CN115377231B - Solar cell and photovoltaic module - Google Patents

Abstract

The embodiment of the application relates to the field of photovoltaics, and provides a solar cell and a photovoltaic module, wherein the solar cell comprises: the substrate is provided with a first edge and a second edge, wherein the first edge is the edge of the substrate along the first direction, and the second edge is the edge of the substrate along the second direction; the passivation layer is positioned on the substrate; at least one main electrode, said main electrode is located on the surface of said passivation layer, said main electrode comprises: two connection pads near the second edge; a connecting line, the connecting line being closed near a port of the second edge, a portion of a surface of the connecting line other than the port being in contact with each of the connecting pads; the first cross-sectional area of the connecting line between the connecting pad and the adjacent second edge is greater than the second cross-sectional area of the connecting line between the connecting pads. The solar cell and the photovoltaic module provided by the embodiment of the application can at least improve the photoelectric conversion efficiency of the solar cell.

Description

Solar cells and photovoltaic modules

Technical field

Embodiments of the present application relate to the field of photovoltaics, and in particular to a solar cell and a photovoltaic module.

Background technique

Reasons that affect the performance of solar cells (such as photoelectric conversion efficiency) include optical losses and electrical losses. Optical losses include reflection losses on the front surface of the cell, shadow losses of contact grid lines, and non-absorption losses in the long wavelength band. Electrical losses include semiconductor surface and internal body losses. Loss of photogenerated carrier recombination, contact resistance between semiconductor and metal gate lines, and contact resistance between metal and semiconductor.

In the solar cell, the current generated by the cell is collected and output by setting the auxiliary grid and the main grid, and the current generated by the cell is transmitted to the component end through the pad provided on the main grid. However, the current collection ability of solar cells in the prior art is weak, which affects the improvement of the photoelectric conversion efficiency of the solar cells.

Contents of the invention

Embodiments of the present application provide a solar cell and a photovoltaic component, which are at least conducive to improving the photoelectric conversion efficiency of the solar cell.

According to some embodiments of the present application, on the one hand, embodiments of the present application provide a solar cell, including: a substrate, the substrate has a first edge and a second edge, the first edge is an edge of the substrate along a first direction, and the second edge is an edge of the substrate. The edge along the second direction; a passivation layer, the passivation layer is located on the substrate; a plurality of secondary electrodes, the plurality of secondary electrodes are arranged at intervals along the second direction on the substrate, the secondary electrodes extend along the first direction, and the secondary electrodes penetrate the passivation The passivation layer is in contact with the substrate; at least one main electrode is located on the surface of the passivation layer. The main electrode includes: two connection pads close to the second edge; a connection line, the port of the connection line close to the second edge is closed, and the connection line except the port The outer part of the surface is in contact with each connection pad; the first cross-sectional area of the connection line between the connection pad and the adjacent second edge is greater than the second cross-sectional area of the connection line between the connection pads.

In some embodiments, the difference between the first cross-sectional area and the second cross-sectional area is proportional to the distance between the connecting pad and the adjacent second edge.

In some embodiments, the first width of the connection line between the connection pads and the second edge is greater than the second width of the connection line between the connection pads.

In some embodiments, it also includes: at least one second connection pad, the second connection pad is located between adjacent connection pads; the connection line is in contact with each second connection pad; for the same main electrode, two adjacent connection pads are located The third cross-sectional area of the connection line between the second connection pads is the smallest.

In some embodiments, the fourth cross-sectional area of the connecting line between the connecting pad and the second connecting pad is greater than or equal to the third cross-sectional area.

In some embodiments, the area of the connection pad is greater than the area of the second connection pad.

In some embodiments, the main electrodes include: two first main electrodes, the first main electrode is close to the first edge; at least one second main electrode, the second main electrode is located between adjacent first main electrodes, and the second main electrode is located between adjacent first main electrodes. The main electrode is located on the surface of the passivation layer.

In some embodiments, the first main electrode includes: two first sub-connection pads close to the second edge, a first connection line, and a port of the first connection line close to the second edge is closed, and the first connection line is other than the port. Part of the surface is in contact with each first sub-connection pad; the fifth cross-sectional area of the first connection line between the first sub-connection pad and the adjacent second edge is larger than the first connection line between the first sub-connection pads. The sixth cross-sectional area of the connecting line.

In some embodiments, the second main electrode includes: a second connection line, a port of the second connection line close to the second edge is closed, and the cross-sectional area of the first connection line is greater than or equal to the cross-sectional area of the second connection line.

In some embodiments, the second main electrode further includes: a second sub-connection pad, the second sub-connection pad is close to the second edge, and the second sub-connection pad is in contact with the second connection line; along the second direction, the first sub-connection pad The first distance of the pad from the second edge is greater than the second distance of the second sub-connection pad from the second edge.

In some embodiments, the intersection of the first edge and the second edge has a chamfer, the first main electrode is close to the chamfer along the second direction, and the first sub-connection pad is located in an edge area outside the chamfer along the second direction.

In some embodiments, the solar cell is a back-contact cell, and the secondary electrode includes: a first electrode and a second electrode spaced apart along the first direction; the main electrode includes: a first grid structure and a second grid spaced apart. Line structure, the first gate line structure is electrically connected to the first electrode, and the second gate line structure is electrically connected to the second electrode.

In some embodiments, the first gate line structure and the second gate line structure are staggered along the first direction.

In some embodiments, along the first direction, the cross-sectional area of the secondary electrode close to the first edge is larger than the cross-sectional area of the secondary electrode far from the first edge.

