Solar cell, preparation method thereof and mask mold

Abstract

The invention relates to a solar cell, a preparation method thereof and a mask mold. According to the preparation method of the solar battery, the mask mold is arranged on the battery piece, glue injection is carried out to form the mask layer with the linear opening, and the grid line is deposited in the linear opening. In the mask mold, the position of the linear protrusion is the position of the linear opening of the mask layer and corresponds to the position of the grid line. According to the preparation method, printing, developing and other processes are not needed, and adhesive residues caused by light diffraction are avoided, so that the situation that pores or cavities are generated at the plating starting position during grid line deposition is avoided, good contact of the bottoms of the grid lines is achieved, and the cell performance is improved. The mask mold can be applied to the preparation method of the solar cell, and corresponding beneficial effects are obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to a solar cell, a preparation method thereof and a mask mold. BACKGROUND

[0002] Currently, the mainstream electrode preparation process of a solar cell is to print conductive silver paste on the surface of a cell sheet, and then to perform solidification sintering to form a silver electrode. However, the conductive silver paste is relatively high in price, resulting in high production cost of the cell. The electrode prepared by using an electroplating process can use a metal such as copper as electrode material at a relatively low price, so the electroplating process for preparing the electrode becomes an important direction for reducing the production cost.

[0003] In the process of preparing the electrode by using the electroplating process, a seed layer needs to be prepared on the surface of the cell sheet first; then a photosensitive adhesive layer is coated on the seed layer (referred to as a coating process), the photosensitive adhesive layer is irradiated by ultraviolet light through a mask plate to transfer the pattern of the mask plate to the photosensitive adhesive layer (referred to as a printing process), and then the unexposed photosensitive adhesive is removed by development (referred to as a development process), so as to obtain a patterned photosensitive adhesive layer; and then a metal is deposited in the opening of the photosensitive adhesive layer by the electroplating process to thicken the seed layer, so as to form a metal electrode with a certain height and width.

[0004] However, in the printing process, due to the light diffraction phenomenon, a slight hinge reaction will occur at the plating position, which causes residual adhesive in the adhesive removal area after development, thereby causing pores or cavities between the grid lines and the seed layer obtained by electroplating, and affecting the contact effect of the two. SUMMARY

[0005] Therefore, it is necessary to provide a solar cell, a preparation method thereof and a mask mold to improve the problem of pores or cavities between the grid lines and the seed layer.

[0006] One of the purposes of the present application is to provide a preparation method of a solar cell, and the scheme is as follows:

[0007] A preparation method of a solar cell, comprising the following steps:

[0008] A mask mold is provided, the mask mold comprises a cover plate and a plurality of linear protrusions distributed on one side of the cover plate, and an adhesive injection space is formed between adjacent linear protrusions;

[0009] The mask mold is arranged on a cell sheet, and the linear protrusions are located between the cell sheet and the cover plate;

[0010] Adhesive is injected into the adhesive injection space, and a mask layer is formed after the adhesive is cured;

[0011] The mask mold is removed, and the positions where the linear protrusions are removed form linear openings of the mask layer;

[0012] Depositing a grid line in the linear opening.

[0013] In one of the embodiments, the linear protrusion has a height of 8-16 μm.

[0014] In one of the embodiments, the linear protrusion has a width of 10-30 μm.

[0015] In one of the embodiments, the linear protrusions are arranged in parallel.

[0016] In one of the embodiments, the cover plate is rectangular.

[0017] In one of the embodiments, the cover plate is a transparent cover plate.

[0018] In one of the embodiments, the glue injection uses light-cured glue.

[0019] In one of the embodiments, the mask mold is made of at least one of PP, PET, and stainless steel.

[0020] In one of the embodiments, before the step of arranging the mask mold on the battery piece, the preparation method further comprises a step of preparing a seed layer on the battery piece, and the grid line is deposited on the seed layer.

[0021] In one of the embodiments, the process of forming the grid line comprises an electroplating process.

[0022] Another object of the present application is to provide a solar cell prepared by the preparation method of any of the above embodiments.

[0023] Still another object of the present application is to provide a mask mold, which has the following scheme:

[0024] A mask mold comprises a cover plate and a plurality of linear protrusions distributed on one side of the cover plate, and glue injection spaces are formed between adjacent linear protrusions.

