Solar cell, manufacturing method of solar cell, photovoltaic module and preparation method of photovoltaic module

Abstract

The invention discloses a solar cell, a manufacturing method of the solar cell, a photovoltaic module and a preparation method of the photovoltaic module, relates to the technical field of solar cells, and aims to solve the problem that the quality of the solar cell is affected due to unbalanced welding of different surfaces in the connection process of a cell piece and a welding strip. The solar cell comprises a cell body, a welding structure and a collector electrode. The battery body has a first surface and a second surface opposite to each other, and the welding structure is formed on the battery body. The collector electrodes are formed on the battery body, the plurality of collector electrodes extend along a first direction and are distributed at intervals along a second direction, and the first direction is different from the second direction. In the first direction, at least part of the collector electrodes are electrically connected with the welding structure. The thickness of at least one end region of at least one part of the welding structure on the first surface is greater than that of at least one end region of at least one part of the welding structure on the second surface.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a manufacturing method thereof, a photovoltaic module and a manufacturing method thereof. Background Art

[0002] A solar cell is a semiconductor device that can convert light energy into electrical energy. Specifically, when a solar cell is exposed to light, the semiconductor substrate included in the solar cell absorbs photons and generates electron-hole pairs. The electron-hole pairs are separated under the action of the built-in electric field of the PN junction, and are respectively led out through the emitter and back field of the solar cell, and finally collected by the electrode structure arranged on the semiconductor substrate.

[0003] The electrode structure generally includes a main grid, a fine grid and a pad, or only includes a fine grid and a pad. Usually, a plurality of pads are arranged at intervals, and at least one end of some or all of the fine grids is connected to the end of the pad.

[0004] In the actual welding process, the welding ribbon is welded to multiple pads. However, when the welding ribbon is welded to different sides of the solar cell, the different sides of the solar cell are heated unevenly due to the welding environment, which often leads to uneven welding, or even over-welding or under-welding, affecting the quality of the solar cell. Summary of the invention

[0005] The purpose of the present invention is to provide a solar cell and a method for making the same, a photovoltaic module and a method for making the same, which are used to reduce or eliminate the uneven welding on different surfaces during the connection between the cell and the welding strip, thereby improving the quality of the solar cell.

[0006] In order to achieve the above-mentioned objectives, in a first aspect, the present invention provides a solar cell. The solar cell comprises: a battery body, a welding structure and a collector electrode. The battery body has a first surface and a second surface opposite to each other, and the welding structure is formed on the battery body. The collector electrode is formed on the battery body, and a plurality of collector electrodes extend along a first direction and are spaced apart along a second direction, wherein the first direction is different from the second direction. Along the first direction, at least part of the collector electrode is electrically connected to the welding structure. The thickness of at least the end region of at least part of the welding structure located on the first surface is greater than the thickness of at least the end region of at least part of the welding structure located on the second surface. It should be noted that the welding structure in the present application is not limited to a simple pad, and one understanding of the above-mentioned welding structure can also be a combined structure formed by a pad and a fine grid (i.e., a collector electrode) overlapping the pad. It should be noted that the above-mentioned welding structure does not only include the area where the joint and the collector electrode overlap, but includes the entire "combined structure".

[0007] In the solar cell provided by the present invention, the thickness of at least the end region of at least part of the welding structure located on the first surface is greater than the thickness of at least part of the welding structure located on the second surface. Therefore, the welding resistance of at least part of the welding structure located on the first surface is better than that of at least part of the welding structure located on the second surface. Based on this, when the welding temperature of the first surface is higher than that of the second surface, when the connector (such as a welding strip) is connected to the welding structure located on the first surface and the second surface, the welding imbalance with the second surface during the connection between the welding structure located on the first surface and the welding strip, or even the situation of over-welding and breaking the grid, can be reduced or eliminated, thereby improving the quality of the solar cell. Further, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the solar cell provided by the present application increases the welding process window for the welding of photovoltaic modules. In addition, the solar cell can be a busbar-free solar cell, whose first and second surfaces are not blocked by the busbar, which effectively reduces optical loss and improves the power generation efficiency of the solar cell. Furthermore, the slurry content required for printing the busbar can be reduced, reducing the production cost of the solar cell.

[0008] In one implementation, the collector electrode located on the second surface is formed integrally with at least a portion of the welding structure located on the second surface. It can be seen that, in general, the material of the collector electrode located on the second surface is the same as the material of at least a portion of the welding structure located on the second surface. The material used to make the collector electrode is generally a material with higher corrosiveness (such as a burn-through slurry). Based on this, when the collector electrode located on the second surface is formed integrally with at least a portion of the welding structure located on the second surface, the contact area between the collector electrode located on the second surface and at least a portion of the welding structure located on the second surface and the doped semiconductor layer can be increased to reduce the contact resistance, thereby improving the cell efficiency of the solar cell. Furthermore, compared with the separate printing of the collector electrode located on the second surface and the pad located on the second surface, the present invention not only reduces the number of printed screens and reduces printing costs; at the same time, it also reduces the number of printing times of solar cells and reduces the risk of fragmentation.

[0009] In one implementation, the solar cell further includes: a first bus electrode. The first bus electrode is formed on the first side of the battery body, and a plurality of first bus electrodes extend along the second direction and are spaced apart along the first direction. At least two welding structures located on the first side are spaced apart along the second direction and are electrically connected to the first bus electrode. And / or, the solar cell further includes a second bus electrode, and the second bus electrode is formed on the second side of the battery body. A plurality of second bus electrodes extend along the second direction and are spaced apart along the first direction. At least two welding structures located on the second side are spaced apart along the second direction and are electrically connected to the second bus electrode.