According to some embodiments of the present application, on the other hand, the embodiments of the present application also provide a photovoltaic module, including: a battery string, the battery string is composed of a plurality of solar cells as in any of the above embodiments; an encapsulation layer, the encapsulation layer is The cover plate is used to cover the surface of the battery string; the cover plate is used to cover the surface of the packaging layer away from the battery string.

The technical solutions provided by the embodiments of this application have at least the following advantages:

In the solar cell provided by the embodiment of the present application, the main electrode includes a connecting pad and a connecting wire. By setting the width of the connecting wire to be thinner, the effective shading area can be reduced, while resistance loss can be reduced, thereby increasing the total power of the module. In addition, since the connection lines that make up the main gate are more densely distributed, there can be more contact points between the main gate and the fine gate, and the current conduction path at the silicon wafer cracks and micro-cracks is more optimized, so the loss caused by micro-cracks is greatly reduced, which is beneficial to improving the output of the production line. The first cross-sectional area of the connecting line between the connecting pad and the adjacent second edge is greater than the second cross-sectional area of the connecting line between the connecting pads, and the width of the connecting line located at the second edge and the connecting pad is larger, and can Relieve the welding stress of the connection pad to form good contact between the solder strip and the main electrode; in addition, the wider connection line can relieve the collection pressure of the connection pad and improve the carrier transmission capacity. The wider connection line has More transmission area is used to collect current, and thinner connection lines can reduce the shielding area and reduce optical loss.

Description of the drawings

One or more embodiments are exemplified by the figures in the corresponding drawings. These illustrative illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limit; in order to To more clearly illustrate the technical solutions in the embodiments of the present application or traditional technologies, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. , for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a solar cell provided by an embodiment of the present application;

Figure 2 is a partial structural schematic diagram of a solar cell provided by an embodiment of the present application;

Figure 3 is another structural schematic diagram of a solar cell provided by an embodiment of the present application;

Figure 4 is a schematic structural diagram of the first main electrode in the solar cell provided by an embodiment of the present application;

Figure 5 is another structural schematic diagram of the first main electrode in the solar cell provided by an embodiment of the present application;

Figure 6 is a schematic structural diagram of the second main electrode in the solar cell provided by an embodiment of the present application;

Figure 7 is a schematic structural diagram of a secondary electrode in a solar cell provided by an embodiment of the present application;

Figure 8 is another structural schematic diagram of a solar cell provided by an embodiment of the present application;

Figure 9 is another partial structural schematic diagram of a solar cell provided by an embodiment of the present application;

Figure 10 is a schematic structural diagram of a photovoltaic module provided by an embodiment of the present application.

Detailed ways

It can be known from the background art that the photoelectric conversion efficiency of solar cells in the prior art is not good.

Analysis found that one of the reasons for the poor photoelectric conversion efficiency of existing technology solar cells is that in conventional solar cells, due to limitations in the refining process of single crystal silicon for preparing the substrate, single crystal silicon rods can currently only be made into round shapes. After the silicon rod comes out, it is sliced, which is to cut the cross section of the silicon rod into single crystal silicon wafers (after the area is calculated, it can not only maximize the illumination area in one unit, but also save the silicon rod material to the maximum extent, and also save the silicon rod material to the greatest extent. To facilitate the production of cells and components), chamfers are often provided at the junction of the first edge and the second edge of the substrate to reduce the stress on the outside of the silicon wafer and avoid micro damage to the corners of the silicon wafer. At the same time, in order to ensure that the welding strip does not exceed the chamfer of the battery during welding, there needs to be a certain distance between the welding point and the chamfer of the battery, which makes the carrier transport path in the chamfer area too long, resulting in increased transport losses. In addition, if the solder joints or ribbons are close to the edge of the solar cell, it may cause cracks in the solar cell during the subsequent lamination process and affect the performance of the solar cell.

Embodiments of the present application provide a solar cell. The main electrode includes a connecting pad and a connecting line. By setting the width of the connecting line to be thinner, the effective shading area can be reduced, while resistance loss can be reduced, thereby increasing the total power of the module. In addition, since the connection lines that make up the main gate are more densely distributed, there can be more contact points between the main gate and the fine gate, and the current conduction path at the silicon wafer cracks and micro-cracks is more optimized, so the loss caused by micro-cracks is greatly reduced, which is beneficial to improving the output of the production line. The first cross-sectional area of the connecting line between the connecting pad and the adjacent second edge is greater than the second cross-sectional area of the connecting line between the connecting pads, and the width of the connecting line located at the second edge and the connecting pad is larger, and can Relieve the welding stress of the connection pad to form good contact between the solder strip and the main electrode; in addition, the wider connection line can relieve the collection pressure of the connection pad and improve the carrier transmission capacity. The wider connection line has More transmission area is used to collect current.

Each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of the present application, many technical details are provided to enable readers 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 this application can also be implemented.

Figure 1 is a schematic structural diagram of a solar cell provided by an embodiment of the present application; Figure 2 is a partial structural schematic diagram of a solar cell provided by an embodiment of the present application; Figure 3 is a schematic diagram of a solar cell provided by an embodiment of the present application. Another schematic structural diagram; Figure 4 is a schematic structural diagram of the first main electrode in the solar cell provided by one embodiment of the present application; Figure 5 is another schematic structural diagram of the first main electrode in the solar cell provided by one embodiment of the present application. Structural schematic diagram; Figure 6 is a schematic structural diagram of the second main electrode in the solar cell provided by one embodiment of the present application; Figure 7 is a schematic structural diagram of the secondary electrode in the solar cell provided by one embodiment of the present application; Figure 8 is Another schematic structural diagram of a solar cell provided by an embodiment of the present application; FIG. 9 is another partial structural schematic diagram of a solar cell provided by an embodiment of the present application.

