Preparation method of solar cell electrode

Abstract

The preparation method of the solar cell electrode comprises the steps that S11, a solar cell piece is covered with a printing mold, an electrode pattern groove to be printed is formed in the side, making contact with a solar cell, of the printing mold, and the groove is filled with printing paste; s12, sintering the solar cell, wherein the printing mold and a bearing piece of the solar cell piece or an adsorption piece below the solar cell piece are magnetically adsorbed during sintering; wherein at least one of the printing mold and the bearing part or the adsorption part comprises a magnetic part, and the other one comprises a magnetic part or is provided with a magnetic substance. By adopting the method provided by the invention, narrower grid lines can be printed; the grid line printing precision is high, and the height consistency is good; triangles and other grid line shapes can be printed, and the module power is improved. One-time metallization of multiple layers of slurry can be achieved by filling multiple layers of slurry, and the requirements of slurry at different positions are met. Meanwhile, the main grid, the fine grid and the bonding pad electrode can be prepared at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cell preparation, and particularly relates to a method for preparing a solar cell electrode. Background Art

[0002] Cell metallization is one of the important links in the manufacturing process of photovoltaic cells. Through the printing and sintering of conductive printing pastes, metallized electrodes are prepared on the front and back sides of silicon wafers, so as to form a tight and efficient ohmic contact between the electrodes and the cells, and export the photo-generated carriers from the cells. Metallization is related to aspects such as the production cost and conversion efficiency of cells, and ultimately affects the choice of future cell paths. Therefore, the optimization of metallization technology has not only become a key area for each cell manufacturer to focus on in order to achieve the cost reduction plan, but also become the focus of industry attention.

[0003] Screen printing is a technology for grid metallization on the front side of silicon-based solar cells. At present, the mainstream photovoltaic cell electrode metallization process mainly uses the mature screen printing technology, but the screen printing technology also has certain limitations, such as limitations on the aspect ratio and line width of grid lines, and problems such as uneven printing.

[0004] Under the condition of not increasing the series resistance of the cell, reducing the width of the fine grid is beneficial to reducing the shading loss and reducing the amount of front silver used. At present, the width of the sub-grid lines of Topcon cell screen printing is generally 25μm, and the width of the sub-grid lines of HJT cell screen printing is generally 35μm. And due to the existence of the mesh wiring, the grid lines will have the problem of uneven height, which hinders the improvement of the photoelectric conversion efficiency of the cell, and at the same time causes the cost of the printing paste to be relatively high. Moreover, the screen plates used in screen printing have problems such as being damaged and deformed after long-term use, which is also one of the reasons restricting the reduction of the cost of cells. Summary of the Invention

[0005] In order to solve the problems existing in the prior art screen printing, the present invention proposes that a printing mold is covered on the solar cell and is attached tightly to the cell by means of magnetic attraction below, and the preparation of the solar cell electrode is completed after sintering.

[0006] The present invention provides a method for preparing a solar cell electrode, including the following steps,

[0007] S11 Cover a printing mold on the solar cell. Wherein, a groove for the electrode pattern to be printed is provided on the side of the printing mold in contact with the solar cell, and the groove is filled with a printing paste;

[0008] S12 Sinter the solar cell. Wherein, during sintering, the printing mold and the carrier of the solar cell or the magnetic adsorbent below the solar cell are magnetically adsorbed;

[0009] Among them, at least one of the printing die and the carrier or the adsorbing member includes a magnetic member, and the other includes a magnetic member or has magnetic substances.

[0010] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, a magnet is provided on the carrier, or the adsorbing member is a magnet, and the printing die has magnetic substances or is a magnetic member.

[0011] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the carrier includes a carrier table and an electromagnet.

[0012] As a further preference of the present invention, a method for preparing a solar cell electrode of the present invention includes the following steps

[0013] S31 Fill the printing paste into the groove of the printing die;

[0014] S32 Place the printing die with the groove side facing down and cover it on the solar cell wafer placed on the carrier;

[0015] S33 Send the carrier, the solar cell wafer, and the printing die into a sintering furnace for sintering. When sintering, the electromagnet is in an open state;

[0016] S34 Send the carrier, the solar cell wafer, and the printing die out of the sintering furnace;

[0017] S35 Remove the printing die from the solar cell wafer.

