Back contact battery and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a back contact battery and a photovoltaic module, and the back contact battery comprises a battery substrate which is provided with a first edge; a first grid line, a second grid line, a first connecting line and a second connecting line, the first connecting line is connected with the first grid line, and the second connecting line is connected with the second grid line; the first connecting line comprises an edge connecting line adjacent to the first edge, and the edge connecting line is not provided with a welding part; the second connecting line comprises a collecting part and a spacing part, and the collecting part is connected with the second grid line; one end of the connecting structure is connected with the edge connecting line, and the other end of the connecting structure penetrates through the interval part and is connected with the first connecting line adjacent to the edge connecting line; the end, adjacent to the connecting structure, of the collecting part serves as a first part, the remaining collecting part serves as a second part, and the width of the first part in the second direction is larger than that of the second part in the second direction. The back contact cell provided by the embodiment of the invention at least can improve the photoelectric conversion efficiency of the back contact cell.

Description

Technical Field

[0001] The embodiments of the present application relate to the photovoltaic field, and in particular to a back-contact cell and a photovoltaic module. Background Art

[0002] At present, with the gradual depletion of fossil energy, solar cells are becoming more and more widely used as a new energy alternative. Solar cells are devices that convert sunlight into electrical energy. Solar cells use the photovoltaic principle to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0003] There are two main reasons that affect the photoelectric conversion efficiency and yield of solar cells. One is optical loss, which includes shading loss, carrier recombination loss of the substrate, carrier recombination loss of the highly doped film layer, and refractive loss of the film layer. The other is electrical loss, which includes the resistance loss of the material itself, the contact loss of the electrode, the contact loss between the soldering ribbon and the solar cell, and the problem of cold soldering between the soldering ribbon and the solar cell.

[0004] Therefore, there is an urgent need in the art to provide a solar cell and a photovoltaic module that can reduce electrical loss and optical loss, thereby improving the photoelectric conversion efficiency of the corresponding solar cell and the yield of the photovoltaic module. Summary of the invention

[0005] The embodiments of the present application provide a back-contact cell and a photovoltaic module, which are at least beneficial to improving the photoelectric conversion efficiency of the back-contact cell.

[0006] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a back-contact battery, including: a battery substrate, the battery substrate having a first edge; first grid lines and second grid lines alternately arranged along a first direction; first connecting lines and second connecting lines alternately arranged along a second direction, the first connecting lines are connected to the first grid lines, and the second connecting lines are connected to the second grid lines; wherein the first connecting lines include edge connecting lines adjacent to the first edge, and no welding portion is provided on the edge connecting lines; the second connecting lines include a collecting portion and a spacing portion, and the collecting portion is connected to the second grid lines; a connecting structure, one end of the connecting structure is connected to the edge connecting line, and the other end passes through the spacing portion and is connected to the first connecting line arranged adjacent to the edge connecting line; wherein the collecting portion adjacent to the end of the connecting structure serves as the first portion, and the remaining collecting portion serves as the second portion, and the width of the first portion along the second direction is greater than the width of the second portion along the second direction.

[0007] In some embodiments, a distance d between the second gate line close to the connection structure and the connection structure and a length L of the first portion along the first direction satisfy the following relationship: d≤L≤2d.

[0008] In some embodiments, a length L of the first portion along the first direction ranges from 0.5 mm to 2 mm.

[0009] In some embodiments, the second gate line includes a second collection area and a second bus area, the second connecting line is connected to the second bus area, and the second bus area serves as a welding portion of the second gate line; the width of the second bus area along the first direction is greater than the width of the second collection area along the first direction.

[0010] In some embodiments, a pad is further included, and the pad is located at the intersection of a portion of the second connecting line and the second gate line.

[0011] In some embodiments, the number of the connection structures ranges from 5 to 24.

[0012] In some embodiments, the number of the second gate lines located between adjacent connection structures ranges from 6 to 12.

[0013] In some embodiments, a width of the first portion along the second direction ranges from 50 μm to 100 μm.

[0014] According to some embodiments of the present application, on the other hand, the embodiments of the present application provide a photovoltaic module, including: a battery string, the battery string is formed by connecting a plurality of back-contact batteries as described in any of the above embodiments; a packaging film, the packaging film covers the battery string; and a cover plate, the cover plate is located on a side of the packaging film away from the battery string.

[0015] In some embodiments, the battery string includes: a back-contact battery; a soldering ribbon, which is electrically connected to a second connecting wire; an insulating layer, which is located between the connecting structure and the soldering ribbon; wherein the first portion of the second connecting wire is away from the top surface of the battery substrate and is flush with the top surface of the insulating layer away from the connecting structure.

