Electrode transfer printing method of photovoltaic cell and photovoltaic cell
The gate lines with a multi-layer electrode structure are formed on the photovoltaic cell substrate by thermal transfer method, which solves the problem that the gate lines in the prior art do not meet expectations, and improves the conductivity, plasticity and contact resistance of the gate lines.
Patent Information
- Application Number
- CN202410141803.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-01
- Publication Date
- 2025-08-05
AI Technical Summary
In the existing photovoltaic cell manufacturing process, the line type of the gate line does not meet expectations, laser transfer has problems with poor alignment accuracy and matching slurry parameters. A single electrode slurry cannot meet the requirements of conductivity, plasticity and contact resistance at the same time, and the multi-layer electrode structure preparation efficiency is low and the binding force is poor.
By adopting the thermal transfer method, multiple layers of different electrode slurries are filled in the groove of the transfer substrate. By adjusting the preset distance between the transfer substrate and the photovoltaic cell substrate, transfer of the electrode slurry layer is realized, forming a gate line of the multi-layer electrode structure.
The conductivity, plasticity and contact resistance performance of the gate line are improved, and the gate line type is flexibly adjusted, which improves the overall performance of the gate line.
Smart Images
Figure CN120435110A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of photovoltaic technology, and in particular to a photovoltaic cell electrode transfer method and a photovoltaic cell. Background Art
[0002] With the development of new energy technologies, photovoltaic cells have emerged. Photovoltaic cells are semiconductor devices that convert sunlight directly into electricity. They are environmentally friendly and do not cause environmental pollution. Furthermore, sunlight is a renewable resource. Therefore, photovoltaic cells are a new type of battery with broad development prospects.
[0003] In traditional technology, during the production and manufacturing process of photovoltaic cells, it is necessary to use methods such as screen printing or laser transfer to print slurry on the front and back of the cell substrate to form the main grid lines and secondary grid lines on the front and back of the cell substrate to achieve metallization of the photovoltaic cell.
[0004] However, the photovoltaic cells obtained by using the current photovoltaic cell manufacturing process have the problem that the line shape of the grid lines does not meet expectations. Summary of the Invention
[0005] Based on this, it is necessary to provide a photovoltaic cell electrode transfer method and a photovoltaic cell that can improve the line shape of the grid line of the photovoltaic cell in order to solve the above technical problems.
[0006] In a first aspect, the present invention provides a method for transferring electrodes of a photovoltaic cell, the method comprising:
[0007] Obtaining a photovoltaic cell substrate, wherein a contact electrode layer is printed on a first side surface of the photovoltaic cell substrate in a thickness direction;
[0008] Obtaining a transfer substrate, wherein a groove is formed on a first side surface of the transfer substrate;
[0009] Filling the groove on the first side of the transfer substrate with electrode slurry to form an electrode slurry layer;
[0010] The first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate are arranged relative to each other at a preset distance, and the second side surface of the transfer substrate is heated so that the electrode slurry layer filled in the groove is transferred to the contact electrode layer, wherein, when the first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate are arranged relative to each other, the orthographic projection of the contact electrode layer on the photovoltaic cell substrate covers the orthographic projection of the groove on the photovoltaic cell substrate.
[0011] In one embodiment, filling the groove on the first side of the transfer substrate with electrode slurry to form the electrode slurry layer includes: sequentially filling multiple layers of different electrode slurries in the groove to form the electrode slurry layer.
[0012] In one embodiment, the step of sequentially filling multiple layers of different electrode slurries in the groove to form the electrode slurry layer comprises:
[0013] Applying a first electrode paste in the groove to form a first sub-electrode paste layer, wherein the material of the first electrode paste includes at least one of silver, aluminum, tin and lead;
[0014] coating a second electrode paste on the first electrode paste layer in the groove to form a second sub-electrode paste layer, wherein the material of the second electrode paste includes at least one of silver, copper and aluminum;
[0015] A third electrode paste is coated on the second electrode paste layer in the groove to form a third sub-electrode paste layer, wherein the material of the third electrode paste includes at least one of silver and copper.
[0016] In one embodiment, the transfer substrate is a hard substrate.