According to some embodiments of the present application, with reference to Figures 1 to 9, a solar cell includes: a substrate 100. The substrate 100 has a first edge 101 and a second edge 102. The first edge 101 is an edge of the substrate 100 along the first direction X. The two edges 102 are edges of the substrate 100 along the second direction Y; a passivation layer, the passivation layer is located on the substrate 100; a plurality of secondary electrodes 120, the plurality of secondary electrodes 120 are arranged at intervals along the second direction Y on the substrate 100, The secondary electrode 120 extends along the first direction Connection pad 113; connection line 114, the port of the connection line 114 close to the second edge 102 is closed, and part of the surface of the connection line 114 except the port is in contact with each connection pad 113; located between the connection pad 113 and the adjacent second edge 102 The first cross-sectional area of the connecting lines 114 between the connecting pads 113 is greater than the second cross-sectional area of the connecting lines 114 between the connecting pads 113 .

In some embodiments, the solar cell may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multicomponent compound solar cell. Specifically, the multicomponent compound solar cell may be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper solar cell, or a cadmium sulfide solar cell. Indium selenide solar cells or perovskite solar cells. Solar cells can also be PERC cells (Passivated Emitter and Rear Cell, passivated emitter and rear cell), PERT cells (Passivated Emitter and Rear Totally-diffused cell, passivated emitter back surface fully-diffused cell), TOPCon cells (Tunnel Any one of Oxide Passivated Contact (tunnel oxide layer passivated contact battery) and HIT/HJT battery (Heterojunction Technology, heterojunction battery). Take the structure of the solar cell shown in Figure 2 as an example.

The substrate 100 is a region that absorbs incident photons to generate photogenerated carriers. In some embodiments, the substrate 100 is a silicon substrate 100, which may include one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In other embodiments, the material of the substrate 100 may also be silicon carbide, organic materials or multi-component compounds. Multi-component compounds may include, but are not limited to, perovskite, gallium arsenide, cadmium telluride, copper indium selenide and other materials. Illustratively, the substrate 100 in the embodiment of the present application is a single crystal silicon substrate.

In some embodiments, the front side of the substrate 100 is a light-receiving surface that absorbs incident light, and the back side of the substrate 100 is a backlight surface. There are doping elements in the substrate 100. The type of doping elements is N-type or P-type. The N-type elements can be group V elements such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element or arsenic (As) element. Elements, P-type elements can be Group III elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element. For example, when the substrate 100 is a P-type substrate 100, its internal doping element type is P-type. For another example, when the substrate 100 is an N-type substrate, the internal doping element type is N-type.

In some embodiments, substrate 100 includes opposing first and second surfaces 104 , 105 . The first surface 104 of the substrate 100 has an emitter 106 therein, and the emitter 106 has a different doping element type than the substrate 100 . And the surface of the emitter 106 may have a textured structure, so that the first surface 104 of the substrate 100 has a smaller reflectivity of incident light, thereby increasing the absorption and utilization of light.

In addition, the first direction X and the second direction Y may be perpendicular to each other, or there may be an included angle less than 90 degrees, for example, 60 degrees, 45 degrees, 30 degrees, etc. The first direction X and the second direction Y are not the same direction. That’s it. In order to facilitate explanation and understanding, in this embodiment, the first direction X and the second direction Y are perpendicular to each other as an example. In a specific application, the first direction The angle setting between them is adjusted, which is not limited in this embodiment.

In some embodiments, the intersection of the first edge 101 and the second edge 102 has a chamfer 103 along the second direction Y, and the connection pad 113 is located in an edge area outside the chamfer 103 along the second direction Y. In this way, the connection pad 113 is not located in the area directly facing the chamfer 103, which can avoid cracks and micro-cracks at the chamfer 103 during welding or lamination; the connection pad 113 is close to the chamfer 103, so the current collected at the chamfer 103 can be collected in the shortest time. The transmission path is collected by the welding ribbon, reducing path loss and improving the cell efficiency of the solar cell. Specifically, referring to FIG. 1 , the distance between the side of the connection pad 113 close to the second edge 102 and the side of the chamfer 103 facing the connection pad is smaller or adjacent. In this way, the connection pad 113 can be considered to be located along the second edge of the chamfer 103 . The edge area outside direction Y. The smaller distance may mean that the distance is smaller than the gate pitch between adjacent secondary electrodes 120 .

In some embodiments, along the second direction Y, the length between the end of the connection pad 113 and the edge of the chamfer 103 along the second direction Y is less than or equal to the gate pitch between adjacent secondary electrodes 120. It is further explained that The current collected at the chamfer 103 can be collected by the welding ribbon through the shortest transmission path, reducing path loss and improving the cell efficiency of the solar cell.

In some embodiments, the passivation layer can be a single-layer structure or a stacked layer structure, and the material of the passivation layer can be silicon oxide, silicon nitride, silicon oxynitride, silicon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide. one or more of the materials. The passivation layer may include a first passivation layer 111 and a second passivation layer 112. The first passivation layer 111 is located on the surface of the emitter 106 away from the substrate 100. The first passivation layer 111 may be regarded as a front passivation layer. The second passivation layer 112 is located on the second surface 105 of the substrate 100, and the second passivation layer 112 can be regarded as a rear passivation layer.

