Back contact batteries and photovoltaic modules

Abstract

This application relates to the photovoltaic field, providing a back-contact battery and a photovoltaic module. The back-contact battery includes: a battery substrate having a first edge; a first grid line and a second grid line; a first connecting line and a second connecting line, the first connecting line being connected to the first grid line and the second connecting line being connected to the second grid line; the first connecting line includes an edge connecting line adjacent to the first edge, without a welding portion; the second connecting line includes a collecting portion and a spacer portion, the collecting portion being connected to the second grid line; one end of a connecting structure is connected to the edge connecting line, and the other end passes through the spacer portion and is connected to the first connecting line adjacent to the edge connecting line; the end of the collecting portion adjacent to the connecting structure is designated as a first portion, and the remaining collecting portion is designated as a second portion, the width of the first portion along a second direction being greater than the width of the second portion along the second direction. The back-contact battery provided by this application embodiment can at least improve the photoelectric conversion efficiency of the back-contact battery.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a back contact battery and a photovoltaic module. Background Technology

[0002] Currently, with the gradual depletion of fossil fuels, solar cells are becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient utilization of electrical energy.

[0003] The main factors affecting the photoelectric conversion efficiency and yield of solar cells include two aspects: optical loss, which includes shading loss, carrier recombination loss of the substrate, carrier recombination loss of highly doped films, and refractive loss of films; and electrical loss, which includes the resistance loss of the material itself, contact loss of the electrodes, contact loss between the solder ribbon and the solar cell, and problems such as poor soldering between the solder ribbon and the solar cell.

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

[0005] This application provides a back-contact battery and a photovoltaic module, which at least helps to improve the photoelectric conversion efficiency of the back-contact battery.

[0006] According to some embodiments of this application, one aspect of this application provides a back contact battery, comprising: a battery substrate having a first edge; a first grid line and a second grid line alternately arranged along a first direction; a first connecting line and a second connecting line alternately arranged along a second direction, wherein the first connecting line is connected to the first grid line, and the second connecting line is connected to the second grid line; wherein the first connecting line includes an edge connecting line adjacent to the first edge, and no welding portion is provided on the edge connecting line; the second connecting line includes a collecting portion and a spacing portion, the collecting portion being connected to the second grid line; a connecting structure, one end of the connecting structure being connected to the edge connecting line, and the other end passing through the spacing portion and connected to the first connecting line adjacent to the edge connecting line; wherein the end of the collecting portion adjacent to the connecting structure is a first portion, and the remaining collecting portion is a second portion, the width of the first portion along the second direction being greater than the width of the second portion along the second direction.

[0007] In some embodiments, the distance d between the second gate line near the connection structure and the connection structure and the length L of the first part along the first direction satisfies the following relationship: d≤L≤2d.

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

[0009] In some embodiments, the second grid line includes a second collection area and a second busbar area, the second connecting line is connected to the second busbar area, and the second busbar area serves as a welding portion of the second grid line; the width of the second busbar 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 also included, the pad being located at the intersection of a portion of the second connection 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, the width of the first part along the second direction ranges from 50 μm to 100 μm.

[0014] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a battery string, the battery string being formed by connecting a plurality of back-contact batteries as described in any of the above embodiments; an encapsulating film covering the battery string; and a cover plate located on the side of the encapsulating film away from the battery string.

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

[0016] The technical solution provided in this application has at least the following advantages:

[0017] The back-contact battery provided in this application embodiment includes a first grid line, a second grid line, a first connecting line, and a second connecting line. The first grid line is connected to the first connecting line, and the second grid line is connected to the second connecting line. The first connecting line includes an edge connecting line near a first edge, and no welding portion is provided on the edge connecting line. One end of the connecting structure is connected to the first connecting line, and the other end passes through a gap and connects to the first connecting line adjacent to the edge connecting line, thereby avoiding the problem of edge breakage of the battery substrate. The connecting structure can collect charge carriers at the edge, improving battery efficiency. The end of the collecting portion adjacent to the connecting structure is designated as the first portion, and the remaining collecting portion is designated 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, that is, the end of the main grid connecting line corresponding to the other polarity of the connecting structure is widened, increasing the welding pull between the solder strip and the battery substrate, and avoiding problems such as incomplete soldering and poor welding quality. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a back contact battery provided in an embodiment of this application;

[0020] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0021] Figure 3 This application provides a schematic diagram of the structure of a collection section in a back contact battery according to an embodiment of the present application.

