Solar cell and preparation method thereof
By applying photosensitive adhesive film in multiple layers and controlling the thickness of each layer, the grid line shape of the copper interconnect solar cell was improved, solving the shading and reliability problems caused by the inverted trapezoidal opening, and improving the efficiency and reliability of the solar cell.
Patent Information
- Application Number
- CN202510323487.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-12-19
AI Technical Summary
In the prior art, the copper electrode grid lines of copper interconnect solar cells have an inverted trapezoidal opening problem after mask development, which leads to an increase in the light-blocking area, loss of cell efficiency and module power, and residual chemicals at the bottom of the grid lines affecting reliability and causing poor film clamping.
A multi-layer coating method for photosensitive adhesive liquid film is adopted, with the thickness of each layer controlled below 4μm and the thickness difference between each layer controlled to improve the solvent dispersion uniformity of the photosensitive adhesive layer. Positive trapezoidal grid lines are formed through electroplating process.
The shape of the grid lines was improved, the shading area was reduced, the conversion efficiency and module power of the solar cells were increased, the film clamping problem was reduced, and the bonding force between the grid lines and the solar cells was enhanced.
Smart Images
Figure CN121174641A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of photovoltaic technology, in particular to a solar cell and a preparation method thereof. BACKGROUND
[0002] In the copper interconnection cell piece technology, the copper electrode grid line is realized by pattern transfer on the photosensitive glue, electroplating and film removal. However, during the patterning, the opening morphology of the mask after development is poor, especially the inverted trapezoidal morphology, as shown in the following figure. Figure 1
[0003] The inverted trapezoidal opening of the mask will cause the grid line to be inverted trapezoidal, which will have the following adverse effects:
[0004] 1. The top of the grid line is wide and the bottom is narrow, which increases the shading area and causes the loss of cell efficiency;
[0005] 2. The inverted trapezoidal morphology is not conducive to the diffuse reflection of light by the grid line compared to the right trapezoidal morphology, resulting in loss of cell efficiency and module power;
[0006] 3. The inverted trapezoidal morphology is not conducive to the wet chemical immersion exchange, and the grid line bottom is prone to residual chemical, affecting the reliability of the cell;
[0007] 4. The photosensitive glue film is easily pressed by the grid line, causing film clamping and incomplete film removal defects. SUMMARY
[0008] Therefore, it is necessary to provide a solar cell and a preparation method thereof to solve the problem of inverted trapezoidal grid line caused by inverted trapezoidal opening of the mask.
[0009] One of the purposes of the present application is to provide a preparation method of a solar cell, as follows:
[0010] A preparation method of a solar cell, comprising the following steps:
[0011] Preparation of a photosensitive glue layer on a cell piece;
[0012] Exposure and development of the photosensitive glue layer to form a deposition groove;
[0013] Deposition of a grid line on the cell piece through the deposition groove;
[0014] The step of preparing the photosensitive glue layer comprises:
[0015] Multiple layers of photosensitive glue solution films are coated, and the next layer of photosensitive glue solution film is coated after the solidification of the previous layer of photosensitive glue solution film. The thickness of each layer of photosensitive glue solution film is below 4 μm.
[0016] In one of the embodiments, the thickness of each layer of the photosensitive glue solution film is 3-4 μm.
[0017] In one of the embodiments, the thickness difference between different layers of the photosensitive glue solution film is below 0.5 μm.
[0018] In one of the embodiments, the number of layers of the photosensitive glue solution film is 2-5.
[0019] In one of the embodiments, the viscosity of the photosensitive glue solution film is 2000±200 cps.
[0020] In one of the embodiments, the ratio of the slot opening width to the slot bottom width of the deposition slot is 0.3-1.
[0021] In one of the embodiments, the ratio of the slot opening width to the slot bottom width of the deposition slot is 0.3-0.6.
[0022] In one of the embodiments, the battery piece is rotated to change the down position and the up position of the doctor blade before coating the next layer of the photosensitive glue solution film.
[0023] In one of the embodiments, the process of depositing the grid lines is an electroplating process.
[0024] Another object of the present application is to provide a solar cell prepared by the preparation method of any of the above embodiments.