[0025] In one of the embodiments, the linear protrusion has a height of 8-16 μm.

[0026] In one of the embodiments, the linear protrusion has a width of 10-30 μm.

[0027] In one of the embodiments, the linear protrusions are arranged in parallel.

[0028] In one of the embodiments, the cover plate is rectangular.

[0029] In one of the embodiments, the cover plate is a transparent cover plate.

[0030] In one embodiment, the glue injection uses light-cured glue.

[0031] In one embodiment, the material of the mask mold comprises at least one of PP, PET, and stainless steel.

[0032] Compared with the conventional scheme, the above-mentioned solar cell and the preparation method thereof and the mask mold have the following beneficial effects:

[0033] The preparation method of the above-mentioned solar cell sets the mask mold on the cell sheet, forms the mask layer with linear openings by glue injection, and then deposits the grid lines in the linear openings. In the mask mold, the position of the linear protrusion is the position of the linear opening of the mask layer, corresponding to the position of the grid line. The above-mentioned preparation method does not need to perform printing, developing and other processes, avoids the residual glue caused by light diffraction, thereby avoiding the case that pores or cavities are generated at the plating position when the grid line is deposited, realizing good contact at the bottom of the grid line, and being beneficial to improving the cell performance.

[0034] The above-mentioned mask mold can be applied to the preparation method of the above-mentioned solar cell to obtain the corresponding beneficial effects. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a flowchart of the preparation method of the solar cell of one embodiment;

[0036] Figure 2 It is a structural schematic diagram of the mask mold used in the preparation method of one embodiment;

[0037] Figure 3 It is Figure 2 It is a right view partial sectional view of the mask mold shown;

[0038] Figure 4 It is a schematic diagram of setting the mask mold on the cell sheet in the preparation method of the solar cell of one embodiment;

[0039] Figure 5 It is a schematic diagram of forming the mask layer by glue injection into the glue injection space in the preparation method of the solar cell of one embodiment;

[0040] Figure 6 It is a schematic diagram of depositing the grid line in the linear opening in the preparation method of the solar cell of one embodiment;

[0041] Figure 7 It is a schematic diagram of removing the mask layer in the preparation method of the solar cell of one embodiment;

[0042] Figure 8 It is a structural schematic diagram of the solar cell of one embodiment;

[0043] Figure 9An electron microscope image of a cross section of the gate line in Example 1.

[0044] Figure 10 An electron microscope image of a cross section of the gate line in Comparative Example 1.

[0045] BRIEF DESCRIPTION OF DRAWINGS

[0046] 1. A mask mold; 11, a cover plate; 12, a linear protrusion; 13, a glue injection space; 2, a solar cell; 20, a cell piece; 21, a gate line; 30, a mask layer; 31, a linear opening; 100, a single crystal silicon wafer; 200, a first intrinsic amorphous silicon layer; 300, a second intrinsic amorphous silicon layer; 400, a first doped microcrystalline silicon layer; 500, a second doped microcrystalline silicon layer; 600, a first transparent conductive layer; 700, a second transparent conductive layer; 800, a first gate line; 900, a second gate line. DETAILED DESCRIPTION

[0047] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order to not unnecessarily obscure the present application.

[0048] In the description of the present application, it is to 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", "circumferential", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely used for convenience of description and simplification of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application.

[0049] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or a specific number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can include at least one of the features, explicitly or implicitly. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0050] In the present application, unless otherwise clearly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] 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 application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0052] As Figure 1 shown, the preparation method of the solar cell of an embodiment of the present application comprises the following steps:

[0053] Step S1, as Figure 2 and Figure 3 shown, a mask mold 1 is provided, the mask mold 1 comprises a cover plate 11 and a plurality of linear protrusions 12 distributed on one side of the cover plate 11, and an injection space 13 is formed between adjacent linear protrusions 12.

[0054] Step S2, as Figure 4 shown, the mask mold 1 is arranged on the cell piece 20, and the linear protrusions 12 are located between the cell piece 20 and the cover plate 11.

[0055] Step S3, as Figure 5 shown, glue is injected into the injection space 13, and the mask layer 30 is formed after the glue is cured.

[0056] Step S4, the mask mold 1 is removed, and the position where the linear protrusions 12 are removed forms the linear openings 31 of the mask layer 30.

