lateral connecting line 320 on both sides are equal, and the lengths of the converging fingers 220 connected to each central connecting line 310 on both sides in the first direction X are equal. The uniform arrangement of the lateral connecting lines 320 and the at least one central connecting line 310 reduces the overall internal resistance of the back-contacted photovoltaic cell, improves the carrier transport efficiency, and thereby increases the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0071] Furthermore, in the first direction X, each of the at least one central connecting line 310 has a first width W1, and each of the lateral connecting lines 320 has a second width W2, where W1 > W2. Since the lateral connecting lines 320 are located at the edge positions of the cell base 100 near the first edges 101, each lateral connecting line 320 is electrically connected to the converging fingers 220 only on one side, and each central connecting line 310 is electrically connected to the converging fingers 220 on both sides. Therefore, the total length of the converging fingers 220 electrically connected to the lateral connecting line 320 is less than the total length of the converging fingers 220 electrically connected to the central connecting line 310.The central connection line 310 must transport more carriers compared to the lateral connection line 320. The central connection line 310 has a greater width than the lateral connection line 320, which reduces the internal resistance of the central connection line 310, improves the carrier transport efficiency, and thereby increases the photoelectric conversion efficiency of the back-contacted photovoltaic cell.In comparison to relevant technologies where the width of the conductor track (corresponding to the at least one connecting line structure 300 in the embodiments of the present disclosure) connected to the fingers (corresponding to the grid line structure 200 in the embodiments of the present disclosure) is uniform, regardless of whether it is wider or narrower, in the present disclosure, based on the total length of the converging fingers 220 connected to the at least one central connecting line 310 and the lateral connecting lines 320, and the total mobility of the carriers to be transported, the width of each central connecting line 310 is set to be greater than that of each lateral connecting line 320.This improves, on the one hand, the carrier transport efficiency and thus the photoelectric conversion efficiency of the back-contacted photovoltaic cell, and on the other hand saves the paste used for the production of the at least one connection line structure 300, thereby reducing production costs.

[0072] In some embodiments, the first width W1 of each middle connecting line 310 satisfies the condition 250 µm ≤ W1 ≤ 400 µm. Preferably, the first width W1 of each middle connecting line 310 is 280 µm, 300 µm, 350 µm, or 370 µm.

[0073] In some embodiments, the second width W2 of each lateral connecting line 320 satisfies the condition 50 µm ≤ W2 ≤ 250 µm. Preferably, the second width W2 of each lateral connecting line 320 is 60 µm, 100 µm, 150 µm, or 200 µm.

[0074] In some embodiments, each of the collecting fingers 210 and the converging fingers 220 has a third width W3 in the second direction Y, which satisfies 15 µm ≤ W3 ≤ 50 µm. Preferably, the third width W3 can be 25 µm, 30 µm, 35 µm, or 40 µm. Furthermore, at locations where converging fingers 220 of the same electrical polarity are connected to at least one central connecting line 310 or the lateral connecting lines 320, the converging fingers 220 and at least one central connecting line or the lateral connecting lines 300 are cross-connected.

[0075] In some embodiments, in the first direction X, for a converging finger 220 connected to a lateral connecting line 320, the distance between an end of the converging finger 220 located near the first edge 101 and the first edge 101 is smaller than the distance between the lateral connecting line 320 and the first edge 101. In other words, the end of the converging finger 220 extends beyond the lateral connecting line 320 of the same electrical polarity to which it is connected. In the second direction Y, the distance between an end of each of the lateral connecting lines 320 and the at least one central connecting line 310 near the second edge 102, as well as the distance between the converging finger 220 of the same electrical polarity that is closest to the second edge 102, and the second edge 102 itself, is smaller than the distance between the converging finger 220 of the same electrical polarity that is closest to the second edge 102 and the second edge 102 itself.In other words, the end of each of the lateral connecting lines 320 and of the at least one central connecting line 310 extends beyond the converging finger 220 of the same electrical polarity that is closest to and connected with the second edge 102. That is, the converging fingers 220 extending in the first direction X penetrate at least one central connecting line 310 and the lateral connecting line 320 (that is closest to the first edge 101) to which the converging fingers 220 are connected, and at least one central connecting line 310 and the lateral connecting line 320 extending in the second direction Y penetrate the converging fingers 220 (that are closest to the second edge 102) to which at least one central connecting line 310 and the lateral connecting line 320 are connected.This cross-connection structure ensures the connection effectiveness between the converging fingers 220 and the at least one connection line structure 300 and avoids problems caused by missing or poor connections due to printing errors.