[0010] In the case of adopting the above technical solution, when the first surface is the light-receiving surface, the first bus electrode can be used to collect the photocurrent generated by the entire battery body when receiving light. Based on this, while improving the battery efficiency of the solar cell, the battery efficiency can also be tested. In addition, since at least two welding structures located on the first surface are spaced apart along the second direction and electrically connected to the first bus electrode. At this time, compared with the case where the welding strip is welded to the first bus electrode only through one welding structure, the welding strip corresponding to the corresponding first bus electrode can be welded through the above-mentioned multiple welding structures, which can make the welding strip and the first bus electrode more firmly welded, thereby improving the welding quality of the solar cell during series welding, and ensuring the stability and safety of the solar cell. Further, compared with the case where there is no main grid (i.e., no first bus electrode) and only a welding pad, since the solar cell in the present application also includes a first bus electrode, and at least two welding structures located on the first surface are spaced apart along the second direction and electrically connected to the first bus electrode. When the number of pads (or welding structures) and the welding qualification rate are less than or equal to the actually required number and welding qualification rate, the first bus electrode electrically connected to the welding structure can replace the welding structure to connect to the welding ribbon to ensure normal operation of the solar cell.

[0011] In one implementation, at least part of the welded structure includes: a first part and a second part, wherein the two second parts are connected to two ends of the first part respectively. The width of the second part gradually decreases in a direction away from the first part. The maximum width of the second part is equal to the width of the first part, and the width direction of the second part and the width direction of the first part are both consistent with the second direction.

[0012] In one implementation, at least part of the welding structure includes: a first part and a second part, wherein the two second parts are respectively connected to two ends of the first part. The width of the second part gradually decreases in a direction away from the first part. The width of the second part is smaller than the width of the first part, and the width direction of the second part and the width direction of the first part are both consistent with the second direction.

[0013] The at least partially welded structure includes two different shapes, which increases the selectivity of the shape of the at least partially welded structure, so that it can be selected according to the actual application scenario. Based on this, the solar cell can be applied to different application scenarios, expanding its scope of application. In addition, since the second part of the welded structure is smaller than the first part, the consumption of conductive materials when making the welded structure can be reduced, thereby reducing the manufacturing cost of the solar cell.

[0014] In one implementation, the thickness of the first part of at least part of the welding structure located on the first surface is greater than the thickness of the first part of at least part of the welding structure located on the second surface. In the case of the above technical solution, the welding resistance of the first part of at least part of the welding structure located on the first surface is better than the welding resistance of the first part of at least part of the welding structure located on the second surface. Further, in combination with the above description, the welding resistance of at least part of the welding structure located on the first surface as a whole is better than the welding resistance of at least part of the welding structure located on the second surface as a whole. Therefore, when the connector (such as a welding strip) is connected to the welding structure located on the first surface, the welding imbalance with the second surface during the connection process between the welding structure located on the first surface and the welding strip, or even the situation of over-welding and breaking the grid, can be further reduced or eliminated, thereby further improving the quality of the solar cell. In addition, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided in the present application further increases the welding process window for the welding of photovoltaic modules.

[0015] In one implementation, each current collecting electrode is contact-connected to at least one welding structure.

[0016] In a second aspect, an embodiment of the present invention further provides a photovoltaic module. The photovoltaic module comprises: a battery string and an encapsulation layer. The battery string is formed by connecting a plurality of solar cells described in the first aspect, and the encapsulation layer is used to cover the surface of the battery string.

[0017] The beneficial effects of the photovoltaic module provided by the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here.

[0018] In a third aspect, the present invention further provides a method for manufacturing a solar cell. The method for manufacturing a solar cell comprises:

[0019] Providing a battery body, the battery body having a first surface and a second surface opposite to each other;

[0020] A plurality of collector electrodes and a plurality of spaced-apart welding structures are formed on the first surface and the second surface of the battery body respectively; the plurality of collector electrodes extend along a first direction and are spaced-apart along a second direction; the first direction is different from the second direction; along the first direction, at least part of the collector electrodes on the first surface are electrically connected to the welding structures on the first surface, and at least part of the collector electrodes on the second surface are electrically connected to the welding structures on the second surface;

[0021] The thickness of at least the end region of at least the portion of the welded structure located on the first side is greater than the thickness of at least the end region of at least the portion of the welded structure located on the second side.

[0022] The beneficial effects of the method for manufacturing a solar cell provided by the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here.

[0023] In one implementation, a plurality of current collecting electrodes and a plurality of welding structures distributed at intervals are integrally formed on the second surface.

[0024] In the case of adopting the above technical solution, since multiple collector electrodes and multiple welding structures are formed integrally, the material of the collector electrode located on the second surface is generally the same as the material of at least part of the welding structure located on the second surface. The material used to make the collector electrode is generally a material with higher corrosiveness (such as a burn-through slurry). Based on this, when the collector electrode located on the second surface is formed integrally with at least part of the welding structure located on the second surface, the contact area between the collector electrode located on the second surface and at least part of the welding structure located on the second surface and the doped semiconductor layer can be increased to reduce the contact resistance, thereby improving the cell efficiency of the solar cell. Furthermore, compared with the separate printing of the collector electrode located on the second surface and the solder pad located on the second surface, the present invention not only reduces the number of printed screens and reduces the printing cost; at the same time, it also reduces the number of printing times of the solar cell and reduces the risk of fragmentation.

[0025] In one implementation, before, after, or simultaneously with forming a plurality of collector electrode structures on the second surface of the battery body, the method for manufacturing a solar cell further includes: forming a plurality of bus electrodes on the second surface of the battery body. The plurality of bus electrodes extend along the second direction and are spaced apart along the first direction. At least two welding structures located on the second surface are spaced apart along the second direction and are electrically connected to the bus electrodes.

[0026] In one implementation, the method for manufacturing a solar cell also includes: forming a first bonding portion and a collecting electrode in steps on the first surface of the battery body; the first bonding portion and the collecting electrode at least partially overlap, and the first bonding portion and the collecting electrode portion overlapping with the first bonding portion form a welding structure.

