Edge passivation method of solar cell, solar cell and photovoltaic module

Abstract

The invention relates to an edge passivation method of a solar cell, the solar cell and a photovoltaic module. The edge passivation method of the solar cell comprises the following steps: preparing a buffer protection structure on the surface of the solar cell; the solar cell is cut; the plurality of cut solar cells are stacked, so that a buffer protection structure is arranged between the adjacent solar cells; and passivating the cut sections of the plurality of solar cells which are arranged in a stacked manner. According to the edge passivation method for the solar cells, the solar cells are stacked, the edges of the solar cells can be efficiently passivated, and the problems that after the solar cells are cut, the cut edges are compounded, and electric leakage is high are solved. The buffer protection structures are prepared on the surfaces of the solar cells, and when the multiple solar cells are stacked, the buffer protection structures are arranged between the adjacent solar cells, so that friction and rigid collision between the solar cells are reduced, and surface damage of the solar cells is reduced.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a method for edge passivation of solar cells, solar cells, and photovoltaic modules. Background Technology

[0002] In the production of solar cells, to reduce the power loss of the modules, solar cells can be cut into two halves using methods such as laser scribing. This increases the number of cells in a single string, reducing the string current and thus lowering the power loss of the cell string.

[0003] After solar cells are cut, the cut surface is relatively rough and there is no passivation film, which can easily lead to leakage at the edge of the solar cell and a large number of auxiliary recombination traps, which seriously affect the performance of the solar cell. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for edge passivation of solar cells, solar cells, and photovoltaic modules to solve the problems of edge recombination and high leakage after solar cells are cut.

[0005] The first aspect of this invention is to provide a method for edge passivation of a solar cell, the scheme of which is as follows:

[0006] An edge passivation method for solar cells includes the following steps:

[0007] A buffer protection structure is fabricated on the surface of a solar cell;

[0008] The solar cells are cut into sections;

[0009] Multiple slit solar cells are stacked together to provide a buffer protection structure between adjacent solar cells;

[0010] The cut sections of the stacked solar cells are passivated.

[0011] In one embodiment, the solar cell is a back-contact cell, and the buffer protection structure is disposed on the front side of the solar cell.

[0012] In one embodiment, the solar cell further has a plurality of pads distributed on the grid lines of the solar cell;

[0013] The buffer protection structure includes a first protection part, the projection of which on the back of the solar cell is located in the interval between the plurality of pads and / or in the interval between the pads and the edge of the solar cell;

[0014] The height of the first protective part is greater than the height of the pad.

[0015] In one embodiment, the buffer protection structure further includes a second protection portion disposed on the front and / or back of the solar cell. The second protection portion surrounds the edge of the slit solar cell and encloses each of the first protection portions. The height of the second protection portion is greater than the height of the first protection portion.

[0016] In one embodiment, the height difference between the first protective part and the pad is 5μm~10μm, and the height difference between the second protective part and the first protective part is 3μm~4μm.

[0017] In one embodiment, the side of the second protective portion away from the edge and / or the side closer to the edge has a wavy curve shape.

[0018] In one embodiment, the radii of the wavy curve are 125° to 145°.

[0019] In one embodiment, the process of preparing the buffer protection structure on the surface of the solar cell includes screen printing, inkjet printing, or spraying.

[0020] In one embodiment, the material of the buffer protection structure includes an organic polymer.

[0021] In one embodiment, the organic polymer is selected from at least one of epoxy resin and organosilicon.

[0022] In one embodiment, the organic polymer has a Tg of 250°C to 500°C.

[0023] In one embodiment, the passivation process includes:

[0024] A passivation film is deposited at the edge of the solar cell.

[0025] In one embodiment, the material of the passivation film is selected from at least one of alumina and silicon nitride.

[0026] In one embodiment, the process for depositing the passivation film is an atomic layer deposition process.

[0027] A second aspect of the present invention is to provide a solar cell, the solution of which is as follows:

[0028] A solar cell, in one embodiment, includes a solar cell body, a buffer protection structure, and a cross-sectional passivation film layer, wherein the solar cell body has a front side and a back side disposed opposite to each other, and the buffer protection structure is disposed on the front side;

[0029] The solar cell body has a positive grid line, a negative grid line, and pads disposed on the positive grid line and the negative grid line;

[0030] The positive and negative grid lines are both disposed on the back side, the solar cell body has a cut cross section, and the cross section passivation film is disposed on the cut cross section.

