Solar cell and photovoltaic module

Abstract

The invention relates to a solar cell and a photovoltaic module, and relates to the field of photovoltaic technology. The solar cell comprises a main body, a plurality of first welding spots and a plurality of second welding spots, wherein the width of the second welding spots is greater than that of the first welding spots; the main body is provided with a first welding area and a second welding area, and the first welding area and the second welding area are distributed on the surface of the main body along a first direction; the first welding area is only provided with a plurality of first welding spots distributed in the second direction, and the second welding area is provided with a plurality of second welding spots distributed in the second direction. According to the invention, hot spot grid breaking can be improved, and the overall cost can be considered at the same time.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a solar cell and a photovoltaic module. Background Technology

[0002] In some solar cells, the grid lines are made smaller by reducing their weight. However, this reduction in grid weight increases resistance, leading to increased heat generation when there is shading. Overheating can be conducted to the vicinity of the main grid, causing the solder ribbon to react with the main grid and resulting in hot spots and grid breakage (EL). Summary of the Invention

[0003] Therefore, it is necessary to provide a solar cell and photovoltaic module to address the problem of hot spot EL grid breakage.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] In a first aspect, embodiments of this application provide a solar cell, including a main body, a plurality of first solder joints and a plurality of second solder joints, wherein the width of the second solder joints is greater than the width of the first solder joints;

[0006] The main body is provided with a first welding area and a second welding area, and the first welding area and the second welding area are distributed on the surface of the main body along a first direction;

[0007] The first welding area has only a plurality of first welding points distributed along the second direction, and the second welding area has a plurality of second welding points distributed along the second direction;

[0008] There is an angle between the first direction and the second direction.

[0009] In one embodiment of the first aspect, the solar cell further includes a plurality of main grids, the main grids being parallel to the second direction;

[0010] Each of the main gates is respectively disposed in the corresponding first welding area or second welding area.

[0011] In one embodiment of the first aspect, one of the adjacent first welding areas and second welding areas is without the main gate configuration.

[0012] In one embodiment of the first aspect, the solar cell further includes a plurality of fine grids parallel to the first direction;

[0013] Each of the first solder joint and the second solder joint is connected to a fine grid.

[0014] In one embodiment of the first aspect, the second welding area is further provided with a plurality of the first welding points, and within a second welding area, the first welding points and the second welding points are all distributed on the same straight line in the second direction.

[0015] In one embodiment of the first aspect, in a second welding area, the first solder joint and the second solder joint are alternately distributed along the second direction;

[0016] Alternatively, in a second welding zone, the first weld point and the second weld point are distributed relative to each other along the centerline of the second welding zone.

[0017] In one embodiment of the first aspect, along the first direction, the two edges of the body are provided only with the first welding area;

[0018] The number of the first welding zones on one edge of the main body is 1-4.

[0019] In one embodiment of the first aspect, the second welding area is disposed in the portion between the two edges of the body;

[0020] At least one first welding zone is provided between two adjacent second welding zones.

[0021] In one embodiment of the first aspect, the width ratio of the first solder joint to the width of the second solder joint is 1:1.1-11.

[0022] Secondly, embodiments of this application also provide a photovoltaic module, including the solar cell and solder strip described in any of the above embodiments, wherein the solder strip is respectively soldered to the welding areas of two adjacent solar cells;

[0023] The width of the second solder joint in the second direction is inversely proportional to the width of the solder strip in the first direction. The width change of the solder strip is D, and the width change of the second solder joint is L, with D:L = 10:5-500.

