Solar cell grid line preparation process and solar cell

Abstract

The invention is suitable for the technical field of solar cells, and provides a solar cell grid line preparation process and a solar cell, and the solar cell grid line preparation process comprises the following steps: providing a cell substrate; preparing a seed layer on the surface of a to-be-prepared grid line of the battery substrate; electroplating the seed layer to form a whole-surface metal layer; preparing a patterned mask on the metal layer, wherein the patterned mask is provided with an opening corresponding to the non-grid line area; and removing the metal layer and the seed layer in a non-grid line area, and removing the mask in a grid line area to form a grid line. The solar cell grid line preparation process provided by the invention has lower requirements on the precision of electroplating equipment, can reduce the electroplating cost, can make the thickness of the prepared grid line more uniform, facilitates the improvement of the current collection capability of the grid line, and facilitates the mass production of solar cells.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a solar cell grid fabrication process and a solar cell. Background Technology

[0002] In solar cells, grid lines are an important structure. They are conductive lines formed on the surface of the solar cell, used to collect electrons generated after photoelectric conversion and guide them to the output terminal. In the fabrication process of solar cells, the use of copper electroplating to prepare grid lines is a crucial technique, directly affecting the performance, appearance, and manufacturing complexity of the solar cell.

[0003] In existing technologies, when solar cell grid lines are fabricated using electroplating, a mask is typically used to cover the non-grid line areas, and electroplating is then performed on the uncovered grid line areas to form patterned grid lines. However, the electroplating process for patterned grid lines requires high precision from the electroplating equipment, resulting in high electroplating costs. Furthermore, the uneven current distribution on the electroplating surface during the patterned grid line electroplating process can easily lead to uneven grid line thickness. Summary of the Invention

[0004] This invention provides a process for fabricating solar cell grid lines, aiming to solve the problems of high precision requirements for electroplating equipment and uneven grid line thickness in existing solar cell grid line fabrication processes.

[0005] This invention is implemented by providing a process for fabricating solar cell grid lines, comprising the following steps:

[0006] Provide battery substrate;

[0007] A seed layer is prepared on the surface of the battery substrate on which the grid lines are to be fabricated.

[0008] A full-surface metal layer is formed by electroplating on the seed layer;

[0009] A patterned mask is fabricated on the metal layer, the patterned mask having openings corresponding to non-gateline regions;

[0010] Remove the metal layer and seed layer from the non-gate area, and remove the mask from the gate area to form the gate line.

[0011] Preferably, the seed layer is made of an alloy, the components of which include functional components and reinforcing components, which are mixed in a certain proportion.

[0012] Preferably, the functional component is one or more of Al, Ag, Cu, and Mg, and the reinforcing component includes any one or more of Mo, Ni, Ti, W, Cr, Si, Mn, Pd, Bi, Nb, Ta, Pa, and V, wherein the content of the functional component is greater than 50%.

[0013] Preferably, the seed layer is formed by any one of the following methods: physical vapor deposition, screen printing, chemical vapor deposition, electroplating, electroless plating, and ion plating.

[0014] Preferably, the step of electroplating a full-surface metal layer on the seed layer includes:

[0015] Metal ions from the electroplating solution are deposited onto the surface of the seed layer using electroplating equipment to form a full-surface metal layer.

[0016] Preferably, the step of preparing a patterned mask on the metal layer includes:

[0017] A full-surface mask is prepared on the metal layer;

[0018] The entire mask is patterned to form the patterned mask.

[0019] Preferably, the step of preparing a patterned mask on the metal layer includes:

[0020] A patterned mask is directly fabricated on the metal layer.

[0021] Preferably, the step of preparing a full-surface mask on the metal layer includes:

[0022] The mask material is coated onto the metal layer by means of printing, spraying, rolling, scraping or dipping.

[0023] The mask material is cured to form the full-surface mask.

[0024] Preferably, the step of preparing a full-surface mask on the metal layer includes:

[0025] The pre-prepared dry film is pressed onto the metal layer to form the full-surface mask.