In some embodiments, the secondary electrode 120 is a grid line of the solar cell, used to collect and aggregate the current of the solar cell. The secondary electrode 120 may be sintered by a burn-through slurry. The material of the secondary electrode 120 may be one or more of aluminum, silver, gold, nickel, molybdenum or copper. In some cases, the secondary electrode 120 refers to a thin gate line or a finger-shaped gate line to be distinguished from a main gate line or a bus bar. The secondary electrode 120 includes: a first electrode 121 that penetrates the first passivation layer 111 and contacts the emitter 106. The first electrode 121 is regarded as an upper electrode or a front electrode; a second electrode 122 that penetrates the first passivation layer 111 and contacts the emitter 106. The second passivation layer 112 is in contact with the second surface 105 of the substrate 100, and the second electrode 122 is regarded as a lower electrode or a back electrode.

In some embodiments, the main electrode 110 is regarded as the main grid of the solar cell. The main grid here is not a main grid in the traditional sense, but a bridge connecting each secondary electrode 120 through the connecting wire 114. The connection pad 113 is connected to the welding strip and is used to collect current. In this way, the width of the connection line 114 can be set thinner, reducing the effective shading area, reducing resistance loss, and increasing the total power of the component; the main electrodes 110 can be set densely. Shorten the path of the current through the fine grid, thereby improving the photoelectric conversion efficiency of the solar cell; the thinner connection wires 114 and the connection pads 113 can also avoid the risk of cracks and micro-cracks in the silicon wafer, thereby reducing the risk of cracks and micro-cracks in the silicon wafer. The main electrode 110 is provided at the edge of the solar cell to improve the current collection capability at the edge and optimize the current collection or conduction path.

In some embodiments, each connection line 114 is electrically connected to each secondary electrode 120 for collecting current of each secondary gate. The width of the connection line 114 is set to be thin, and the width range of the connection line 114 is 20-μm~200-μm. Preferably, the width range of the connection line 114 is 20-150 μm, specifically it can be 28 μm, 58 μm, 98 μm, 135 μm or 150 μm. . In this way, the width range of the connection line 114 can reduce the shielding area, reduce the shadow loss of the contact grid line, and improve the current collection capability.

In some embodiments, the port of the connecting line 114 close to the second edge 102 is closed, which is different from the common harpoon connecting line. That is to say, the connecting line 114 has only one connecting line connected to each connecting pad 113. The harpoon Although the connecting wire can increase the contact points and transmission paths between the main electrode and the secondary electrode, conventional thin connecting wires may cause greater resistance damage to the main electrode and affect battery efficiency; only one connecting wire is provided with at least two Compared with the harpoon connection line composed of three connecting wires, it reduces the cost of slurry and facilitates the alignment of subsequent soldering strips. Among them, the port close to the second edge 102 is not in contact with the connection pad 113, and the connection pad 113 is in contact with the area other than the port of the connection line 114. In this way, when there is a chamfer 103 at the corner of the substrate 100, the connection pad 113 is located in the area directly opposite the chamfer 103, and the connecting wire 114 can be located in the area directly opposite the chamfer 103, thereby collecting the current at the chamfer 103 and reducing The carrier transport path in the chamfer 103 area is reduced to reduce transport losses, and the risk of damage caused by the connection pad 113 being provided at the chamfer 103 can also be avoided.

The cross-sectional area refers to the product of width and height. However, in order to avoid the risk of cracks or micro-cracks in the cells caused by different forces in the subsequent connection with the soldering strip or lamination process, connections are usually set The height of the line 114 is the same everywhere, so that the first cross-sectional area is greater than the second cross-sectional area, it can be regarded that the first width of the connection line 114 between the connection pads 113 and the second edge 102 is greater than the connection line between the connection pads 113 Second width of 114.

In other embodiments, in order to avoid the risk of cracks in the connection lines 114 close to the edge, it is possible to set the height of the connection lines 114 between the connection pads 113 and the second edge 102 (ie, the first sub-connection lines 116 ). Slightly less than the height of the connection lines 114 (ie, the second sub-connection line 117 and the third sub-connection line 118 ) located between the connection pads 113 . Likewise, it can be deduced that the first width of the connection line 114 between the connection pads 113 and the second edge 102 is greater than the second width of the connection line 114 between the connection pads 113 . The width of the first sub-connection line 116 is larger, which can relieve the soldering stress of the connection pad 113, so that good contact is formed between the solder strip and the main electrode 110; in addition, the wider first sub-connection line 116 can relieve the stress on the connection pad. The collection pressure of 113 improves the carrier transmission capability, and the wider first sub-connection line 116 has more transmission area for collecting current.

In some embodiments, the difference between the first cross-sectional area and the second cross-sectional area is proportional to the distance S between the connection pad 113 and the adjacent second edge 102 . When the distance S between the connection pad 113 and the adjacent second edge 102 is larger, the first cross-sectional area is also larger, that is, the first width is also larger, so that the transmission area of the collection current is also larger, thereby alleviating the collection pressure and at the same time Improve battery performance. The difference range between the first cross-sectional area and the second cross-sectional area can be regarded as the difference range between the first width and the second width. The difference range between the first width and the second width is less than 100 μm. Furthermore, the difference range between the first width and the second width The difference in width range is less than 80μm. The difference between the first width and the second width may specifically be 15 μm, 39 μm, 68 μm or 80 μm. In this way, the difference between the first width and the second width can satisfy the requirement that the larger the width of the first sub-connection line 116, the better the ability to collect carriers at the second edge, and the appropriate shielding area, thereby reducing optical loss; the second sub-connection The cross-sectional area of the line 117 and the third sub-connection line 118 is appropriate, the conductivity is good, and the resistance loss is small.