[0024] Compared to related technologies, the advantages of this application are as follows: This application provides a solar cell and photovoltaic module. By setting a wider second solder joint on the second grid line, the resistance of the grid line is reduced, the current conduction capability is improved, the welding quality is guaranteed, and the hot spot grid breakage phenomenon is reduced. In addition, a narrower first solder joint is set on the first grid line, and the first grid line is set between two adjacent second grid lines, which improves the hot spot grid breakage while simultaneously taking into account the overall cost. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of the solar cell in some embodiments of this application. Figure 1 ;

[0027] Figure 2 This is a schematic diagram of the structure of the first welding area in some embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the structure of the second welding area in some embodiments of this application. Figure 1 ;

[0029] Figure 4 This is a schematic diagram of the structure of the second welding area in some embodiments of this application. Figure 2 ;

[0030] Figure 5 This is a schematic diagram of the structure of the second welding area in some embodiments of this application. Figure 3 ;

[0031] Figure 6 This is a schematic diagram of the structure of the solar cell in some embodiments of this application. Figure 2 ;

[0032] Figure 7 This is a schematic diagram of the structure of the solar cell in some embodiments of this application. Figure 3 ;

[0033] Figure 8 This is a schematic diagram of the structure of the solar cell in some embodiments of this application. Figure 4 ;

[0034] Figure 9 for Figure 4 The diagram shows an enlarged view of part A.

[0035] Figure 10 This is a schematic diagram of the structure of the photovoltaic module in some embodiments of this application. Figure 1 ;

[0036] Figure 11 This is a schematic diagram of the structure of the photovoltaic module in some embodiments of this application. Figure 2 .

[0037] Explanation of reference numerals in the attached figures:

[0038] 1000. Photovoltaic modules;

[0039] 100. Solar cell; 110. Main body; 111. First welding area; 112. Second welding area; 120. First solder joint; 130. Second solder joint; 140. Main grid; 150. Fine grid;

[0040] 200, solder strip; 300, cover plate; 400, encapsulating adhesive;

[0041] x, the first direction; y, the second direction. Detailed Implementation

[0042] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0043] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0044] Furthermore, where the term "and / or" appears, "and / or" merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. Where the terms "first" and "second" appear, these terms are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" can explicitly or implicitly include at least one of those features. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0048] See Figure 1 As shown, an embodiment of this application provides a solar cell 100, which includes a main body 110, a plurality of first solder joints 120, and a plurality of second solder joints 130. The main body 110 has a first welding area 111 and a second welding area 112, which are distributed along a first direction x on the surface of the main body 110. The first welding area 111 has only a plurality of first solder joints 120 distributed along a second direction y, and the second welding area 112 has a plurality of second solder joints 130 distributed along the second direction y, wherein the width of the second solder joints 130 is greater than the width of the first solder joints 120.

[0049] For example, the main body 110 is a silicon substrate, which may contain doped elements of either N-type or P-type. N-type elements can be group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), while P-type elements can be group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For instance, when the main body 110 is a P-type substrate, the doped element type is P-type. Similarly, when the main body 110 is an N-type substrate, the doped element type is N-type.

[0050] It should be noted that, Figure 1 This indicates the fabrication of two mirror-image solar cells 100 on a single silicon substrate. Figure 7 and Figure 8 This refers to a single solar cell 100 obtained by cutting a silicon substrate along a cutting line.

[0051] The main body 110 of the solar cell 100 is provided with solder joints, which are then welded to the solder strip 200 to connect multiple solar cells 100 and collect and transmit the current of the solar cells 100. The solder joints are arranged in a linear array along the distribution direction of the solder strip 200, which is the second direction y in the figure of this application.

[0052] In related technologies, the grid lines of solar cells 100 tend to be heavier, which leads to increased resistance at the solder joints, increased heat generation, and the formation of localized hot spots. When the temperature of the hot spot exceeds the melting point of the solder, the solid solder joint will remelt into a liquid state. The liquid solder has extremely high chemical activity and undergoes a violent alloying reaction with the silver paste of the grid lines, forming intermetallic compounds, which in turn leads to grid line breakage.

[0053] Therefore, in this embodiment, a second solder joint 130 with a larger width is provided, thereby increasing the contact area between the solder joint and the solder strip 200, reducing the resistance at the solder joint, improving the current conduction capability, improving the welding quality, and reducing the risk of hot spots.