[0026] Preferably, the step of patterning the entire mask to form the patterned mask includes:

[0027] The photosensitive ink in the corresponding grid line area of ​​the entire mask is exposed, and the opening is formed by removing the photosensitive ink in the non-grid line area through development.

[0028] Preferably, the step of patterning the entire mask to form the patterned mask includes:

[0029] The opening is formed by etching the non-gateline areas of the entire mask using a laser.

[0030] Preferably, the step of directly fabricating a patterned mask on the metal layer includes:

[0031] The patterned mask is printed on the metal layer by a printing press; or, a pre-prepared patterned mask is pressed onto the metal layer by a laminating machine.

[0032] Preferably, the removal of the metal layer and seed layer in the non-gate line regions, and the removal of the mask in the gate line regions to form gate lines, includes:

[0033] The metal layer and seed layer in the non-gate area are etched using a first etchant, and the mask on the surface of the gate area is removed using a second etchant to form the gate line.

[0034] Preferably, after the steps of removing the metal layer and seed layer in the non-gate line regions and removing the mask in the gate line regions to form gate lines, the method further includes:

[0035] Tin plating is performed on the surface of the gate lines.

[0036] Preferably, the step of tin plating on the surface of the gate line includes:

[0037] Tin ions are deposited onto the gate line surface via an electrochemical reaction; or, tin ions are displaced onto the gate line surface via a displacement reaction.

[0038] Preferably, the step of preparing a seed layer on the surface of the battery substrate where the grid lines are to be prepared and the step of electroplating a full-surface metal layer on the seed layer further include:

[0039] Prepare a mask covering the edge portion of the surface of the battery substrate where the grid lines to be fabricated;

[0040] The step of electroplating a full-surface metal layer on the seed layer further includes:

[0041] Remove the mask from the edge portion of the surface of the battery substrate where the grid lines are to be fabricated.

[0042] The present invention also provides a solar cell, wherein the grid lines of the solar cell are prepared using the above-described solar cell grid line preparation process.

[0043] The present invention provides a solar cell grid line fabrication process by first preparing a seed layer on the surface of the cell substrate to be fabricated for the grid line, then electroplating a full-surface metal layer on the seed layer, then preparing a patterned mask on the metal layer, and then removing the metal layer and seed layer in the non-grid line areas and the mask in the grid line areas to form the grid line. Since the masking process is performed after the electroplating process, and the electroplating forms a full-surface metal layer, compared to directly electroplating patterned grid lines, the electroplating process of the solar cell grid line fabrication process of this invention has lower precision requirements for the electroplating equipment, thus reducing electroplating costs. Moreover, due to the use of full-surface electroplating, the conductive probes of the electroplating equipment can make contact with non-grid line areas for electroplating. Subsequent processes can remove the metal layer and seed layer in the contact area of ​​the non-grid line area, so the electroplating process will not leave indentations on the solar cell, thus reducing the impact on the appearance of the solar cell. Furthermore, due to the use of full-surface electroplating, the current distribution across the entire electroplated surface is more uniform, forming a metal layer of uniform thickness. Removing the metal layer and seed layer in the non-grid line areas, and removing the mask in the grid line areas to form grid lines of uniform thickness, is beneficial for improving the current collection capability of the grid lines and is more conducive to the mass production of solar cells. Attached Figure Description

[0044] Figure 1 This is a flowchart of a solar cell grid line fabrication process provided in Embodiment 1 of the present invention;