[0031] In one embodiment, the buffer protection structure includes a first protection portion whose projection on the back surface is located in the interval between the plurality of pads and / or in the interval between the pads and the edge of the solar cell body;

[0032] The height of the first protective part is greater than the height of the solder pad.

[0033] In one embodiment, the projection of each of the first protective portions on the back surface is arranged around one or more of the pads.

[0034] The number of first protective parts and the number of pads are the same, and the positions of the plurality of first protective parts correspond one-to-one with the positions of the plurality of pads. The projection of each first protective part on the back surface is arranged around one of the pads.

[0035] In one embodiment, the buffer protection structure further includes a second protection portion disposed on the back side of the solar cell body. The second protection portion surrounds the edge of the solar cell body and encloses each of the first protection portions, and the height of the second protection portion is greater than the height of the first protection portion.

[0036] In one embodiment, the side of the second protective portion away from the edge and / or the side closer to the edge is a wavy curve shape, the wavy curve shape having an arc of 125°~145°.

[0037] In one embodiment, the material of the buffer protection structure includes an organic polymer.

[0038] In one embodiment, the organic polymer is selected from at least one of epoxy resin and organosilicon.

[0039] In one embodiment, the organic polymer has a Tg of 250°C to 500°C.

[0040] A third aspect of the present invention is to provide a photovoltaic module, the solution of which is as follows:

[0041] A photovoltaic module includes a first encapsulation structure, a second encapsulation structure, and a solar cell obtained by the edge passivation method described in any of the above embodiments or the solar cell described in any of the above embodiments, wherein the solar cell is disposed between the first encapsulation structure and the second encapsulation structure.

[0042] Compared with traditional technologies, the above-mentioned edge passivation method for solar cells, solar cells, and photovoltaic modules have the following beneficial effects:

[0043] The aforementioned edge passivation method for solar cells involves stacking multiple solar cells, efficiently passivating their edges and addressing issues such as edge commingling and high leakage current after solar cell cutting. The inventors discovered during production that edge passivation of stacked solar cells can damage the cell surface, especially when the surface has a textured structure, which is more susceptible to damage and reduces cell conversion efficiency and other performance characteristics. Therefore, a buffer protection structure is fabricated on the surface of the solar cells, and when multiple solar cells are stacked, a buffer protection structure is provided between adjacent cells to reduce friction and rigid collisions, thereby minimizing surface damage.

[0044] The aforementioned solar cell has a buffer protection structure on the front and / or back of the solar cell body. When multiple solar cells are stacked and the edges are passivated, the buffer protection structure between adjacent solar cells can reduce friction and rigid collisions between solar cells, thereby reducing surface damage to the solar cells.

[0045] The photovoltaic modules described above include the solar cells described in any of the above embodiments, and therefore have the corresponding technical features and can obtain the corresponding beneficial effects. Attached Figure Description

[0046] Figure 1 This is a schematic flowchart of an edge passivation method for a solar cell according to one embodiment;

[0047] Figure 2 A schematic diagram illustrating the fabrication of a buffer protection structure on the surface of a solar cell;

[0048] Figure 3 A schematic diagram showing how multiple slit solar cells are stacked and loaded into a carrier boat, and how a passivation film is deposited on the cut sections.

[0049] Figure 4 A schematic diagram of a buffer protection structure fabricated on the surface of a solar cell using a screen printing process;

[0050] Figure 5 This is a schematic diagram of the back structure of the back contact battery. Figure 5In the image, the cut section has been blackened.

[0051] Figure 6 This is a schematic diagram of the front side of the back-contact battery and its buffer protection structure. Figure 6 In the image, the cut section has been blackened.

[0052] Figure 7 A schematic diagram showing the arrangement of the first protection section around a pad of an adjacent solar cell;

[0053] Figure 8 Another schematic diagram showing the first protection section arranged around a pad of an adjacent solar cell;

[0054] Figure 9 This is a schematic diagram illustrating the influence of the insulating material on the back of the solar cell and the first protective layer on the warpage of the solar cell.