[0027] In the case of adopting the above technical solution, since the first joint part and the collector electrode are formed in steps, the first joint part and the collector electrode can be made of different materials. When the first joint part is made of a material with poor corrosion and welding resistance (such as a non-burn-through slurry), the corrosion of the film layer (such as a silicon nitride film layer) below the first joint part by the material with poor corrosion is reduced. At this time, the open circuit voltage and fill factor of the solar cell can be improved, thereby improving the cell efficiency of the solar cell. Furthermore, the use of welding-resistant materials can not only reduce or eliminate the situation of over-welding and grid breaking during the connection process between the welding structure located on the first surface and the welding strip, thereby improving the quality of the solar cell; at the same time, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided by the present application increases the welding process window for the welding of photovoltaic modules.

[0028] In one implementation, the collector electrode penetrates the first connecting portion.

[0029] In the case of adopting the above technical solution, the area where the first joint portion and the collector electrode overlap increases, so the area with relatively large thickness in the formed welding structure increases, and at this time, at least part of the welding structure located on the first surface has better welding resistance. Therefore, when the connector (such as a welding strip) is connected to the welding structure located on the first surface, the situation of unbalanced welding with the second surface during the connection between the welding structure located on the first surface and the welding strip, or even over-welding and grid breaking, can be further reduced or eliminated, thereby further improving the quality of the solar cell. In addition, in the actual welding process, when the solar cell provided by the present application is welded to the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided by the present application further increases the welding process window for the welding of photovoltaic modules.

[0030] In a fourth aspect, the present invention further provides a method for preparing a photovoltaic module. The method for preparing a photovoltaic module comprises: interconnecting and welding a plurality of solar cells as described in the first aspect in an environment heated by a heat source; the heat source is located on one side of the first surface of the solar cell, or the temperature of the first surface is higher than the temperature of the second surface.

[0031] In the actual process of manufacturing photovoltaic modules, since the heat source is located on one side of the first surface of the solar cell, the thermal field temperature of the first surface of the solar cell is higher than the thermal field temperature of the second surface of the solar cell. Combined with the above description, it can be seen that in the solar cell provided by the first aspect, at least the end area of ​​at least part of the welding structure located on the first surface has better welding resistance. Based on this, the difference in welding temperature between the first surface and the second surface can be balanced, so the photovoltaic module prepared using the solar cell provided by the present invention has better quality and higher efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 This is an enlarged view of the structure of the first solar cell in an embodiment of the present invention;

[0034] Figure 2 This is an enlarged view of the structure of the second solar cell in an embodiment of the present invention;

[0035] Figure 3 This is an enlarged view of the structure of the third solar cell in the embodiment of the present invention;

[0036] Figure 4 is an enlarged view of the structure of the fourth solar cell in an embodiment of the present invention;

[0037] Figure 5 This is a schematic structural diagram of a first type of combining portion in an embodiment of the present invention;

[0038] Figure 6 Schematic diagram of the structure of the electrical connection between the first combination portion and the collector electrode in the embodiment of the present invention Figure 1 ;

[0039] Figure 7 Schematic diagram of the structure of the electrical connection between the first combination portion and the collector electrode in the embodiment of the present invention Figure 2 ;

[0040] Figure 8 is a schematic structural diagram of a second combination portion in an embodiment of the present invention;

[0041] Fig. 9 Schematic diagram of the structure of the electrical connection between the second combination portion and the collector electrode in the embodiment of the present invention Figure 1 ;

[0042] Fig.10 Schematic diagram of the structure of the electrical connection between the second combination portion and the collector electrode in the embodiment of the present invention Figure 2 .

[0043] Reference numerals:

[0044] 1-welding structure, 10-end region, 11-first part, 12-second part; 2-collecting electrode, 3-first bus electrode, 4-joining part, 40-small joint part, 41-large joint part, 5-edge region, 6-inner region. DETAILED DESCRIPTION

[0045] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] It should be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0047] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0048] In order to solve the above technical problems, in a first aspect, the present invention provides a solar cell. Figures 1 to 10, the solar cell comprises: a battery body, a welding structure 1 and a collector electrode 2. The battery body has a first surface and a second surface opposite to each other, and the welding structure 1 is formed on the battery body. The collector electrode 2 is formed on the battery body, and a plurality of collector electrodes 2 extend along a first direction A and are spaced apart along a second direction B, wherein the first direction A is different from the second direction B. Along the first direction A, at least part of the collector electrode 2 is electrically connected to the welding structure 1. The thickness of at least the end region 10 of at least part of the welding structure 1 located on the first surface is greater than the thickness of at least the end region 10 of at least part of the welding structure 1 located on the second surface. It should be noted that the welding structure in the present application is not limited to a simple pad, and one understanding of the above-mentioned welding structure can also be a combined structure formed by a pad (i.e., a joint 4) and a fine grid (i.e., a collector electrode 2) overlapping the pad. It should be noted that the above-mentioned welding structure does not only include the area where the joint and the collector electrode overlap, but includes the entire "combined structure".

[0049] The structure and specifications of the battery body can be set according to actual conditions and are not specifically limited here. Furthermore, the first direction and the second direction can be two directions parallel to the surface of the battery body and different from each other. Figure 1 , the first direction A and the second direction B are orthogonal.

[0050] The first surface and the second surface of the battery body are in a relative positional relationship. For example, when the first surface is the front surface of the solar cell, the second surface is the back surface of the solar cell. When the first surface is the back surface of the solar cell, the second surface is the front surface of the solar cell. Preferably, the first surface is the front surface of the solar cell, and the second surface is the back surface of the solar cell.