[0016] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0017] The back contact battery provided by the embodiment of the present application includes a first grid line, a second grid line, a first connection line and a second connection line, wherein the first grid line is connected to the first connection line, the second grid line is connected to the second connection line, the first connection line includes an edge connection line close to the first edge, and no welding part is arranged on the edge connection line, one end of the connection structure is connected to the first connection line, and the other end is provided with a spacer and connected to the first connection line arranged adjacent to the edge connection line, thereby avoiding the problem of edge cracking of the battery substrate, and the carriers at the edge can be collected by the connection structure to improve the battery efficiency. The end of the collecting part adjacent to the connection structure is used as the first part, and the remaining collecting part is used as the second part, the width of the first part along the second direction is greater than the width of the second part along the second direction, that is, the end of the main grid connection line corresponding to the other polarity of the connection structure is widened, the welding tension between the welding strip and the battery substrate is improved, and the problem of cold welding and poor welding quality is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by the figures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the figures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic structural diagram of a back contact battery provided in one embodiment of the present application;

[0020] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0021] Figure 3 A schematic diagram of the structure of a collector in a back contact battery provided in one embodiment of the present application;

[0022] Figure 4 A schematic structural diagram of a back contact battery provided in another embodiment of the present application;

[0023] Figure 5 A partial enlarged view of a back contact battery provided in another embodiment of the present application;

[0024] Figure 6 A schematic structural diagram of a back contact battery provided in yet another embodiment of the present application;

[0025] Figure 7A partial enlarged view of a back contact battery provided in another embodiment of the present application;

[0026] Figure 8 A schematic structural diagram of a photovoltaic module provided in yet another embodiment of the present application;

[0027] Fig. 9 A partial cross-sectional view of a photovoltaic module provided in yet another embodiment of the present application;

[0028] Fig.10 Another partial cross-sectional view of a photovoltaic module provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0029] As can be seen from the background technology, the yield rate of current photovoltaic modules is poor.

[0030] The embodiments of the present application provide a back-contact cell and photovoltaic module. By not setting a welding portion on the edge connecting line to avoid the problem of edge cracking of the cell substrate, a connecting structure is set to achieve the connection between the edge connecting line and the same polarity connecting line, so as to collect carriers in the edge area; secondly, by limiting the width of the second connecting line of the corresponding connecting structure, the welding area between the welding strip and the second connecting line is increased, thereby improving the yield of the photovoltaic module.

[0031] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0032] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0034] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0035] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0036] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0037] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layer are magnified for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component can be "directly" located on the surface of another component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0038] In the description of the embodiments of the present application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

[0039] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the part" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, a component includes a layer, a film, a region, or a plate.

[0040] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0041] According to some embodiments of the present application, on the one hand, an embodiment of the present application provides a back-contact battery.

[0042] Figure 1 A schematic structural diagram of a back contact battery provided in one embodiment of the present application; Figure 2 for Figure 1 A partial enlarged view of the middle A; Figure 3 A schematic structural diagram of a collecting portion in a back contact battery provided in one embodiment of the present application.

[0043] According to some embodiments of the present application, the present application provides a back contact battery. Figure 1 and Figure 2The back contact battery comprises: a battery substrate 100, the battery substrate 100 having a first edge 11; first grid lines 101 and second grid lines 102 arranged alternately along a first direction Y; first connecting lines 111 and second connecting lines 112 arranged alternately along a second direction X, the first connecting lines 111 being connected to the first grid lines 101, and the second connecting lines 112 being connected to the second grid lines 102; wherein the first connecting lines 111 include edge connecting lines 103 adjacent to the first edge 11, and no welding portion is provided on the edge connecting lines 103; and the second connecting lines 112 are arranged alternately along a second direction X. The wiring 112 includes a collecting portion and a spacer portion 104, the collecting portion is connected to the second gate line 102; a connecting structure 110, one end of the connecting structure 110 is connected to the edge connecting line 103, and the other end passes through the spacer portion 104 and is connected to the first connecting line 111 arranged adjacent to the edge connecting line 103; wherein the end of the collecting portion adjacent to the connecting structure 110 serves as the first portion 1121, and the remaining collecting portion serves as the second portion 1122, and the width of the first portion 1121 along the second direction X is greater than the width of the second portion 1122 along the second direction X.

[0044] In some embodiments, the battery substrate 100 can be an IBC (Interdigitated Back Contact), an HPBC (Hybrid Passivated Back Contact), a TBC battery that stacks TOPCon (Tunnel Oxide Passivated Contact) technology and IBC technology, or an HBC battery that stacks HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back contact batteries.

[0045] The battery substrate 100 includes: a substrate, the substrate has a first surface and a second surface that are relatively arranged, the first surface has a velvet structure, and the velvet structure can only add internal reflection of the incident light to reduce optical loss and improve the photoelectric conversion efficiency of the battery. The first surface has a front surface field (FSF), and the conductivity type of its doped ions is the same as the conductivity type of the doped ions of the substrate. The field passivation effect is used to reduce the surface minority carrier concentration, thereby reducing the surface recombination rate, and at the same time, the series resistance can be reduced and the electron transmission capacity can be improved. The first surface also has a first passivation layer and a first anti-reflection layer, the first passivation layer is located on the surface of the front surface field, and the first anti-reflection layer is located on the surface of the first passivation layer. Among them, the battery substrate 100 does not necessarily include a front surface field, a first passivation layer, and a first anti-reflection layer.