[0055] Figure 10 This is a schematic diagram showing that the second protective section has straight lines on both sides;

[0056] Figure 11 This is a schematic diagram showing the wavy curve shape on both sides of the second protective section;

[0057] Figure 12 A schematic diagram showing how multiple stacked solar cells are fed into an atomic layer deposition (ALD) apparatus for edge passivation.

[0058] Figure 13 This is a schematic diagram of the structure of a photovoltaic module according to one embodiment.

[0059] Explanation of reference numerals in the attached figures:

[0060] 11. Printing screen; 13. Printing press; 14. Buffer protection material; 12. Solar cell; 121. Pad; 122. Cut section; 123. Insulating material; 124. Passivation layer; 125. Anti-reflective layer; 15. Buffer protection structure; 151. First protection part; 152. Second protection part; 16. Passivation film layer; 20. Photovoltaic module; 21. First encapsulation structure; 211. Encapsulation panel; 212. First encapsulation film; 22. Second encapsulation structure; 221. Encapsulation backplane; 222. Second encapsulation film; 200. Atomic layer deposition equipment; 210. Deposition chamber; 220. Chamber door; 230. Spray plate; 240. Particle trap; 250. Mechanical pump; 30. Boat. Detailed Implementation

[0061] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be 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 the present invention. However, the present invention can be practiced 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 the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0063] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0064] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0065] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," 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 explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] This invention provides a method for edge passivation of solar cells.

[0067] like Figure 1 As shown, an embodiment of a solar cell edge passivation method includes the following steps:

[0068] Step S110, please further combine Figure 2 As shown, a buffer protection structure 15 is prepared on the surface of the solar cell 12.

[0069] Step S120: The solar cell 12 is cut.

[0070] In step S130, multiple slit solar cells 12 are stacked to create a buffer protection structure 15 between adjacent solar cells 12.

[0071] Step S140, please further combine Figure 3 As shown, the cut cross-section of the multiple stacked solar cells 12 is passivated to form a passivation film layer 16.

[0072] In the above steps, the order of steps S110 and S120 is not limited. Step S110 can be performed first and then step S120, or step S120 can be performed first and then step S110.

[0073] The above-mentioned edge passivation method for solar cells 12 stacks multiple solar cells 12 after slicing, which can efficiently passivate the cut sections of multiple solar cells 12 and solve the problems of recombination and high leakage at the cut sections of solar cells 12.

[0074] The inventors discovered during production that edge passivation of the stacked solar cells 12 may damage the surface of the solar cells 12, for example, by scratching the passivation layer on the cell surface. In particular, when the solar cell surface has a textured structure, because the textured structure is a pyramidal structure of a specific shape to achieve a good anti-reflection effect, the textured structure is more susceptible to damage, which reduces the conversion efficiency and other performance characteristics of the solar cells.

[0075] Therefore, the above method prepares a buffer protection structure 15 on the surface of the solar cell 12, and when multiple solar cells 12 are stacked, there is a buffer protection structure 15 between adjacent solar cells 12, so as to reduce friction and rigid collision between solar cells 12, thereby reducing surface damage to the solar cell 12.

[0076] In step S110, the process of preparing the buffer protection structure 15 on the surface of the solar cell 12 is a coating process.

[0077] For example, the coating process is, but is not limited to, screen printing, inkjet printing, spraying, etc.

[0078] In a specific example, a buffer protection structure 15 is fabricated on the surface of the solar cell 12 using a screen printing process. For example... Figure 4 As shown, a printing screen 11 with a corresponding pattern is first designed according to the pattern of the buffer protection structure 15. Then, the buffer protection material 14 is printed onto the surface of the solar cell 12 through the printing screen 11 using a printing press 13.

[0079] In some examples, the buffer protection structure 15 is made of an insulating material. For example, the material of the buffer protection structure 15 includes an organic polymer. Exemplarily, the organic polymer is selected from at least one of epoxy resin and organosilicon. Furthermore, the material of the buffer protection structure 15 may also include additives dispersed in the organic polymer, such as anti-aging additives. The material of the buffer protection structure 15 may also include inorganic fillers dispersed in the organic polymer.

[0080] Since passivation typically requires the deposition of a passivation film 16 at relatively high temperatures, the buffer protection structure 15 preferably possesses good heat resistance. For example, if the temperature inside the passivation equipment is 250℃±50℃, to ensure the buffer protection structure 15 functions properly at this temperature, the glass transition temperature (Tg) of the organic polymer used is preferably above 250℃, for example, 250℃~500℃. Further, the glass transition temperature of the organic polymer is preferably above 300℃, for example, 300℃~500℃. The glass transition temperature can be obtained through thermal analysis methods such as DSC (differential scanning calorimetry) and TG (thermogravimetric analysis).