[0045] Figure 2 This is a flowchart of a solar cell grid line fabrication process provided in Embodiment 2 of the present invention; Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0047] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0048] 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 technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0049] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0051] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0052] The present invention provides a solar cell grid line fabrication process by first preparing a seed layer on the surface of the cell substrate to be fabricated for the grid line, then electroplating a full-surface metal layer on the seed layer, then preparing a patterned mask on the metal layer, and then removing the metal layer and seed layer in the non-grid line area and the mask in the grid line area to form the grid line. Since the masking process is performed after the electroplating process, and the electroplating forms a full-surface metal layer, compared to directly electroplating patterned grid lines, the electroplating process of the solar cell grid line fabrication process of this invention has lower precision requirements for electroplating equipment, thus reducing electroplating costs. Moreover, since electroplating is performed before masking, the conductive probes of the electroplating equipment can make contact with non-grid line areas for electroplating. Subsequent processes can remove the metal layer and seed layer in the contact area of ​​the non-grid line area, so the electroplating process will not leave indentations on the solar cell, thus reducing the impact on the appearance of the solar cell. Furthermore, since full-surface electroplating is used, the current distribution across the entire electroplated surface is more uniform, forming a metal layer of uniform thickness. Removing the metal layer and seed layer in the non-grid line areas, and removing the mask in the grid line areas to form grid lines of uniform thickness, is beneficial for improving the current collection capability of the grid lines and is more conducive to the mass production of solar cells.

[0053] Example 1

[0054] Please refer to Figure 1 This invention provides a process for fabricating solar cell grid lines, including the following steps:

[0055] Step S1: Provide the battery substrate;

[0056] In this embodiment of the invention, the solar cell is a double-sided contact cell, and the cell substrate is a double-sided contact cell for which the grid lines are to be fabricated, meaning that one of the positive and negative grid lines of the solar cell is located on the light-facing side of the solar cell, and the other is located on the back-facing side of the solar cell. Alternatively, the solar cell is a back-contact cell, and the cell substrate is a back-contact cell for which the grid lines are to be fabricated, meaning that both the positive and negative grid lines of the solar cell are located on the back-facing side of the solar cell. The fabrication process of the cell substrate adopts existing conventional solar cell fabrication processes, which will not be elaborated here.

[0057] Furthermore, in the case of a double-sided contact solar cell, grid lines need to be fabricated on both sides of the cell substrate, and the grid lines are fabricated using the solar cell grid line fabrication process of the present invention. Alternatively, only one side can be fabricated using the solar cell grid line fabrication process of the present application, while the other side can be fabricated using other methods.

[0058] Furthermore, in the case of a back-contact solar cell, grid lines need to be fabricated on the back side of the cell substrate. The grid lines are fabricated using the solar cell grid line fabrication process described in this application.

[0059] In this embodiment of the invention, the battery substrate has film openings in the area where the grid lines are to be set, so that the prepared seed layer can form a conductive contact with the battery substrate through the openings. For example, the solar cell is a back-contact cell, and the film openings on the back side of the back-contact cell penetrate the back passivation layer of the back-contact cell, allowing the seed layer to contact the battery substrate through the film openings.

[0060] Step S2: Prepare a seed layer on the surface of the battery substrate where the grid lines are to be fabricated;

[0061] The surface of the battery substrate to be fabricated for the grid lines includes the grid line region to be fabricated and the non-grid line region where no grid lines need to be fabricated.

[0062] As an embodiment of the present invention, the seed layer is made of an alloy, the components of which include functional components and reinforcing components. The functional components and reinforcing components are mixed in a certain proportion. The functional components can enhance the back reflection effect, and the reinforcing components improve the adhesion between the metal layer and the silicon substrate of the battery substrate.

[0063] As an embodiment of the present invention, the functional component is one or more of Al, Ag, Cu, and Mg, and the reinforcing component includes any one or more of Mo, Ni, Ti, W, Cr, Si, Mn, Pd, Bi, Nb, Ta, Pa, and V. The content of the functional component is greater than 50%, which is beneficial to enhancing the bonding strength between the metal layer and the silicon substrate of the battery substrate.

[0064] As an embodiment of the present invention, the seed layer is formed by any one of the following methods: physical vapor deposition, screen printing, chemical vapor deposition, electroplating, electroless plating, and ion plating.