[0017] In one embodiment, the preset distance is 0.
[0018] In one embodiment, the second side surface of the transfer substrate is opposite to the first side surface of the transfer substrate, and heating the second side surface of the transfer substrate includes:
[0019] A heating roller is used to roll at a uniform speed on the second side surface of the transfer substrate to heat the second side surface of the transfer substrate.
[0020] In one embodiment, after the electrode slurry layer filled in the groove is transferred onto the contact electrode layer, the method further includes: cleaning the groove; and drying the cleaned groove.
[0021] In one embodiment, the cross section of the groove is an inverted trapezoid, and the size of the groove gradually decreases from the first side surface close to the transfer substrate to the first side surface away from the transfer substrate.
[0022] In a second aspect, the present application provides a photovoltaic cell, comprising:
[0023] photovoltaic cell substrates;
[0024] A contact electrode layer is provided on the photovoltaic cell substrate;
[0025] The electrode slurry layer is arranged on a side of the contact electrode layer away from the photovoltaic cell substrate, wherein the electrode slurry layer is formed by the aforementioned photovoltaic cell electrode transfer method.
[0026] In one embodiment, the electrode slurry layer comprises:
[0027] a third sub-electrode slurry layer, disposed on a side of the contact electrode layer away from the photovoltaic cell substrate, wherein the material of the third sub-electrode slurry layer includes at least one of silver and copper;
[0028] a second sub-electrode slurry layer, disposed on a side of the third sub-electrode slurry layer away from the photovoltaic cell substrate, wherein the material of the second sub-electrode slurry layer includes at least one of silver, copper and aluminum;
[0029] The first sub-electrode slurry layer is arranged on a side of the second sub-electrode slurry layer away from the photovoltaic cell substrate, wherein the material of the first sub-electrode slurry layer includes at least one of silver, aluminum, tin and lead.
[0030] The aforementioned photovoltaic cell electrode transfer method and photovoltaic cell first obtain a photovoltaic cell substrate, with a contact electrode layer printed on a first side surface along the thickness direction of the photovoltaic cell substrate. The contact electrode layer serves as the first layer structure of the photovoltaic cell grid lines. A transfer substrate is then obtained, with a groove formed on the first side surface of the transfer substrate. The grooves on the first side surface of the transfer substrate are then filled with electrode slurry to form an electrode slurry layer. Then the first side of the transfer substrate and the first side of the photovoltaic cell substrate are arranged relative to each other at a preset distance, and the second side of the transfer substrate is heated so that the electrode slurry layer filled in the groove is transferred to the contact electrode layer, thereby forming the grid line structure of the photovoltaic cell through the electrode slurry layer and the contact electrode layer. Since thermal transfer is adopted, the preset distance between the first side of the transfer substrate and the first side of the photovoltaic cell substrate can be adjusted during the transfer process. Compared with laser transfer, the distance adjustment is more free, so the preset distance can be flexibly adjusted according to the required grid line line shape to improve the grid line shape. In addition, the multi-layer electrode structure composed of the electrode slurry layer and the contact electrode layer can give the obtained grid line a variety of different characteristics, improve the performance of the grid line, and enable the prepared grid line electrode to have advantages such as good plasticity, good conductivity and low contact resistance. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0032] Figure 1 1 is a schematic flow chart of a method for transferring electrodes of a photovoltaic cell according to an embodiment;
[0033] Figure 2 A schematic structural diagram of a photovoltaic cell substrate in one embodiment;
[0034] Figure 3 A schematic structural diagram of a transfer substrate in one embodiment;
[0035] Figure 4 A schematic diagram of a slurry coating process according to one embodiment;
[0036] Figure 5 FIG2 is a second schematic diagram of a slurry coating process according to an embodiment;
[0037] Figure 6 The third schematic diagram of the process of coating slurry in one embodiment;
[0038] Figure 7 FIG4 is a fourth schematic diagram of a slurry coating process according to an embodiment;
[0039] Figure 8 Schematic diagram of a process for filling electrode slurry in one embodiment;
[0040] Figure 9 is a schematic diagram of heating a transfer substrate in one embodiment;
[0041] Figure 10 A schematic diagram of a transfer substrate after heating in one embodiment;
[0042] Figure 11 Schematic diagram of a transfer process in one embodiment;
[0043] Figure 12 Schematic diagram of the structure of a photovoltaic cell in one embodiment.