[0025] Compared with the conventional scheme, the above solar cell and the preparation method thereof have the following beneficial effects:
[0026] The preparation method of the above solar cell divides the preparation of the photosensitive glue layer into multi-layer coating of the photosensitive glue solution film, and controls the thickness of each layer of the photosensitive glue solution film to be below 4 μm, which can improve the dispersion uniformity of the solvent inside the photosensitive glue solution film, improve the condition that the solvent at the bottom of the film layer volatilizes slowly and the solvent at the surface of the film layer volatilizes quickly, and further improve the opening morphology of the exposure and development of the prepared photosensitive glue layer, so that the inverted trapezoidal opening is improved. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 The electron microscope graph of the inverted trapezoidal opening in the photosensitive glue layer;
[0028] Figure 2 The schematic graph of the components in the photosensitive glue;
[0029] Figure 3 The schematic graph of the components in the photosensitive glue after exposure;
[0030] Figure 4a schematic diagram of exposed and unexposed regions of the photosensitive adhesive;
[0031] Figure 5 a schematic diagram of the structure of the photosensitive adhesive layer in an embodiment;
[0032] Figure 6 a schematic diagram of the structure of the solar cell in an embodiment;
[0033] Figure 7 a scanning electron microscope image of the deposition tank of the photosensitive adhesive layer in Example 1;
[0034] Figure 8 a scanning electron microscope image of the deposition tank of the photosensitive adhesive layer in Example 2;
[0035] Figure 9 a scanning electron microscope image of the deposition tank of the photosensitive adhesive layer in Example 3;
[0036] Figure 10 a scanning electron microscope image of the deposition tank of the photosensitive adhesive layer in Example 4;
[0037] Figure 11 a scanning electron microscope image of the deposition tank of the photosensitive adhesive layer in Example 5.
[0038] BRIEF DESCRIPTION OF DRAWINGS
[0039] 10, photosensitive adhesive layer; 11, first sub-layer; 12, second sub-layer; 13, third sub-layer; 2, solar cell; 100, single crystal silicon wafer; 200, first intrinsic amorphous silicon layer; 300, second intrinsic amorphous silicon layer; 400, first doped microcrystalline silicon layer; 500, second doped microcrystalline silicon layer; 600, first transparent conductive layer; 700, second transparent conductive layer; 800, first grid line; 900, second grid line. DETAILED DESCRIPTION
[0040] 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 details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the present application. Therefore, the specific embodiments described herein are not intended to be limiting, but rather are to serve as examples for the practicing the present application.
[0041] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.
[0042] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.
[0043] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly 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.
[0044] 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 the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0045] As Figure 2 shown, the photosensitive adhesive includes components such as solvent, photosensitive agent, resin, and additives.
[0046] During the exposure process, the photosensitive adhesive will undergo cross-linking reaction after being irradiated by specific wavelength light (such as ultraviolet light, deep ultraviolet light, extreme deep ultraviolet light, etc.) or electron beam, so that its solubility in the developing solution changes significantly. Specifically, the positive photosensitive adhesive becomes soluble in the exposed area, while the negative photosensitive adhesive becomes insoluble in the exposed area. Through the treatment of the developing solution, the soluble part is removed, and the insoluble part is retained, thereby forming a patterned photosensitive adhesive layer.
[0047] Taking a negative photosensitive resist as an example, the photosensitive agent is photosensitive during exposure, can absorb light energy of a specific wavelength, thereby generating free radicals, the free radicals initiate monomer polymerization, and new free radicals are generated, thereby generating a chain reaction, as shown in Figure 3 and Figure 4 The cross-linking degree of the photosensitive resist in the exposed area increases, so that the exposed area becomes insoluble. The non-photosensitive area does not undergo cross-linking reaction and is soluble in the developing solution, and can be removed after development to form a deposition groove.
[0048] After research, a small amount of solvent molecules will still remain in the obtained dry film layer after the photosensitive resist liquid film is subjected to drying treatment. An undesirable drying process can cause a certain difference in solvent content at different thickness positions of the photosensitive resist. Since the heat source radiation of the oven is transmitted from the surface of the film to the bottom and gradually weakened, the solvent near the substrate is not easy to volatilize during drying of the photosensitive resist, and compared with that, the solvent at the surface position of the film layer is easier to volatilize. The difference in volatilization rate of the solvent at the surface and the bottom of the photosensitive resist after drying causes a difference in solvent content, the surface has a small solvent concentration, and the bottom has a large solvent concentration. This causes a difference in light path reflection and absorption between the surface and the bottom of the film, and further causes a difference in cross-linking reaction, so that the opening morphology appears an undesirable inverted trapezoidal shape.