[0081] The material of the buffer protection structure 15 is preferably a transparent material to avoid blocking light and affecting the absorption of light by the solar cell 12. In addition, the buffer protection structure 15 can also be removed after edge passivation treatment, for example, by cleaning the buffer protection structure 15 with a cleaning solution, or by other means.

[0082] To adapt to the screen printing process, the viscosity of the adhesive used to prepare the buffer protection structure 15 is preferably 12000mPas~21000mPas, and more preferably 16000mPas~20000mPas.

[0083] In some examples, the adhesive used to prepare the buffer protective structure 15 is a two-component epoxy resin adhesive, including component A and component B. Component A consists of resin, solvent, filler, and various additives, while component B is a curing agent. The curing speed and crosslinking density of the adhesive can be controlled by adjusting the proportion of component B, depending on specific needs. For example, the mass ratio of component A to component B is 90:15-96:5. Further, the mass ratio of component A to component B is 90:10 to 97:7.

[0084] In some examples, the adhesive used to prepare the buffer protective structure 15 is a two-component silicone adhesive, comprising component A and component B. Component A consists of resin, solvent, filler, and various additives, while component B is a curing agent. The curing speed and crosslinking density of the adhesive can be controlled by adjusting the proportion of component B, depending on specific needs. For example, the mass ratio of component A to component B is 1:6 to 6:1. Further, the mass ratio of component A to component B is 1:5 to 5:1.

[0085] The glass transition temperatures of the two-component epoxy resin adhesive and the two-component silicone adhesive mentioned above are above 350℃, and they have a significant advantage over materials such as EVA composite adhesive. EVA composite adhesive has good bonding effect, but it is more difficult to use for printing.

[0086] Traditional solar cells, such as PERC (passivated emitter back contact), TOPCon (tunneling oxide passivated contact), and HJT (heterojunction) cells, have grid lines on both the front and back sides. Through experimental research and production practice, the inventors discovered that the grid lines on the front and back sides can reduce the contact between the surface films of adjacent solar cells to a certain extent, protecting the textured surface structure. Therefore, when these traditional solar cells are stacked and edge passivated, the damage to the textured surface structure is relatively small.

[0087] For back-contact solar cells, where both the positive and negative grid lines are located on the back side, the PN junction and grid lines (including the positive and negative grid lines) are all situated on the back. The textured surface on the front side lacks any protective structure against mechanical scratches, making it highly susceptible to scratches from adjacent stacked cells. This can damage the pyramidal structure on the front side or scratch the passivation layer. Especially during edge passivation of the stacked solar cells 12, the deposited atoms of the passivation film can easily penetrate the gaps between the stacked cells 12 and deposit at the edges. The pads on the grid lines at the edges are also prone to reduced welding performance due to the deposited passivation film, decreasing the reliability of the cell string welding, and even leading to ineffective current conduction because the solder ribbon cannot form a proper weld with the pads. Therefore, for back-contact solar cells, before edge passivation of the stacked structure, a buffer protection structure 15 is prepared on the surface of the solar cell 12. The buffer protection structure 15 significantly reduces surface damage to the solar cell 12.

[0088] Among them, such as Figure 3 As shown, the front film layer is, for example, at least one of the passivation layer 124 and the antireflection layer 125.

[0089] In some examples, the solar cell 12 has positive and negative grid lines, both of which are located on the back side, while the buffer protection structure 15 is located on the front side. In this example, the front side of the solar cell 12 has no grid lines, making the front film layer more susceptible to damage. Therefore, the buffer protection structure 15 is provided on the front side. When multiple solar cells 12 are stacked, the buffer protection structure 15 can reduce friction and rigid impacts on the front film layer, thereby protecting the front side of the solar cell 12. When multiple solar cells 12 are stacked, it is preferable that two adjacent solar cells 12 face each other with their front and back sides facing each other, respectively.