In some embodiments, the first width ranges from 20 μm to 200 μm. Preferably, the first width ranges from 20 μm to 150 μm, and specifically may be 28 μm, 58 μm, 98 μm, 135 μm or 150 μm. In this way, the width range of the first sub-connection line 116 can reduce the shielding area, reduce the shadow loss of the contact grid line, and improve the current collection capability.

In some embodiments, the second width ranges from 20 μm to 100 μm. Preferably, the second width ranges from 20 μm to 80 μm, and specifically may be 28 μm, 39 μm, 52 μm, 71 μm or 80 μm. In this way, the cross-sectional area of the second sub-connection line 117 and the third sub-connection line 118 is appropriate, the conductivity is good, and the resistance loss is small.

In some embodiments, the distance S between the connection pad 113 and the adjacent second edge 102 ranges from 3mm to 15mm. Preferably, the distance S ranges from 3mm to 13mm. The distance S can specifically be 3mm, 5.8mm, 9.4mm or 13mm. The distance between the connection pad and the second edge 102 is moderate, which can collect carriers on the second edge 102 and avoid risks such as cracks and damage caused by welding the ribbon.

In some embodiments, the connection pad 113 can be regarded as a contact point between the main electrode 110 and the solder ribbon. The connection pad 113 can be in contact with the secondary electrode 120 , or it may not be in contact with the secondary electrode 120 , but with the connection wire 114 through the connection wire 114 . The secondary electrode 120 is electrically connected.

In some embodiments, it also includes: at least one second connection pad 115, the second connection pad 115 is located between the connection pads 113; the connection line 114 is in contact with each second connection pad 115; for the same main electrode 110, The third cross-sectional area of the connection line 114 (ie, the third sub-connection line 118) between two adjacent second connection pads 115 is the smallest; or the connection line 114 includes a first sub-connection line located between the second edge and the connection pad 113 116. The second sub-connection line 117 located between the second connection pad and the third sub-connection line 118 located between the adjacent second connection pads. The third sub-connection line 118 has the smallest third cross-sectional area. . In a specific example, the fourth cross-sectional area of the second sub-connection line 117 is equal to the third cross-sectional area. The width of the connection line 114 (the second sub-connection line 117 and the third sub-connection line 118) in the middle area is thin, which can reduce the gate line shielding area. In another specific example, the fourth cross-sectional area of the second sub-connection line 117 is larger than the third cross-sectional area. In this way, the first cross-sectional area is the largest, the fourth cross-sectional area is the second, and the third cross-sectional area is the smallest, ensuring that the middle of the base 100 The shielding area of the region is smaller, the width of the edge region is larger, and the connection line 114 has better contact with the secondary electrode 120, thereby having a better ability to collect current.

In some embodiments, the area of the connection pad 113 is larger than the area of the second connection pad 115 . When the area of the connection pad 113 located at the edge is large, it can be used as a reference for aligning the soldering strip to avoid welding offset between the soldering strip and the main electrode 110; a large area of the connecting pad 113 can also relieve the welding pressure of the soldering strip. , while improving the ability of the edge to collect current.

In some embodiments, the main electrode provided in this application is a connection line composed of multiple sub-connection lines, and the width of the first sub-connection line 116 is greater than the width of the second sub-connection line 117 and the third sub-connection line 118, Compared with only one connection line with decreasing or increasing width, the design method of the connecting line provided by this application is more conducive to the alignment of the soldering strips, reduces the difficulty of the preparation process, and reduces the shielding area of the non-edge area of the substrate, thus Has higher photoelectric conversion efficiency.

In some embodiments, referring to Figure 3, the main electrodes include: two first main electrodes 130, the first main electrodes 130 are close to the first edge 101; at least one second main electrode 140, the second main electrode 140 is located adjacent to Between the first main electrodes 130, the second main electrode 140 is located on the surface of the passivation layer.

In some embodiments, the first main electrode 130 includes: two first sub-connection pads 131 close to the second edge 102; a first connection line 132, and the port of the first connection line 132 close to the second edge 102 is closed. A portion of the surface of a connection line 132 other than the port is in contact with each first sub-connection pad 131; the fifth cross-sectional area of the first connection line 132 located between the first sub-connection pad 131 and the adjacent second edge 102 is greater than The sixth cross-sectional area of the first connection line 132 located between the first sub-connection pads 131 .

In some embodiments, it also includes: at least one third sub-connection pad 133, the third sub-connection pad 133 is located between the first sub-connection pads 131; the first connection line 132 is in contact with each third sub-connection pad 133; For the same first main electrode 130, the seventh cross-sectional area of the first connection line 132 located between two adjacent third sub-connection pads 133 is the smallest; or the first connection line includes the first connection line located at the second edge and the first sub-connection The first connection section 134 of the pad 131, the second connection section 136 between the third sub-connection pad and the first sub-connection pad, and the third connection section 137 between the third sub-connection pad, the third connection section The seventh cross-sectional area is the smallest. In a specific example, referring to FIG. 4 , the eighth cross-sectional area of the second connecting section 136 is equal to the seventh cross-sectional area. The width of the first connection line 132 in the middle area is thinner, which can reduce the gate line shielding area. In another specific example, referring to FIG. 5 , the eighth cross-sectional area of the second connecting section 136 is larger than the seventh cross-sectional area. In this way, the fifth cross-sectional area is the largest, the eighth cross-sectional area is the second, and the seventh cross-sectional area is the smallest, ensuring that the shielding area in the middle area of the substrate 100 is small, the width of the edge area is large, and the contact between the first connection line 132 and the secondary electrode 120 is ensured. Better, thus having better ability to collect current.