[0049] Based on the above research, the present application provides a preparation method of a solar cell to solve the problem of the inverted trapezoidal grid lines caused by the inverted trapezoidal opening of the mask.
[0050] The preparation method of the solar cell of an embodiment of the present application comprises the following steps:
[0051] Step S1: preparing a photosensitive resist layer on the cell sheet.
[0052] Step S2: exposing and developing the photosensitive resist layer to form a deposition groove.
[0053] Step S3: depositing a grid line on the cell sheet through the deposition groove.
[0054] The step of preparing the photosensitive resist layer (step S1) comprises:
[0055] The photosensitive resist liquid film is coated in multiple layers, and the next layer of photosensitive resist liquid film is coated after the previous layer of photosensitive resist liquid film is cured. The thickness of each layer of photosensitive resist liquid film is below 4 μm.
[0056] The preparation method of the solar cell divides the preparation of the photosensitive resist layer into multiple layers of coating of the photosensitive resist liquid film, and controls the thickness of each layer of photosensitive resist liquid film to be below 4 μm, which can improve the dispersion uniformity of the solvent inside the photosensitive resist liquid film, improve the condition that the solvent volatilizes slowly at the bottom of the film layer and volatilizes quickly at the surface of the film layer, and further improve the deposition groove morphology of the prepared photosensitive resist layer after exposure and development, so that the inverted trapezoidal deposition groove is improved.
[0057] In some examples, the number of layers of the photosensitive glue solution film is 2-5. Further, in some examples, the number of layers of the photosensitive glue solution film is 3-4.
[0058] In the above preparation method, the thickness of each layer of the photosensitive glue solution film is less than 4 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, etc. In this thickness range, the difference in solvent evaporation rate between the surface and the bottom of the photosensitive glue solution film during drying is small, effectively improving the situation that the surface of the dried film layer has a low solvent concentration and the bottom has a high solvent concentration. In some examples, the thickness of each layer of the photosensitive glue solution film is 3-4 μm. Further, the thickness of each layer of the photosensitive glue solution film is 3.5-4 μm.
[0059] Alternatively, the thickness of each layer of the photosensitive glue solution film can be the same or different. When the thickness of different photosensitive glue solution films is different, the difference in thickness between different layers of the photosensitive glue solution film is less than 0.5 μm. By controlling the difference in thickness between different layers of the photosensitive glue solution film to be less than 0.5 μm, the internal solvent dispersion uniformity of different layers of the photosensitive glue solution film is close, improving the composition uniformity of the cured photosensitive glue layer.
[0060] In some examples, the curing temperature of each layer of the photosensitive glue solution film is 90-100°C, for example, 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, or a range between any two of the above values. Alternatively, the curing temperature of each layer of the photosensitive glue solution film can be the same or different.
[0061] In some examples, the curing time of each layer of the photosensitive glue solution film is 0.5-1.5 min, for example, 0.5 min, 0.7 min, 0.9 min, 1.1 min, 1.3 min, 1.5 min, etc. Alternatively, the curing time of each layer of the photosensitive glue solution film can be the same or different.
[0062] For example, in the traditional process, the thickness of the photosensitive glue solution film coated at one time is 11-13 μm, and then cured at 105°C for 8 min. According to the above preparation method, the photosensitive glue layer can be divided into 3 layers and coated and cured in turn. Specifically, as shown in FIG. 1, the photosensitive glue solution film is coated and cured in three layers, and the thickness of each layer is 3-4 μm. The curing temperature of each layer is 90-100°C, and the curing time of each layer is 0.5-1.5 min. Figure 5As shown, a first layer of photosensitive glue solution film is first coated on the battery sheet, with a thickness of 4 μm. The first layer of photosensitive glue solution film is cured at 95°C for 2 min, to obtain a first sub-layer 11. Then, a second layer of photosensitive glue solution film is coated on the first sub-layer 11, with a thickness of 4 μm. The second layer of photosensitive glue solution film is cured at 95°C for 1.5 min, to obtain a second sub-layer 12. Then, a third layer of photosensitive glue solution film is coated on the second sub-layer 12, with a thickness of 4 μm. The third layer of photosensitive glue solution film is cured at 100°C for 5 min, to obtain a third sub-layer 13. The first sub-layer 11, the second sub-layer 12 and the third sub-layer 13 together form the photosensitive glue layer 10.