[0044] Description of reference numerals:
[0045] 10 - photovoltaic cell substrate, 20 - contact electrode layer, 30 - transfer substrate, 40 - electrode slurry layer, 50 - scraper, 100 - first sub-electrode slurry layer, 200 - second sub-electrode slurry layer, 300 - third sub-electrode slurry layer, 60 - heating roller, 70 - heating fan. DETAILED DESCRIPTION
[0046] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.
[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.
[0048] It will be understood that the terms "first," "second," etc. used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element.
[0049] Spatially relative terms such as "under," "beneath," "beneath," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the drawings is turned over, the element or feature described as "under" or "beneath" or "beneath" the other elements will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" can include both upper and lower orientations. In addition, the device can also include alternative orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.
[0050] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.
[0051] As described in the background art, the photovoltaic cells obtained by the manufacturing process of photovoltaic cells in the prior art have the problem that the line shape of the grid lines does not meet expectations. The inventors have found that the reason for this problem is that in the prior art, screen printing or laser transfer is usually used to print slurry on the front and back of the battery substrate to form the main grid lines and auxiliary grid lines located on the front and back of the battery substrate to achieve the metallization of the photovoltaic cell. However, since laser transfer requires precise control of the matching relationship between the slurry parameters and the laser power, the technical barriers are relatively high. If the laser power is too low, the pressure generated between the slurry and the transparent carrier is less than the adhesion force, and the slurry cannot be separated from the carrier; if the laser power is too high, the slurry will splash, causing the line width to widen or deform. Only when the laser power is such that the pressure generated between the slurry and the transparent carrier can just overcome the adhesion force, can the grid lines have the best morphology. Therefore, laser transfer is a non-contact transfer, and during laser transfer, the distance between the transfer substrate and the battery substrate needs to meet certain stringent requirements and cannot be freely adjusted, so there are problems such as poor alignment accuracy and poor grid line shape, such as grid line bending. In addition, in the prior art, there is only one electrode slurry used for laser transfer, and it is directly printed on the silicon wafer of the battery substrate. In this way, there is only one electrode slurry transferred on the silicon wafer, and the performance of the grid line is better. The grid line needs to have good electrical conductivity, good grid line plasticity, good contact silicon wafer ability, low silicon wafer contact resistance and other properties. And a single slurry cannot meet the above requirements at the same time. In addition, a multi-layer electrode structure can also be adopted in the prior art, but for the multi-layer electrode structure, it needs to be prepared layer by layer during the preparation process, which not only has low preparation efficiency but also poor bonding strength.
[0052] Based on the above reasons, the present invention provides an electrode transfer method for a photovoltaic cell, which can first form an electrode slurry layer on a transfer substrate, and then use thermal transfer to transfer the electrode slurry layer to a contact electrode layer to produce a gate line. A multi-layer electrode structure is adopted, and the electrode slurry can be designed as needed so that the gate line meets the advantages of good conductivity, good gate line plasticity, good silicon wafer contact capability, low silicon wafer contact resistance, etc., and the preset distance between the first side of the transfer substrate and the first side of the photovoltaic cell substrate is adjustable. Compared with laser transfer, the distance adjustment is more free, so the preset distance can be flexibly adjusted according to the required gate line line shape to improve the obtained gate line line shape.
[0053] In one embodiment, Figure 1 As shown, a method for transferring electrodes of a photovoltaic cell is provided, the method comprising steps S100-S130.
[0054] Step S100: obtaining a photovoltaic cell substrate.
[0055] Wherein, a contact electrode layer is printed on the first side surface of the photovoltaic cell substrate along the thickness direction.
[0056] Among them, the photovoltaic cell substrate can be a heterojunction (Heterojunction with intrinsic Thinlayer, abbreviated as HJT) solar cell substrate. The heterojunction solar cell structure is usually centered on a silicon substrate, and a layer of intrinsic amorphous silicon thin film is deposited between the doped amorphous silicon and the silicon substrate on both sides of the silicon substrate. After taking this process measure, the performance of the PN junction is improved, and the conversion efficiency of the heterojunction solar cell is improved.