[0054] In this application, the area where solder joints are distributed in a linear array is defined as the welding area, and different solder joints are distinguished by a first solder joint 120 and a second solder joint 130, wherein the width of the second solder joint 130 in the second direction y is greater than that of the first solder joint 120. Simultaneously, the welding area is divided into a first welding area 111 and a second welding area 112 based on the different distribution of solder joints.

[0055] Continue reading Figure 2As shown, for example, the first welding area 111 has no second solder joints 130, but only a plurality of first solder joints 120 distributed along the second direction y. Thus, while the second welding area 112 can satisfy the requirement of reducing hot spot risk, several first welding areas 111 are adaptively provided. The provision of the first welding areas 111 greatly reduces the solder cost of the solder joints, thereby reducing the production cost of the solar cell 100.

[0056] Continue reading Figure 3 and Figure 4 As shown, for example, the second welding area 112 is provided with a plurality of second solder points 130 distributed along the second direction y, thereby reducing the resistance at the solder point by widening the second solder points 130, thereby reducing heat generation and reducing the risk of hot spot EL gate breakage.

[0057] Thus, by arranging the first welding area 111 and the second welding area 112 along the first direction x, it is not necessary to widen the solder joints of the entire welding area, thereby reducing the overall cost while ensuring the reduction of resistance.

[0058] Understandably, in this embodiment, the main body 110 has a rectangular structure, and correspondingly, the first direction xy and the second direction yx are perpendicular. However, in other embodiments, the first direction xy and the second direction yx may also be set at an angle, and the angle may be 10°, 15°, 30°, 45°, 60°, 70°, 80°, etc., which are not specifically limited here.

[0059] See again Figure 3 As shown, in some embodiments, only second solder joints 130 are provided in the second welding area 112, and each second solder joint 130 is distributed along a second direction y-line within the second welding area 112. In this way, the surface hot spot problem of the solar cell 100 is significantly improved, and by providing the second welding area 112 separately, the risk of hot spot EL grid breakage can be reduced while reducing the production cost of the solar cell 100.

[0060] See again Figure 4 As shown, in some embodiments, the second welding area 112 is further provided with a plurality of first solder joints 120. Within a second welding area 112, the first solder joints 120 and the second solder joints 130 are all distributed on the same straight line in the second direction y. Thus, by providing the first solder joints 120 within the second welding area 112, both the local hot spots can be reduced by the second solder joints 130, and the solder cost can be reduced by providing the first solder joints 120.

[0061] It is understandable that, since the second welding area 112 is provided with the first welding point 120, the number of first welding areas 111 between two adjacent second welding areas 112 should not be too many, so as to avoid too many first welding points 120 in some areas, which would prevent the application from effectively reducing the hot spot EL gate breakage effect.

[0062] Optionally, in this specific embodiment, the number of first welding areas 111 between two adjacent second welding areas 112 is 1-3.

[0063] See again Figure 4 As shown, in one embodiment, in a second welding area 112, the first solder joint 120 and the second solder joint 130 are alternately distributed along the second direction y.

[0064] For example, a first solder point 120 is provided between two adjacent second solder points 130 to reduce the use of solder at the solder point while reducing the risk of hot spot EL gate breakage.

[0065] Of course, in other embodiments, multiple first solder points 120 may be provided between two adjacent second solder points 130 to further reduce solder costs, but the need to reduce the risk of hot spot EL gate breakage must also be met. The specific choice can be made according to actual needs, and no specific limitation is made here.

[0066] Continue reading Figure 5 As shown, in one embodiment, in a second welding area 112, the first solder joint 120 and the second solder joint 130 are distributed opposite each other along the centerline of the second welding area 112.