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

[0023] Figure 5 A partially enlarged view of a back contact battery provided in another embodiment of this application;

[0024] Figure 6 A schematic diagram of a back contact battery provided in another embodiment of this application;

[0025] Figure 7A partially enlarged view of a back contact battery provided in another embodiment of this application;

[0026] Figure 8 A schematic diagram of a photovoltaic module provided in another embodiment of this application;

[0027] Figure 9 A partial cross-sectional view of a photovoltaic module provided in another embodiment of this application;

[0028] Figure 10 Another partial cross-sectional view of a photovoltaic module provided in yet another embodiment of this application. Detailed Implementation

[0029] As can be seen from the background technology, the yield rate of current photovoltaic modules is not good.

[0030] This application provides a back-contact battery and a photovoltaic module. By not setting a welding part on the edge connection line to avoid the problem of edge breakage of the battery substrate, a connection structure is set to connect the edge connection line and the same polarity connection line, thereby collecting charge carriers in the edge region. Secondly, by limiting the width of the second connection line corresponding to the connection structure, the welding area between the solder strip and the second connection line is increased, thereby improving the yield of the photovoltaic module.

[0031] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0034] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" 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 portion of the edge of the entire surface.

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

[0039] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0040] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0041] According to some embodiments of this application, one aspect of this application provides a back contact battery.

[0042] Figure 1 This is a schematic diagram of a back contact battery provided in an embodiment of this application; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of a collection section in a back contact battery according to an embodiment of this application.

[0043] According to some embodiments of this application, one aspect of this application provides a back contact battery. (See reference...) Figure 1 and Figure 2The back contact battery includes: a battery substrate 100, the battery substrate 100 having a first edge 11; a first grid line 101 and a second grid line 102 alternately arranged along a first direction Y; a first connecting line 111 and a second connecting line 112 alternately arranged along a second direction X, the first connecting line 111 being connected to the first grid line 101, and the second connecting line 112 being connected to the second grid line 102; wherein, the first connecting line 111 includes an edge connecting line 103 adjacent to the first edge 11, and the edge connecting line 103 is not provided with a welding part; the second connecting line 111... Wiring 112 includes a collecting part and a spacing part 104. The collecting part is connected to the second grid line 102. A connecting structure 110 is provided. One end of the connecting structure 110 is connected to the edge connecting line 103, and the other end passes through the spacing part 104 and is connected to the first connecting line 111 which is adjacent to the edge connecting line 103. The end of the collecting part adjacent to the connecting structure 110 is designated as the first part 1121, and the remaining collecting part is designated as the second part 1122. The width of the first part 1121 along the second direction X is greater than the width of the second part 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 combining TOPCon (Tunnel Oxide Passivated Contact) technology and IBC technology, or an HBC battery combining 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 having a first surface and a second surface disposed opposite to each other; the first surface having a textured structure, which allows only internal reflection of incident light to be introduced, thereby reducing optical loss and improving the photoelectric conversion efficiency of the battery; the first surface having a front surface field (FSF), the conductivity type of the doped ions of which is the same as that of the doped ions of the substrate, utilizing the field passivation effect to reduce the minority carrier concentration on the surface, thereby reducing the surface recombination rate, and also reducing the series resistance and improving the electron transport capability; the first surface also having a first passivation layer and a first antireflection layer, the first passivation layer being located on the surface of the front surface field, and the first antireflection layer being located on the surface of the first passivation layer. However, the battery substrate 100 does not necessarily include a front surface field, a first passivation layer, and a first antireflection layer.