[0046] The second surface of the substrate has alternately arranged regions I and II, where region I is one of the P region or the N region, and region II is the other of the P region or the N region, with a gap between the P region and the N region, wherein the first gate line 101 is located in region I, and the second gate line 102 is located in region II.

[0047] In some embodiments, there is no gap between the P region and the N region, and an insulating film layer is provided between the P region and the N region to achieve insulation between the P region and the N region, thereby achieving insulation between the first gate line 101 and the second gate line 102 .

[0048] In some embodiments, the spacer region gap is flush with the P region and the N region, that is, the substrate is not etched, and the P region and the N region are insulated by some isolating film layers, which may be a passivation layer or an intrinsic semiconductor layer.

[0049] In some embodiments, the spacer region gap is lower than the P region and the spacer region gap is lower than the N region. The spacer region gap has a groove, which extends from the second surface toward the first surface. The groove is used to achieve automatic isolation between regions of different conductive types, which can eliminate the leakage caused by the formation of PN junctions between heavily doped P regions and N regions in the IBC battery, thereby affecting the battery efficiency.

[0050] In some embodiments, the surface of the spacer gap may be a polished surface structure, and the surface of the spacer gap may be a suede surface structure.

[0051] In some embodiments, the P region and the N region may have a tunneling silicon oxide layer and a doped polysilicon layer, respectively, wherein the P region has a P-type doped polysilicon layer and the N region has an N-type doped polysilicon layer. In other embodiments, the P region and the N region may have an intrinsic amorphous silicon layer, a doped amorphous silicon layer and a transparent conductive layer, respectively, wherein the P region has a P-type doped amorphous silicon layer and the N region has an N-type doped amorphous silicon layer.

[0052] In some embodiments, a second passivation layer and a second anti-reflection layer are disposed on the P region, the N region, and the spacer region, and the first gate line 101 and the second gate line 102 are located on the second anti-reflection layer.

[0053] In some embodiments, the cell substrate 100 has a first edge 11, a second edge 12 arranged opposite to the first edge 11, and two third edges (not shown) for connecting the first edge 11 and the second edge 12. The junction of the first edge 11 and the third edge and the junction of the second edge and the third edge have chamfers. The reason for the formation of the chamfers is that in conventional solar cells, due to the limitation of the monocrystalline silicon process for preparing the substrate, the monocrystalline silicon rod can only be made into a round shape at present. After the silicon rod is produced, it is sliced, that is, the cross section of the silicon rod is cut into the shape of a monocrystalline silicon wafer (after the area is calculated, it can maximize the illumination area within a unit, and can also maximize the saving of silicon rod materials, and is also convenient for the production of cell substrates and components). Chamfers are often set at the junctions of various boundaries of the substrate to reduce the stress outside the silicon wafer and avoid micro damage to the corners of the silicon wafer.

[0054] In some embodiments, if the sum of the first connection line 111 and the second connection line 112 is an even number, then Figure 1 , the conductive type of the second edge connecting line corresponding to the second edge 12 of the substrate is the same as the conductive type of the second connecting line 112, then the first connecting line 111 arranged adjacent to the second edge connecting line should also be designed corresponding to the above-mentioned second connecting line 112, that is, the second edge connecting line passes through the disconnection point of the first connecting line 111 and is connected to the adjacent second connecting line 112.

[0055] In other embodiments, if the sum of the first connecting line and the second connecting line is an odd number, the conductive type of the second edge connecting line corresponding to the second edge of the substrate is the same as the conductive type of the first connecting line, the setting of the second edge connecting line is the same as the setting of the edge connecting line, and the second connecting line arranged adjacent to the second edge connecting line must also be designed like the corresponding second connecting line mentioned above.

[0056] No welding portion is provided at the edge connection line 103 close to the first edge 11, so as to avoid the damage of the edge of the battery substrate due to the stress of the welding strip.

[0057] A connection structure 110 is provided to connect the edge connection line 103 with a first connection line 111 provided adjacent to the edge connection line 103 to increase the collection rate of the current generated by the substrate at the first edge 11 and reduce the defective rate of the battery.

[0058] In some embodiments, the material of the connection structure 110 is the same as that of the first gate line 101. The slurry of the connection structure 110 is the same as that of the first gate line 101, that is, the connection structure 110 is composed of a burn-through slurry, and the connection structure 110 also penetrates the passivation layer to be electrically connected to the corresponding collection film layer, so that the connection structure 110 can not only realize the current through-connection between the edge connection line 103 and the adjacent first connection line 111, but the connection structure 110 can also collect the current on the substrate surface by itself, thereby increasing the collection path and improving the efficiency of current collection.