[0051] “At least part of the current collecting electrodes are electrically connected to the welding structure along the first direction” can be understood as: Figure 1 As shown, from the perspective of relative positional relationship, a single collector electrode 2 has only a few welded structures 1 distributed at intervals along the first direction A. For example, in a solar cell without a main grid, each collector electrode 2 has only a few welded structures 1 distributed at intervals along the first direction A. Or, as Figure 4 As shown, the solar cell includes a plurality of collector electrodes 2, only some of the collector electrodes 2 are electrically connected to the welding structure 1, and some of the collector electrodes 2 are not electrically connected to the welding structure 1; or Figure 6 As shown, a certain collector electrode 2 does not completely penetrate a certain welding structure 1 along the first direction A, and the collector electrode 2 is only electrically connected to a partial area of ​​the welding structure 1; or Figure 7 As shown, a certain collector electrode 2 completely penetrates a certain welding structure 1 along a first direction A.

[0052] See also Figures 1 to 10In the solar cell provided by the embodiment of the present invention, the thickness of at least the end region 10 of at least part of the welding structure 1 located on the first surface is greater than the thickness of at least part of the welding structure 1 located on the second surface. Therefore, the welding resistance of at least part of the welding structure 1 located on the first surface is better than that of at least part of the welding structure 1 located on the second surface. Based on this, when the welding temperature of the first surface is higher than that of the second surface, when the connector (such as the welding strip) is connected to the welding structure 1 located on the first surface, the situation of over-welding and grid breaking during the connection between the welding structure 1 located on the first surface and the welding strip can be reduced or eliminated, so as to better balance the welding of the second surface, thereby improving the quality of the solar cell. Further, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen that the solar cell provided by the present application increases the welding process window for the welding of photovoltaic modules. In addition, the solar cell can be a busbar-free solar cell, whose first and second surfaces are not blocked by the busbar, which effectively reduces optical loss and improves the power generation efficiency of the solar cell. Furthermore, the slurry content required for printing the busbar can be reduced, reducing the production cost of the solar cell.

[0053] In the present application, the thickness of at least the end region 10 of at least a portion of the welded structure 1 of the first surface can be understood as the average thickness of at least the end region 10 of at least a portion of the welded structure 1 of the first surface, that is, the average thickness of at least the end region 10 of at least a portion of the welded structure 1 of the first surface is greater than the average thickness of at least the end region 10 of at least a portion of the welded structure 1 of the second surface; however, in actual processes, the thickness of at least the end region 10 of at least a portion of the welded structure 1 of the first surface is not uniform, especially when the thickness is increased by arranging a stacking structure between the collector electrode and the welding structure. At this time, the thickness of at least the end region 10 of at least a portion of the welded structure 1 of the first surface is greater than the thickness of at least the end region 10 of at least a portion of the welded structure 1 of the second surface. It can be understood that the thickness of a portion of the at least end region of the first surface is greater than the thickness of a portion of the at least end region 10 of the second surface, or the maximum thickness of the at least end region of the first surface is greater than the maximum thickness of the at least end region 10 of the second surface.

[0054] As a possible implementation, the collector electrode located on the second surface is formed integrally with at least part of the welding structure located on the second surface. It can be seen from this that, in general, the material of the collector electrode located on the second surface is the same as the material of at least part of the welding structure located on the second surface. The material used to make the collector electrode in this application is generally a material with higher corrosiveness (such as a burn-through slurry). Based on this, when the collector electrode located on the second surface is formed integrally with at least part of the welding structure located on the second surface, the contact area between the collector electrode located on the second surface and at least part of the welding structure located on the second surface and the doped semiconductor layer can be increased to reduce the contact resistance, thereby improving the battery efficiency of the solar cell. Furthermore, compared with the separate printing of the collector electrode located on the second surface and the pad located on the second surface, the embodiment of the present invention not only reduces the number of printed screens and reduces the printing cost; at the same time, it also reduces the number of printing times of the solar cell and reduces the risk of fragmentation.

[0055] As a possible implementation manner, the solar cell further includes a first bus bar electrode and / or a second bus bar electrode.

[0056] See also Figures 2 to 10 When the solar cell further includes a first bus electrode 3 , the first bus electrode 3 is formed on the first surface of the cell body, and a plurality of first bus electrodes 3 extend along the second direction B and are spaced apart along the first direction A. At least two welding structures 1 located on the first surface are spaced apart along the second direction B and are electrically connected to the first bus electrode 3 .

[0057] When the first surface is a light-receiving surface, the first bus electrode 3 can be used to collect the photocurrent generated by the entire battery body when receiving light. Based on this, while improving the battery efficiency of the solar cell, the battery efficiency can also be tested. In addition, since at least two welding structures 1 located on the first surface are spaced along the second direction B and electrically connected to the first bus electrode 3. At this time, compared with the situation where the welding strip is welded to the first bus electrode 3 only through one welding structure 1, the welding strip corresponding to the corresponding first bus electrode 3 can be welded through the above-mentioned multiple welding structures 1, which can make the welding strip and the first bus electrode 3 more firmly welded, thereby improving the welding quality of the solar cell during series welding, and ensuring the stability and safety of the solar cell. Further, compared with the situation where there is no main grid (i.e., no first bus electrode) and only a pad, since the solar cell in the present application also includes a first bus electrode 3, and at least two welding structures 1 located on the first surface are spaced along the second direction B and electrically connected to the first bus electrode 3. When the number of pads (or welding structures 1) and the welding qualification rate are less than or equal to the actually required number and welding qualification rate, the first bus electrode 3 electrically connected to the welding structure 1 can replace the welding structure 1 to connect with the welding ribbon to ensure normal operation of the solar cell.

[0058] When the solar cell further includes a second bus electrode, the second bus electrode is formed on the second surface of the cell body. A plurality of second bus electrodes extend along the second direction and are spaced apart along the first direction. At least two welding structures located on the second surface are spaced apart along the second direction and are electrically connected to the second bus electrode.