[0067] For example, taking a second welding area 112 as an example, along the second direction y, half of the second welding area 112 is set as the first solder joint 120, and the other half is set as the second solder joint 130. This can also meet the effective current output of a single solder strip 200, and reduce the overall resistance and reduce local hot spots.

[0068] Continue reading Figure 6 As shown, it can be understood that, based on the above embodiment, two adjacent second welding areas 112 should be centrally symmetrically distributed. That is, on the same side of two adjacent second welding areas 112, one is set as a first solder point 120 and the other is set as a second solder point 130. In this way, the problem of too many first solder points 120 on one side of the solar cell 100, which would lead to an increase in hot spots on one side, can be avoided.

[0069] See again Figure 1As shown, in some embodiments, the solar cell 100 further includes multiple main grids 140, which are parallel to the second direction y. Each main grid 140 is disposed in a corresponding first welding area 111 or second welding area 112, and each main grid 140 is connected to all solder joints of the corresponding welding area.

[0070] For example, in a solar cell 100 having a main grid 140, solder joints are distributed on the main grid 140 and then soldered to the solder joints by solder ribbon 200 to collect and transmit the collected current of the main grid 140.

[0071] Understandably, the solar cell 100 should also have fine grids 150 parallel to the first direction x, and each fine grid 150 is connected to the main grid 140 so that the current of each fine grid 150 is collected and output through the main grid 140.

[0072] Continue reading Figure 7 As shown, in some embodiments, one of an adjacent set of first welding areas 111 and second welding areas 112 is not provided with a main gate 140.

[0073] For example, some welding areas can be directly supplied with current through the solder strip 200 without the need for the main grid 140, thereby reducing the printing material of the main grid 140 and lowering costs.

[0074] Optionally, there is a welding area without main grid 140 between two adjacent main grids 140, so as to ensure the uniformity of the distribution of main grids, so as to meet the current output capability of solar cell 100 while reducing costs.

[0075] In some embodiments, the solar cell 100 further includes a plurality of fine grids 150, which are parallel to the first direction x, and each first solder joint 120 and second solder joint 130 is connected to a fine grid 150.

[0076] For example, this embodiment is applied to a gridless solar cell. A gridless solar cell can reduce the number of main grids 140, thereby significantly reducing the amount of silver paste required for the main grids 140, and thus reducing the cost of the solar cell 100. In the gridless solar cell 100, each fine grid 150 is arranged parallel to the first direction x, and each solder joint is distributed along the second direction y and connected to a corresponding fine grid 150. After soldering the solder joints located in the same soldering area with solder ribbons 200 parallel to the second direction y, the current of the solar cell 100 is collected and output.

[0077] It is understandable that multiple solder joints along the first direction x can be distributed on the same fine grid 150 or on different fine grids 150, and no specific limitation is made here.

[0078] In summary, in this embodiment of the application, by combining the arrangement of the first welding area 111 and the second welding area 112 in the gridless cell, the production cost of the solar cell 100 is further reduced, and the risk of hot spot EL grid breakage is effectively reduced.

[0079] In some embodiments, along the first direction x, the two edges of the body 110 are provided with only the first welding area 111.

[0080] Understandably, the edges of the main body 110 are closer to the boundary of the photovoltaic module 1000, making it easier for heat to be conducted to the external environment rather than accumulating inside the module. Therefore, provided that the heat dissipation conditions meet the requirements of this application, first welding areas 111 can be provided on both sides of the edges of the main body 110. Meanwhile, the middle of the main body 110 can have its resistance reduced by widening the second solder joint 130 in the second welding area 112, thereby reducing heat generation and lowering the risk of hot spot EL grid breakage.

[0081] In some embodiments, the number of first welding areas 111 on one edge of the body 110 is 1-4.

[0082] For example, the number of first welding areas 111 on an edge can be one, two, three, four, etc., and the specific number can be reasonably selected according to the distribution density of the grid lines and the heat dissipation conditions of the photovoltaic module 1000, and is not specifically limited here. By setting the first welding area 111 on the edge of the main body 110, the risk of hot spot EL grid breakage can be reduced while the production cost of the solar cells 100 can be reduced.