[0057] Step S5, as Figure 6 shown, the grid lines 21 are deposited in the linear openings 31.

[0058] Step S6, as Figure 7 shown, the mask layer 30 is removed.

[0059] Thus, the grid lines 21 are formed on the cell piece 20.

[0060] The preparation method of the solar cell is performed by disposing the mask mold 1 on the cell sheet 20, forming the mask layer 30 with the linear opening 31 by glue injection, and then depositing the grid lines 21 in the linear opening 31. In the mask mold 1, the positions of the linear protrusions 12 are the positions of the linear openings 31 of the mask layer 30, which correspond to the positions of the grid lines 21. The preparation method does not need printing, developing and other processes, avoids residual glue caused by light diffraction, thereby avoiding the case that holes or cavities are generated at the plating starting position when the grid lines 21 are deposited, and realizing good contact at the bottom of the grid lines 21, which is beneficial to improve the performance of the cell.

[0061] In addition, the preparation method can simplify the preparation process of the mask layer 30, reduce equipment investment, and reduce production cost.

[0062] In the mask mold 1, the height of the linear protrusion 12 defines the thickness of the mask layer 30. The "height" is the distance between the side of the linear protrusion 12 away from the cover plate 11 and the cover plate 11. The height of the linear protrusion 12 can be designed according to the thickness of the mask layer 30 to be obtained. In some examples, in the mask mold 1, the height of the linear protrusion 12 is 8-16 μm, and specifically for example, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, etc.

[0063] In the mask mold 1, the width of the linear protrusion 12 defines the width of the linear opening 31 of the mask layer 30, and also defines the width of the prepared grid lines 21. The "width" is the size in the direction perpendicular to the extension direction of the linear protrusion 12 and parallel to the cell sheet 20. In some examples, in the mask mold 1, the width of the linear protrusion 12 is 10-30 μm, and specifically for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc.

[0064] The shape of the cover plate 11 of the mask mold 1 is designed according to the shape of the cell sheet 20, which can be but is not limited to rectangular.

[0065] In the mask mold 1, the positions of the linear protrusions 12 correspond to the positions of the grid lines 21. As shown in some examples, a plurality of linear protrusions 12 are arranged in parallel. Figure 2

[0066] Further, the linear protrusion 12 extends from one end of the cover plate 11 to the opposite end.

[0067] In step S3, the glue injection is performed for example from one end of the glue injection space 13, and the glue liquid is made to flow to the other end of the glue injection space 13 by applying pressure. In addition, the glue injection can also be performed from both ends of the glue injection space 13 respectively.

[0068] ​In some examples, the glue is a light-curing glue. The light-curing glue can be cured by light without heating. In other examples, a heat-curing glue can also be used.

[0069] The mask mold 1 is preferably made of a flexible material, especially the linear protrusions 12, to avoid damaging the surface of the cell sheet 20, such as PP, PET, etc. In addition, the mask mold 1 can also be made of a rigid material, such as stainless steel, etc.

[0070] In addition, a release layer can be provided on the inner wall of the glue injection space 13 of the mask mold 1 to facilitate separation from the mask layer 30 obtained by curing.

[0071] The material of the release layer is, for example, but not limited to, polytetrafluoroethylene, silicone rubber, wax release agent, etc.

[0072] In some examples, the cover plate 11 is a transparent cover plate. In this way, it is convenient to observe the glue injection condition and facilitate the light curing of the light-curing glue.

[0073] In some examples, before the step of arranging the mask mold 1 on the cell sheet 20 (step 2), the method for preparing a solar cell further comprises a step of preparing a seed layer on the cell sheet 20.

[0074] The seed layer, for example, comprises metal copper. The thickness of the seed layer is, for example, 150 nm to 250 nm, and is specifically, for example, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, etc. The process for preparing the seed layer is, for example, a physical vapor deposition (PVD) process, specifically, for example, evaporation, magnetron sputtering, etc.

[0075] In some examples, before the step of depositing the grid lines 21, the method for preparing a solar cell further comprises a step of performing an edge wrapping treatment on the cell sheet 20.

[0076] The edge wrapping treatment is to wrap an edge wrapping glue on the edge of the cell sheet 20. The width of the edge wrapping glue is, for example, 30 μm to 60 μm. The thickness of the edge wrapping glue is, for example, 8 μm to 14 μm.