[0065] Step S3: Electroplating is performed on the seed layer to form a full-surface metal layer;

[0066] In this embodiment of the invention, a solar cell grid line fabrication process is provided. First, a seed layer is prepared on the surface of the cell substrate on which the grid lines are to be fabricated. Then, a full-surface metal layer is formed by electroplating on the seed layer. Next, a patterned mask is prepared on the metal layer. Finally, the metal layer and seed layer in the non-grid line areas, as well as the mask in the grid line areas, are removed to form the grid lines. Because the masking process is performed after the electroplating process, and the electroplating forms a full-surface metal layer, compared to directly electroplating patterned grid lines, the solar cell grid line fabrication process of this invention has lower precision requirements for the electroplating equipment, thus reducing electroplating costs. Moreover, because a full-surface metal layer is used... In the surface electroplating method, the conductive probes of the electroplating equipment can make contact with non-grid areas for electroplating. Subsequently, the metal layer and seed layer of the contact area in the non-grid area can be removed. Therefore, the electroplating process will not leave indentations on the solar cell, thus not affecting the appearance of the solar cell. Moreover, since the entire surface is electroplated, the current distribution of the entire electroplated surface is more uniform, which can form a metal layer of uniform thickness. After removing the metal layer and seed layer in the non-grid area and removing the mask in the grid area to form grid lines of uniform thickness, it is beneficial to improve the current collection capacity of the grid lines and is more conducive to the mass production of solar cells.

[0067] As an embodiment of the present invention, step S3 includes:

[0068] Metal ions from the electroplating solution are deposited onto the surface of the seed layer using electroplating equipment to form a full-surface metal layer.

[0069] The metal layer completely covers the surface of the seed layer, forming a full-surface metal layer. The electroplating equipment can be a horizontal electroplating machine, a vertical electroplating machine, or a tank electroplating machine. The electroplating thickness and time of the metal layer can be set as needed. Preferably, the metal layer is a copper layer. The electroplating solution can be a copper sulfate solution, and the metal ions are copper ions. Of course, copper plating additives, stannous sulfate, and tin plating additives can also be added to the electroplating solution.

[0070] Step S4: A patterned mask is prepared on the metal layer, the patterned mask having openings corresponding to the non-gateline regions;

[0071] In this embodiment of the invention, a full-area mask can be prepared on the metal layer first, and then the full-area mask can be patterned to form a patterned mask with openings; alternatively, a patterned mask with openings can be prepared directly on the metal layer.

[0072] As an embodiment of the present invention, step S4 includes:

[0073] Fabricate a full-surface mask on a metal layer;

[0074] The entire mask is patterned to form a patterned mask.

[0075] In this embodiment, a full-area mask is first prepared on the metal layer, and then the full-area mask is patterned to form a patterned mask, which can improve the processing accuracy of the patterned mask.

[0076] As an embodiment of the present invention, step S4, the step of preparing a full-surface mask on the metal layer includes:

[0077] The mask material is coated onto the metal layer by means of printing, spraying, rolling, scraping or dipping.

[0078] The mask material is cured to form a full-surface mask.

[0079] In this embodiment, the preparation of a full-surface mask on the metal layer can be achieved by coating the mask material onto the metal layer using methods such as printing, spraying, roller coating, scraping, or immersion. This facilitates the preparation of a full-surface mask with uniform thickness and is easy to process. Specifically, the mask material can be printed onto the metal layer using a printing machine, or sprayed onto the metal layer using a spraying device; it can be roller-coated onto the metal layer using a roller coating device; it can be scraped onto the metal layer using a scraping device; or it can be immersed in an immersion device to coat the mask material onto the metal layer.

[0080] As an embodiment of the present invention, coating the mask material onto the metal layer by immersion includes:

[0081] Immerse the battery substrate in the working tank;

[0082] Inside the working tank, the mask material is attached to the entire surface of the metal layer.

[0083] The working tank can accommodate the battery substrate and the mask material, facilitating the attachment of the mask material to the battery substrate within the tank and reducing the risk of the mask material overflowing from the tank during attachment. The mask material can be a photosensitive ink, or it can comprise a solution in which the solute includes at least one of resin and kaolin, and the solvent includes at least one of acetone and PMA. In other words, the solute in the solution includes one or more of resin and kaolin, and the solvent includes one or more of acetone and PMA. Of course, the mask material can also be other materials.

[0084] Specifically, the working trough may include the groove of a trough machine, the groove of a chain machine, or the groove of other equipment. No specific form of the working trough is limited here.