[0083] In other embodiments, a second welding area 112 may also be provided at the edge of the main body 110 to minimize the risk of hot spot EL gate breakage, but this has the problem of excessively high solder cost.

[0084] In some embodiments, the second welding area 112 is disposed in the portion between the two edges of the body 110, i.e., the middle portion of the body 110, thereby reducing heat generation in the middle portion of the body 110.

[0085] For example, at least one first welding area 111 can be provided between two adjacent second welding areas 112, thereby effectively reducing the amount of solder used in the solder joints through the first solder joints 120 in the first welding area 111, so as to reduce the overall cost. However, the number of intervals between the first welding areas 111 should also be reasonably limited to avoid too many first welding areas 111, which would lead to excessively high local resistance of the solar cell 100 and may still cause local hot spots.

[0086] Continue reading Figure 9 As shown, in some embodiments, the width ratio of the first solder joint 120 to the width ratio of the second solder joint 130 is 1:1.1-11.

[0087] For example, the width of the second solder joint 130 in the second direction y is W1, and the width of the first solder joint 120121 in the second direction y is W2, where 1:1.1≤W1 / W2≤11. The width ratio of the first solder joint 120 and the second solder joint 130 can be reasonably selected according to actual needs.

[0088] Optionally, W1 can be 5um-1000um and W2 can be 15um-2000um, so as to increase the contact area between the solder joint and the solder strip 200 by widening the second solder joint 130, thereby reducing the resistance at the solder joint and reducing the formation of hot spots.

[0089] Continue reading Figure 10 and Figure 11 As shown, embodiments of this application also provide a photovoltaic module 1000, including solar cells 100, solder ribbons 200, cover plates 300 and encapsulating adhesive 400 as in any of the above embodiments. Two adjacent solar cells 100 are electrically connected by solder ribbons 200. Two cover plates 300 are provided and are respectively located on the upper and lower sides of the photovoltaic module 1000. The encapsulating adhesive 400 is filled between the two cover plates 300 to encapsulate and fix the battery string formed by the electrical connection of the solar cells 100.

[0090] It is understood that the types of solar cells 100 provided in this application include, but are not limited to, passivated emitter rear cell (PERC), tunnel oxide passivated contact cell (TOPCon), intrinsic thin-film heterojunction cell (HJT), interdigitated back contact cell (IBC), perovskite cell, etc.

[0091] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front-surface silver electrode, a front-surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type substrate silicon layer, a localized aluminum back field, a metallic aluminum back electrode, and a back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back side, replacing the all-aluminum back field, enhancing light reflection within the silicon substrate, reducing the recombination rate on the back side, and improving the cell efficiency by 0.5%-1%.

[0092] For TOPCon cells, along their thickness direction, the TOPCon cell sequentially includes a silver electrode, a front-surface silicon nitride passivation layer, a boron-doped emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and the silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure can block minority carrier recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes band bending on the silicon wafer surface, resulting in a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby increasing the cell's conversion efficiency.

[0093] For an HJT cell, along its thickness direction, the HJT cell sequentially includes a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type substrate silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0094] For an IBC cell, along its thickness direction, it sequentially includes a silicon nitride anti-reflection layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride anti-reflection layer, and a silver electrode. IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precisely controllable junction depth. The absence of grid lines on the front side eliminates light-blocking current loss from the metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to its back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front-surface recombination rates and surface reflection.

[0095] For a perovskite solar cell, along its thickness direction, it sequentially comprises a substrate material, a conductive thin film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials possess a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with minimal loss, thus generating high photogenerated voltage and current, resulting in high photoelectric conversion efficiency.