[0059] In some embodiments, the slurry of the connection structure 110 is the same as the slurry of the main grid, that is, the connection structure 110 is composed of a non-burn-through type slurry, and the connection structure 110 is located on the surface of the passivation layer. In this way, it is not necessary to layout the area I and the area II on the surface of the substrate below the connection structure 110 to prevent the connection structure 110 from being in electrical contact with the doped area of ​​another polarity, resulting in a short circuit. In addition, the connection structure 110 can avoid damage to the passivation layer, so that the integrity of the film layer of the passivation layer can be guaranteed, thereby improving the passivation effect of the passivation layer on the substrate, which is beneficial to reducing the optical loss of the solar cell, thereby improving the photoelectric conversion efficiency of the solar cell. In addition, since the non-burn-through type slurry does not have too much glass powder to damage the PN junction, it can effectively reduce metal recombination, increase the open circuit voltage of the solar cell, and improve the conversion efficiency of the solar cell.

[0060] Among them, the traditional slurry includes a mixture of metal powder, glass powder and organic carrier. Non-burn-through slurry refers to a slurry that contains less glass powder than the traditional slurry. During the sintering process, its burn-through ability is weak and it does not need or cannot burn through the passivation layer. Burn-through slurry refers to a slurry that has a strong burn-through ability during the sintering process and can burn through the passivation layer.

[0061] In some embodiments, the connection structure 110 may be a film layer or a conductive line having a conductive material, and it is only necessary to realize the electrical connection between the edge connection line 103 and the adjacent first connection line 111 .

[0062] The end of the collecting portion adjacent to the connecting structure 110 serves as the first portion 1121, and the remaining collecting portion serves as the second portion 1122. The width of the first portion 1121 along the second direction X is greater than the width of the second portion 1122 along the second direction X, that is, the end of the main grid connecting line corresponding to the other polarity of the connecting structure 110 is widened to increase the welding tension between the welding strip and the battery substrate, thereby avoiding the problem of cold welding and poor welding quality.

[0063] In some embodiments, reference Figure 2, the interval d between the second grid line 102 close to the connection structure 110 and the connection structure 110 and the length L of the first portion 1121 along the first direction Y satisfy the following relationship: d≤L≤2d. This proportional relationship can improve the welding quality, thereby reducing the contact resistance and improving the battery efficiency, and can also reduce the amount of the second connection line 112 and reduce the cost.

[0064] In some embodiments, the length L of the first portion 1121 along the first direction Y ranges from 0.5 mm to 2 mm.

[0065] The length L of the first portion 1121 along a direction Y ranges from 0.5 mm to 1 mm, 1 mm to 1.5 mm, or 1.5 mm to 2 mm. The length L of the first portion 1121 along a direction Y may be 0.5 mm, 0.7 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.7 mm, or 2 mm.

[0066] In some embodiments, the distance d between the second gate line 102 close to the connection structure 110 and the connection structure 110 ranges from 0.3 mm to 1.5 mm.

[0067] The distance d between the second gate line 102 near the connection structure 110 and the connection structure 110 is in the range of 0.3 mm to 0.6 mm, 0.6 mm to 1.1 mm or 1.1 mm to 1.5 mm. The distance d between the second gate line 102 near the connection structure 110 and the connection structure 110 can be 0.3 mm, 0.5 mm, 0.7 mm, 1.1 mm, 1.3 mm or 1.5 mm.

[0068] In some embodiments, a distance d between the second gate line 102 close to the connection structure 110 and the connection structure 110 is greater than or equal to a distance between the adjacent first gate line 101 and the second gate line 102 .

[0069] In some embodiments, the width of the connection structure 110 is greater than or equal to the width of the first gate line 101. The larger width of the connection structure 110 can improve the efficiency of collecting carriers, reduce contact resistance, and thus reduce the electrical loss of the solar cell and improve the photoelectric conversion efficiency of the cell.

[0070] In some embodiments, the number of connection structures 110 ranges from 5 to 24. The number of connection structures 110 can shorten the path from the current collected by the edge connection line 103 to the second first connection line 111, that is, the path length from each edge region to the second connection line 112 can be reduced, thereby reducing path loss.

[0071] In some embodiments, the number of connection structures 110 may be 5 to 8, 8 to 10, 10 to 13, 13 to 15, 15 to 18, 18 to 21, or 21 to 24. The number of connection structures 110 may be 5, 7, 9, 12, 14, 17, 19, 22, or 23.

[0072] In some embodiments, the number of second gate lines 102 between adjacent connection structures 110 ranges from 6 to 12. By limiting the number range of second gate lines 102 between adjacent connection structures 110, the distance between adjacent connection structures 110 is controlled, and the impact on the second connection lines 112 is reduced under the premise of satisfying the shortest path, thereby reducing the welding impact between the second connection lines 112 and the welding strip, thereby satisfying the balance between the battery yield and the battery photoelectric conversion efficiency.

[0073] The number of the second gate lines 102 between adjacent connection structures 110 may be 6 to 8, 8 to 10, or 10 to 12. The number of the second gate lines 102 between adjacent connection structures 110 may be 7, 9, 10, or 11.