[0063] Generally, in the photosensitive glue component, the resin, photosensitive agent and additives are mixed and packaged, and the solvent is provided separately. The user sets the amount of solvent to be added according to the requirements. The wide range of solvent usage will result in significant differences in the proportion of solvent in the photosensitive glue even if the thickness of the photosensitive glue is the same. The varying proportion of solvent will inevitably result in a non-fixed ratio of solvent, photosensitive agent, resin and additives in a unit volume. The commonly used solvent PGMEA in photosensitive glue is a low light transmission material. If a single exposure energy, exposure pitch and baking parameter is used, there will be differences in the absorption and reflection of light in the entire thickness range of the photosensitive glue, resulting in differences in cross-linking reaction at different positions, and thus the morphology after development is uncontrollable.
[0064] Therefore, it is necessary to control the amount of photosensitive glue, which directly affects the viscosity of the glue solution. Therefore, it is necessary to control the viscosity range of the photosensitive glue, for example, to control the viscosity of the photosensitive glue within 2000±200 cps, so as to make the concentration ratio of each component in the photosensitive glue more consistent between batches, thereby reducing the variables of incident light in the glue film.
[0065] In some examples, before coating the next layer of photosensitive glue solution film, the battery sheet is rotated by a certain angle before coating, such as 180 degrees, to change the down position and the up position of the scraper. In this way, the uniformity of the coating thickness can be improved.
[0066] It can be understood that the deposition groove formed after the photosensitive glue layer is exposed and developed is a linear groove to form a linear grid electrode. In some examples, the ratio of the slot width to the groove bottom width of the deposition groove is 0.3-1. The "width" is the size in the direction perpendicular to the extension direction of the deposition groove. Further, in some examples, the ratio of the slot width to the groove bottom width of the deposition groove is 0.3-0.6. In some specific examples, the ratio of the slot width to the groove bottom width of the deposition groove is, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.
[0067] In some examples, before the step of preparing the photosensitive glue layer (step S1), the method for preparing the solar cell further comprises a step of preparing a seed layer on the cell piece. The seed layer comprises, for example, metal copper. The process for preparing the seed layer is, for example, a physical vapor deposition (PVD) process, specifically, evaporation, magnetron sputtering, etc.
[0068] In some examples, the process for depositing the grid lines is an electroplating process.
[0069] In some examples, the step of depositing the grid lines comprises:
[0070] A bulk metal layer is plated on the seed layer by an electroplating process. The bulk metal layer comprises, for example, metal copper.
[0071] Further, in some examples, the step of depositing the grid lines further comprises:
[0072] A protective metal layer is plated on the bulk metal layer by an electroplating process. The protective metal layer comprises, for example, metal tin.
[0073] Optionally, the 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), a back contact cell (BC cell), etc.
[0074] The following further describes the method for preparing the solar cell of the present application by taking a heterojunction cell as an example.
[0075] As shown in Figure 6 In some examples, the cell piece comprises: a single crystal silicon piece 100; a first intrinsic amorphous silicon layer 200, a first doped microcrystalline silicon layer 400, and a first transparent conductive layer 600 arranged on a first side surface of the single crystal silicon piece 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 a second side surface of the single crystal silicon piece 100.
[0076] When preparing the grid lines, a seed layer is deposited on the first transparent conductive layer 600. The process for depositing the seed layer is, for example, a physical vapor deposition (PVD) process, specifically, evaporation, magnetron sputtering, etc.
[0077] A photosensitive glue layer is prepared on the seed layer. The photosensitive glue solution film is coated in multiple layers, and the next layer of photosensitive glue solution film is coated after the previous layer of photosensitive glue solution film is cured. The thickness of each layer of photosensitive glue solution film is below 4 μm.