[0085] Among them, the mask material has high fluidity, so it is not necessary to use a lamination process or screen printing process to attach the mask material to the working surface on the worktable. The mask material can be attached to the entire surface of the metal layer in the working tank.

[0086] As an embodiment of the present invention, before immersing the battery substrate in the working tank, the method further includes:

[0087] The battery substrate is transported to the working tank using a transfer mechanism.

[0088] In this embodiment, a transmission mechanism can be used to transport the battery substrate without human intervention, which helps to improve manufacturing efficiency and reduce the risk of fragmentation.

[0089] As an embodiment of the present invention, coating a masking material onto a metal layer by spraying includes:

[0090] A masking material is sprayed onto the metal layer of the battery substrate inside the working tank.

[0091] In this embodiment, spraying the mask material onto the metal layer improves manufacturing efficiency. Furthermore, the working tank can accommodate mask material not attached to the battery substrate, facilitating reuse and reducing costs.

[0092] Specifically, the spraying pressure is 0.1 kg to 5 kg. For example, 0.1 kg, 0.2 kg, 0.8 kg, 1 kg, 1.5 kg, 2 kg, 2.5 kg, 4 kg, 4.8 kg, and 5 kg. This ensures that the spraying pressure is within a suitable range, avoiding both insufficient pressure (which would prevent spraying) and excessive pressure (which would cause debris).

[0093] In some embodiments, a masking material is coated onto the metal layer of the battery substrate within the working tank. Specifically, the coating includes spin coating, rod coating, etc. This provides more ways to attach the masking material, which is beneficial for adapting to more practical production scenarios.

[0094] As an embodiment of the present invention, curing to form a full-surface mask includes:

[0095] Using a transport mechanism, the battery substrate with the mask material attached is transported from the working tank to the curing tank;

[0096] In this way, the battery substrate can be transported using a transmission mechanism without human intervention, which helps to improve production efficiency and reduce the risk of breakage.

[0097] Specifically, a robotic arm can be used to place the battery substrate into the transfer mechanism, or a conveyor belt can be used to transport the battery to the transfer mechanism.

[0098] As an embodiment of the present invention, curing the mask material to form the full-surface mask includes:

[0099] The masking material attached to the working surface is dried to evaporate the solvent in the masking material.

[0100] In this way, by drying and evaporating the solvent in the masking material, the masking material becomes a solid coating and is fixed on the working surface of the battery substrate.

[0101] It is understood that in other embodiments, the solvent in the masking material can also be evaporated by allowing it to stand. The standing time should be greater than or equal to 5 minutes. This avoids incomplete solvent evaporation caused by a standing time that is too short.

[0102] In some embodiments, the drying temperature is 50°C-100°C, and the drying time is greater than or equal to 10 seconds.

[0103] This ensures that the drying temperature is within a suitable range, avoiding both excessively low temperatures that lead to slow curing and incomplete solvent evaporation, and excessively high temperatures that result in wasted energy. Furthermore, maintaining a suitable drying time prevents incomplete solvent evaporation caused by a drying time that is too short.

[0104] Specifically, the drying temperature is, for example, 50°C, 52°C, 60°C, 80°C, 90°C, 98°C, or 100°C.

[0105] Specifically, the drying time is, for example, 10s, 12s, 15s, 20s, or 25s.

[0106] In some embodiments, the coating thickness is 0.1 μm-5 μm. For example, it is 0.1 μm, 0.2 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 4.8 μm, or 5 μm.

[0107] This ensures that the coating thickness is within a suitable range, avoiding the situation where a thin coating would prevent etching masking and thus affect the linewidth, and also avoiding the situation where a thick coating would waste materials and affect the contact between the gate line and the electroplated cathode.

[0108] Preferably, the coating thickness is 2μm-2.5μm. For example, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, and 2.5μm. This further optimizes the coating thickness, balancing masking effect and material conservation, resulting in a better overall effect.