[0059] Further, see Figures 2 to 10 , the first bus electrode 3 and / or the second bus electrode intersect with at least part of the collector electrode 2, at this time the collector electrode 2 can collect the carriers generated in the corresponding area of ​​the battery body, when the first bus electrode 3 and / or the second bus electrode intersect with at least part of the collector electrode 2, the carriers collected by the collector electrode 2 can be collected by the first bus electrode 3 and / or the second bus electrode. Based on this, the current collection path can be shortened to reduce the transmission resistance of the carriers on the collector electrode 2 to the first bus electrode 3 and / or the second bus electrode. It should be noted that the first bus electrode and / or the second bus electrode can be a continuous bus electrode or a discontinuous bus electrode. When the first bus electrode and / or the second bus electrode are discontinuous bus electrodes, there is a situation where the collector electrode does not intersect with the bus electrode.

[0060] Further, the first bus electrode is formed integrally with the joint located on the first surface. It can be seen that, in general, the material of the first bus electrode is the same as the material of the joint located on the first surface. The material used to make the first bus electrode in this application is generally a material with poor corrosion and resistance to welding (such as non-burn-through slurry). The corrosion of the film layer (such as silicon nitride film layer) below the joint by the material with poor corrosion is reduced, and the open circuit voltage and fill factor of the solar cell can be improved at this time, thereby improving the cell efficiency of the solar cell. Further, the use of a welding-resistant material can not only reduce or eliminate the situation of over-welding and grid breaking during the connection process between the welding structure located on the first surface and the welding strip, thereby improving the quality of the solar cell; at the same time, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen that the use of the solar cell provided by the present application increases the welding process window for the welding of photovoltaic modules.

[0061] The number of the first bus electrodes and the number of the second bus electrodes can be set according to actual conditions. In the embodiment of the present invention, the number of the first bus electrodes is equal to the number of the second bus electrodes. When the first surface is the front surface and the second surface is the back surface, the number of the collector electrodes located on the first surface is less than the number of the collector electrodes located on the second surface.

[0062] The above-mentioned welding structure has various shapes and can be designed according to actual needs. The following description takes two possible shapes as examples. It should be understood that the following description is only for understanding and is not used for specific limitation.

[0063] The first one: see Figure 6 and Figure 7 , at least part of the welded structure 1 comprises: a first part 11 and a second part 12, wherein the two second parts 12 are respectively connected to both ends of the first part 11. The width of the second part 12 gradually decreases in a direction away from the first part 11. The maximum width of the second part 12 is equal to the width of the first part 11, and the width direction of the second part 12 and the width direction of the first part 11 are both consistent with the second direction B.

[0064] Specifically, the width of the first part 11 is equal at all locations along the first direction A. The width of the second part 12 at the junction with the first part 11 is equal. The cross-sectional shape of the first part 11 is rectangular, and the cross-sectional shape of the second part 12 is trapezoidal.

[0065] Second: See Fig. 9 and Fig.10 , at least part of the welding structure 1 includes: a first part 11 and a second part 12, and the two second parts 12 are respectively connected to the two ends of the first part 11. The width of the second part 12 gradually decreases along the direction away from the first part 11. The width of the second part is smaller than the width of the first part 11, and the width direction of the second part 12 and the width direction of the first part 11 are both consistent with the second direction B.

[0066] Specifically, the width of the first portion 11 is equal at all locations along the first direction A. The width of the second portion is smaller than that of the first portion 11. The cross-sectional shape of the first portion 11 is rectangular, and the cross-sectional shape of the second portion 12 is trapezoidal.

[0067] The at least partial welding structure 1 mentioned above includes two different shapes, which increases the selectivity of the shape of at least part of the welding structure 1, so that it can be selected according to the actual application scenario. Based on this, the solar cell can be applied to different application scenarios, expanding its scope of application. Furthermore, the size of the first part 11 of the welding structure 1 of the above two shapes is larger than the size of the second part 12, so the first part 11 can completely cover the corresponding first bus electrode 3 or the second bus electrode to ensure the firmness of the connection between the welding structure 1 and the first bus electrode 3 or the second bus electrode. In addition, since the second part 12 in the welding structure 1 is smaller than the first part 11, the consumption of conductive materials when making the welding structure 1 can be reduced to reduce the manufacturing cost of the solar cell.

[0068] In an alternative approach, see Figure 7 and Fig.10 , the thickness of the first portion 11 of at least the portion of the welded structure 1 located on the first surface is greater than the thickness of the first portion 11 of at least the portion of the welded structure 1 located on the second surface. At this time, the welding resistance of the first portion 11 of at least the portion of the welded structure 1 located on the first surface is better than that of the first portion 11 of at least the portion of the welded structure located on the second surface.

[0069] It should be understood that the thickness of the first portion 11 of the at least partial welded structure 1 of the first surface can be understood as the average thickness of the first portion 11 of the at least partial welded structure 1 of the first surface, that is, the average thickness of the first portion 11 of the at least partial welded structure 1 of the first surface is greater than the average thickness of the first portion 11 of the at least partial welded structure 1 of the second surface; however, in actual processes, the thickness of the first portion 11 of the at least partial welded structure 1 of the first surface is not uniform, especially when the thickness is increased by setting a stacking structure between the collector electrode and the first portion 11. At this time, the thickness of the first portion 11 of the at least partial welded structure 1 of the first surface is greater than the thickness of the first portion 11 of the at least partial welded structure 1 of the second surface, which can be understood as the thickness of a partial area of ​​the first portion 11 of the first surface is greater than the thickness of a partial area of ​​the first portion 11 of the second surface, or the maximum thickness of the first portion 11 of the first surface is greater than the maximum thickness of the first portion 11 of the second surface.

[0070] See also Figure 5 , Figure 7 , Figure 8 and Fig.10 , combined with the above description that “the thickness of at least the end region 10 of at least the portion of the welded structure 1 located on the first surface is greater than the thickness of at least the end region 10 of at least the portion of the welded structure 1 located on the second surface”.