[0078] Exemplarily, as shown in Figure 5As shown, first, a first layer of photosensitive glue solution film is coated on the battery piece, with a thickness of 4 μm. The first layer of photosensitive glue solution film is cured at 95°C for 2 min, to obtain a first sub-layer 11. Then, a second layer of photosensitive glue solution film is coated on the first sub-layer 11, with a thickness of 4 μm. The second layer of photosensitive glue solution film is cured at 95°C for 1.5 min, to obtain a second sub-layer 12. Then, a third layer of photosensitive glue solution film is coated on the second sub-layer 12, with a thickness of 4 μm. The third layer of photosensitive glue solution film is cured at 100°C for 5 min, to obtain a third sub-layer 13. The first sub-layer 11, the second sub-layer 12 and the third sub-layer 13 form the photosensitive glue layer 10.
[0079] The photosensitive glue layer 10 is exposed and developed, to form a strip-shaped deposition groove in the photosensitive glue layer 10, with the seed layer exposed.
[0080] A main metal layer is plated on the area exposed by the seed layer through an electroplating process. The main metal layer includes, for example, metal copper. Further, a protective metal layer is plated on the main metal layer through an electroplating process. The protective metal layer includes, for example, metal tin.
[0081] The photosensitive glue layer 10 is removed using an alkaline solution such as a sodium hydroxide solution, and the seed layer in the area originally covered by the photosensitive glue layer 10 is removed using an acidic solution such as sulfuric acid, to complete the preparation of the first grid line 800.
[0082] Then, the second grid line 900 is prepared on the second transparent conductive layer 700 in the same way.
[0083] The preparation method of the above solar cell divides the preparation of the photosensitive glue layer into multiple layers of coating of photosensitive glue solution film, and controls the thickness of each layer of photosensitive glue solution film to be below 4 μm, which can improve the dispersion uniformity of the solvent inside the photosensitive glue solution film, improve the condition that the solvent volatilizes slowly at the bottom of the film layer and volatilizes quickly on the surface of the film layer, and further improve the deposition groove morphology of the prepared photosensitive glue layer after exposure and development, so that the inverted trapezoidal deposition groove is improved.
[0084] Improving the inverted trapezoidal deposition groove can obtain the following beneficial effects:
[0085] 1. The cross-sectional shape of the grid line is improved, forming a grid line with a rectangular or right trapezoidal morphology, reducing the light-shielding area of the grid line, and improving the conversion efficiency of the solar cell;
[0086] 2. The film clamping problem caused by poor grid line morphology is reduced, so that the photosensitive glue can be completely removed;
[0087] 3. Compared with the inverted trapezoidal morphology, the right trapezoidal morphology of the grid line can improve the diffuse reflection of incident light and improve the power of the module;
[0088] 4. Compared with the inverted trapezoidal shape, the binding force between the grid lines and the cell sheet is enhanced in the positive trapezoidal shape, which lays a foundation for developing fine grid lines.
[0089] Further, the present application also provides a solar cell prepared by the preparation method of any of the examples.
[0090] The following specific examples are provided to further illustrate the present application. The present application provides the following specific examples for better further understanding of the present application, and is not limited to the specific embodiments, and does not limit the protection scope of the present application.
[0091] Example 1
[0092] The present embodiment provides a preparation method of a solar cell, comprising the following steps:
[0093] Step 1, providing a cell sheet, the cell sheet comprising: a single crystal silicon sheet; a first intrinsic amorphous silicon layer, a first doped microcrystalline silicon layer and a first transparent conductive layer arranged on a first side surface of the single crystal silicon sheet; and a second intrinsic amorphous silicon layer, a second doped microcrystalline silicon layer and a second transparent conductive layer arranged on a second side surface of the single crystal silicon sheet.
[0094] Step 2, depositing a seed layer on the first transparent conductive layer by magnetron sputtering. The material of the seed layer is metal copper.
[0095] Step 3, preparing a photosensitive adhesive layer on the seed layer. First, a first layer of photosensitive adhesive liquid film is coated on the cell sheet, with a thickness of 3 μm. The first layer of photosensitive adhesive liquid film is cured at 95 ℃ for 2 min to obtain a first sublayer. Then, a second layer of photosensitive adhesive liquid film is coated on the basis of the first sublayer, with a thickness of 3 μm. The second layer of photosensitive adhesive liquid film is cured at 95 ℃ for 1.5 min to obtain a second sublayer. Then, a third layer of photosensitive adhesive liquid film is coated on the basis of the second sublayer, with a thickness of 3 μm. The third layer of photosensitive adhesive liquid film is cured at 95 ℃ for 5 min to obtain a third sublayer. The first sublayer, the second sublayer and the third sublayer above constitute the photosensitive adhesive layer.