[0046] The second surface of the substrate has alternating regions I and II, where region I is either region P or region N, and region II is either region P or region N. There is a gap between region P and region N. 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 gap region is flush with the P-region and the N-region, i.e., the substrate is not etched. The P-region and the N-region are insulated from each other by some insulating film layer, which can be a passivation layer or an intrinsic semiconductor layer.

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

[0050] In some embodiments, the surface of the gap can be a polished surface or a velvety surface.

[0051] In some embodiments, the P-region and N-region may each have a tunneling silicon oxide layer and a doped polycrystalline silicon layer, respectively, wherein the P-region has a P-type doped polycrystalline silicon layer and the N-region has an N-type doped polycrystalline silicon layer. In other embodiments, the P-region and N-region may each 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 battery substrate 100 has a first edge 11, a second edge 12 disposed opposite to the first edge 11, and two third edges (not shown) for connecting the first edge 11 and the second edge 12. Chamfers are formed at the junctions of the first edge 11 and the third edges, and at the junctions of the second edge and the third edge. The reason for the chamfers is that, in conventional solar cells, due to limitations in the refining process of monocrystalline silicon used to prepare the substrate, monocrystalline silicon rods can currently only be made into round shapes. After the silicon rod is produced, it is sliced, which means cutting the cross-section of the silicon rod into the shape of a monocrystalline silicon wafer (the area is calculated so that within a unit, the illumination area can be maximized, silicon rod material can be saved to the maximum extent, and it is also convenient for the production of battery substrates and modules). Chamfers are often set at the junctions of the various boundaries of the substrate to reduce the external stress of the silicon wafer and avoid micro-damage to the edges of the silicon wafer.

[0054] In some embodiments, if the sum of the first connecting line 111 and the second connecting line 112 is an even number, then refer to Figure 1 If the conductivity type of the second edge connecting line corresponding to the second edge 12 of the substrate is the same as that of the second connecting line 112, then the first connecting line 111 adjacent to the second edge connecting line should also be designed in the same way as the second connecting line 112, that is, the second edge connecting line passes through the break of the first connecting line 111 and connects 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 odd, then the conductivity type of the second edge connecting line corresponding to the second edge of the substrate is the same as that of the first connecting line. In this case, the setting of the second edge connecting line is the same as that of the edge connecting line, and the second connecting line arranged adjacent to the second edge connecting line should also be designed in the same way as the second connecting line described above.

[0056] By not providing a welding part on the edge connection line 103 near the first edge 11, the problem of damage to the edge of the battery substrate caused by the stress of the solder strip can be avoided.

[0057] A connection structure 110 is provided, and the connection structure 110 is used to connect the edge connection line 103 to the first connection line 111 which is adjacent to the edge connection line 103, so as to improve the collection rate of the current generated by the substrate at the first edge 11 and reduce the battery defect rate.

[0058] In some embodiments, the material of the connection structure 110 is the same as that of the first gate line 101. The paste of the connection structure 110 is the same as that of the first gate line 101, that is, the connection structure 110 is made of a burn-through paste. The connection structure 110 also penetrates the passivation layer and is electrically connected to the corresponding collection film layer. In this way, the connection structure 110 can not only realize the current flow 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 itself, thereby increasing the collection path and improving the efficiency of current collection.

[0059] In some embodiments, the paste of the connection structure 110 is the same as that of the main grid, i.e., the connection structure 110 is composed of a non-burn-through paste. The connection structure 110 is located on the surface of the passivation layer. This eliminates the need for specific arrangement of regions I and II on the substrate surface below the connection structure 110 to prevent electrical contact and short circuits between the connection structure 110 and the doped region of the opposite polarity. Furthermore, the connection structure 110 does not damage the passivation layer, thus ensuring the integrity of the passivation layer and improving its passivation effect on the substrate. This helps reduce optical losses in the solar cell and improves its photoelectric conversion efficiency. In addition, since the non-burn-through paste does not contain excessive glass powder that could damage the PN junction, it effectively reduces metal recombination, increases the open-circuit voltage of the solar cell, and improves its conversion efficiency.