[0109] As an embodiment of the present invention, coating a mask material onto a metal layer by roller coating includes:

[0110] A roller is used to evenly coat the surface of the metal layer with mask material. The mask thickness can be adjusted by the slurry viscosity and roller pressure. The mask uniformity can be achieved within ±1.5µm. Single-sided or double-sided roller coating can be performed simultaneously according to actual requirements, which can reduce debris, increase yield, and improve production capacity.

[0111] As an embodiment of the present invention, coating the mask material onto the metal layer by a scraping method includes:

[0112] Use a scraper to evenly coat the metal layer surface with masking material.

[0113] As another embodiment of the present invention, the preparation of a full-surface mask on a metal layer further includes:

[0114] The pre-prepared dry film is pressed onto the metal layer to form a full-surface mask.

[0115] In this embodiment, a pre-prepared dry film can be pressed onto a metal layer using a laminating machine to form a full-surface mask. This preparation method is simple and helps to reduce production costs.

[0116] As an embodiment of the present invention, the step of patterning the entire mask to form a patterned mask includes:

[0117] The photosensitive ink in the corresponding grid line area of ​​the entire mask is exposed, and the photosensitive ink in the non-grid line area is removed by development to form an opening.

[0118] In this embodiment, the photosensitive ink in the corresponding grid line areas of the entire mask undergoes a cross-linking reaction during exposure. The unreacted photosensitive ink in the grid line areas can subsequently be washed away with a chemical solution to form openings, thereby forming a patterned mask with openings. This exposes the metal layer in the non-grid line areas, allowing for the removal of the metal layer and seed layer in the non-grid line areas, while retaining the metal layer in the grid line areas to form the grid lines. The exposure process can involve covering the grid line areas of the entire mask with a mask plate, irradiating the grid line areas of the entire mask with an ultraviolet lamp, or irradiating the grid line areas of the entire mask with a laser.

[0119] In another embodiment of the present invention, the step of patterning the entire mask to form a patterned mask further includes:

[0120] A laser is used to etch openings into the non-gateline areas of the entire mask.

[0121] In this embodiment, a full-area mask is first prepared on a metal layer, and then laser etching is used to etch the corresponding non-gateline areas of the full-area mask to form a patterned mask with openings. This method offers better precision and a simpler etching process. Alternatively, an etching solution can be used to etch the corresponding non-gateline areas of the full-area mask to form openings.

[0122] In another embodiment of the present invention, step S4 includes:

[0123] Patterned masks are fabricated directly on metal layers.

[0124] In this embodiment, the patterned mask is prepared in one step, which simplifies the process and reduces the number of production steps.

[0125] In this embodiment, the step of directly fabricating a patterned mask on a metal layer includes:

[0126] Patterned masks are printed onto a metal layer using a printing press or pre-prepared patterned masks are laminated onto a metal layer using a laminating machine.

[0127] In this embodiment, a patterned mask with openings can be directly printed onto the metal layer using a printing press, which offers fast preparation speed and high precision in patterning. Alternatively, a pre-patterned mask with openings can be pressed onto the metal layer using a laminating machine. This preparation method is simple and helps reduce production costs.

[0128] Step S5: Remove the metal layer and seed layer from the non-gate area, and remove the mask from the gate area to form the gate line.

[0129] In this embodiment, the metal layer and seed layer in the non-gate area are etched using a first etching solution, and the mask on the surface of the gate area is removed using a second etching solution, thereby forming the gate line.

[0130] In one embodiment of the present invention, the first etching solution is an acid solution and the second etching solution is an alkaline solution.

[0131] Specifically, the alkaline solution includes at least one of KOH and NaOH. In other words, the alkaline solution includes one or all of KOH and NaOH. The acidic solution includes sulfuric acid and hydrogen peroxide, and may also include sulfuric acid and sodium persulfate.

[0132] In this way, the metal layer and seed layer in the non-gate area, as well as the mask on the surface of the gate area, can be removed simply and efficiently, which helps to improve manufacturing efficiency.

[0133] Example 2

[0134] Please refer to Figure 2 Based on Example 1, the solar cell grid line fabrication process in this example further includes:

[0135] Step S6: Tin plating is performed on the surface of the gate line.