[0077] In some examples, the process for depositing the grid lines 21 comprises an electroplating process.

[0078] In some examples, the step of depositing the grid lines 21 comprises:

[0079] depositing a main metal layer on the seed layer by an electroplating process.

[0080] The main metal layer comprises, for example, metal copper. The thickness of the main metal layer is, for example, 8 μm to 10 μm, and specifically, for example, 8 μm, 8.2 μm, 8.4 μm, 8.6 μm, 8.8 μm, 9 μm, 9.2 μm, 9.4 μm, 9.6 μm, 9.8 μm, 10 μm, etc.

[0081] Further, in some examples, the step of depositing to form the grid lines 21 further comprises:

[0082] Plating the protective metal layer on the main metal layer by an electroplating process.

[0083] The protective metal layer comprises, for example, metal tin. The thickness of the protective metal layer is, for example, 2 μm to 5 μm, and specifically, for example, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc.

[0084] In some examples, after step S5, the method for preparing a solar cell further comprises the following steps:

[0085] The mask layer 30 is removed.

[0086] The edge sealing adhesive is removed as the edge sealing treatment is performed on the cell sheet 20.

[0087] The method for removing the mask layer 30 and the edge sealing adhesive can be, but is not limited to, alkali washing. The alkali washing is performed, for example, by using a sodium carbonate solution with a concentration of 8 g / L.

[0088] After the mask layer 30 and the edge sealing adhesive are removed, the seed layer is exposed.

[0089] Further, the cell sheet 20 is subjected to a back etching treatment to remove the exposed seed layer. The back etching treatment is performed by immersing the cell sheet 20 in a back etching solution. The back etching solution comprises, for example, sulfuric acid with a concentration of 2.5 g / L and hydrogen peroxide with a concentration of 10 g / L.

[0090] In some examples, after step S5, the method for preparing a solar cell further comprises the following steps:

[0091] The cell sheet 20 on which the grid lines 21 are formed is subjected to a light injection treatment.

[0092] In some examples, the temperature of the light injection treatment is 200 °C to 220 °C, and specifically, for example, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, etc.

[0093] In some examples, the time of the light injection treatment is 60 s to 120 s, and specifically, for example, 60 s, 70 s, 80 s, 90 s, 100 s, 120 s, etc.

[0094] In some examples, after step S6, the method for preparing a solar cell further comprises the following steps:

[0095] Removing the seed layer in the non-grid line area.

[0096] Optionally, the above-mentioned solar cell can be, but is not limited to, a passivated emitter rear contact cell (PERC cell), a tunnel oxide passivated contact cell (TOPCon cell), a heterojunction cell (HJT cell), etc.

[0097] The following takes the heterojunction cell as an example to further describe the preparation method of the solar cell of the present application.

[0098] Figure 8 The structure of the solar cell 2 of an embodiment is shown, and the preparation method of the solar cell 2 includes the following steps:

[0099] A cell piece 20 is provided, which includes a single crystal silicon wafer 100, a first intrinsic amorphous silicon layer 200, a first doped microcrystalline silicon layer 400 and a first transparent conductive layer 600 arranged on the back surface of the single crystal silicon wafer 100, and a second intrinsic amorphous silicon layer 300, a second doped microcrystalline silicon layer 500 and a second transparent conductive layer 700 arranged on the front surface of the single crystal silicon wafer 100.

[0100] In some examples, the back surface and / or the front surface of the single crystal silicon wafer 100 has a pyramid texture structure. The height of the pyramid is, for example, 2 μm-8 μm.

[0101] In some examples, the first doped microcrystalline silicon layer 400 is P-type doped, such as boron doped. The second doped microcrystalline silicon layer 500 is N-type doped, such as phosphorus doped.

[0102] In some examples, the thickness of the first intrinsic amorphous silicon layer 200 is 3 nm-9 nm. The thickness of the second intrinsic amorphous silicon layer 300 is 3 nm-6 nm. The thickness of the first doped microcrystalline silicon layer 400 is 5 nm-15 nm. The thickness of the second doped microcrystalline silicon layer 500 is 5 nm-10 nm. The thickness of the first transparent conductive layer 600 is 90 nm-110 nm. The thickness of the second transparent conductive layer 700 is 90 nm-110 nm.