[0060] Traditional slurries consist of a mixture of metal powder, glass powder, and an organic carrier. Non-burn-through slurries contain less glass powder than traditional slurries, resulting in weak burn-through capability during sintering; they do not require or cannot burn through the passivation layer. Burn-through slurries, on the other hand, exhibit strong burn-through capability during sintering, enabling them to burn through the passivation layer.

[0061] In some embodiments, the connection structure 110 can be a film layer or a conductive line with 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 collection section adjacent to the connecting structure 110 is designated as the first section 1121, and the remaining collection section is designated as the second section 1122. The width of the first section 1121 along the second direction X is greater than the width of the second section 1122 along the second direction X. That is, the end of the main grid connection line corresponding to the other polarity of the connecting structure 110 is widened to improve the welding pull between the solder strip and the battery substrate and avoid problems such as incomplete soldering and poor welding quality.

[0063] In some embodiments, reference Figure 2The distance d between the second grid line 102 near the connecting structure 110 and the connecting structure 110 satisfies the following relationship with the length L of the first part 1121 along the first direction Y: d ≤ L ≤ 2d. This proportional relationship can improve the welding quality, thereby reducing contact resistance and increasing battery efficiency, and can also reduce the amount of the second connecting line 112, thereby reducing costs.

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

[0065] The length L of the first part 1121 along one direction Y is in the range of 0.5mm to 1mm, 1mm to 1.5mm, or 1.5mm to 2mm. The length L of the first part 1121 along one direction Y can be 0.5mm, 0.7mm, 1.1mm, 1.3mm, 1.5mm, 1.7mm, or 2mm.

[0066] In some embodiments, the distance d between the second gate line 102 near 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 connecting structure 110 and the connecting structure 110 ranges from 0.3mm to 0.6mm, 0.6mm to 1.1mm, or 1.1mm to 1.5mm. The distance d between the second gate line 102 near the connecting structure 110 and the connecting structure 110 can be 0.3mm, 0.5mm, 0.7mm, 1.1mm, 1.3mm, or 1.5mm.

[0068] In some embodiments, the distance d between the second gate line 102 near the connection structure 110 and the connection structure 110 is greater than or equal to the 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. A larger width of the connection structure 110 can improve the efficiency of collecting charge carriers, reduce contact resistance, thereby reducing the electrical losses of the solar cell and improving 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 make the path of the current collected by the edge connection line 103 to the second first connection line 111 shorter, that is, can reduce the path length from each edge region to the second connection line 112, thereby reducing path loss.

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

[0072] In some embodiments, the number of second gate lines 102 located between adjacent connection structures 110 ranges from 6 to 12. By limiting the range of the number of second gate lines 102 located between adjacent connection structures 110, the distance between adjacent connection structures 110 is controlled, thereby reducing the impact on the second connection lines 112 while satisfying the shortest path condition, and further reducing the welding impact between the second connection lines 112 and the solder ribbon, thereby achieving a balance between battery yield and battery photoelectric conversion efficiency.

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

[0074] In some embodiments, reference Figure 3 The width W1 of the first part 1121 along the second direction X ranges from 50μm to 100μm. Since the width W1 of the first part 1121 along the second direction X is within this range, the larger width of the first part 1121 results in a higher alignment probability between the solder strip and the first part 1121, and consequently a larger contact area between them. This avoids problems such as poor soldering and high contact resistance caused by a small soldering area, thereby improving the yield of photovoltaic modules.

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

[0076] refer to Figure 3 The width W2 of the second part 1122 along the second direction X ranges from 10μm to 50μm.