[0136] In this embodiment, tin plating on the surface of the gate lines effectively protects them, prevents rusting, and enhances their solderability. Preferably, a chemical tin plating process is used to prepare a tin layer with a thickness of 2–3 μm.

[0137] As an embodiment of the present invention, tin plating on the gate line surface includes:

[0138] Tin ions are deposited onto the gate line surface via an electrochemical reaction; or, tin ions are displaced onto the gate line surface via a displacement reaction.

[0139] In this embodiment, the tin plating process can form a tin layer on the gate line surface using an electrochemical reaction or a displacement reaction. Specifically, the metal ions Sn in the mixed solution of stannous sulfate and additives are deposited onto the gate line surface through an electrochemical reaction, or the metal ions Sn in the mixed solution of stannous sulfate and additives are replaced onto the gate line surface through a displacement reaction.

[0140] Example 3

[0141] Based on either of the embodiments in Example 1 and Example 2, between step S2 and step S3, the following further step is taken: preparing a mask covering the edge portion of the surface of the battery substrate to be fabricated for the grid lines;

[0142] Step S3 is followed by removing the mask from the edge portion of the surface of the battery substrate where the grid lines are to be fabricated.

[0143] Specifically, an etching solution can be used to etch away the mask covering the surface edge of the gate line to be fabricated. This mask covering the surface edge of the gate line can react with an alkaline solution, specifically an alkaline solution.

[0144] The step of removing the mask from the edge portion of the surface of the battery substrate where the gate lines to be fabricated is to be formed can be located between steps S3 and S4, between steps S4 and S5, or after step S5. Preferably, the step of removing the mask from the edge portion of the surface of the battery substrate where the gate lines to be fabricated is to be formed is located between steps S3 and S4.

[0145] Example 4

[0146] This invention also provides a solar cell, wherein the grid lines of the solar cell are fabricated using the solar cell grid line fabrication process described in any of the above embodiments. The solar cell of this embodiment can reduce the precision requirements of the electroplating equipment, thus reducing electroplating costs, without affecting the appearance of the solar cell; moreover, it is beneficial to improve the current collection capability of the grid lines and is more conducive to the mass production of solar cells.

[0147] This invention provides a solar cell grid line fabrication process that involves first preparing a seed layer on the surface of the solar cell substrate where the grid lines are to be fabricated, then electroplating a full-surface metal layer on the seed layer, followed by fabricating a patterned mask on the metal layer, and finally removing the metal layer and seed layer in the non-grid line areas, as well as the mask in the grid line areas, to form the grid lines. Since the masking process is performed after the electroplating process, and the electroplating forms a full-surface metal layer, the precision requirements for the electroplating equipment are lower compared to electroplating patterned grid lines, thus reducing electroplating costs. Furthermore, because it employs an electroplating-then-masking approach, and a full-surface electroplating method, the electroplating... The conductive probes of the plating equipment can make contact with non-grid areas for electroplating. Subsequently, the metal layer and seed layer of the contact area in the non-grid area can be removed. Therefore, the electroplating process will not leave indentations on the solar cell, thus reducing the impact on the appearance of the solar cell. Moreover, since the whole-surface electroplating is used, the current distribution of the entire electroplated surface is more uniform, which can form a metal layer of uniform thickness. Then, the metal layer and seed layer in the non-grid area are removed, and the mask in the grid area is removed to form grid lines of uniform thickness, which is conducive to improving the current collection capacity of the grid lines and is more conducive to the mass production of solar cells.

[0148] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for fabricating solar cell grid lines, characterized in that, Includes the following steps: Provide battery substrate; A seed layer is prepared on the surface of the battery substrate on which the grid lines are to be fabricated. A full-surface metal layer is formed by electroplating on the seed layer; A patterned mask is fabricated on the metal layer, the patterned mask having openings corresponding to non-gateline regions; Remove the metal layer and seed layer from the non-gate area, and remove the mask from the gate area to form the gate line.