In some embodiments, the second main electrode 140 includes: a second connection line 142 , a port of the second connection line 142 close to the second edge 102 is closed, and a cross-sectional area of the first connection line 132 is greater than or equal to that of the second connection line 142 . area, for the second main electrode 140 in the non-edge area, a second connection line 142 with a smaller width is set so that the gate line shielding area of the second main electrode 140 is smaller; for the first main electrode 130 in the edge area, In other words, setting the first connection line 132 with a larger width increases the cross-sectional area of electrical contact between the first connection line 132 and each secondary electrode 120, and reduces the resistance of the first connection line 132. Compared with a thinner one, The second connection line 142 improves the current collection and transmission capabilities of the first connection line 132 near the edge of the substrate 100, thereby improving the overall edge current collection capability and photoelectric conversion efficiency of the solar cell.

In some embodiments, the first spacing m between the first main electrode 130 and the adjacent second main electrode 140 is not equal to the second spacing n between the adjacent second main electrodes 140 . In a specific example, the first spacing m is greater than the second spacing n, the first main electrode 130 is close to the first edge 101, and the main electrodes at the edge are arranged sparsely, so that the battery sheets can be avoided during welding and lamination. Risks such as micro cracks may occur. In another specific example, the first spacing m is smaller than the second spacing n, ensuring that the first main electrode 130 and the second main electrode 140 are densely packed at the edge, and the path of the current from the secondary electrode 120 to the main electrode is short, thereby reducing losses and contribute to the electrode's ability to collect current at the edges.

In some embodiments, the first connection line 132 and the second connection line 142 are made of the same material, that is, the first connection line 132 and the second connection line 142 are formed under the same manufacturing process.

In some embodiments, the second main electrode 140 further includes: a second sub-connection pad 141, the second sub-connection pad 141 is close to the second edge 102, the second sub-connection pad 141 contacts the second connection line 142; along the second In the direction Y, the first distance between the first sub-connection pad 131 and the second edge 102 is greater than the second distance between the second sub-connection pad 141 and the second edge 102 . Since the junction of the first edge 101 and the second edge 102 of the substrate 100 has a chamfer 103 , the first sub-connection pad 131 is located far away from the second edge 102 , and the second sub-connection pad 141 is disposed farther than the first sub-connection pad 131 . Being close to the second edge 102 can shorten the current transmission path at the second edge 102 and improve the current collection capability of the second edge 102 .

In some embodiments, referring to Figures 3 and 6, one end of the second connection line 142 is closed close to the port of the second edge 102, and part of the surface of the second connection line 142 other than the port is in contact with the second sub-connection pad 141; located at The ninth cross-sectional area of the second connection line 142 (ie, the fourth section 144) between the second sub-connection pad 141 and the adjacent second edge 102 is larger than the second connection line 142 between the second sub-connection pads (ie, the fourth section 144). That is, the tenth cross-sectional area of the fifth paragraph 146). The technical concept of the ninth cross-sectional area being larger than the tenth cross-sectional area and the technical effects achieved are the same as or similar to the technical concept of the first cross-sectional area being larger than the second cross-sectional area and the technical effects achieved, and will not be described in detail here.

In some embodiments, referring to FIGS. 3 and 7 , along the first direction The current collection and transmission capabilities of the secondary electrode 120 at 101.

In some embodiments, the number of busbars may be 0, that is, the solar cell is a busbarless cell, or the solar cell is an MBB (multiple busbar) cell.

In some embodiments, referring to FIG. 1 and FIG. 8 , the main electrode is in contact with a side of at least one connection pad close to the first edge 101 . The connection line is closer to the first edge 101, and the ability of the connection line to collect current at the first edge 101 is enhanced, and there is at least one connection line width between the connection pad and the first edge 101. The edge can be avoided during welding and lamination. Damage problems caused by poor stress. The secondary electrode 120 is in contact with the side of the connection pad away from the first edge 101. In this way, the current collected by the secondary electrode can be directly collected by the connection pad and converged on the welding strip, thereby reducing the current transmission path.

In some embodiments, the solar cell is a back contact cell, such as an IBC (Interdigitated backcontact, interdigitated back contact) cell. Referring to FIG. 9 , the back contact cell includes: a substrate 100 and a third blunt electrode located on the first surface 104 of the substrate 100 . passivation layer 107; the first doped region 108 and the second doped region 109 located on the second surface 105 of the substrate 100; the fourth passivation layer 119, the fourth passivation layer 119 is located in the first doped region 108 and the second doped region The surface of the substrate 100 of the impurity region 109; the first electrode 121, the first electrode 121 penetrates the fourth passivation layer 119 and is connected to the first doping region 108; the second electrode 122, the second electrode 122 penetrates the fourth passivation layer 119 and is connected to The second doped region 109 is connected. In other embodiments, the back contact battery includes: a substrate, a third passivation layer located on a first surface of the substrate; a first doped region located on the second surface of the substrate, and the first doped region may have the same conductivity type as the substrate , can also have different conductivity types from the substrate; the tunnel oxide layer and the doped polysilicon layer are located on the second surface of the substrate; the fourth passivation layer is located on the second surface of the substrate; A doped region, the surface of the doped polysilicon layer; a first electrode, the first electrode penetrates the fourth passivation layer and is connected to the doped polysilicon layer; a second electrode, the second electrode penetrates the fourth passivation layer and the first doped polysilicon layer area connection. In still other embodiments, a back contact cell includes: a substrate, a third passivation layer located on a first surface of the substrate; a second surface of the substrate having a tunnel oxide layer and a first doped polysilicon layer and a second doped polysilicon layer; The fourth passivation layer is located on the surface of the first doped polysilicon layer, the second doped polysilicon layer and the substrate; the first electrode penetrates the fourth passivation layer and the first doped polysilicon layer. Connection; the second electrode, the second electrode penetrates the fourth passivation layer and is connected to the second doped polysilicon layer. It can be understood that the above-mentioned first surface is the front surface of the silicon substrate, the second surface is the back surface of the silicon substrate, the first doped region is one of the N-type doped region or the P-type doped region, and the second doped region The region is the other one of an N-type doped region or a P-type doped region.