[0074] In some embodiments, reference Figure 3 , the width W1 of the first portion 1121 along the second direction X ranges from 50 μm to 100 μm. When the width W1 of the first portion 1121 along the second direction X is within the above range, the width of the first portion 1121 is relatively large, thereby promoting a higher probability of alignment between the welding strip and the first portion 1121, and thus a larger contact area between the welding strip and the first portion 1121, which can avoid the problem of high contact resistance caused by cold welding and a small welding area, and thus improve the yield of the photovoltaic module.

[0075] The width W1 of the first portion 1121 along the second direction X is in the range of 50 μm to 60 μm, 60 μm to 70 μm, 70 μm to 80 μm, 80 μm to 90 μm or 90 μm to 100 μm. The width W1 of the first portion 1121 along the second direction X may be 52 μm, 55 μm, 57 μm, 59 μm, 62 μm, 64 μm, 68 μm, 71 μm, 74 μm, 78 μm, 83 μm, 86 μm, 89 μm, 94 μm, 96 μm or 99 μm.

[0076] refer to Figure 3 , a width W2 of the second portion 1122 along the second direction X is in the range of 10 μm to 50 μm.

[0077] The width W2 of the second portion 1122 along the second direction X ranges from 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm or 40 μm to 50 μm. The width W2 of the second portion 1122 along the second direction X may be 12 μm, 15 μm, 17 μm, 19 μm, 22 μm, 24 μm, 28 μm, 31 μm, 34 μm, 38 μm, 43 μm, 46 μm, 49 μm or 50 μm.

[0078] refer to Figure 3 , a width W3 of the second gate line 102 along the first direction Y ranges from 20 μm to 100 μm.

[0079] The width W3 of the second gate line 102 along the first direction Y is in the range of 20 μm to 40 μm, 40 μm to 60 μm, 60 μm to 70 μm, 70 μm to 90 μm or 90 μm to 100 μm. The width W3 of the second gate line 102 along the first direction Y can be 22 μm, 29 μm, 37 μm, 42 μm, 49 μm, 54 μm, 58 μm, 63 μm, 69 μm, 72 μm, 79 μm, 83 μm, 89 μm, 94 μm, 96 μm or 99 μm.

[0080] In some embodiments, the spacing between the edge connection line 103 and the adjacent second connection line 112 is a first spacing S1 (not shown in the figure), and the first spacing S1 is less than or equal to the second spacing S2 between the adjacent first connection line 111 and the second connection line 112. In this way, the first spacing between the edge connection line 103 and the adjacent second connection line 112 is more appropriate, and in the layout that does not waste the shielding area of ​​the edge connection line 103, the second connection line 112 and the first connection line 111, the layout between the edge connection line 103 and the adjacent first connection line 111 can achieve the minimum migration distance and the minimum migration loss of the carriers on the substrate, thereby improving the open circuit voltage of the solar cell.

[0081] It is worth noting that the first spacing refers to the spacing between the area where the axis of the edge connection line is located and the axis of the adjacent second connection line. The embodiment of the present application does not limit the specific meaning of the first spacing. For example, the first spacing can also be the distance between the side of the edge connection line close to the first edge and the side of the adjacent second connection line away from the first edge, or the shortest distance between the edge connection line and the adjacent second connection line.

[0082] In some embodiments, the first spacing S1 ranges from 0.2 mm to 0.7 mm, 0.2 mm to 0.35 mm, 0.35 mm to 0.46 mm, 0.46 mm to 0.58 mm, 0.58 mm to 0.63 mm, or 0.63 mm to 0.7 mm.

[0083] In some embodiments, the second spacing S2 (not shown) between adjacent first connection lines 111 and second connection lines 112 ranges from 0.3 mm to 0.8 mm. The second spacing S2 between adjacent first connection lines 111 and second connection lines 112 ranges from 0.3 mm to 0.35 mm, 0.35 mm to 0.43 mm, 0.43 mm to 0.5 mm, 0.5 mm to 0.58 mm, 0.58 mm to 0.66 mm, 0.66 mm to 0.72 mm, or 0.72 mm to 0.8 mm.

[0084] The solar cell provided in the embodiment of the present application includes a first grid line 101, a second grid line 102, a first connecting line 111 and a second connecting line 112, wherein the first grid line 101 is connected to the first connecting line 111, the second grid line 102 is connected to the second connecting line 112, the first connecting line 111 includes an edge connecting line 103 close to the first edge 11, and no welding portion is provided on the edge connecting line 103, one end of the connecting structure 110 is connected to the first connecting line 111, and the other end passes through the spacer 104 and is connected to the first connecting line 111 arranged adjacent to the edge connecting line 103, thereby avoiding the problem of edge breakage of the battery substrate, and the carriers at the edge can be collected through the connecting structure 110 to improve the battery efficiency. The end of the collecting portion adjacent to the connecting structure 110 serves as the first portion 1121, and the remaining collecting portion serves as the second portion 1122. The width of the first portion 1121 along the second direction X is greater than the width of the second portion 1122 along the second direction X, that is, the end of the main grid connecting line corresponding to the other polarity of the connecting structure 110 is widened to increase the welding tension between the welding strip and the battery substrate, thereby avoiding the problem of cold welding and poor welding quality.