[0103] A seed layer is deposited on the first transparent conductive layer 600. The seed layer, for example, includes metal copper. The thickness of the seed layer is, for example, 150 nm-250 nm. The process of depositing the seed layer is, for example, a physical vapor deposition (PVD) process, specifically, evaporation, magnetron sputtering, etc.

[0104] As shown in FIGS. 1 and 2, a mask mold 1 is provided, which includes a cover plate 11 and a plurality of linear protrusions 12 distributed on one side of the cover plate 11, and a glue injection space 13 is formed between adjacent linear protrusions 12. Figure 2 Figure 3 As shown in FIGS. 1 and 2, a mask mold 1 is provided, which includes a cover plate 11 and a plurality of linear protrusions 12 distributed on one side of the cover plate 11, and a glue injection space 13 is formed between adjacent linear protrusions 12.

[0105] ​In some examples, the plurality of linear protrusions 12 are arranged in parallel. The linear protrusions 12 have a height of, for example, 8-16 μm and a width of, for example, 10-30 μm.

[0106] A mask layer 30 is prepared on the seed layer. The mask mold 1 is arranged on the seed layer, with the linear protrusions 12 between the solar cell sheet 20 and the cover plate 11. Glue is injected into the glue injection space 13, and the mask layer 30 is formed after curing. The mask mold 1 is removed, and the positions of the linear protrusions 12 form linear openings 31 of the mask layer 30. The linear openings 31 expose the seed layer.

[0107] A main metal layer is plated on the exposed area of the seed layer by an electroplating process. The main metal layer is made of copper. A protective metal layer is plated on the main metal layer by an electroplating process. The protective metal layer is made of tin.

[0108] The mask layer 30 is removed using an alkaline solution such as sodium hydroxide solution, and the seed layer in the area originally covered by the mask layer 30 is removed using an acidic solution such as sulfuric acid, to complete the preparation of the first grid line 800.

[0109] Then, the second grid line 900 is prepared on the second transparent conductive layer 700 in the same way.

[0110] The above method for preparing a solar cell involves arranging the mask mold 1 on the solar cell sheet 20, injecting glue to form the mask layer 30 with linear openings 31, and depositing the grid line 21 in the linear openings 31. In the mask mold 1, the positions of the linear protrusions 12 are the positions of the linear openings 31 of the mask layer 30, corresponding to the positions of the grid line 21. The above method does not require printing and developing processes, avoiding residue caused by light diffraction, thereby avoiding the formation of pores or cavities at the plating start position during deposition of the grid line 21, and achieving good contact at the bottom of the grid line 21.

[0111] In addition, the above method can simplify the preparation process of the mask layer 30, reduce equipment investment, and reduce production costs.

[0112] Further, the present application also provides a solar cell prepared by any of the above methods.

[0113] Further, the present application also provides a mask mold 1 as described above. The mask mold 1 includes a cover plate 11 and a plurality of linear protrusions 12 distributed on one side of the cover plate 11, with glue injection spaces 13 formed between adjacent linear protrusions 12.

[0114] The above mask mold 1 can be applied to the above method for preparing a solar cell, to obtain the corresponding beneficial effects.

[0115] The following specific examples are provided to further illustrate the present application. The present application provides the following specific examples for better further understanding the present application, and is not limited to the specific examples, and does not constitute a limitation on the scope of protection of the present application.

[0116] Example 1

[0117] The present embodiment provides a preparation method of a solar cell, comprising the following steps:

[0118] Step 1, providing a phosphorus-doped single crystal silicon wafer with a thickness of 100 μm, and performing a texturing cleaning treatment to form a pyramid texturing structure on both sides of the single crystal silicon wafer.

[0119] Step 2, using a PECVD deposition device to deposit a first intrinsic amorphous silicon layer and a phosphorus-doped first doped microcrystalline silicon layer on the first side of the single crystal silicon wafer, and to deposit a second intrinsic amorphous silicon layer and a boron-doped second doped microcrystalline silicon layer on the second side of the single crystal silicon wafer. The thickness of the first intrinsic amorphous silicon layer is 4 nm. The thickness of the first doped microcrystalline silicon layer is 7 nm. The thickness of the second intrinsic amorphous silicon layer is 6 nm. The thickness of the second doped microcrystalline silicon layer is 7 nm.