[0071] At this time, the following situation exists: when a certain collector electrode 2 completely penetrates the joint 4 along the first direction A, the combined structure formed by the joint 4 and the part of the collector electrode 2 overlapping with the joint 4 is a welding structure 1. At this time, the thickness of the first part 11 and the second part 12 in the welding structure 1 (that is, the area where the joint 4 and the collector electrode 2 overlap along the first direction A) is greater than the thickness of at least the end area 10 of at least part of the welding structure 1 located on the second surface.

[0072] At this time, the overall welding resistance of at least part of the welding structure located on the first side is better than the overall welding resistance of at least part of the welding structure located on the second side. Therefore, when the connector (such as a welding strip) is connected to the welding structure located on the first side, the situation of unbalanced welding with the second side or even over-welding and grid breaking during the connection process between the welding structure located on the first side and the welding strip can be further reduced or eliminated, thereby further improving the quality of the solar cell. In addition, in the actual welding process, when the solar cell provided by the present application is welded to the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided by the present application further increases the welding process window for the welding of photovoltaic modules.

[0073] The number of coupling parts to be provided on the battery body and the sizes of the coupling parts are different according to actual needs. Three possible situations are described below as examples. It should be understood that the following description is only for understanding and is not intended to be a specific limitation.

[0074] Example 1: When the solar cell includes only a relatively small joint portion (referred to as a small joint portion for the convenience of subsequent description), each collector electrode is contact-connected to at least one welding structure.

[0075] For example, see Figure 1 When the solar cell only includes a cell body, a small joint 40 and a collector electrode 2, along the first direction A, at least one small joint 40 is distributed on each collector electrode 2; along the second direction B, multiple small joints 40 are distributed at intervals.

[0076] Example 2: When the solar cell only includes a relatively large joint (referred to as a large joint for the convenience of subsequent description), at least one collector electrode contacts and connects to at least one welding structure.

[0077] For example, see Figure 2 When the solar cell includes a cell body, a first bus electrode 3, a large junction 41 and a collector electrode 2, along a first direction A, at least one collector electrode 2 is electrically connected to a large junction 41; along a second direction B, a plurality of large junctions 41 are spaced apart and electrically connected to the first bus electrode 3.

[0078] Example 3: The battery body includes two edge regions spaced apart along the second direction, and an internal region between the two edge regions. When the solar cell includes the battery body, the large junction, the small junction, the first bus electrode, and the collector electrode at the same time, the large junction is located in the edge region, and the collector electrode located in the edge region is electrically connected to a large junction; the small junction is located in the internal region, and each collector electrode located in the internal region contacts and connects to at least one small junction.

[0079] For example, see Figure 3 and Figure 4 In the edge region 5, along the first direction A, a plurality of large joints 41 are arranged at intervals, and the same collector electrode 2 is electrically connected to the plurality of large joints 41 at the same time. In the inner region 6, along the first direction A, at least one small joint 40 is arranged on each collector electrode 2; along the second direction B, a plurality of small joints 40 are arranged at intervals. Furthermore, along the second direction B, the large joints 41 and the small joints 40 are arranged at intervals and electrically connected to the first bus electrode 3.

[0080] It should be noted that the above three examples are described based on the first side of the battery body. The relative position relationship and relative quantity relationship of the large joint, small joint, first bus electrode and collecting electrode on the second side of the battery body can be roughly consistent with the first side, but are not required to be completely consistent.

[0081] In a second aspect, an embodiment of the present invention further provides a photovoltaic module. The photovoltaic module comprises: a battery string and an encapsulation layer. The battery string is formed by connecting a plurality of solar cells described in the first aspect, and the encapsulation layer is used to cover the surface of the battery string.

[0082] The beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here.

[0083] Specifically, the battery string can be directly connected by a plurality of solar cells described in the first aspect, or the battery string includes a plurality of segmented battery cells formed by segmenting the solar cells described in the first aspect. In other words, the solar cell can be a whole solar cell or a half solar cell. When the solar cell is a half solar cell, the whole solar cell can be cut along a cutting line located in the separation area. The "separation area" will not be described in detail here, as long as it can meet the actual needs.

[0084] In a third aspect, an embodiment of the present invention further provides a method for manufacturing a solar cell. The method for manufacturing a solar cell comprises:

[0085] First, a battery body is provided, wherein the battery body has a first surface and a second surface opposite to each other;

[0086] Next, a plurality of current collecting electrodes and a plurality of spaced-apart welding structures are formed on the first surface and the second surface of the battery body respectively;

[0087] Exemplarily, a first bonding portion and a collector electrode are formed in steps on the first surface of the battery body; the first bonding portion at least partially overlaps with the collector electrode, and the first bonding portion and the collector electrode portion overlapping with the first bonding portion form a welding structure.

[0088] In the case of adopting the above technical solution, since the first joint part and the collector electrode are formed in steps, the first joint part and the collector electrode can be made of different materials. When the first joint part is made of a material with poor corrosion and welding resistance (such as a non-burn-through slurry), the corrosion of the film layer (such as a silicon nitride film layer) below the first joint part by the material with poor corrosion is reduced. At this time, the open circuit voltage and fill factor of the solar cell can be improved, thereby improving the cell efficiency of the solar cell. Furthermore, the use of welding-resistant materials can not only reduce or eliminate the situation of over-welding and grid breaking during the connection process between the welding structure located on the first surface and the welding strip, thereby improving the quality of the solar cell; at the same time, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided by the present application increases the welding process window for the welding of photovoltaic modules.

[0089] The above-mentioned “the first bonding portion at least partially overlaps with the collector electrode” can be understood as: Figure 1 As shown, from the perspective of relative positional relationship, a single collector electrode 2 has only a few first joints distributed at intervals along the first direction A; for example, in a solar cell without a main grid, each collector electrode 2 has only a few first joints distributed at intervals along the first direction A. Or, as Figure 4 As shown, the solar cell includes a plurality of collector electrodes 2, only some of the collector electrodes 2 overlap with the first joint portion, and some of the collector electrodes 2 do not overlap with the first joint portion. Figure 6 As shown, the collector electrode 2 does not completely penetrate the first joint portion along the first direction A, but only overlaps with the end region 10 of the first joint portion. Figure 7 As shown, along the first direction A, the collector electrode 2 completely penetrates the first connecting portion.