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

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

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

[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. Thus, the first spacing between the edge connection line 103 and the adjacent second connection line 112 is more suitable. In the arrangement without wasting the shading area of ​​the edge connection line 103, the second connection line 112, and the first connection line 111, the arrangement 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 charge 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 connecting line is located and the axis of the adjacent second connecting line. The embodiments of this application do 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 connecting line close to the first edge and the side of the adjacent second connecting line away from the first edge, or the shortest distance between the edge connecting line and the adjacent second connecting line.

[0082] In some embodiments, the first spacing S1 ranges from 0.2 mm to 0.7 mm. The first spacing S1 ranges from 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 in the figures) between adjacent first connecting lines 111 and second connecting lines 112 ranges from 0.3 mm to 0.8 mm. The second spacing S2 between adjacent first connecting lines 111 and second connecting 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 this application includes a first grid line 101, a second grid line 102, a first connecting line 111, and a second connecting line 112. The first grid line 101 is connected to the first connecting line 111, and the second grid line 102 is connected to the second connecting line 112. The first connecting line 111 includes an edge connecting line 103 near the first edge 11, and no welding part 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 a spacer 104 and is connected to the first connecting line 111 which is adjacent to the edge connecting line 103. This avoids the problem of edge breakage of the battery substrate. The connecting structure 110 can collect charge carriers at the edge and improve the battery efficiency. The end of the collection section adjacent to the connecting structure 110 is designated as the first section 1121, and the remaining collection section is designated as the second section 1122. The width of the first section 1121 along the second direction X is greater than the width of the second section 1122 along the second direction X. That is, the end of the main grid connection line corresponding to the other polarity of the connecting structure 110 is widened to improve the welding pull between the solder strip and the battery substrate and avoid problems such as incomplete soldering and poor welding quality.

[0085] Accordingly, another embodiment of this application also provides a solar cell. The difference from the previous embodiment is that the first grid line of the solar cell provided in the other embodiment includes a first busbar region and a first collection region. The width of the first busbar region is greater than the width of the first collection region. The second grid line includes a second busbar region and a second collection region. The width of the second busbar region is greater than the second collection region. The first busbar region serves as the welding part of the first grid line, and the second busbar region serves as the welding part of the second grid line. The parts that are the same as those in the above embodiment will not be described in detail here.

[0086] Figure 4 This is a schematic diagram of a solar cell provided in another embodiment of this application; Figure 5 This is a partially enlarged view of a solar cell provided in another embodiment of this application.

[0087] refer to Figure 4 and Figure 5The solar cell includes: a cell substrate 200 having a first edge 21; first grid lines 201 and second grid lines 202 alternately arranged along a first direction Y; and first connecting lines 211 and second connecting lines 212 alternately arranged along a second direction X, wherein the first connecting line 211 is connected to the first grid line 201, and the second connecting line 212 is connected to the second grid line 202; wherein the first connecting line 211 includes an edge connecting line 203 adjacent to the first edge 21, and the edge connecting line 203 has no welding portion; the second connecting line 211... Wiring 212 includes a collecting part and a spacing part 204. The collecting part is connected to the second grid line 202. A connecting structure 210 is provided, with one end connected to the edge connecting line 203 and the other end passing through the spacing part 204 and connected to the first connecting line 211 which is adjacent to the edge connecting line 203. The end of the collecting part adjacent to the connecting structure 210 is designated as the first part 2121, and the remaining collecting part is designated as the second part 2122. The width of the first part 2121 along the second direction X is greater than the width of the second part 2122 along the second direction X.