[0120] Step 3, using a magnetron sputtering device to deposit a first transparent conductive layer on the first doped microcrystalline silicon layer, and to deposit a second transparent conductive layer on the second doped microcrystalline silicon layer. The thickness of the first transparent conductive layer is 100 nm. The thickness of the second transparent conductive layer is 100 nm.

[0121] Step 4, depositing a seed layer with a thickness of 100 nm on the first transparent conductive layer by magnetron sputtering. The material of the seed layer is metal copper.

[0122] Step 5, providing a mask mold, the mask mold comprising a cover plate and a plurality of linear protrusions distributed on one side of the cover plate, and an injection space being formed between adjacent linear protrusions. The plurality of linear protrusions are arranged in parallel. The height of the linear protrusion is 10 μm, and the width is 20 μm.

[0123] Step 6, setting the mask mold on the seed layer, so that the linear protrusions are located between the cell wafer and the cover plate. Using a syringe to inject light-curing glue from one end of the injection space, and making the glue flow to the other end of the injection space by applying pressure.

[0124] Step 7, after the injection is completed, performing light curing to form a mask layer.

[0125] Step 8, demolding, and the position of the linear protrusion forms a linear opening of the mask layer. The linear opening exposes the seed layer.

[0126] Step 9, performing copper electroplating process on the cell wafer obtained in step 8 in a copper sulfate electroplating solution, to deposit a conductive main body layer with a thickness of 8 μm on the seed layer in the linear opening.

[0127] Step 10: The battery cell obtained in step 9 is subjected to tin electroplating in a tin methanesulfonate electroplating solution to deposit a conductive protective layer with a thickness of 2 μm on the conductive substrate layer.

[0128] Step 11: Clean the battery cell obtained in step 10 with an alkaline solution to remove the mask layer, and then clean it with a dilute sulfuric acid solution to remove the seed layer in the non-grid line area, thus obtaining the first grid line.

[0129] Step 12: Prepare the second gate line on the second transparent conductive layer using the same method.

[0130] Step 13: Perform light injection treatment on the solar cell obtained in step 12. The light injection treatment temperature is 220℃ and the time is 40s.

[0131] The electron microscope image of the grid line cross-section in this embodiment is as follows: Figure 9 As shown. By Figure 9 It is evident that there are no pores between the gate lines and the seed layer after electroplating, and the two have good contact.

[0132] Comparative Example 1

[0133] The method for preparing the solar cell in this comparative example includes the following steps:

[0134] Step 1: Provide a phosphorus-doped monocrystalline silicon wafer with a thickness of 100 μm and perform a texturing and cleaning process to form a pyramidal textured surface structure on both sides of the monocrystalline silicon wafer.

[0135] Step 2: Using a PECVD deposition system, a first intrinsic amorphous silicon layer and a phosphorus-doped first-doped microcrystalline silicon layer are deposited on the first side of the monocrystalline silicon wafer, and a second intrinsic amorphous silicon layer and a boron-doped second-doped microcrystalline silicon layer are deposited on the second side of the monocrystalline silicon wafer. The thickness of the first intrinsic amorphous silicon layer is 4 nm. The thickness of the first-doped microcrystalline silicon layer is 7 nm. The thickness of the second intrinsic amorphous silicon layer is 6 nm. The thickness of the second-doped microcrystalline silicon layer is 7 nm.

[0136] Step 3: A first transparent conductive layer is deposited on the first doped microcrystalline silicon layer using a magnetron sputtering apparatus, and a second transparent conductive layer is deposited on the second doped microcrystalline silicon layer. The thickness of the first transparent conductive layer is 100 nm. The thickness of the second transparent conductive layer is 100 nm.

[0137] Step 4: Deposit a seed layer with a thickness of 100 nm on the first transparent conductive layer by magnetron sputtering. The seed layer is made of metallic copper.

[0138] Step 5: Coat the copper seed layer with photosensitive emulsion to prepare a photosensitive emulsion layer with a thickness of 10 μm.

[0139] Step 6, according to the designed grid line pattern, the photosensitive adhesive layer in the non-grid line area is irradiated by laser, so that the photosensitive adhesive in the non-grid line area is denatured.

[0140] Step 7, the photosensitive adhesive in the grid line area is removed by cleaning with sodium carbonate solution, and the photosensitive adhesive in the non-grid line area is retained due to denaturation and cannot be removed by cleaning with sodium carbonate solution, thereby forming a deposition groove exposing the seed layer.