[0090] Furthermore, such as Figure 5 As shown, in some examples, the solar cell 12 also has multiple pads 121. The pads 121 are used to connect to the solder ribbon during the production of the photovoltaic module 20. The multiple pads 121 are located on the back side of the solar cell 12. The multiple pads 121 are distributed along the positive and negative grid lines. In some examples, the multiple pads 121 are arranged in an array. For example, the multiple pads 121 on the back side of the cell are arranged in an 18×36 array.

[0091] like Figure 6 As shown, in some examples, the buffer protection structure 15 includes a first protection portion 151. The projection of the first protection portion 151 on the back side is located in the intervals between the plurality of pads 121 and / or in the intervals between the pads 121 and the edges of the solar cells 12. Thus, when the plurality of solar cells 12 are stacked such that two adjacent solar cells 12 face each other with their front and back sides respectively, the first protection portion 151 abuts against the back side of the adjacent solar cell 12 and is located in the intervals between the plurality of pads 121 and / or in the intervals between the pads 121 and the edges of the solar cells 12.

[0092] The height of the first protective portion 151 is greater than the height of the pad 121, thereby preventing the front film layer of the solar cell 12 from contacting the pad 121 on the adjacent solar cell 12. For example, in some examples, the height difference between the first protective portion 151 and the pad 121 is 5 μm to 10 μm. Further, in some examples, the height difference between the first protective portion 151 and the pad 121 is 6 μm to 9 μm. In some specific examples, the height difference between the first protective portion 151 and the pad 121 is 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, etc.

[0093] For example, in some examples, the height of pad 121 is 10 μm, and the height of the first protection portion 151 is set to 15 μm to 20 μm. Further, the height of the first protection portion 151 is set to 16 μm to 19 μm. In some specific examples, the height of the first protection portion 151 is set to 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm, 20 μm, etc.

[0094] In some examples, the projection of each first protective portion 151 on the back surface is arranged around one or more pads 121. In this way, it is possible to better prevent the front film layer of the solar cell 12 from contacting the pads 121 on the adjacent solar cell 12.

[0095] Furthermore, in some examples, the number of first protective portions 151 and pads 121 is the same, and the positions of the plurality of first protective portions 151 correspond one-to-one with the positions of the plurality of pads 121. The projection of each first protective portion 151 on the back surface is arranged around a pad 121. Thus, as Figure 7 and Figure 8 As shown, when multiple solar cells 12 are stacked, the first protective part 151 is arranged around a pad 121 of an adjacent solar cell 12, which can more effectively prevent the pad 121 on the back of the back contact solar cell 12 from directly contacting the film layer on the front of the adjacent solar cell 12 and scratching the film layer on the front of the back contact solar cell 12.

[0096] For example, a plurality of pads 121 on the back side of the solar cell 12 are arranged in an array, and a plurality of first protective portions 151 arranged in an array are correspondingly provided on the front side of the solar cell 12. The projection of each first protective portion 151 on the back side is arranged around a pad 121. Exemplarily, the back side of the solar cell 12 has 18 columns of pads 121 distributed in the horizontal direction and 36 rows of pads 121 distributed in the vertical direction, and correspondingly, a plurality of first protective portions 151 arranged in an array are provided on the front side of the cell, with 18 columns of first protective portions 151 distributed in the horizontal direction and 36 rows of first protective portions 151 distributed in the vertical direction.

[0097] In this example, the first protective portion 151 is an annular structure. Further, the first protective portion 151 is an annular structure corresponding to the shape of the corresponding pad 121. For example, if the pad 121 is rectangular, then the first protective portion 151 is a rectangular annular structure.

[0098] Preferably, the shape and size of the inner hole of the first protective part 151 are consistent with the shape and size of the pad 121. In this way, when the solar cells 12 are stacked, the first protective part 151 and the pad 121 can fit together more perfectly. This design can effectively save glue and protect the surface of the solar cell 12 to the maximum extent.

[0099] In some examples, the width of the first protective portion 151 is 1mm to 2mm. Further, in some examples, the width of the first protective portion 151 is 1.2mm to 1.8mm. In some specific examples, the width of the first protective portion 151 is 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, etc. Exemplarily, the pad 121 is rectangular in shape, with dimensions of 1.5mm × 2.1mm, and the outer ring dimension of the first protective portion 151 is (2.5~3.5mm) × (3.1~4.1mm), specifically 3mm × 3.6mm.