[0090] When the collector electrode penetrates the first joint, the area where the first joint and the collector electrode overlap increases, so the area with a relatively large thickness in the formed welding structure increases, and at this time, the welding resistance of at least part of the welding structure located on the first side is better than that of the second side. Therefore, when the connector (such as a welding strip) is connected to the welding structure located on the first side, the situation of unbalanced welding with the second side or even over-welding and breaking the grid during the connection between the welding structure located on the first side and the welding strip can be further reduced or eliminated, thereby further improving the quality of the solar cell. In addition, in the actual welding process, when the solar cell provided by the present application is welded with the welding strip, a higher welding power can be selected. When a higher welding power is selected, if the welding power fluctuates and decreases during the actual welding process, the final welding reliability can be guaranteed as long as the final welding power meets the actual welding requirements. It can be seen from this that the use of the solar cell provided by the present application further increases the welding process window for the welding of photovoltaic modules.

[0091] In an optional manner, a plurality of collector electrodes and a plurality of spaced-apart welding structures are integrally formed on the second surface. In an embodiment of the present invention, the collector electrodes on the second surface are integrally formed with at least part of the welding structures on the second surface.

[0092] In the case of adopting the above technical solution, since multiple collector electrodes and multiple welding structures are formed integrally, or the collector electrode located on the second surface is formed integrally with at least part of the welding structure located on the second surface. Therefore, in general, the material of the collector electrode located on the second surface is the same as the material of at least part of the welding structure located on the second surface. The material used to make the collector electrode in this application is generally a material with higher corrosiveness (such as a burn-through slurry). Based on this, when the collector electrode located on the second surface is formed integrally with at least part of the welding structure located on the second surface, the contact area between the collector electrode located on the second surface and at least part of the welding structure located on the second surface and the doped semiconductor layer can be increased to reduce the contact resistance, thereby improving the battery efficiency of the solar cell. Furthermore, compared with the separate printing of the collector electrode located on the second surface and the pad located on the second surface, the embodiment of the present invention not only reduces the number of printed screens and reduces the printing cost; at the same time, it also reduces the number of printing times of the solar cell and reduces the risk of fragmentation.

[0093] See also Figures 1 to 10, the above-mentioned multiple collector electrodes 2 extend along the first direction A and are spaced apart along the second direction B; the first direction A is different from the second direction B; along the first direction A, at least part of the collector electrodes 2 located on the first surface are electrically connected to the welding structure 1 located on the first surface, and at least part of the collector electrodes 2 located on the second surface are electrically connected to the welding structure 1 located on the second surface; the thickness of at least the end region 10 of at least part of the welding structure 1 located on the first surface is greater than the thickness of at least the end region 10 of at least part of the welding structure 1 located on the second surface. The beneficial effects of the method for manufacturing a solar cell provided by the embodiment of the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and are not described in detail here.

[0094] As a possible implementation, see Figures 2 to 10 Before, after or at the same time as forming a plurality of collector electrodes 2 structures on the first surface of the battery body, the method for manufacturing a solar cell further includes: forming a plurality of bus electrodes (corresponding to the first bus electrode 3 described in the first aspect) on the first surface of the battery body. The plurality of bus electrodes extend along the second direction B and are spaced apart along the first direction A. At least two welding structures 1 located on the first surface are spaced apart along the second direction B and are electrically connected to the bus electrodes.

[0095] Specifically, a plurality of first bus electrodes and a plurality of spaced-apart joints located on the first surface are integrally formed on the first surface (i.e., the first joint described above). Since the first bus electrode and the first joint are integrally formed, it can be seen that, in general, the material of the first bus electrode is the same as the material of the first joint. The material used to make the first bus electrode is generally a material with poor corrosion and resistance to welding (e.g., non-burn-through slurry). As for the benefits of using a material with poor corrosion and resistance to welding to make the first joint, please refer to the previous description, which will not be repeated here.

[0096] In the case of adopting the above technical solution, when the first surface is the light-receiving surface, the bus electrode can be used to collect the photocurrent generated by the entire battery body when receiving light. Based on this, while improving the battery efficiency of the solar cell, the battery efficiency can also be tested. In addition, since at least two welding structures located on the first surface are spaced apart along the second direction and electrically connected to the bus electrode. At this time, compared with the case where the welding strip is welded to the bus electrode only through one welding structure, the welding strip corresponding to the corresponding bus electrode can be welded through the above-mentioned multiple welding structures, which can make the welding strip and the bus electrode welded more firmly, thereby improving the welding quality of the solar cell during series welding, and ensuring the stability and safety of the solar cell. Further, compared with the case where there is no main grid (i.e., no bus electrode) and only a welding pad, since the solar cell in the present application also includes a bus electrode, and at least two welding structures located on the first surface are spaced apart along the second direction and electrically connected to the bus electrode. When the number of pads (or welding structures) and the welding pass rate are less than or equal to the actual required number and welding pass rate, the bus electrode electrically connected to the welding structure can replace the welding structure to connect with the welding strip to ensure the normal operation of the solar cell.

[0097] As a possible implementation, before or after forming a plurality of collector electrode structures on the second surface of the battery body, the method for manufacturing a solar cell further includes: forming a plurality of bus electrodes (corresponding to the second bus electrodes described in the first aspect) on the second surface of the battery body. The plurality of bus electrodes extend along the second direction and are spaced apart along the first direction. At least two welding structures located on the second surface are spaced apart along the second direction and are electrically connected to the bus electrodes.

[0098] In summary, the method for manufacturing a solar cell provided by the present invention uses a screen to achieve simultaneous printing of the bus electrode located on the first surface and the junction located on the first surface, and uses the collecting electrode on the first surface to screen-print the collecting electrode located on the first surface; uses the bus electrode on the second surface to screen-print the bus electrode located on the second surface, and uses a screen to achieve simultaneous printing of the collecting electrode located on the second surface and the junction located on the second surface.