[0088] In some embodiments, the first grid line 201 includes a first collection area 2012 and a first busbar area 2011. A first connecting line 211 is connected to the first busbar area 2011, which serves as a welding portion of the first grid line 201. The width of the first busbar area 2011 along the first direction Y is greater than the width of the first collection area 2012 along the first direction Y. By increasing the welding area between the first grid line 201 and the solder strip through the first busbar area 2011, the problem of fused grid caused by the excessively thin grid line of the first grid line 201 and the poor welding quality caused by the small welding area are avoided, 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 busbar area 2021. The second connecting line 212 is connected to the second busbar area 2021, which serves as a welding portion of the second grid line 202. The width of the second busbar area 2021 along the first direction Y is greater than the width of the second collection area 2022 along the first direction Y. By increasing the welding area between the second grid line 202 and the solder strip through the second busbar area 2021, the problem of fused grid caused by the excessively thin grid line of the second grid line 202 and the poor welding quality caused by the small welding area are avoided, thereby improving the yield of the photovoltaic module. Secondly, the larger area of ​​the second busbar area 2021 can also avoid the problem of poor welding between the second grid line 202 adjacent to the connection structure 210 and the solder 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 shape of the second busbar 2021 can be a shuttle shape, rectangle, square, hexagon, octagon, etc. The shape of the first busbar 2011 can be a shuttle shape, rectangle, square, hexagon, octagon, etc.

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

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

[0093] The distance d between the second grid line 202 near the connecting structure 210 and the connecting structure 210 satisfies the following relationship with the length L of the first part 2121 along the first direction Y: d ≤ L ≤ 2d. The length L of the first part 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 near the connection structure 210 and the connection structure 210 ranges from 0.3 mm to 1.5 mm.

[0095] In some embodiments, the distance d between the second gate line 202 near the connection structure 210 and the connection structure 210 is greater than or equal to the 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 connection structures 210 ranges from 5 to 24.

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

[0099] It is worth noting that in another embodiment, 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 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] Accordingly, another embodiment of this application also provides a solar cell. The difference from the previous embodiment is that the first grid line of the solar cell provided in the other embodiment includes a first pad, and the second grid line includes a second pad. The first pad serves as the welding part of the first grid line, and the second pad serves as the welding part of the second grid line. The parts that are the same as those in the above embodiment will not be described in detail here.

[0101] Figure 6 A schematic diagram of a solar cell provided in another embodiment of this application; Figure 7 This is a partially enlarged view of a solar cell provided in another embodiment of this application.

[0102] refer to Figure 6 and Figure 7 The solar cell includes: a cell substrate 300 having a first edge 31; first grid lines 301 and second grid lines 302 alternately arranged along a first direction Y; and first connecting lines 311 and second connecting lines 312 alternately arranged along a second direction X, wherein the first connecting line 311 is connected to the first grid line 301, and the second connecting line 312 is connected to the second grid line 302; wherein the first connecting line 311 includes an edge connecting line 303 adjacent to the first edge 31, and the edge connecting line 303 has no welding portion; the second connecting line 311... Wiring 312 includes a collecting part and a spacing part 304. The collecting part is connected to the second grid line 302. A connecting structure 310 is provided, with one end connected to the edge connecting line 303 and the other end passing through the spacing part 304 and connected to the first connecting line 311 which is adjacent to the edge connecting line 303. The end of the collecting part adjacent to the connecting structure 310 is designated as the first part 3121, and the remaining collecting part is designated as the second part 3122. The width of the first part 3121 along the second direction X is greater than the width of the second part 3122 along the second direction X.

[0103] In some embodiments, the solar cell further includes pads located at the intersection of a portion of the second connection line 312 and the second gate line 302; the pads are also located at the intersection of a portion of the first connection line 311 and the first gate line 301. Specifically, the pad located at the intersection of the first connection line 311 and the first gate line 301 is designated as the first pad 305, and the pad located at the intersection of the second connection line 312 and the second gate line 302 is designated as the second pad 306.

[0104] The distance d between the second grid line 302 near the connecting structure 310 and the connecting structure 310 satisfies the following relationship with the length L of the first part 3121 along the first direction: d≤L≤2d. The length L of the first part 3121 along the first direction ranges from 0.5mm to 2mm.