[0076] Furthermore, in the second direction Y, the end of the central connecting line 310 near the second edge 102 is spaced away from the converging finger 220 of opposite electrical polarity, which is closest to the second edge 102. In other words, the end of the central connecting line 310 near the second edge 102 does not extend beyond the straight line on which the converging finger 220 of opposite electrical polarity, which is closest to the second edge 102, lies. That is, the central connecting line 310 and the converging finger 220 of opposite electrical polarity, which is closest to the second edge 102, are separated from each other in the first direction X. This separation prevents short circuits that could occur if the central connecting line 310 and the converging finger 220, which is closest to the second edge 102, were connected due to printing errors or other reasons.

[0077] A plurality of weld structures 400 are arranged on the second surface of the cell base 100. The weld structures 400 are electrically connected to the collecting fingers 210 or to the at least one connecting conductor structure 300. The weld structures 400 are used for welding with strips, for exporting the current generated by the back-contacted photovoltaic cell to an external circuit, and for achieving series or parallel connections between back-contacted photovoltaic cells to form a closed current path.

[0078] The weld structures 400 include first weld structures 410 and second weld sections 420. The first weld structures 410 are arranged in the edge regions 120 and are electrically connected to the at least one connecting line structure 300 in the edge regions 120. The second weld structures 420 are arranged in the central region 110 and are electrically connected to the collecting fingers 210 in the central region 110.The carriers collected by the converging fingers 220 are successively transferred to the external circuit via at least one connecting line structure 300 and the first welding structures 410 in order to reduce the number of welding structures 400 arranged in the edge areas 120, to avoid problems such as cracks in the cell base 100 due to stress concentrations during welding of the welding structures 400 and the strips, and deformations of the cell base 100 due to different coefficients of thermal expansion between the cell base 100 and the strips, thereby improving the production yield of the back-contacted photovoltaic cell and extending its lifetime.The carriers collected by the collecting fingers 210 are transferred directly to the external circuit via the second welded structure 420, whereby such a transmission path is shorter, thereby improving the carrier transport efficiency and thus increasing the photoelectric conversion efficiency of the back-contacted photovoltaic cell in the embodiments of the present disclosure.

[0079] The first weld structures 410 and the second weld structures 420 of the same electrical polarity are arranged at intervals in the second direction Y, which facilitates welding with strips extending in the second direction Y and exhibiting the same electrical polarity. In some embodiments of the present disclosure, the second weld structures 420 of the same electrical polarity are evenly distributed based on the number of first weld structures 410 of the same electrical polarity, such that the number of second weld sections 420 corresponding to each first weld structure 410 of the same electrical polarity is equal.In some embodiments of the present disclosure, adjacent second weld sections 420 with different electrical polarity in the first direction X are spaced evenly in the first direction X, and adjacent first weld structures 420 with the same electrical polarity in the second direction Y are spaced evenly in the first direction Y to achieve a more uniform distribution of the second weld structures 420 in the central region 110 and to further avoid deformation or tearing of the cell base 100 by welding.

[0080] The first weld structures 410 are arranged in the first direction X at equal intervals, which facilitates a uniform distribution of the internal stresses in the cell base 100 after welding the first weld structures 410 and the second weld structures 420 to the strips and avoids deformation or tearing of the cell base 100 due to local stress concentrations.

[0081] The first weld structures 410 are arranged at the end positions of the at least one connection line structure 300 near the central area 110. That is, the first weld structures 410 are arranged on the side of the edge areas 120 facing away from the second edges 102, thereby further preventing deformation or tearing at the edge positions of the cell base 100.

[0082] Furthermore, in the first direction X, the width dimensions of the first weld structure 410 and the second weld structure 420 are the same, which facilitates simultaneous formation during the printing process in production.

[0083] In the second direction Y, the first welded structure 410 has a first length L1 and the second welded structure 420 has a second length L2, where L1 > L2. The first welded structure 410 includes at least one central welded section 411 and a pair of lateral welded sections 412. The total length of all converging fingers 220 electrically connected to each central welded section 411 is less than the length of the collecting finger 210 electrically connected to each second welded structure 420. The total length of all converging fingers 220 electrically connected to each lateral welded section 412 is greater than the length of the collecting finger 210 electrically connected to each second welded structure 420. The length dimension of the first welded structure 410 is greater than that of the second welded structure 420, thus providing high carrier transport efficiency.