[0100] For back-contact batteries, insulating material needs to be printed on the back to separate the positive and negative grid lines, preventing the solder ribbon from conducting between the positive and negative grid lines during soldering on the solar cell 12, which would cause leakage. The difference between the first protection part 151 and the insulating material in the above example includes: the insulating material is disposed on the back of the solar cell 12 to electrically isolate the positive and negative grid lines; the first protection part 151 in the above example is disposed on the front of the solar cell 12, providing mechanical buffer protection for adjacent solar cells 12 between stacked cells, protecting the front film layer, especially the front textured structure.

[0101] like Figure 9 As shown, the insulating material 123 on the back of the solar cell 12 undergoes curing shrinkage during post-printing curing, increasing the warpage of the solar cell 12. This makes the solar cell 12 prone to microcracks or even breakage during module fabrication. In the above example, by providing a first protective part 151 on the front of the solar cell 12, curing shrinkage also occurs during post-printing curing. This can offset the warpage stress on the front of the solar cell 12 during the curing of the insulating material 123 on the back of the solar cell 12, reducing the occurrence of microcracks or breakage during module fabrication due to excessive warpage on one side of the solar cell 12.

[0102] The degree of warpage of the solar cell 12 is related to the weight of the insulating material 123 printed onto the solar cell 12; the greater the weight of the insulating material 123, the greater the warpage. If the weight of the insulating material 123 separating the positive and negative electrode grid lines of the solar cell 12 is 50 mg, then the weight of the buffer protection structure 15 located on the front side of the solar cell 12 is preferably 20 mg to 30 mg, which can effectively improve warpage. The height and weight of the buffer protection structure 15 can be achieved through the design of the screen printing stencil parameters, such as mesh count, wire diameter, and yarn thickness. For example, a screen printing stencil with a mesh count of 500, a wire diameter of 8 μm, and a yarn thickness of 15 μm can achieve the aforementioned height and wet weight of the buffer protection structure 15.

[0103] like Figure 6As shown, in some examples, the buffer protection structure 15 includes a second protection portion 152. The second protection portion 152 is disposed on the front and / or back of the solar cell 12. The second protection portion 152 surrounds the edge of the diced solar cell 12 and encloses each of the first protection portions 151. In this example, by providing the second protection portion 152, on the one hand, the second protection portion 152 can protect the front film layer of the solar cell 12; on the other hand, the second protection portion 152 is close to the edge to be passivated and disposed along the edge of the cross section, so that isolating the second protection portion 152 during the deposition of the passivation film layer 16 can reduce the passivation process gas, prevent the passivation process gas from depositing on the surface of the solar cell 12, and reduce the passivation process gas circumferential deposition.

[0104] In some examples, the height of the second protective portion 152 is greater than the height of the first protective portion 151. Thus, the second protective portion 152 can effectively block process gases from entering the gap between adjacent solar cells 12, preventing the plating around the edges during passivation from affecting the pads and the textured surface.

[0105] In some of these examples, the height difference between the second protective part 152 and the first protective part 151 is 3 μm to 4 μm.

[0106] exist Figure 10 In the example shown, the second protective part 152 is straight on the side away from the edge of the cross section and / or on the side close to the edge of the cross section.

[0107] like Figure 11 In the example shown, the second protective portion 152 has a wavy curve shape on the side away from the edge and / or the side closer to the edge. Compared to a straight shape, the curvature formed by the wavy curve shape can change the airflow direction, which can more effectively reduce the impact of process gases on the solar cell 12 and reduce the occurrence of plating around.

[0108] In some examples, the radii of the wavy curve are 125° to 145°. Further, in some examples, the radii of the wavy curve are 127° to 143°. In some specific examples, the radii of the wavy curve are 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, 135°, 136°, 137°, 138°, 139°, 140°, 141°, 142°, 143°, 144°, 145°, etc., or a range between any two of the above values.

[0109] When the side of the second protective part 152 near the edge of the solar cell 12 is a straight line, the distance between the side of the second protective part 152 near the edge of the solar cell 12 and the edge is, for example, 1μm to 4μm.

[0110] When the side of the second protective part 152 near the edge of the solar cell 12 is a wavy line, the minimum distance between the side of the second protective part 152 near the edge of the solar cell 12 and the edge is, for example, 1μm to 3μm, and the maximum distance is, for example, 3μm to 5μm. In some examples, in step S120, the solar cell 12 can be cut by, but is not limited to, laser scribing.