[0141] Step 8, the battery piece obtained in step 7 is subjected to copper electroplating process in a copper electroplating solution, and a conductive main body layer with a thickness of 8 μm is deposited on the seed layer in the linear opening.

[0142] Step 9, the battery piece obtained in step 8 is subjected to tin electroplating process in a stannous methanesulfonate electroplating solution, and a conductive protective layer with a thickness of 2 μm is deposited on the conductive main body layer.

[0143] Step 10, the battery piece obtained in step 9 is cleaned with an alkali solution to remove the mask layer, and then cleaned with a dilute sulfuric acid solution to remove the seed layer in the non-grid line area, thereby obtaining the first grid line.

[0144] Step 11, the second grid line is prepared on the second transparent conductive layer in the same way.

[0145] Step 12, the solar cell obtained in step 11 is subjected to light injection treatment, and the temperature of the light injection treatment is 220°C and the time is 40 s.

[0146] The grid line distribution and size of Comparative Example 1 and Example 1 are consistent.

[0147] The electron microscope image of the cross section of the grid line in the present comparative example is shown in Figure 10 As can be seen from Figure 10 , there are pores between the grid line and the seed layer after electroplating.

[0148] The solar cells prepared in the above examples and comparative examples are subjected to performance test, and the test results are shown in Table 1.

[0149] Table 1 Performance test results of the solar cells prepared in the examples and comparative examples

[0150]

[0151] Comparing Figure 9 and Figure 10 it can be seen that, compared with Comparative Example 1, the pores and cavities between the grid line and the seed layer after electroplating in Example 1 are obviously improved, and the contact effect of the two is improved. As can be seen from the results in Table 1, compared with Comparative Example 1, the photoelectric conversion efficiency and short-circuit current of the solar cell prepared in Example 1 are improved.

[0152] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered within the scope of the present disclosure.

[0153] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for fabricating a solar cell, characterized in that, Includes the following steps: A mask mold (1) is provided, the mask mold (1) includes a cover plate (11) and a plurality of linear protrusions (12) distributed on one side of the cover plate (11), and an injection space (13) is formed between adjacent linear protrusions (12). The mask mold (1) is placed on the battery cell (20) so that the linear protrusion (12) is located between the battery cell (20) and the cover plate (11); Glue is injected into the glue injection space (13), and after the glue cures, a mask layer (30) is formed. When the mask mold (1) is removed, the linear protrusion (12) is removed to form a linear opening (31) in the mask layer (30). A grid line (21) is deposited in the linear opening (31).

2. The preparation method according to claim 1, characterized in that, The height of the linear protrusion (12) is 8μm~16μm; And / or, the width of the linear protrusion (12) is 10μm~30μm; And / or, multiple linear protrusions (12) are arranged in parallel.

3. The preparation method according to claim 1, characterized in that, The cover plate (11) is rectangular; And / or, the cover plate (11) is a transparent cover plate; And / or, the material of the mask mold (1) includes at least one of PP, PET, and stainless steel.

4. The preparation method according to claim 1, characterized in that, The adhesive used for injection is a light-curing adhesive.

5. The preparation method according to claim 1, characterized in that, Before the step of setting the mask mold (1) on the battery cell (20), the preparation method further includes the step of preparing a seed layer on the battery cell (20); the grid line (21) is deposited on the seed layer.

6. The preparation method according to any one of claims 1 to 5, characterized in that, The process for forming the gate line (21) includes an electroplating process.

7. A solar cell, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A mask mold (1), characterized in that, It includes a cover plate (11) and multiple linear protrusions (12) distributed on one side of the cover plate (11), with an injection space (13) formed between adjacent linear protrusions (12).

9. The mask mold (1) as described in claim 8, characterized in that, The height of the linear protrusion (12) is 8μm~16μm; And / or, the width of the linear protrusion (12) is 10μm~30μm; And / or, multiple linear protrusions (12) are arranged in parallel.

10. The mask mold (1) as described in claim 8 or 9, characterized in that, The cover plate (11) is rectangular; And / or, the cover plate (11) is a transparent cover plate; And / or, the material of the mask mold (1) includes at least one of PP, PET, and stainless steel.

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