[0084] In some embodiments, the first length L1 of the first weld structure 410 satisfies 0.4 mm ≤ L1 ≤ 2.1 mm. Preferably, the first length L1 of the first weld structure 410 is 0.8 mm, 1 mm, 1.2 mm or 1.4 mm.

[0085] In some embodiments, the second length L2 satisfies 0.08 mm ≤ L2 ≤ 0.4 mm. Preferably, the second length L2 is 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm.

[0086] Furthermore, in the second direction Y, each central weld section 411 has a third length L3 and each lateral weld section 412 has a fourth length L4, where L3 < L4. Since the lateral weld sections 412 are positioned closer to the edge of the cell base 100 and the length dimension of the lateral weld section 412 is greater than that of the second weld structure 420, the increased length dimension of the lateral weld sections 412 increases the weld tensile force after joining the lateral weld sections 412 to the strip, thereby improving the overall structural stability of the back-contacted photovoltaic cell.

[0087] In some embodiments, the third length L3 satisfies 0.4 mm ≤ L3 ≤ 0.8 mm. Preferably, the third length L3 is 0.5 mm, 0.6 mm, 0.65 mm or 0.7 mm.

[0088] In some embodiments, the fourth length L4 satisfies 0.8 mm ≤ L4 ≤ 2.1 mm. Preferably, the fourth length L4 is 0.95 mm, 1 mm, 1.2 mm or 1.4 mm.

[0089] Furthermore, in the second direction Y, the distance dimension between adjacent collecting fingers 210 or between adjacent converging fingers 220 is a distance length g, and the length dimension of the lateral weld sections 412 is the fourth length L4, where 4g > L4 > 2g. The length dimension of the lateral weld section 412 is more than twice the distance length g and less than four times the distance length g, so that the lateral weld section 412 can pass through the gaps 2201 between converging fingers of opposite electrical polarity and connect electrically with the converging fingers 220 or collecting fingers 210 of the same electrical polarity.The lateral weld section 412 can be directly connected to the converging fingers 220 or the collecting fingers 210, thereby shortening the carrier transport path length, improving the carrier transport efficiency and thus increasing the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0090] In some embodiments, the distance g between adjacent collecting fingers 210 or between adjacent converging fingers 220 is 0.5 mm ≤ g ≤ 2 mm. Preferably, the distance g between adjacent collecting fingers 210 or between adjacent converging fingers 220 is 0.8 mm, 0.92 mm, 1 mm or 1.2 mm.

[0091] The first weld structures 410 include the central weld sections 411 and the lateral weld sections 412. The central weld sections 411 are electrically connected to the at least one central connecting line 310. The lateral weld sections 412 are electrically connected to the lateral connecting lines 320. The central weld sections 411 and the lateral weld sections 412, which are arranged in the same edge region, are arranged at intervals in the first direction X.

[0092] In the first direction X, the distance between a lateral weld section 412 and the corresponding first edge 101 is greater than the distance between the lateral connecting line 320 and the first edge 101. As a result, the lateral weld area 412 is located further away from the first edge 101 than the lateral connecting line 320, thus further preventing deformation or tearing at the edge positions of the cell base 100.

[0093] The at least one connection line structure 300 further includes at least one extension connection line 330. The extension connection line 330 extends in the first direction X and is arranged between the lateral weld section 412 and the lateral connection line 320. Two ends of at least one extension connection line 330 are each electrically connected to a lateral weld section 412 and a lateral connection line 320.

[0094] Furthermore, the extension line 330 has a fourth width W4 in the second direction Y. The second width W2 of the lateral connection line 320 satisfies the condition W2=W4. The width of the extension line 330 corresponds to the width of the lateral connection line 320, thus preventing the total internal resistance of the lateral connection line 320 and the extension line 330 from increasing due to an insufficient width of the extension line 330, which would reduce the carrier transport efficiency of the lateral connection line 320.