[0111] In some of these examples, in step S130, multiple stacked solar cells 12 are loaded into the same carrier 30 (e.g., a graphite carrier, a quartz carrier, etc.).

[0112] In some of these examples, in step S130, the edges of the stacked solar cells 12 to be passivated face the same side.

[0113] In some of these examples, the passivation process in step S140 includes:

[0114] A passivation film 16 is deposited on the cut section 122 of the solar cell 12.

[0115] Optionally, the passivation film 16 may be made of at least one of aluminum oxide and silicon nitride, but not limited to aluminum oxide. In some examples, the passivation film 16 is made of aluminum oxide.

[0116] In some of these examples, the process for depositing the passivation film 16 is atomic layer deposition (ALD).

[0117] Figure 12 This is a schematic diagram illustrating the process of feeding multiple stacked solar cells 12 into an atomic layer deposition apparatus 200 for edge passivation. The atomic layer deposition apparatus 200 includes a deposition chamber 210, a chamber door 220 and a spray plate 230 disposed at the inlet of the deposition chamber 210, and a particle trap 240 and a mechanical pump 250 disposed at the outlet of the deposition chamber 210.

[0118] The aforementioned edge passivation method for solar cells 12 involves stacking multiple solar cells 12, which can efficiently passivate the cut sections 122 of the multiple solar cells 12. This method reduces friction and rigid collisions between solar cells 12 by creating a buffer protection structure 15 on the surface of the solar cells 12 and ensuring that adjacent solar cells 12 have this buffer protection structure 15 when stacked, thereby reducing surface damage to the solar cells 12.

[0119] Furthermore, the present invention also provides a solar cell 12. The solar cell 12 can be obtained by the edge passivation method described above.

[0120] One embodiment of the solar cell 12 includes a solar cell body, a buffer protection structure 15, and a cross-sectional passivation film layer. The solar cell body has a front side and a back side disposed opposite to each other.

[0121] The solar cell body has positive grid lines, negative grid lines, and pads 121 disposed on the positive and negative grid lines. Both the positive and negative grid lines are located on the back side. A buffer protection structure 15 is disposed on the front side. The solar cell body has a cut cross-section. A passivation film layer is disposed on the cut cross-section.

[0122] By setting a buffer protection structure 15 on the main body of the solar cell, when multiple solar cells 12 are stacked and edge passivation is performed, the friction and rigid collision between adjacent solar cells 12 can be reduced due to the buffer protection structure 15, thereby reducing surface damage to the solar cells 12.

[0123] The buffer protection structure 15 is set as described above, and the structure of the main body of the solar cell is as described above regarding the structure of the solar cell, so it will not be repeated here.

[0124] Furthermore, the present invention also provides a photovoltaic module.

[0125] like Figure 13 As shown, a photovoltaic module 20 of one embodiment includes a first encapsulation structure 21, a second encapsulation structure 22, and a solar cell 12 obtained by the edge passivation method of any of the above examples or the solar cell 12 of any of the above examples. The solar cell 12 is disposed between the first encapsulation structure 21 and the second encapsulation structure 22.

[0126] In some of these examples, the first encapsulation structure 21 includes an encapsulation panel 211 and a first encapsulation film 212 disposed between the encapsulation panel 211 and the solar cell 12.

[0127] For example, the material of the encapsulation panel 211 is, for example, but not limited to, glass, organic polymers, etc.

[0128] For example, the first encapsulating film 212 can be one or more of EVA, POE, TPO, TPU, and PVB, but is not limited to. The first encapsulating film 212 can be a single layer or a multilayer stack.

[0129] In some of these examples, the second encapsulation structure 22 includes an encapsulation backplate 221 and a second encapsulation film 222 disposed between the encapsulation backplate 221 and the solar cell 12.

[0130] For example, the material of the aforementioned encapsulation backplate 221 may be, for example, but not limited to, glass, organic polymers, etc.

[0131] For example, the second encapsulating film 222 can be one or more of EVA, POE, TPO, TPU, and PVB, but is not limited to. The second encapsulating film 222 can be a single layer or a multilayer stack.

[0132] 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.