[0057] Specifically, the heterojunction may include: a silicon substrate; a first doped amorphous silicon layer; and a first intrinsic amorphous silicon layer disposed between the first doped amorphous silicon layer and the front surface of the silicon substrate, with the silicon substrate and the first doped amorphous silicon layer having the same doping type; a second doped amorphous silicon layer; and a second intrinsic amorphous silicon layer disposed between the back surface of the silicon substrate and the second doped amorphous silicon layer, with the silicon substrate and the second doped amorphous silicon layer having opposite doping types. In a heterojunction structure, a PN junction is formed by two different semiconductor materials. The silicon substrate is made of n-type doped single-crystal silicon (c-Si). A first intrinsic amorphous silicon (ia-Si) layer and an N-type first doped amorphous silicon (na-Si) layer are sequentially formed on the front surface of the silicon substrate. On the back surface of the silicon substrate, a second intrinsic amorphous silicon layer and a P-type second doped amorphous silicon (pa-Si) layer are sequentially formed to form a back surface field, thereby forming a PN junction for current transmission. The first and second intrinsic amorphous silicon layers are used to passivate surface defects, thereby generating a higher operating voltage. Furthermore, the amorphous silicon on the front of the silicon substrate can be hydrogenated. The a-Si:H light incident window has higher transparency, a larger band gap, and a higher open-circuit voltage. Furthermore, hydrogen atoms can passivate the silicon substrate, resulting in higher conversion efficiency. The gate lines of the heterojunction solar cell can be embedded on one side of the heterojunction along the thickness direction, serving as a metal electrode.
[0058] The contact electrode layer must be made of a conductive material with low contact resistance with the cell, and can be at least one of silver and copper. The thickness of the contact electrode layer can range from 1μm to 50μm, and can be selected based on actual conditions. The contact electrode layer can be designed to have a relatively low thickness, thereby ensuring a stable bond between the contact electrode layer and the photovoltaic cell substrate and low contact resistance. A relatively high thickness of the contact electrode layer not only wastes slurry and results in an excessively thick overall electrode layer, but can also affect current transmission.
[0059] Exemplarily, a layer of anti-reflection film is also coated on the first side of the photovoltaic cell substrate, which can reduce or eliminate the reflected light on the optical surface of the photovoltaic cell substrate, thereby increasing the light transmittance of the photovoltaic cell substrate, so that the sunlight received by the photovoltaic cell substrate can be fully absorbed by the photovoltaic cell substrate, thereby improving the energy receiving efficiency.
[0060] The schematic structural diagram of the photovoltaic cell substrate 10 can be as follows: Figure 2 As shown, a contact electrode layer 20 is printed on a first side surface of the photovoltaic cell substrate 10 along the thickness direction.
[0061] Step S110, obtaining a transfer substrate.
[0062] A groove is provided on the first side surface of the transfer substrate to facilitate accommodating the electrode slurry through the groove.
[0063] In step S120 , the groove on the first side of the transfer substrate is filled with electrode slurry to form an electrode slurry layer.
[0064] The electrode slurry is filled into the groove of the transfer substrate and then dried to form an electrode slurry layer.
[0065] The structural diagram of the transfer substrate 30 for forming the electrode slurry layer 40 can be as follows: Figure 3 shown.
[0066] In step S130 , the first side of the transfer substrate and the first side of the photovoltaic cell substrate are positioned opposite to each other at a preset distance, and the second side of the transfer substrate is heated to transfer the electrode slurry layer filled in the groove to the contact electrode layer.
[0067] In which, when the first side surface of the transfer substrate is arranged opposite to the first side surface of the photovoltaic cell substrate, the orthographic projection of the contact electrode layer on the photovoltaic cell substrate covers the orthographic projection of the groove on the photovoltaic cell substrate, thereby ensuring that the electrode slurry layer can completely cover the contact electrode layer.