[0099] In a fourth aspect, an embodiment of the present invention further provides a method for preparing a photovoltaic module. The method for preparing a photovoltaic module comprises: interconnecting and welding a plurality of solar cells as described in the first aspect in an environment heated by a heat source, wherein the heat source is located on one side of the first surface of the solar cell, or the temperature of the first surface is higher than the temperature of the second surface.

[0100] In the actual process of manufacturing photovoltaic modules, the welding of the welding ribbon of the double-sided solar cell is generally heated by a thermal radiation source (such as an infrared lamp), and the thermal radiation source is usually located on one side of the first side of the solar cell, resulting in the thermal field temperature of the first side of the solar cell being higher than the thermal field temperature of the second side of the solar cell. Therefore, the welding resistance of the welding structure in the first side of the solar cell is high. Combined with the foregoing description, it can be seen that in the solar cell provided by the first aspect, the welding resistance of at least the end area of ​​at least part of the welding structure located on the first side is better than the welding resistance of the second side. Based on this, the difference in welding temperature between the first side and the second side can be balanced, so the photovoltaic module prepared using the solar cell provided by the embodiment of the present invention has better quality and higher efficiency.

[0101] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0102] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A solar cell, characterized in that: include: A battery body having a first surface and a second surface opposite to each other; A welding structure formed on the battery body; A current collecting electrode formed on the battery body; The plurality of collector electrodes extend along a first direction and are spaced apart along a second direction; the first direction is different from the second direction; along the first direction, at least part of the collector electrodes are electrically connected to the welding structure; The thickness of at least an end region of at least a portion of the welding structure located on the first surface is greater than the thickness of at least an end region of at least a portion of the welding structure located on the second surface.

2. The solar cell according to claim 1, characterized in that: The collector electrode located on the second surface is formed integrally with at least a portion of the welding structure located on the second surface.

3. The solar cell according to claim 1, characterized in that The solar cell further comprises: a first bus electrode formed on the first surface of the battery body; a plurality of the first bus electrodes extending along the second direction and spaced apart along the first direction; at least two welding structures located on the first surface spaced apart along the second direction and electrically connected to the first bus electrode; And / or, a second bus electrode is formed on the second surface of the battery body; a plurality of the second bus electrodes extend along the second direction and are spaced apart along the first direction; at least two of the welding structures located on the second surface are spaced apart along the second direction and are electrically connected to the second bus electrode.

4. The solar cell according to any one of claims 1 to 3, characterized in that: At least part of the welding structure includes: a first part and a second part, two second parts are respectively connected to the two ends of the first part; the width of the second part gradually decreases along the direction away from the first part; the maximum width of the second part is equal to the width of the first part, and the width direction of the second part and the width direction of the first part are both consistent with the second direction.

5. The solar cell according to any one of claims 1 to 3, characterized in that: At least part of the welding structure includes: a first part and a second part, two second parts are respectively connected to the two ends of the first part; the width of the second part gradually decreases along the direction away from the first part; the width of the second part is smaller than the width of the first part, and the width direction of the second part and the width direction of the first part are both consistent with the second direction.

6. The solar cell according to claim 4 or 5, characterized in that: The thickness of the first portion of at least a portion of the welding structure located on the first surface is greater than the thickness of the first portion of at least a portion of the welding structure located on the second surface.

7. The solar cell according to claim 4, characterized in that: Each of the current collecting electrodes is contact-connected to at least one of the welding structures.

8. A photovoltaic module, characterized in that: The photovoltaic module comprises: A battery string, wherein the battery string is formed by connecting a plurality of solar cells according to any one of claims 1 to 7; The encapsulation layer is used to cover the surface of the battery string.

9. A method for manufacturing a solar cell, characterized in that: include: Providing a battery body, the battery body having a first surface and a second surface opposite to each other; A plurality of collector electrodes and a plurality of spaced-apart welding structures are formed on the first and second surfaces of the battery body, respectively; the plurality of collector electrodes extend along a first direction and are spaced-apart along a second direction; the first direction is different from the second direction; along the first direction, at least a portion of the collector electrodes on the first surface are electrically connected to the welding structures on the first surface, and at least a portion of the collector electrodes on the second surface are electrically connected to the welding structures on the second surface; The thickness of at least an end region of at least a portion of the welding structure located on the first surface is greater than the thickness of at least an end region of at least a portion of the welding structure located on the second surface.

10. The method for manufacturing a solar cell according to claim 9, characterized in that: A plurality of the collector electrodes and a plurality of welding structures distributed at intervals are integrally formed on the second surface.

11. The method for manufacturing a solar cell according to claim 9, characterized in that: Before, after or simultaneously with forming a plurality of collector electrode structures on the second surface of the battery body, the method for manufacturing a solar cell further comprises: A plurality of bus electrodes are formed on the second surface of the battery body; the plurality of bus electrodes extend along the second direction and are spaced apart along the first direction; at least two welding structures located on the second surface are spaced apart along the second direction and are electrically connected to the bus electrodes.

12. The method for manufacturing a solar cell according to any one of claims 9 to 11, characterized in that: The method for manufacturing the solar cell further includes: A first bonding portion and the collector electrode are formed step by step on the first surface of the battery body; the first bonding portion at least partially overlaps with the collector electrode, and the first bonding portion and the collector electrode portion overlapping with the first bonding portion form the welding structure.

13. The method for manufacturing a solar cell according to claim 12, characterized in that: The collector electrode penetrates the first coupling portion.

14. A method for preparing a photovoltaic module, characterized in that: include: In an environment heated by a heat source, a plurality of solar cells according to any one of claims 1 to 7 are interconnected and welded; the heat source is located on one side of the first surface of the solar cell, or the temperature of the first surface is higher than the temperature of the second surface.

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