[0096] See Figure 10As shown, taking a TOPCon cell as an example, between two adjacent solar cells 100, one end of the solder ribbon 200 is soldered to the back solder joint of one solar cell 100, and the other end is soldered to the front solder joint of the other solar cell 100. Furthermore, one end of the solder ribbon is connected to the P-region solder joint of one solar cell 100, and the other end is connected to the N-region solder joint of the other solar cell 100.

[0097] See Figure 11 As shown, taking an IBC cell as an example, the solder ribbons are all located on the back of the solar cell 100. Between two adjacent solar cells 100, one end of the solder ribbon 200 is soldered to the P-region solder point on the back of one solar cell 100, and the other end is soldered to the N-region solder point on the back of the other solar cell 100.

[0098] Furthermore, the width of the second solder joint 130 in the second direction y is inversely proportional to the width of the solder strip 200 in the first direction x. The change in width of the solder strip 200 is D, and the change in width of the second solder joint 130 is L, with D:L = 10:5-500. That is, the width of the second solder joint 130 decreases as the width of the solder strip 200 decreases. When the width of the solder strip 200 decreases by 1µm, the width of the second solder joint 130 increases by 0.5µm-50µm accordingly. Thus, even with a decrease in the width of the solder strip 200, the wider solder joint ensures the contact area between the solder strip 200 and the solder joint, thereby reducing the resistance at the solder joint connection and reducing hot spots. Conversely, with a wider solder strip 200, the width of the second solder joint 130 can be appropriately reduced, thereby reducing the resistance while reducing the amount of solder used at the solder joint, thus lowering the overall cost of the photovoltaic module 1000.

[0099] This embodiment has the solar cell 100 of any of the above embodiments, and therefore has all the beneficial effects of the solar cell 100 of any of the above embodiments, which will not be described in detail here.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solar cell, characterized in that, It includes a main body, multiple first solder joints and multiple second solder joints, wherein the width of the second solder joint is greater than the width of the first solder joint; The main body is provided with a first welding area and a second welding area, and the first welding area and the second welding area are distributed on the surface of the main body along a first direction; The first welding area has only a plurality of first welding points distributed along the second direction, and the second welding area has a plurality of second welding points distributed along the second direction; There is an angle between the first direction and the second direction.

2. The solar cell according to claim 1, characterized in that, The solar cell also includes multiple main grids, which are parallel to the second direction; Each of the main gates is respectively disposed in the corresponding first welding area or second welding area.

3. The solar cell according to claim 2, characterized in that, One of the adjacent first welding area and second welding area is not equipped with the main gate.

4. The solar cell according to claim 1, characterized in that, The solar cell further includes multiple fine grids, which are parallel to the first direction; Each of the first solder joint and the second solder joint is connected to a fine grid.

5. The solar cell according to claim 1, characterized in that, The second welding area is also provided with a plurality of the first welding points. Within a second welding area, the first welding points and the second welding points are all distributed on the same straight line in the second direction.

6. The solar cell according to claim 5, characterized in that, In a second welding area, the first weld point and the second weld point are alternately distributed along the second direction; Alternatively, in a second welding zone, the first weld point and the second weld point are distributed relative to each other along the centerline of the second welding zone.

7. The solar cell according to claim 1, characterized in that, Along the first direction, the two edges of the main body are provided only with the first welding area; The number of the first welding zones on one edge of the main body is 1-4.

8. The solar cell according to claim 7, characterized in that, The second welding area is located between the two edges of the main body; At least one first welding zone is provided between two adjacent second welding zones.

9. The solar cell according to claim 1, characterized in that, The width ratio of the first solder joint to the width of the second solder joint is 1:1.1-11.

10. A photovoltaic module, characterized in that, The solar cell and solder strip according to any one of claims 1 to 9 are included, wherein the solder strip is respectively soldered to the soldering area of ​​two adjacent solar cells; The width of the second solder joint in the second direction is inversely proportional to the width of the solder strip in the first direction. The width change of the solder strip is D, and the width change of the second solder joint is L, with D:L = 10:5-500.

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