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

[0106] In some embodiments, the distance d between the second gate line 302 near the connection structure 310 and the connection structure 310 is greater than or equal to the 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 second gate lines 302 located between adjacent connection structures 310 ranges from 6 to 12.

[0110] It is worth noting that in another embodiment, 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 grid line 301, and the second grid line 302 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 grid line 101, and the second grid line 102 in the previous embodiment.

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

[0112] Accordingly, based on some embodiments of this application, reference is made to Figure 8 Another aspect of this application provides a photovoltaic module, including: a battery string, which is formed by connecting a plurality of solar cells 40 as described in any of the above embodiments; an encapsulating film 41 covering the battery string; and a cover plate 42 located on the side of the encapsulating film 41 away from the battery string.

[0113] In some embodiments, in conjunction with reference Figure 8 and Figure 9 The battery string includes: solar cells; solder ribbons electrically connected to a second connecting wire; and an insulating layer located between the connecting structure and the solder ribbons.

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

[0115] In some embodiments, there is no gap 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 the area between the solder strip connected to the first connection line and the second grid, and the end surface of the second grid adjacent to the solder strip connected to the first connection line, to provide electrical insulation between the solder strip connected to the first connection line and the second grid. Similarly, the insulating layer 406 also covers the area between the solder strip connected to the second connection line and the first grid, the end surface of the first grid adjacent to the solder strip connected to the second connection line, and the area between the connection structure and the solder strip connected to the second connection line, to provide electrical insulation between the solder strip connected to the second connection line and the first grid, and insulation between the solder strip connected to the second connection line and the connection structure.

[0117] refer to Figure 9 The first part and the second part are flush. The top surface of the insulating layer, which is away from the connecting structure, is higher than the top surface of the first part. The height of the solder strip is lifted by the insulating layer. However, the welding area between the second connecting line and the solder strip is increased by widening the first part.

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

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

[0120] It is worth noting that the first encapsulating film and the second encapsulating film still have a dividing line before the lamination process. After the lamination process, the photovoltaic module will no longer have the concept of the first encapsulating film and the second encapsulating film. That is, the first encapsulating film and the second encapsulating film have formed an integral encapsulating film 41.

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

[0122] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A back-contact battery, characterized in that, include: A battery substrate having a first edge; The first grid lines and the second grid lines are arranged alternately along the first direction; A first connecting line and a second connecting line are alternately arranged along a second direction. The first connecting line is connected to the first grid line, and the second connecting line is connected to the second grid line. The first connecting line includes an edge connecting line adjacent to the first edge, and no welding part is provided on the edge connecting line. The second connecting line includes a collecting part and a spacing part, and the collecting part is connected to the second grid line. A connecting structure, one end of which is connected to the edge connecting line, and the other end of which passes through the interval and is connected to the first connecting line disposed adjacent to the edge connecting line; The collecting portion adjacent to the end of the connecting structure is designated as the first portion, and the remaining collecting portion is designated 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 battery according to claim 1, characterized in that, The distance d between the second gate line near the connection structure and the connection structure and the length L of the first part along the first direction satisfy the following relationship: d≤L≤2d.

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

4. The back contact battery according to claim 1 or 2, characterized in that, The second grid line includes a second collection area and a second busbar area. The second connecting line is connected to the second busbar area, and the second busbar area serves as a welding part of the second grid line. The width of the second busbar area along the first direction is greater than the width of the second collection area along the first direction.

5. The back contact battery according to claim 1 or 2, characterized in that, It also includes pads located at the intersection of a portion of the second connection line and the second gate line.

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

7. The back contact battery 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 battery according to claim 1, characterized in that, The width of the first part 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 as described in any one of claims 1 to 8; An encapsulating film covering the battery string; A cover plate, the cover plate being located on the side of the encapsulating 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 solder strip, which is electrically connected to a second connecting line; an insulating layer, which is located between the connecting structure and the solder strip; wherein the top surface of the first part of the second connecting line away from the battery substrate is flush with the top surface of the insulating layer away from the connecting structure.

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