[0085] Correspondingly, another embodiment of the present application also provides a solar cell, which is different from the previous embodiment in that the first grid line of the solar cell provided by the other embodiment includes a first bus area and a first collection area, the width of the first bus area is greater than the width of the first collection area, the second grid line includes a second bus area and a second collection area, the width of the second bus area is greater than the second collection area, the first bus area serves as a welding part of the first grid line, and the second bus area serves as a welding part of the second grid line. The parts that are the same as the above embodiments will not be described in detail here.

[0086] Figure 4 A schematic structural diagram of a solar cell provided in another embodiment of the present application; Figure 5 A partially enlarged view of a solar cell provided in another embodiment of the present application.

[0087] refer to Figure 4 and Figure 5The solar cell comprises: a cell substrate 200, the cell substrate 200 having a first edge 21; first grid lines 201 and second grid lines 202 arranged alternately along a first direction Y; first connecting lines 211 and second connecting lines 212 arranged alternately along a second direction X, the first connecting lines 211 being connected to the first grid lines 201, and the second connecting lines 212 being connected to the second grid lines 202; wherein the first connecting lines 211 include edge connecting lines 203 adjacent to the first edge 21, and no welding portion is provided on the edge connecting lines 203; and the second connecting lines 212 are arranged alternately along a second direction X. The wiring 212 includes a collecting portion and a spacer portion 204, the collecting portion is connected to the second gate line 202; a connecting structure 210, one end of the connecting structure 210 is connected to the edge connecting line 203, and the other end passes through the spacer portion 204 and is connected to the first connecting line 211 arranged adjacent to the edge connecting line 203; wherein the end of the collecting portion adjacent to the connecting structure 210 serves as the first portion 2121, and the remaining collecting portion serves as the second portion 2122, and the width of the first portion 2121 along the second direction X is greater than the width of the second portion 2122 along the second direction X.

[0088] In some embodiments, the first grid line 201 includes a first collection area 2012 and a first bus area 2011, the first connection line 211 is connected to the first bus area 2011, and the first bus area 2011 serves as a welding portion of the first grid line 201; the width of the first bus area 2011 along the first direction Y is greater than the width of the first collection area 2012 along the first direction Y. The welding area between the first grid line 201 and the welding strip is increased by the first bus area 2011, thereby avoiding the problem of fuse grid caused by the grid line of the first grid line 201 being too thin and the problem of poor welding quality caused by a small welding area, thereby improving the yield of the photovoltaic module.

[0089] In some embodiments, the second grid line 202 includes a second collection area 2022 and a second bus area 2021, the second connection line 212 is connected to the second bus area 2021, and the second bus area 2021 serves as a welding portion of the second grid line 202; the width of the second bus area 2021 along the first direction Y is greater than the width of the second collection area 2022 along the first direction Y. The second bus area 2021 increases the welding area between the second grid line 202 and the welding strip, thereby avoiding the problem of the fuse grid caused by the grid line of the second grid line 202 being too thin and the problem of poor welding quality caused by the small welding area, thereby improving the yield of the photovoltaic module; secondly, the large area of ​​the second bus area 2021 can also avoid the problem of cold welding between the second grid line 202 adjacent to the connection structure 210 and the welding strip caused by the insulation problem of the connection structure 210, thereby further improving the yield of the photovoltaic module.

[0090] In some embodiments, the second confluence area 2021 may be in the shape of a shuttle, rectangle, square, hexagon, octagon, etc. The first confluence area 2011 may be in the shape of a shuttle, rectangle, square, hexagon, octagon, etc.

[0091] In some embodiments, the width of the first confluence region 2011 is 10 um to 50 um.

[0092] In some embodiments, the width of the second bus region 2021 is 20 um to 100 um.

[0093] The distance d between the second gate line 202 and the connection structure 210 and the length L of the first portion 2121 along the first direction Y satisfies the following relationship: d≤L≤2d. The length L of the first portion 2121 along the first direction Y ranges from 0.5 mm to 2 mm.

[0094] In some embodiments, the distance d between the second gate line 202 close to the connection structure 210 and the connection structure 210 ranges from 0.3 mm to 1.5 mm.

[0095] In some embodiments, a distance d between the second gate line 202 close to the connection structure 210 and the connection structure 210 is greater than or equal to a distance between the adjacent first gate line 201 and the second gate line 202 .

[0096] In some embodiments, the width of the connection structure 210 is greater than or equal to the width of the first gate line 201 .

[0097] In some embodiments, the number of the connection structures 210 ranges from 5 to 24.

[0098] In some embodiments, the number of the second gate lines 202 located between adjacent connection structures 210 ranges from 6 to 12.