[0068] Among them, the second side of the transfer substrate is heated, and the heating method is not limited. It can be vertical heating or roller heating, etc. When heated, the electrode slurry layer will evaporate and generate steam. The steam will be squeezed between the electrode slurry layer and the transfer substrate. When the amount of steam reaches a certain level, the electrode slurry layer will fall off from the groove on the first side of the transfer substrate, and then fall onto the contact electrode layer, completing the transfer.
[0069] In this embodiment, a photovoltaic cell substrate is first obtained. A contact electrode layer is printed on a first side surface along the thickness direction of the photovoltaic cell substrate. The contact electrode layer serves as the first layer of the photovoltaic cell grid lines. A transfer substrate is then obtained. A groove is formed on the first side surface of the transfer substrate. The grooves on the first side surface of the transfer substrate are then filled with electrode slurry to form an electrode slurry layer. Then the first side of the transfer substrate and the first side of the photovoltaic cell substrate are arranged relative to each other at a preset distance, and the second side of the transfer substrate is heated so that the electrode slurry layer filled in the groove is transferred to the contact electrode layer, thereby forming the grid line structure of the photovoltaic cell through the electrode slurry layer and the contact electrode layer. Since thermal transfer is adopted, the preset distance between the first side of the transfer substrate and the first side of the photovoltaic cell substrate can be adjusted during the transfer process. Compared with laser transfer, the distance adjustment is more free, so the preset distance can be flexibly adjusted according to the required grid line line shape to improve the grid line shape. In addition, the multi-layer electrode structure composed of the electrode slurry layer and the contact electrode layer can give the obtained grid line a variety of different characteristics, improve the performance of the grid line, and enable the prepared grid line electrode to have advantages such as good plasticity, good conductivity and low contact resistance.
[0070] In one embodiment, step S120 is to fill the groove on the first side of the transfer substrate with electrode slurry to form an electrode slurry layer, which specifically includes sequentially filling multiple layers of different electrode slurries in the groove to form the electrode slurry layer.
[0071] The electrode paste can be filled into the groove of the first side of the transfer substrate using a scraper filled with electrode paste. Multiple scrapers filled with different electrode pastes can be used to sequentially fill multiple layers of different electrode pastes into the groove to form a multi-layer stacked electrode paste layer.
[0072] For example, refer to Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 , Figure 4-Figure 7 It is a schematic diagram of a process of sequentially using scrapers 50 filled with electrode paste (for example, three scrapers filled with three different electrode pastes) to coat three different electrode paste layers into the grooves of the transfer substrate 30 .
[0073] Among them, the three different electrode pastes can have different functions respectively. For example, the first layer of electrode paste stacked on the groove has good plasticity, thereby reducing the shading area. The second layer of electrode paste stacked on the groove has low resistance and good conductivity, thereby reducing the loss during current transmission. The third layer of electrode paste stacked on the groove has low contact resistance. Therefore, after subsequent transfer, since the third layer of electrode paste stacked on the groove needs to contact the contact electrode layer, the contact resistance is low, which can ensure better transmission of current signals and better current collection capabilities, thereby improving the photoelectric conversion efficiency of solar cells.
[0074] In this embodiment, by sequentially filling multiple layers of different electrode pastes in the groove to form a multi-layer stacked electrode paste layer, the performance of the gate line finally formed can be improved, so that the gate line can simultaneously have the advantages of good conductivity, good gate line plasticity, good silicon wafer contact capability, and low silicon wafer contact resistance.
[0075] In one embodiment, Figure 8 As shown, step S120 is to fill the groove on the first side of the transfer substrate with electrode slurry to form an electrode slurry layer. More specifically, the process includes steps S800 to S820.
[0076] Step S800 : coating the first electrode slurry in the groove to form a first sub-electrode slurry layer.
[0077] The material of the first electrode paste includes at least one of silver, aluminum, tin, and lead. The first electrode paste needs to be a plastic conductive material to have good plasticity. Since the first sub-electrode paste layer becomes the outermost conductive layer of the electrode after transfer, a plastic conductive material is selected for the outermost conductive layer of the electrode to impart plasticity to the outer surface of the formed electrode, thereby improving the plasticity of the gate line.
[0078] Step S810 , coating the second electrode slurry on the first electrode slurry layer in the groove to form a second sub-electrode slurry layer.