[0133] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for edge passivation of a solar cell, characterized in that, Includes the following steps: A buffer protection structure is fabricated on the surface of a solar cell; The solar cells are cut into sections; Multiple slit solar cells are stacked together to provide a buffer protection structure between adjacent solar cells; The cut sections of the stacked solar cells are passivated.

2. The edge passivation method for solar cells as described in claim 1, characterized in that, The solar cell is a back-contact cell, and the buffer protection structure is located on the front side of the solar cell.

3. The edge passivation method for solar cells as described in claim 2, characterized in that, The solar cell also has multiple pads, which are distributed on the grid lines of the solar cell. The buffer protection structure includes a first protection part, the projection of which on the back of the solar cell is located in the interval between the plurality of pads and / or in the interval between the pads and the edge of the solar cell; The height of the first protective part is greater than the height of the pad.

4. The edge passivation method for solar cells as described in claim 3, characterized in that, The buffer protection structure further includes a second protection part, which is disposed on the front and / or back of the solar cell. The second protection part surrounds the edge of the slit solar cell and encloses each of the first protection parts. The height of the second protection part is greater than the height of the first protection part.

5. The edge passivation method for solar cells as described in claim 4, characterized in that, The height difference between the first protective part and the pad is 5μm~10μm, and the height difference between the second protective part and the first protective part is 3μm~4μm.

6. The edge passivation method for solar cells as described in claim 4, characterized in that, The second protective part has a wavy curve shape on the side away from the edge and / or the side closer to the edge.

7. The edge passivation method for solar cells as described in claim 6, characterized in that, The arc of the wavy curve is 125°~145°.

8. The edge passivation method for a solar cell as described in any one of claims 1 to 7, characterized in that, The process for preparing the buffer protection structure on the surface of the solar cell includes screen printing, inkjet printing, or spraying.

9. The edge passivation method for a solar cell as described in any one of claims 1 to 7, characterized in that, The material of the buffer protection structure includes organic polymers; The organic polymer is selected from at least one of epoxy resin and organosilicon; the Tg of the organic polymer is 250℃~500℃.

10. The edge passivation method for a solar cell as described in any one of claims 1 to 7, characterized in that, The passivation process includes: A passivation film is deposited at the edge of the solar cell; The material of the passivation film is selected from at least one of aluminum oxide and silicon nitride; The process for depositing the passivation film is atomic layer deposition.

11. A solar cell, characterized in that, The solar cell includes a solar cell body, a buffer protection structure, and a cross-sectional passivation film layer. The solar cell body has a front side and a back side that are disposed opposite to each other, and the buffer protection structure is disposed on the front side. The solar cell body has a positive grid line, a negative grid line, and pads disposed on the positive grid line and the negative grid line; The positive and negative grid lines are both disposed on the back side, the solar cell body has a cut cross section, and the cross section passivation film is disposed on the cut cross section.

12. The solar cell as described in claim 11, characterized in that, The buffer protection structure includes a first protection part, the projection of which on the back surface is located in the interval between the plurality of pads and / or in the interval between the pads and the edge of the solar cell body; The height of the first protective part is greater than the height of the solder pad.

13. The solar cell as described in claim 12, characterized in that, The projection of each of the first protective portions on the back surface is arranged around one or more of the pads; The number of first protective parts and the number of pads are the same, and the positions of the plurality of first protective parts correspond one-to-one with the positions of the plurality of pads. The projection of each first protective part on the back surface is arranged around one of the pads.

14. The solar cell as described in claim 12, characterized in that, The buffer protection structure further includes a second protection part, which is disposed on the back side of the solar cell body. The second protection part surrounds the edge of the solar cell body and encloses each of the first protection parts. The height of the second protection part is greater than the height of the first protection part.

15. The solar cell as described in claim 14, characterized in that, The second protective portion has a wavy curve shape on the side away from the edge and / or the side closer to the edge, with the wavy curve having an arc of 125°~145°; and / or The material of the buffer protection structure includes organic polymers; The organic polymer is selected from at least one of epoxy resin and organosilicon; The organic polymer has a Tg of 250℃~500℃.

16. A photovoltaic module, characterized in that, The device includes a first encapsulation structure, a second encapsulation structure, and a solar cell obtained by the edge passivation method of any one of claims 1 to 10 or a solar cell of any one of claims 11 to 15, wherein the solar cell is disposed between the first encapsulation structure and the second encapsulation structure.

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