[0099] It is worth noting that the battery substrate 200, the first connecting line 211, the second connecting line 212, the edge connecting line, the second edge 22, the second edge connecting line, and the connecting structure 210 in another embodiment refer to the battery substrate 100, the first connecting line 111, the second connecting line 112, the edge connecting line, the second edge 12, the second edge 12 connecting line, and the connecting structure 110 in the previous embodiment.

[0100] Correspondingly, another embodiment of the present application further provides a solar cell, which is different from the previous embodiment in that the first grid line of the solar cell provided by the further embodiment includes a first welding pad, and the second grid line includes a second welding pad. The first welding pad serves as a welding part of the first grid line, and the second welding pad serves as a welding part of the second grid line. The parts that are the same as the above embodiments will not be described in detail here.

[0101] Figure 6 A schematic structural diagram of a solar cell provided in yet another embodiment of the present application; Figure 7 A partially enlarged view of a solar cell provided in yet another embodiment of the present application.

[0102] refer to Figure 6 and Figure 7 The solar cell comprises: a cell substrate 300, the cell substrate 300 having a first edge 31; first grid lines 301 and second grid lines 302 arranged alternately along a first direction Y; first connecting lines 311 and second connecting lines 312 arranged alternately along a second direction X, the first connecting lines 311 being connected to the first grid lines 301, and the second connecting lines 312 being connected to the second grid lines 302; wherein the first connecting lines 311 include edge connecting lines 303 adjacent to the first edge 31, and no welding portion is provided on the edge connecting lines 303; and the second connecting lines 312 are arranged alternately along a second direction X. The wiring 312 includes a collecting portion and a spacer portion 304, the collecting portion is connected to the second gate line 302; a connecting structure 310, one end of the connecting structure 310 is connected to the edge connecting line 303, and the other end passes through the spacer portion 304 and is connected to the first connecting line 311 arranged adjacent to the edge connecting line 303; wherein the end of the collecting portion adjacent to the connecting structure 310 serves as the first portion 3121, and the remaining collecting portion serves as the second portion 3122, and the width of the first portion 3121 along the second direction X is greater than the width of the second portion 3122 along the second direction X.

[0103] In some embodiments, the solar cell further includes a pad, which is located at the intersection of a portion of the second connection line 312 and the second grid line 302; the pad is also located at the intersection of a portion of the first connection line 311 and the first grid line 301. The pad located at the intersection of the first connection line 311 and the first grid line 301 is used as the first pad 305, and the pad located at the intersection of the second connection line 312 and the second grid line 302 is used as the second pad 306.

[0104] The distance d between the second gate line 302 near the connection structure 310 and the connection structure 310 and the length L of the first portion 3121 along the first direction satisfy the following relationship: d≤L≤2d. The length L of the first portion 3121 along the first direction ranges from 0.5 mm to 2 mm.

[0105] In some embodiments, the distance d between the second gate line 302 close to the connection structure 310 and the connection structure 310 ranges from 0.3 mm to 1.5 mm.

[0106] In some embodiments, a distance d between the second gate line 302 close to the connection structure 310 and the connection structure 310 is greater than or equal to a distance between the adjacent first gate line 301 and the second gate line 302 .

[0107] In some embodiments, the width of the connection structure 310 is greater than or equal to the width of the first gate line 301 .

[0108] In some embodiments, the number of connection structures 310 ranges from 5 to 24.

[0109] In some embodiments, the number of the second gate lines 302 located between adjacent connection structures 310 ranges from 6 to 12.

[0110] It is worth mentioning that the battery substrate 300, the first connecting line 311, the second connecting line 312, the edge connecting line 303, the second edge 32, the connecting structure 310, the first gate line 301 and the second gate line 302 in another embodiment refer to the battery substrate 100, the first connecting line 111, the second connecting line 112, the edge connecting line 103, the second edge 12, the connecting structure 110, the first gate line 101 and the second gate line 102 in the previous embodiment.

[0111] Figure 8 A schematic structural diagram of a photovoltaic module provided in yet another embodiment of the present application; Fig. 9 A partial cross-sectional view of a photovoltaic module provided in yet another embodiment of the present application; Fig.10 Another partial cross-sectional view of a photovoltaic module provided in yet another embodiment of the present application.

[0112] Accordingly, according to some embodiments of the present application, reference Figure 8 On the other hand, an embodiment of the present application provides a photovoltaic module, including: a battery string, the battery string is formed by connecting a plurality of solar cells 40 as in any of the above embodiments; a packaging film 41, the packaging film 41 covers the battery string; and a cover plate 42, the cover plate 42 is located on a side of the packaging film 41 away from the battery string.

[0113] In some embodiments, in conjunction with reference Figure 8 and Fig. 9 The battery string includes: a solar cell; a welding strip, which is electrically connected to the second connecting line; and an insulating layer, which is located between the connecting structure and the welding strip.