[0079] The second electrode paste includes at least one of silver, copper, and aluminum. The second electrode paste needs to be a material with low resistance and good electrical conductivity, thereby reducing current transmission loss and improving current accuracy.
[0080] Step S820 , coating a third electrode slurry on the second electrode slurry layer in the groove to form a third sub-electrode slurry layer.
[0081] The third electrode paste includes at least one of silver and copper. The third electrode paste needs to be a material with low contact resistance, good contact with the silicon wafer, and low silicon wafer contact resistance, thereby maintaining stable current transmission and good contact of the battery.
[0082] For example, the first sub-electrode slurry layer 100, the second sub-electrode slurry layer 200, and the third sub-electrode slurry layer 300 can refer to Figure 7 shown.
[0083] Optionally, the cross-section of the groove is an inverted trapezoid, and the size of the groove gradually decreases from the first side surface close to the transfer substrate to the first side surface far from the transfer substrate. This minimizes the light-shielding area of the outermost first sub-electrode slurry layer, minimizing the shading of the solar cell's light-receiving surface, thereby allowing the solar cell to receive more sunlight and improving energy reception efficiency.
[0084] In this embodiment, by sequentially forming a first sub-electrode slurry layer, a second sub-electrode slurry layer, and a third sub-electrode slurry layer in the groove, the performance of the gate line finally formed can be improved, so that the gate line can simultaneously have the advantages of good conductive performance, good gate line plasticity, good silicon wafer contact capability, and lower silicon wafer contact resistance.
[0085] In one embodiment, the transfer substrate is a hard substrate.
[0086] Among them, the transfer substrate can be a hard substrate, so that on the one hand, the hard substrate can be reused as long as it is cleaned. On the other hand, compared with the flexible film substrate, the hard substrate itself has a smaller deformation during the transfer process, thereby ensuring that the line shape of the grid line will not undergo unexpected deformation (such as bending, etc.), which can improve the accuracy of the line shape of the grid line and improve the line shape of the grid line.
[0087] Optionally, the preset distance between the first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate can be 0. Since the transfer substrate is a hard substrate and thermal transfer is used, the preset distance can be 0. Therefore, the first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate can be directly attached to each other for thermal transfer. In this case, the formed grid lines can be almost guaranteed to be straight lines, with a better linear shape.
[0088] In this embodiment, by using a hard substrate as the transfer substrate, the line shape of the gate line can be improved, and combined with the thermal transfer method, the preset distance can be 0, which can ensure that the obtained gate line is almost a straight line.
[0089] In one embodiment, step S130 involves positioning the first side of the transfer substrate and the first side of the photovoltaic cell substrate relative to each other at a predetermined distance, and heating the second side of the transfer substrate. This includes heating the second side of the transfer substrate by rolling a heating roller at a constant speed on the second side of the transfer substrate.
[0090] The second side surface of the transfer substrate is opposite to the first side surface of the transfer substrate, so that the heating roller rolls at a uniform speed on the second side surface of the transfer substrate, thereby uniformly heating the transfer substrate.
[0091] The transfer substrate can be rotated 180 degrees so that the first side of the transfer substrate faces downward, and then the first side of the transfer substrate is aligned with the first side of the photovoltaic cell substrate so that the orthographic projection of the contact electrode layer on the photovoltaic cell substrate overlaps the orthographic projection of the groove on the photovoltaic cell substrate. When heated, the electrode slurry layer evaporates and generates steam, which is squeezed between the electrode slurry layer and the transfer substrate. When the steam reaches a certain level, the electrode slurry layer will fall off from the groove on the first side of the transfer substrate and then fall onto the contact electrode layer, completing the transfer.
[0092] For example, Figure 9 As shown, the first side surface of the transfer substrate 30 is arranged opposite to the first side surface of the photovoltaic cell substrate 10 at a preset distance, and the heating roller 60 is used to roll at a uniform speed on the second side surface of the transfer substrate 30 to heat the second side surface of the transfer substrate 30.
[0093] For example, Figure 10 As shown, the electrode paste layer (including the first sub-electrode paste layer 100 , the second sub-electrode paste layer 200 , and the third sub-electrode paste layer 300 ) will fall off from the groove on the first side of the transfer substrate 30 and then fall onto the contact electrode layer 20 .