It is worth noting that the “back contact battery” refers to that both the positive electrode and the negative electrode are in contact with the structure on the back side of the substrate 100 and collect current, and does not involve the front side of the substrate 100 .

In some embodiments, the back contact cell includes: a substrate 100 having a first edge 101 and a second edge 102. The first edge 101 is an edge of the substrate 100 along the first direction X, and the second edge 102 is an edge of the substrate 100 along the first direction X. The edge in the second direction Y; a passivation layer, the passivation layer is located on the substrate 100; a plurality of secondary electrodes 120, the plurality of secondary electrodes 120 are arranged at intervals along the second direction Y on the substrate 100, and the secondary electrodes 120 are arranged along the first direction Extended by , the port of the connecting line 114 close to the second edge 102 is closed, and part of the surface of the connecting line 114 other than the port is in contact with each connecting pad 113; A cross-sectional area is larger than a second cross-sectional area of the connection lines 114 located between the connection pads 113 .

In some embodiments, the difference between the first cross-sectional area and the second cross-sectional area is proportional to the distance between the connecting pad and the adjacent second edge. The first width of the connection line between the connection pads and the second edge is greater than the second width of the connection line between the connection pads.

In some embodiments, the secondary electrode includes: a first electrode 121 and a second electrode 122 spaced apart along the first direction. The first electrode 121 is one of a positive electrode and a negative electrode, and the second electrode 122 is one of a positive electrode and a negative electrode. One of the negative electrodes. In the embodiment of the present application, the first electrode 121 is a positive electrode and the second electrode 122 is a negative electrode as an example. The secondary electrode 120 includes first electrodes 121 and second electrodes 122 spaced apart along the second direction Y.

In some embodiments, the main electrode includes: a first gate line structure 151 and a second gate line structure 152 arranged at intervals. The first gate line structure 151 is electrically connected to each first electrode 121 , and the second gate line structure 152 is electrically connected to each first electrode 121 . Each second electrode 122 is electrically connected. Specifically, the first main electrode includes a first edge gate line and a second edge gate line. The first edge gate line is electrically connected to each first electrode 121 , and the second edge gate line is electrically connected to each second electrode 122 . The second main electrode includes a first gate line and a second gate line.

In some embodiments, the first gate line structure 151 and the second gate line structure 152 are arranged in a staggered manner along the first direction The distance between the grid structure 152 and the second edge is different, which reduces the consumption of metallized conductive silver paste of the solar cell and shortens the distance for current collection in the fine grid direction, reducing the fragmentation rate. In addition, at least a part of the main grid may not be exposed to the end of the secondary electrode close to the second edge, which is not only beautiful but also ensures the adaptive length of the positive and negative electrodes of the battery sheet, and avoids the risk of short circuit between electrodes of different polarities.

In the solar cell provided by the embodiment of the present application, the main electrode 110 includes a connecting pad 113 and a connecting wire 114. By setting the width of the connecting wire 114 to be thinner, the effective shading area can be reduced, while resistance loss can be reduced, thereby increasing the total power of the module. In addition, since the connection lines 114 that make up the main gate are more densely distributed, there can be more contact points between the main gate and the fine gate, and the path of current conduction in the silicon wafer's hidden cracks and micro-cracks is more optimized, so the problems caused by micro-cracks The loss is greatly reduced, which is beneficial to increasing the output of the production line. The first cross-sectional area of the connecting line 114 between the connecting pad 113 and the adjacent second edge 102 is greater than the second cross-sectional area of the connecting line 114 between the connecting pads 113 , and the connection between the second edge 102 and the connecting pad 113 The wider width of the line 114 can relieve the welding stress of the connection pad 113, so that a good contact is formed between the solder ribbon and the main electrode 110; in addition, the wider connection line 114 can relieve the collection pressure of the connection pad 113 and increase the load. The transmission capacity of currents, wider connection lines have more transmission area for collecting current.

Figure 10 is a schematic structural diagram of a photovoltaic module provided by an embodiment of the present application.

Correspondingly, embodiments of the present application also provide a photovoltaic module. Referring to Figure 10, the photovoltaic module includes a battery string. The battery string is connected by a plurality of solar cells 20 provided in the above embodiments; an encapsulation layer 21 is used. Cover the surface of the battery string; the cover plate 22 is used to cover the surface of the packaging layer 21 away from the battery string. The solar cells 20 are electrically connected in the form of a whole piece or multiple slices to form multiple battery strings, and the multiple battery strings are electrically connected in series and/or in parallel.