[0095] In some embodiments, the converging fingers 220 further include interrupted grids 221, which are arranged on the side of the lateral weld sections 412 near the first edges 101, as well as extension connecting fingers 230 for connecting the interrupted grids 221 to the converging fingers 220. The interrupted grid 221 and the converging finger 220 of the same electrical polarity extend in the first direction X. The extension connecting fingers 230 extend in the second direction Y and electrically connect an interrupted grid 221 to an adjacent converging finger 220 of the same electrical polarity. The arrangement of the interrupted grids 221 and the extension connecting fingers 230 increases the coverage of the grid line structure 200 on the surface of the cell base 100, thereby improving the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0096] In some embodiments, the collecting fingers 210 further include interrupted grids 211, which are arranged on the side of the lateral weld sections 412 near the first edges 101, as well as extension connecting fingers 240 for connecting the interrupted grids 211 to the collecting fingers 210. The interrupted grid 211 and the collecting finger 210 of the same electrical polarity extend in the first direction X. The extension connecting fingers 240 extend in the second direction Y and electrically connect an interrupted grid 211 to an adjacent collecting finger 210 of the same electrical polarity. By arranging the interrupted grids 211 and the extension connecting fingers 240, the coverage of the grid line structure 200 on the surface of the cell base 100 is increased, thereby improving the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0097] In some embodiments where interrupted grids 221 are arranged between lateral connection lines 320 and lateral weld sections 412, the extension connecting finger 230 connects the interrupted grid 221 to a converging finger 220. The extension connecting finger extends through the gap between a converging finger 220 of a different electrical polarity, adjacent to the interrupted grid 221, and the lateral connection line 320. In some embodiments where interrupted grids 221 are arranged on the side of the lateral weld sections 412 near the first edge 101 and not between the lateral connection lines 320, the extension connecting fingers 230 connect the interrupted grids 221 to collecting fingers 210, and the extension connecting fingers 230 extend in the second direction Y on the side near the first edge 101.

[0098] As in Fig. Figure 2 shows a schematic structural diagram of a back-contacted photovoltaic cell according to one embodiment of the present disclosure. In other embodiments, the back-contacted photovoltaic cell additionally includes auxiliary connection lines 340. The auxiliary connection lines 340 are arranged on both sides of the cell base 100 near the first edges 101. The auxiliary connection lines 340 extend in the second direction Y, cross the central region 110, and are electrically connected on both sides to the side connection lines 320. The collector fingers 210 within the central region 110 extend through the auxiliary connection lines 340 of the same electrical polarity, so that the auxiliary connection lines 340 are electrically connected to the collector fingers 210 of the same electrical polarity within the central region 110.By arranging the auxiliary connection lines 340 in the central area, the carriers collected by the collecting fingers 210 can be effectively transported in the central area, thus avoiding problems caused by non-connection or poor connection due to printing errors and thereby improving carrier transport efficiency.

[0099] The arrangement of the auxiliary connection lines 340 enables carriers, which are collected by the at least one connection line structure 300 in the edge regions via the converging fingers 220, to be transferred into the external circuit not only via the lateral weld sections 412, but also via the second weld structures 420 on the collecting fingers 210, thereby reducing the overall internal resistance of the back-contacted photovoltaic cell, improving the carrier transport efficiency and thereby increasing the photoelectric conversion efficiency of the back-contacted photovoltaic cell.

[0100] Furthermore, the auxiliary connecting lines 340 and the collecting fingers 210 are cross-connected. This means that the distance between the end of a collecting finger 210 (which is electrically connected to the auxiliary connecting line 340) and the first edge 101 is smaller than the distance between the auxiliary connecting line 340 and the first edge 101. This cross-connection structure ensures the effectiveness of the connection between the collecting fingers 210 and the auxiliary connecting lines 340 and avoids problems such as missing or poor connections due to printing errors.

[0101] In the first direction X, the auxiliary connecting lines 340 have a fifth width W5. The second width W2 of each lateral connecting line 320 and the third width W3 (as in Fig. (3 shown) each collecting finger 210 and each converging finger 220 must satisfy W2 > W5 > W3. The widths are set based on the carrier mobility collected and transported by the lateral connecting lines 320, auxiliary connecting lines 340, collecting fingers 210, and converging fingers 220. This avoids the problem of high internal resistance due to uniformly small dimensions. It also avoids the problem of excessive paste consumption and increased production costs due to uniformly large dimensions. The width settings of the lateral connecting lines 320, auxiliary connecting lines 340, collecting fingers 210, and converging fingers 220 improve carrier transport efficiency, thereby increasing the photoelectric conversion efficiency of the back-contacted photovoltaic cell and reducing production costs.