[0096] Step 4, exposing and developing the photosensitive adhesive layer to form a strip-shaped deposition groove in the photosensitive adhesive layer, and the deposition groove exposes the seed layer.
[0097] Step 5, plating a main metal layer on the exposed area of the seed layer by electroplating process. The material of the main metal layer is metal copper. A protective metal layer is plated on the main metal layer by electroplating process. The material of the protective metal layer is metal tin.
[0098] Step 6, removing the photosensitive adhesive layer using sodium hydroxide solution, and then removing the seed layer in the area originally covered by the photosensitive adhesive layer using sulfuric acid, to complete the preparation of the first grid line.
[0099] Then, a second gate line is prepared on the second transparent conductive layer in the same way.
[0100] The SEM image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 7
[0101] Example 2
[0102] The difference between this embodiment and Example 1 is that in Step 3, a first layer of photosensitive adhesive liquid film is first coated on the battery sheet, with a thickness of 5 μm. The first layer of photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a first sublayer. Then, a second layer of photosensitive adhesive liquid film is coated on the first sublayer, with a thickness of 5 μm. The second layer of photosensitive adhesive liquid film is cured at 95°C for 1.5 min to obtain a second sublayer. Then, a third layer of photosensitive adhesive liquid film is coated on the second sublayer, with a thickness of 5 μm. The third layer of photosensitive adhesive liquid film is cured at 95°C for 5 min to obtain a third sublayer. The first sublayer, the second sublayer and the third sublayer above constitute the photosensitive adhesive layer.
[0103] The SEM image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 8
[0104] Example 3
[0105] The difference between this embodiment and Example 1 is that in Step 3, a first layer of photosensitive adhesive liquid film is first coated on the battery sheet, with a thickness of 4 μm. The first layer of photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a first sublayer. Then, a second layer of photosensitive adhesive liquid film is coated on the first sublayer, with a thickness of 4 μm. The second layer of photosensitive adhesive liquid film is cured at 95°C for 1.5 min to obtain a second sublayer. Then, a third layer of photosensitive adhesive liquid film is coated on the second sublayer, with a thickness of 4 μm. The third layer of photosensitive adhesive liquid film is cured at 95°C for 5 min to obtain a third sublayer. The first sublayer, the second sublayer and the third sublayer above constitute the photosensitive adhesive layer.
[0106] The SEM image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 9
[0107] Example 4
[0108] The difference between this embodiment and embodiment 1 is that in step 3, a first layer of the photosensitive adhesive liquid film is coated on the battery sheet, with a thickness of 4 μm. The first layer of the photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a first sublayer. Then, a second layer of the photosensitive adhesive liquid film is coated on the first sublayer, with a thickness of 4 μm. The second layer of the photosensitive adhesive liquid film is cured at 95°C for 1.5 min to obtain a second sublayer. Then, a third layer of the photosensitive adhesive liquid film is coated on the second sublayer, with a thickness of 4 μm. The first sublayer and the second sublayer constitute the photosensitive adhesive layer.
[0109] The electron microscope image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 10
[0110] Example 5
[0111] The difference between this embodiment and embodiment 1 is that in step 3, a first layer of the photosensitive adhesive liquid film is coated on the battery sheet, with a thickness of 4 μm. The first layer of the photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a first sublayer. Then, a second layer of the photosensitive adhesive liquid film is coated on the first sublayer, with a thickness of 4 μm. The second layer of the photosensitive adhesive liquid film is cured at 95°C for 1.5 min to obtain a second sublayer. Then, a third layer of the photosensitive adhesive liquid film is coated on the second sublayer, with a thickness of 4 μm. The third layer of the photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a third sublayer. Then, a fourth layer of the photosensitive adhesive liquid film is coated on the third sublayer, with a thickness of 4 μm. The fourth layer of the photosensitive adhesive liquid film is cured at 95°C for 5 min to obtain a fourth sublayer. The first sublayer, the second sublayer, the third sublayer and the fourth sublayer constitute the photosensitive adhesive layer.