Specifically, in some embodiments, multiple battery strings may be electrically connected through conductive charges. The encapsulation layer 21 includes a first encapsulation layer 211 and a second encapsulation layer 212. The first encapsulation layer 211 covers one of the front or the back of the solar cell 20, and the second encapsulation layer covers the other of the front or the back of the solar cell 20. , specifically, at least one of the first encapsulation layer 211 or the second encapsulation layer 212 may be an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene co-elastomer (POE) adhesive film, or a polyterephthalene Ethylene glycol formate (PET) film and other organic encapsulating films. In some embodiments, the cover 22 may be a glass cover, a plastic cover, or other cover with a light-transmitting function. Specifically, the surface of the cover plate 22 facing the encapsulation layer 21 may be a concave and convex surface, thereby increasing the utilization of incident light. The cover 22 includes a first cover 221 and a second cover 222 . The first cover 221 is opposite to the first encapsulation layer 211 , and the second cover 222 is opposite to the second encapsulation layer 212 .

Although this application discloses preferred embodiments as above, it is not used to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, this application The scope of protection shall be subject to the scope defined by the claims of this application. In addition, the embodiments in the description of this application and the drawings shown are only examples, and do not cover the entire scope protected by the claims of this application.

Those of ordinary skill in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and spirit of the present application. scope. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be subject to the scope defined by the claims.

Claims (15)

1. A solar cell, comprising:

the substrate comprises a first edge and a second edge, wherein the first edge is an edge of the substrate along a first direction, and the second edge is an edge of the substrate along a second direction;

A passivation layer on the substrate;

the auxiliary electrodes are arranged on the substrate at intervals along the second direction, extend along the first direction and penetrate through the passivation layer to be in contact with the substrate;

at least one main electrode, said main electrode is located on the surface of said passivation layer, said main electrode comprises: two connection pads near the second edge; a connecting line, the connecting line being closed near a port of the second edge, a portion of a surface of the connecting line other than the port being in contact with each of the connecting pads; the first cross-sectional area of the connecting line between the connecting pad and the adjacent second edge is larger than the second cross-sectional area of the connecting line between the connecting pads;

at least two second connection pads located between adjacent ones of the connection pads; the connecting wires are contacted with each second connecting pad;

the connecting wire comprises a first sub-connecting wire, a second sub-connecting wire and a third sub-connecting wire which are sequentially connected, wherein the first sub-connecting wire is a connecting wire positioned between the connecting pad and the second edge, the second sub-connecting wire is a connecting wire positioned between the connecting pad and the second connecting pad, and the third sub-connecting wire is a connecting wire positioned between two adjacent second connecting pads; the first sub-connecting wire is contacted with the connecting pad;

The extending direction of the second sub-connecting wire and the extending direction of the third sub-connecting wire are the same as the second direction;

wherein each connecting wire is electrically connected with each auxiliary electrode;

the main electrode includes: two first main electrodes, the first main electrodes being adjacent to the first edge; the junction of the first edge and the second edge is provided with a chamfer, and the first main electrode is close to the chamfer.

2. The solar cell of claim 1, wherein a difference between the first cross-sectional area and the second cross-sectional area is proportional to a distance between the connection pad and the adjacent second edge.

3. The solar cell of claim 1, wherein a first width of the connection line between the connection pads and the second edge is greater than a second width of the connection line between the connection pads.

4. The solar cell according to claim 1, wherein the third cross-sectional area of the connection line between two adjacent second connection pads is smallest for the same main electrode.

5. The solar cell according to claim 4, wherein a fourth cross-sectional area of the connection line between the connection pad and the second connection pad is equal to or larger than the third cross-sectional area.

6. The solar cell of claim 4, wherein the area of the connection pad is greater than the area of the second connection pad.

7. The solar cell of claim 1, wherein the main electrode comprises: and at least one second main electrode, wherein the second main electrode is positioned between the adjacent first main electrodes, and the second main electrode is positioned on the surface of the passivation layer.

8. The solar cell of claim 7, wherein the first main electrode comprises: two first sub-connection pads near the second edge, a first connection line, and a port of the first connection line near the second edge is closed, a portion of a surface of the first connection line except the port is in contact with each of the first sub-connection pads; the fifth cross-sectional area of the first connection line between the first sub-connection pads and the adjacent second edge is greater than the sixth cross-sectional area of the first connection line between the first sub-connection pads.

9. The solar cell of claim 8, wherein the second main electrode comprises: and the second connecting line is closed near the port of the second edge, and the sectional area of the first connecting line is larger than or equal to that of the second connecting line.

10. The solar cell of claim 9, wherein the second main electrode further comprises: a second sub-connection pad adjacent to the second edge, the second sub-connection pad in contact with the second connection line; along the second direction, a first distance between the first sub-connection pad and the second edge is greater than a second distance between the second sub-connection pad and the second edge.

11. The solar cell of claim 8, wherein in the second direction, the first sub-connection pad is located at an edge region of the chamfer that is other than in the second direction.

12. The solar cell of claim 1, wherein the solar cell is a back contact cell, and the sub-electrode comprises: first and second electrodes arranged at intervals along the first direction; the main electrode includes: the first grid line structure is electrically connected with the first electrode, and the second grid line structure is electrically connected with the second electrode.

13. The solar cell of claim 11, wherein the first and second grid line structures are arranged offset along the first direction.

14. The solar cell of claim 1, wherein a cross-sectional area of the sub-electrode proximate the first edge is greater than a cross-sectional area of the sub-electrode distal the first edge in the first direction.

15. A photovoltaic module, comprising:

a battery string formed by connecting a plurality of solar cells according to any one of claims 1 to 14;

an encapsulation layer for covering the surface of the battery string;

and the cover plate is used for covering the surface, far away from the battery strings, of the packaging layer.