[0094] In this embodiment, a heating roller is used to roll at a uniform speed on the second side surface of the transfer substrate, thereby achieving a thermal transfer effect.
[0095] In one embodiment, after the electrode slurry layer filled in the groove is transferred onto the contact electrode layer, the electrode transfer method for a photovoltaic cell further includes: cleaning the groove, and drying the cleaned groove.
[0096] Among them, the transfer substrate can be a hard substrate, so the hard substrate can be reused as long as it is cleaned. The hard substrate after transfer can be immersed in alcohol, and the residual slurry can be cleaned by ultrasonic cleaning. The cleaned hard substrate can then be dried (for example, by using a heating fan for drying) and then recycled.
[0097] For example, the transfer process is as follows Figure 11As shown, the grooves of the rigid substrate (transfer substrate) 30 are first filled with electrode slurry to form an electrode slurry layer. A heated roller 60 is then rolled at a constant speed on the second side of the rigid substrate 30 to heat the second side of the rigid substrate 30, thereby transferring the electrode slurry layer to the photovoltaic cell substrate 10. The rigid substrate 30 is then cleaned, and the cleaned grooves are then dried using a heated fan 70. The dried rigid substrate 30 can be recycled.
[0098] In this embodiment, the transfer substrate may be a hard substrate, so that the hard substrate can be recycled as long as it is cleaned, thus saving costs.
[0099] It should be understood that although Figure 1 、 Figure 8 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 、 Figure 8 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The order of execution of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.
[0100] In one embodiment, Figure 12 As shown, a photovoltaic cell is provided, comprising: a photovoltaic cell substrate 10, a contact electrode layer 20, and an electrode slurry layer 40, wherein:
[0101] The contact electrode layer 20 is disposed on the photovoltaic cell substrate 10 .
[0102] The electrode slurry layer 40 is disposed on a side of the contact electrode layer 20 away from the photovoltaic cell substrate 10 .
[0103] The electrode slurry layer 40 is formed by the electrode transfer method of the photovoltaic cell in the above embodiment.
[0104] In this embodiment, the electrode slurry layer of the photovoltaic cell is formed by adopting the electrode transfer method of the photovoltaic cell in the above-mentioned embodiment. Therefore, during the transfer process, the preset distance between the first side of the transfer substrate and the first side of the photovoltaic cell substrate can be adjusted. Compared with laser transfer, the distance adjustment is more free, so the preset distance can be flexibly adjusted according to the required line shape of the grid line to improve the line shape of the obtained grid line. In addition, the multi-layer electrode structure composed of the electrode slurry layer and the contact electrode layer can give the obtained grid line a variety of different characteristics, improve the performance of the grid line, and enable the prepared grid line electrode to have advantages such as good plasticity, good conductivity and low contact resistance.
[0105] In one embodiment, see Figure 12 The electrode slurry layer 40 includes: a third sub-electrode slurry layer 300, a second sub-electrode slurry layer 200, and a first sub-electrode slurry layer 100, wherein:
[0106] The third sub-electrode slurry layer 300 is disposed on a side of the contact electrode layer 20 away from the photovoltaic cell substrate 10 .
[0107] The material of the third sub-electrode paste layer 300 includes at least one of silver and copper.
[0108] The second sub-electrode slurry layer 2200 is disposed on a side of the third sub-electrode slurry layer 300 away from the photovoltaic cell substrate 10 .
[0109] The material of the second sub-electrode paste layer 200 includes at least one of silver, copper and aluminum.
[0110] The first sub-electrode slurry layer 100 is disposed on a side of the second sub-electrode slurry layer 200 away from the photovoltaic cell substrate 10 .
[0111] The material of the first sub-electrode paste layer 100 includes at least one of silver, aluminum, tin and lead.
[0112] In this embodiment, by providing a first sub-electrode slurry layer, a second sub-electrode slurry layer, and a third sub-electrode slurry layer, the performance of the gate line finally formed can be improved, so that the gate line can simultaneously have the advantages of good conductive performance, good gate line plasticity, good silicon wafer contact capability, and lower silicon wafer contact resistance.