[0102] In some embodiments, the fifth width W5 satisfies the condition 30 µm ≤ W5 ≤ 200 µm. Preferably, the fifth width W5 can be 50 µm, 70 µm, 85 µm, or 110 µm.

[0103] Accordingly, another embodiment of the present disclosure also provides a photovoltaic module. As in Fig.As shown in Figure 4, the photovoltaic module includes a cell string 1, ribbons, an encapsulation film 2, and a cover plate 3. The cell string 1 is formed by connecting a plurality of back-contacted photovoltaic cells, which are the back-contacted photovoltaic cells described in the embodiments above. The ribbons connect adjacent back-contacted photovoltaic cells. The encapsulation film 2 covers the surfaces of the back-contacted photovoltaic cells. The cover plate 3 is arranged on the surface of the encapsulation film 2, facing away from the back-contacted photovoltaic cells. Parts that are the same as or corresponding to the previous embodiment can be referred to the corresponding description of the previous embodiment, and the detailed description is not repeated here.

[0104] In some embodiments, where the cell base 100 is obtained by dividing a whole cell into 1 / N parts, the grid line structure 200, at least one connection line structure 300, and weld structures 400 are first formed on the surface of the whole cell by a screen printing process, and then the whole cell is divided into the N-part cell base 100 of the embodiments of the present disclosure to construct the back-contacted photovoltaic cell. The bands connect adjacent back-contacted photovoltaic cells to form a cell string. In other embodiments, the cell base 100 is a whole cell, and the grid line structure 200, at least one connection line structure 300, and weld structures 400 are formed on the surface of the cell base 100 by a screen printing process to directly construct the back-contacted photovoltaic cell.The strips connect adjacent back-contacted photovoltaic cells to form a cell string.

[0105] The encapsulation film material can be an ethylene vinyl acetate copolymer film (EVA copolymer film), a polyolefin elastomer film (POE film), a polyvinyl butyral film (PVB film), or another organic encapsulation film.

[0106] The cover plate can be a glass cover plate, a plastic cover plate, or other cover plates with a light-transmitting function. In some embodiments, the surface of the cover plate facing the encapsulation film can be textured to increase the utilization of the incident light.

[0107] A person skilled in the art will understand that the embodiments described above are specific embodiments for implementing the present disclosure. In practical applications, various changes to form and details can be made without deviating from the scope of protection and spirit of the present disclosure. A person skilled in the art can make various changes and modifications without deviating from the spirit and scope of protection of the present disclosure. The scope of protection of the present disclosure is therefore defined by the claims.