[0112] The electron microscope image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 11
[0113] Comparative Example 1
[0114] The difference between this embodiment and embodiment 1 is that in step 3, a first layer of the photosensitive adhesive liquid film is coated on the battery sheet, with a thickness of 4 μm. The first layer of the photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a first sublayer. Then, a second layer of the photosensitive adhesive liquid film is coated on the first sublayer, with a thickness of 4 μm. The second layer of the photosensitive adhesive liquid film is cured at 95°C for 1.5 min to obtain a second sublayer. Then, a third layer of the photosensitive adhesive liquid film is coated on the second sublayer, with a thickness of 4 μm. The third layer of the photosensitive adhesive liquid film is cured at 95°C for 2 min to obtain a third sublayer. Then, a fourth layer of the photosensitive adhesive liquid film is coated on the third sublayer, with a thickness of 4 μm. The fourth layer of the photosensitive adhesive liquid film is cured at 95°C for 5 min to obtain a fourth sublayer. The first sublayer, the second sublayer, the third sublayer and the fourth sublayer constitute the photosensitive adhesive layer.
[0115] The electron microscope image of the deposition groove of the photosensitive adhesive layer in this embodiment is shown in Figure 1
[0116] The solar cells prepared in the above examples and comparative examples are tested for performance, and the test results are shown in Table 1.
[0117] Table 1 Test results of the solar cells prepared in the examples and comparative examples
[0118]
[0119] From table 1, Figure 1 , Figures 7-11 The results show that the present application can obtain the following beneficial effects by preparing the photosensitive adhesive layer by coating the photosensitive adhesive solution film in multiple layers, improving the inverted trapezoidal deposition groove:
[0120] 1. The shading area of the grid line is reduced, and the conversion efficiency of the solar cell is improved by about 0.03 percentage points;
[0121] 2. The film clamping problem caused by poor grid line appearance is reduced, and the film removal rate is reduced from 0.05% to 0.02%-0.04%;
[0122] 3. Compared with the inverted trapezoidal shape, the grid line with the right trapezoidal shape can improve the diffuse reflection of incident light and improve the module power by 1-3W.
[0123] The technical scheme developed by the present application can greatly improve the product quality and enhance the technical competitiveness.
[0124] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.
[0125] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.
Claims
1. A method for producing a solar cell, characterized by, The method comprises the following steps: preparing a photosensitive glue layer on a battery piece; exposing and developing the photosensitive glue layer to form a deposition groove; depositing a grid line on the battery piece through the deposition groove; wherein the step of preparing the photosensitive glue layer comprises: coating a photosensitive glue liquid film in multiple layers, and coating the next layer of the photosensitive glue liquid film after the previous layer of the photosensitive glue liquid film is solidified, and the thickness of each layer of the photosensitive glue liquid film is less than 4 microns.
2. The method for producing a solar cell according to claim 1, wherein The thickness of each layer of the photosensitive glue liquid film is 3 microns to 4 microns.
3. The method for producing a solar cell according to claim 2, wherein The thickness difference between different layers of the photosensitive glue liquid film is less than 0.5 microns.
4. The method for producing a solar cell according to any one of claims 1 to 3, wherein The number of layers of the photosensitive glue liquid film is 2 to 5.
5. The method for producing a solar cell according to any one of claims 1 to 3, wherein The viscosity of the photosensitive glue liquid film is 2000±200 cps.
6. The method for producing a solar cell according to any one of claims 1 to 3, wherein The deposition groove is a linear groove, and the ratio of the groove opening width to the groove bottom width of the deposition groove is 0.3 to 1.
7. The method for producing a solar cell according to claim 6, wherein The ratio of the groove opening width to the groove bottom width of the deposition groove is 0.3 to 0.
6.
8. The method for producing a solar cell according to any one of claims 1 to 3, 7, wherein Before coating the next layer of the photosensitive glue liquid film, the battery piece is rotated to change the down position and the up position of the doctor blade, and then the next layer of the photosensitive glue liquid film is coated.
9. The method for producing a solar cell according to any one of claims 1 to 3, 7, wherein The process of depositing the grid line is an electroplating process.
10. A solar cell, characterized by Prepared by the preparation method of any one of claims 1-9.