[0113] Throughout this specification, references to terms such as "some embodiments," "other embodiments," and "desired embodiments" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Although these terms are used interchangeably throughout this specification, they do not necessarily refer to the same embodiment or example.
[0114] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0115] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.
Claims
1. A method for transferring electrodes of photovoltaic cells, characterized in that: The method comprises: Obtaining a photovoltaic cell substrate, wherein a contact electrode layer is printed on a first side surface of the photovoltaic cell substrate in a thickness direction; Obtaining a transfer substrate, wherein a groove is formed on a first side surface of the transfer substrate; Filling the groove on the first side of the transfer substrate with electrode slurry to form an electrode slurry layer; The first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate are arranged relative to each other at a preset distance, and the second side surface of the transfer substrate is heated so that the electrode slurry layer filled in the groove is transferred to the contact electrode layer, wherein, when the first side surface of the transfer substrate and the first side surface of the photovoltaic cell substrate are arranged relative to each other, the orthographic projection of the contact electrode layer on the photovoltaic cell substrate covers the orthographic projection of the groove on the photovoltaic cell substrate.
2. The method for transferring electrodes of a photovoltaic cell according to claim 1, wherein: The step of filling the groove on the first side of the transfer substrate with electrode slurry to form an electrode slurry layer includes: sequentially filling multiple layers of different electrode slurries in the groove to form the electrode slurry layer.
3. The method for transferring electrodes of a photovoltaic cell according to claim 2, wherein: The step of sequentially filling multiple layers of different electrode slurries in the groove to form the electrode slurry layer comprises: Applying a first electrode paste in the groove to form a first sub-electrode paste layer, wherein the material of the first electrode paste includes at least one of silver, aluminum, tin and lead; coating a second electrode paste on the first electrode paste layer in the groove to form a second sub-electrode paste layer, wherein the material of the second electrode paste includes at least one of silver, copper and aluminum; A third electrode paste is coated on the second electrode paste layer in the groove to form a third sub-electrode paste layer, wherein the material of the third electrode paste includes at least one of silver and copper.
4. The method for transferring electrodes of a photovoltaic cell according to claim 1, wherein: The transfer substrate is a hard substrate.
5. The method for transferring electrodes of a photovoltaic cell according to claim 4, wherein: The preset distance is 0.
6. The method for transferring electrodes of a photovoltaic cell according to claim 4, wherein: The second side surface of the transfer substrate is opposite to the first side surface of the transfer substrate, and heating the second side surface of the transfer substrate includes: A heating roller is used to roll at a uniform speed on the second side surface of the transfer substrate to heat the second side surface of the transfer substrate.
7. The method for transferring electrodes of a photovoltaic cell according to claim 1, wherein: After the electrode slurry layer filled in the groove is transferred onto the contact electrode layer, the method further includes: cleaning the groove; The cleaned groove is dried.
8. The method for transferring electrodes of a photovoltaic cell according to claim 1, wherein: The cross section of the groove is an inverted trapezoid, and the size of the groove gradually decreases from the first side surface close to the transfer substrate to the first side surface far away from the transfer substrate.
9. A photovoltaic cell, characterized in that: include: photovoltaic cell substrates; A contact electrode layer is provided on the photovoltaic cell substrate; An electrode slurry layer is provided on a side of the contact electrode layer away from the photovoltaic cell substrate, wherein the electrode slurry layer is formed by the photovoltaic cell electrode transfer method according to any one of claims 1 to 8.
10. The photovoltaic cell according to claim 9, characterized in that The electrode slurry layer comprises: a third sub-electrode slurry layer, disposed on a side of the contact electrode layer away from the photovoltaic cell substrate, wherein the material of the third sub-electrode slurry layer includes at least one of silver and copper; a second sub-electrode slurry layer, disposed on a side of the third sub-electrode slurry layer away from the photovoltaic cell substrate, wherein the material of the second sub-electrode slurry layer includes at least one of silver, copper and aluminum; The first sub-electrode slurry layer is arranged on a side of the second sub-electrode slurry layer away from the photovoltaic cell substrate, wherein the material of the first sub-electrode slurry layer includes at least one of silver, aluminum, tin and lead.