Claims

[1] Back-contacted photovoltaic cell comprising: a cell base (100) with a central area (110) and two peripheral areas (120) arranged on two opposite sides of the central area (110); a plurality of first fingers (210) and a plurality of second fingers (220), wherein the plurality of first fingers (210) is arranged in the central region (110) and the plurality of second fingers (220) is arranged in the two outer regions (120), wherein the plurality of first fingers (210) extends in a first direction (X) and is arranged at intervals in a second direction (Y) that intersects the first direction (X), wherein the two outer regions (120) are spaced apart from each other in the second direction (Y);wherein the plurality of second fingers (220) comprises a plurality of first sets and a plurality of second sets arranged alternately in the second direction (Y) at intervals, wherein the second fingers (220) in the same set of the plurality of first sets and the plurality of second sets extend along the same straight line in the first direction (X) and adjacent second fingers (220) in the same set are spaced apart from each other in the first direction (X); at least one central connecting line (310) and a pair of lateral connecting lines (320) arranged in each of the two boundary regions (120), wherein the at least one central connecting line (310) and the pair of lateral connecting lines (320) extend in the second direction (Y); wherein the pair of lateral connecting lines (320) is each arranged close to two opposite edges of the cell base (100) in the first direction (X), and the at least one central connecting line (310) is arranged between the pair of lateral connecting lines (320) in a common boundary region (120), wherein one connecting line of the at least one central connecting line (310) and one connecting line of the pair of lateral connecting lines (320) are each electrically connected to second fingers (220) having the same electrical polarity as the respective connecting line in the plurality of second fingers (220); and a pair of auxiliary connecting lines (340) which is located close to the two opposite edges, extends in the second direction (Y) through the central area (110) and is each electrically connected to the pair of lateral connecting lines (320); where in the first direction (X) the pair of lateral connecting lines (320) is wider than the pair of auxiliary connecting lines (340). [2] Back-contacted photovoltaic cell with a central area (110) and two edge areas (120) arranged on two opposite sides of the central area (110), comprising: at least one grid line structure comprising a first grid line structure in the central region (110) and two second grid line structures in the two boundary regions (120), wherein the first grid line structure includes a plurality of first fingers (210), the plurality of first fingers (210) extending continuously in a first direction (X) and arranged at intervals in a second direction (Y) intersecting the first direction (X), the two boundary regions (120) being spaced apart in the second direction (Y), wherein the second grid line structure includes at least one first set of second fingers (220) and at least one second set of second fingers (220) arranged alternately at intervals in the second direction (Y), the first set of second fingers (220) and the second set of second fingers (220) each including a plurality of second fingers (220).which extends along the same straight line in the first direction (X) and is spaced apart; two connection line structures, each arranged in the two boundary regions (120), wherein the two connection line structures each include at least one central connection line (310) and a pair of lateral connection lines (320), wherein the at least one central connection line (310) and the pair of lateral connection lines (320) extend in the second direction (Y), wherein the pair of lateral connection lines (320) is each arranged close to two opposite edges of the back-contacted photovoltaic cell in the first direction (X), and the at least one central connection line (310) is arranged between the pair of lateral connection lines (320), wherein one connection line of the at least one central connection line (310) and of the pair of lateral connection lines (320) is electrically connected to second fingers (220).which have the same electrical polarity as the respective connecting line in which at least one first set of second fingers (220) and in which at least one second set of second fingers (220) have; and, a pair of auxiliary connecting lines (340) located close to the two opposite edges, extending in the second direction (Y) through the central area (110) and each electrically connected to the pair of lateral connecting lines (320); where in the first direction (X) the pair of lateral connecting lines (320) is wider than the pair of auxiliary connecting lines (340). [3] Photovoltaic cell according to claim 1, wherein in the first direction (X) the at least one central connecting line (310) has a greater width than the pair of lateral connecting lines (320). [4] Photovoltaic cell according to claim 3, wherein in the first direction (X) the at least one central connecting line (310) has a first width W1 and the pair of lateral connecting lines (320) has a second width W2; in the second direction (Y) the plurality of first fingers (210) and the plurality of second fingers (220) have a third width W3, wherein W1 > W2 > W3, 400 µm ≥ W1 ≥ 250 µm, 250 µm ≥ W2 ≥ 50 µm, 50 µm ≥ W3 ≥ 15 µm. [5] Photovoltaic cell according to claim 1, further comprising a plurality of weld structures electrically connected to the plurality of first fingers (210), the at least one central connecting line (310) or the pair of lateral connecting lines (320), wherein the plurality of weld structures includes: a plurality of first weld structures (410) arranged in the two edge regions (120) near the central region (110), and a respective first weld structure (410) from the plurality of first weld structures (410) electrically connected to a connecting line having the same electrical polarity as the respective first weld structure (410) in the at least one central connecting line (310) and the pair of lateral connecting lines (320); a plurality of second weld structures (420) arranged in the central area (110) and comprising a first group of second weld structures (420) with first electrical polarity, electrically connected to first fingers (210) having the first electrical polarity in the plurality of first fingers (210), and a second