2. The solar cell grid line fabrication process according to claim 1, characterized in that, The seed layer is made of an alloy, the components of which include functional components and reinforcing components, which are mixed in a certain proportion.

3. The solar cell grid line fabrication process according to claim 2, characterized in that, The functional component is one or more of Al, Ag, Cu, and Mg, and the reinforcing component includes any one or more of Mo, Ni, Ti, W, Cr, Si, Mn, Pd, Bi, Nb, Ta, Pa, and V, wherein the content of the functional component is greater than 50%.

4. The solar cell grid line fabrication process according to claim 1, characterized in that, The seed layer is formed by any one of the following methods: physical vapor deposition, screen printing, chemical vapor deposition, electroplating, electroless plating, and ion plating.

5. The solar cell grid line fabrication process according to claim 1, characterized in that, The step of electroplating a full-surface metal layer on the seed layer includes: Metal ions from the electroplating solution are deposited onto the surface of the seed layer using electroplating equipment to form a full-surface metal layer.

6. The solar cell grid line fabrication process according to claim 1, characterized in that, The step of preparing a patterned mask on the metal layer includes: A full-surface mask is prepared on the metal layer; The entire mask is patterned to form the patterned mask.

7. The solar cell grid line fabrication process according to claim 1, characterized in that, The step of preparing a patterned mask on the metal layer includes: A patterned mask is directly fabricated on the metal layer.

8. The solar cell grid line fabrication process according to claim 6, characterized in that, The step of preparing a full-surface mask on the metal layer includes: The mask material is coated onto the metal layer by means of printing, spraying, rolling, scraping or dipping. The mask material is cured to form the full-surface mask.

9. The solar cell grid line fabrication process according to claim 6, characterized in that, The step of preparing a full-surface mask on the metal layer includes: The pre-prepared dry film is pressed onto the metal layer to form the full-surface mask.

10. The solar cell grid line fabrication process according to claim 6, characterized in that, The step of patterning the entire mask to form the patterned mask includes: The photosensitive ink in the corresponding grid line area of ​​the entire mask is exposed, and the opening is formed by removing the photosensitive ink in the non-grid line area through development.

11. The solar cell grid line fabrication process according to claim 6, characterized in that, The step of patterning the entire mask to form the patterned mask includes: The opening is formed by etching the non-gateline areas of the entire mask using a laser.

12. The solar cell grid line fabrication process according to claim 7, characterized in that, The step of directly fabricating a patterned mask on the metal layer includes: The patterned mask is printed on the metal layer by a printing press; or, a pre-prepared patterned mask is pressed onto the metal layer by a laminating machine.

13. The solar cell grid line fabrication process according to claim 1, characterized in that, The process of removing the metal layer and seed layer in the non-gate line regions and removing the mask in the gate line regions to form gate lines includes: The metal layer and seed layer in the non-gate area are etched using a first etchant, and the mask on the surface of the gate area is removed using a second etchant to form the gate line.

14. The solar cell grid line fabrication process according to claim 1, characterized in that, After the steps of removing the metal layer and seed layer in the non-gate line regions and removing the mask in the gate line regions to form gate lines, the method further includes: Tin plating is performed on the surface of the gate lines.

15. The solar cell grid line fabrication process according to claim 14, characterized in that, The step of tin plating on the surface of the gate line includes: Tin ions are deposited onto the gate line surface via an electrochemical reaction; or, tin ions are displaced onto the gate line surface via a displacement reaction.

16. The solar cell grid line fabrication process according to claim 1, characterized in that, Between the step of preparing a seed layer on the surface of the battery substrate where the grid lines are to be fabricated and the step of electroplating a full-surface metal layer on the seed layer, the following is also included: Prepare a mask covering the edge portion of the surface of the battery substrate where the grid lines to be fabricated; The step of electroplating a full-surface metal layer on the seed layer further includes: Remove the mask from the edge portion of the surface of the battery substrate where the grid lines are to be fabricated.

17. A solar cell, characterized in that, The grid lines of the solar cell are fabricated using the solar cell grid line fabrication process as described in any one of claims 1 to 16.

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