[0114] In some embodiments, multiple battery strings and multiple battery substrates may be electrically connected via a welding ribbon 420, and the welding ribbon 420 is welded to a welding portion on the battery substrate. For example, one end of the welding ribbon 420 is electrically connected to a welding portion of a first grid line of a first battery substrate, and the other end of the welding ribbon 420 is electrically connected to a welding portion of a second grid line of an adjacent second battery substrate.

[0115] In some embodiments, no space is provided between the battery substrates, that is, the battery substrates overlap each other.

[0116] In some embodiments, the insulating layer 406 covers a portion of the surface of the solar cell 40, for example, the insulating layer 406 covers between the welding strip connected to the first connecting line and the second fine grid, and the end surface of the second fine grid adjacent to the welding strip connected to the first connecting line, so as to electrically insulate the welding strip connected to the first connecting line and the second fine grid; similarly, the insulating layer 406 also covers between the welding strip connected to the second connecting line and the first fine grid, and the end surface of the first fine grid adjacent to the welding strip connected to the second connecting line, as well as between the connecting structure and the welding strip connected to the second connecting line, so as to electrically insulate the welding strip connected to the second connecting line and the first fine grid, and to insulate the welding strip connected to the second connecting line from the connecting structure.

[0117] refer to Fig. 9 The first part is flush with the second part, the top surface of the insulating layer away from the connecting structure is higher than the top surface of the first part, and the height of the soldering strip is raised by the insulating layer. However, the widening design of the first part increases the soldering area between the second connecting line and the soldering strip.

[0118] refer to Fig.10 The first portion of the second connecting line away from the top surface of the battery substrate is flush with the top surface of the insulating layer away from the connecting structure.

[0119] In some embodiments, the encapsulation film 41 includes a first encapsulation film and a second encapsulation film, the first encapsulation film covers one of the front side or the back side of the solar cell, and the second encapsulation film covers the other of the front side or the back side of the solar cell. Specifically, at least one of the first encapsulation film or the second encapsulation film can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film or a polyethylene terephthalate (PET) film.

[0120] It is worth noting that there is a boundary line between the first packaging film and the second packaging film before the lamination process. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first packaging film and the second packaging film, that is, the first packaging film and the second packaging film have formed an integral packaging film 41.

[0121] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation film, and the second cover plate is opposite to the second encapsulation film; or the first cover plate is opposite to one side of the solar cell, and the second cover plate is opposite to the other side of the solar cell.

[0122] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A back contact battery, characterized in that: include: A battery substrate, wherein the battery substrate has a first edge; First grid lines and second grid lines are alternately arranged along a first direction; First connecting lines and second connecting lines are alternately arranged along a second direction, the first connecting lines are connected to the first gate lines, and the second connecting lines are connected to the second gate lines; wherein the first connecting lines include edge connecting lines adjacent to the first edge, and no welding portion is provided on the edge connecting lines; the second connecting lines include a collecting portion and a spacing portion, and the collecting portion is connected to the second gate lines; A connection structure, one end of which is connected to the edge connection line, and the other end of which passes through the spacer and is connected to the first connection line arranged adjacent to the edge connection line; The end of the collecting portion adjacent to the connecting structure serves as the first portion, and the remaining collecting portion serves as the second portion. The width of the first portion along the second direction is greater than the width of the second portion along the second direction.

2. The back contact cell according to claim 1, characterized in that: A distance d between the second gate line close to the connection structure and the connection structure and a length L of the first portion along the first direction satisfy the following relationship: d≤L≤2d.

3. The back contact battery according to claim 2, characterized in that: A length L of the first portion along the first direction ranges from 0.5 mm to 2 mm.

4. The back contact cell according to claim 1 or 2, characterized in that: The second gate line includes a second collection area and a second bus area. The second connection line is connected to the second bus area, and the second bus area serves as a welding portion of the second gate line. The width of the second bus area along the first direction is greater than the width of the second collection area along the first direction.

5. The back contact cell according to claim 1 or 2, characterized in that: It also includes a pad, and the pad is located at the intersection of a portion of the second connecting line and the second gate line.

6. The back contact cell according to claim 1, characterized in that: The number of the connection structures ranges from 5 to 24.

7. The back contact cell according to claim 1, characterized in that: The number of the second gate lines located between adjacent connection structures ranges from 6 to 12.

8. The back contact cell according to claim 1, characterized in that: The width of the first portion along the second direction ranges from 50 μm to 100 μm.

9. A photovoltaic module, characterized in that: include: A battery string, wherein the battery string is formed by connecting a plurality of back-contact batteries according to any one of claims 1 to 8; A packaging film, wherein the packaging film covers the battery string; A cover plate is located on a side of the packaging film away from the battery string.

10. The photovoltaic module according to claim 9, characterized in that: The battery string includes: a back contact battery; A welding strip, the welding strip is electrically connected to the second connecting wire; an insulating layer, the insulating layer is located between the connecting structure and the welding strip; wherein the first portion of the second connecting wire is away from the top surface of the battery substrate and is flush with the top surface of the insulating layer away from the connecting structure.

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