group of second weld structures (420) with second electrical polarity, electrically connected to first fingers (210) having the second electrical polarity in the plurality of first fingers (210). [6] Photovoltaic cell according to claim 5, wherein the adjacent second fingers (220) of the same set are spaced apart from each other in the first direction (X) by a gap (2201); wherein each first weld structure (410) has two ends, each electrically connected to second fingers (220) having the same electrical polarity as the respective first weld structure (410) in two adjacent sets that are closest to the central area (110) in the plurality of first sets and the plurality of second sets, or wherein each first weld structure (410) has one end that is electrically connected to second fingers (220) that have the same electrical polarity as the respective first weld structure (410) in a first set that is closest to the central area (110) in the plurality of first sets and the plurality of second sets, and the other end that is electrically connected to a first finger (210),which has the same electrical polarity as the respective first weld structure (410) and is closest to the edge regions (120) in the plurality of first fingers (210); wherein the respective first weld structure (410) extends in the second direction (Y) from one end to the other end through the gap (2201) between adjacent second fingers (220) which have a different electrical polarity than the respective first weld structure (410), in a second set which is closest to the central area (110) in the plurality of first sets and the plurality of second sets. [7] Photovoltaic cell according to claim 5 or 6, wherein the plurality of first weld structures (410) includes at least one central weld section (411) and a pair of lateral weld sections (412), wherein the at least one central weld section (411) is electrically connected to the at least one central connecting line (310) and the pair of lateral weld sections (412) is electrically connected to the pair of lateral connecting lines (320); wherein the photovoltaic cell further comprises extension connection lines (330) which each electrically connect a respective lateral weld section (412) of the pair of lateral weld sections (412) to a corresponding lateral weld section (412) of the pair of lateral connection lines (320); wherein a distance between the respective lateral weld section (412) and a first edge (101) that is closest to the respective lateral weld section is greater than the distance between the corresponding lateral connecting line (320) and the first edge (101). [8] Photovoltaic cell according to claim 7, wherein in the second direction (Y) the central weld section (411) has a third length L3, the lateral weld section (412) has a fourth length L4, wherein L4 > L3. [9] Photovoltaic cell according to claim 7, wherein in the second direction (Y) the lateral weld section (412) has a fourth length L4, a distance dimension between adjacent first fingers (210) or adjacent second fingers (220) is a distance length G, wherein 4 × G > L4 > 2 × G. [10] Photovoltaic cell according to claim 1, wherein in the first direction (X) the lateral connecting line (320) has a second width W2 and the auxiliary connecting line (340) has a fifth width W5, wherein 250 µm ≥ W2 ≥ 50 µm and 200 µm ≥ W5 ≥ 30 µm. [11] Photovoltaic cell according to claim 7, wherein the plurality of second fingers includes (220): a first interrupted grid arranged on one side of the respective lateral weld section (412) facing the first edge (101), and a first extension connecting finger extending in the second direction (Y) and located on the side of the respective lateral weld section (412) facing the first edge (101), and electrically connected to the interrupted grid and a second finger (220) having the same electrical polarity as the first extension connecting finger. [12] Photovoltaic cell according to claim 1, wherein two end edges of the cell base extending in the second direction (Y) are first edges (101) and two end edges of the cell base extending in the first direction (X) are second edges; wherein a distance between a first end of the respective connecting line and a corresponding second edge that is closest to the first end in the second direction (Y) is smaller than a distance from the corresponding second edge to a second finger (220) that is electrically connected to the respective connecting line and is closest to the corresponding second edge in the plurality of second fingers (220); and wherein the distance between a second end of a second finger (220) which is electrically connected to a corresponding lateral connecting line (320) in the first direction (X) and a corresponding first edge (101) which is closest to the second end is smaller than the distance between the lateral connecting line (320) and the corresponding first edge (101). [13] Photovoltaic cell according to claim 1, wherein each auxiliary connection line (340) of the pair of auxiliary connection lines (340) is electrically connected to first fingers (210) which have the same electrical polarity as the respective auxiliary connection line (340) in the plurality of first fingers (210). [14] Photovoltaic cell according to claim 13, wherein the two end edges of the cell base extending in the second direction (Y) are first edges (101) and the two end edges of the cell base extending in the first direction (X) are second edges; and wherein the distance between a third end of the first fingers (210) electrically connected to the respective auxiliary connection line (340) and a corresponding first edge (101) nearest to the respective auxiliary connection line (340) in the second direction (Y) is less than the distance between the auxiliary connection line (340) and the corresponding first edge (101). [15] Photovoltaic module, comprising: at least one cell string (1) formed by connecting a plurality of back-contacted photovoltaic cells, wherein each of the back-contacted photovoltaic cells is a back-contacted photovoltaic cell according to any one of claims 1 to 14; Strips configured to connect adjacent back-contacted photovoltaic cells of the multitude of back-contacted photovoltaic cells; at least one encapsulation film (2) configured to cover the surfaces of the plurality of back-contacted photovoltaic cells; and at least one cover plate (3) which is arranged on a surface of the at least one encapsulation film (2) away from the plurality of rear-contacted photovoltaic cells.

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