[0018] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the sintering furnace is a roller sintering furnace. A roller conveyor device is provided inside the sintering furnace. The solar cell enters from one end of the sintering furnace through the conveyor device and is output from the other end to complete sintering;

[0019] Among them, in the direction perpendicular to the conveying direction, a spaced first roller and a second roller are respectively provided, and a voltage is applied between the two. When the carrier, the solar cell, and the printing die are conveyed into the sintering furnace and move on the roller conveyor device, the positive and negative poles of the electromagnet on the carrier respectively fall on the first roller and the second roller, so that the electromagnet remains in an open state.

[0020] As a further preference of the present invention, a method for preparing a solar cell electrode of the present invention includes the following steps

[0021] S41 Fill the printing paste into the groove of the printing die;

[0022] S42 Place the printing die with the groove side facing down and cover it on the solar cell wafer;

[0023] S43 Feed the solar cell and the printing mold into the sintering furnace for sintering. During sintering, the electromagnet of the adsorbing component under the conveying device of the sintering furnace is in the on state;

[0024] S44 Send the solar cell and the printing mold out of the sintering furnace;

[0025] S45 Remove the printing mold from the solar cell.

[0026] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the sintering furnace is a chain-type or roller-type sintering furnace. A chain-type or roller-type conveying device is provided inside the sintering furnace. The solar cell enters from one end of the sintering furnace through the conveying device and is output from the other end to complete sintering;

[0027] Wherein, an electromagnet is provided under the conveying device as an adsorbing component.

[0028] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the grooves of the printing mold include at least one of sub-grid grooves, main-grid grooves, and pad grooves.

[0029] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the width of the groove corresponding to the fine grid of the printing mold is 5 - 35 μm, the depth is 5 - 35 μm, and the depth-to-width ratio is 10 - 400%.

[0030] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the thickness of the printing mold is 50 - 500 μm.

[0031] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, the cross-sectional shape of the groove is trapezoidal, triangular, rectangular, arc-shaped, upper trapezoidal and lower triangular, and the cross-section of the printed grid line corresponding thereto is trapezoidal, triangular, rectangular, arc-shaped or lower trapezoidal and upper triangular.

[0032] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, a flange is provided on the outer edge of the side of the printing mold having the groove, and the height of the flange is greater than or equal to the thickness of the cell.

[0033] As a further preference of the present invention, in a method for preparing a solar cell electrode of the present invention, before step S11, it further includes S21, the step of filling the printing paste in the groove of the printing mold, wherein one layer or multiple layers of printing paste are filled in the groove.

[0034] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the beneficial effects include:

[0035] (1) By using the method of the present invention, grid lines that are narrower and have a larger aspect ratio than screen printing can be made. It can be achieved in the range of 5 - 35 μm, and there will be no edge extension problem of screen printing.

[0036] (2) When the screen plate of screen printing in the prior art is used, there will be a deformation problem. After the screen plate is deformed, the spacing of the printed grid lines will change, and the printing accuracy is low. The printing mold of the present invention has no deformation problem, has high grid line printing accuracy, and has more advantages for SE alignment.

[0037] (3) The method of the present invention has good consistency in the height of printed grid lines.

[0038] (4) The present invention can design the groove type according to customer requirements. The adjustment range of the aspect ratio of the printed grid lines is very large, and the plasticity of the grid lines is good; triangular grid line shapes and the like can be designed in combination with components to improve the power of the components.

[0039] (5) The present invention can achieve the one - time metallization of multiple layers of paste by filling multiple layers of paste to meet the paste requirements at different positions.

[0040] (6) The present invention can simultaneously prepare the main grid, fine grid and pads, greatly improving the electrode preparation efficiency of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0042] Figures 1 to 3 It is a process schematic diagram of a method for preparing an electrode of a solar cell according to the present invention;

[0043] Figure 4 It is a structural schematic diagram of a printing mold according to an embodiment of the present invention;

[0044] Figure 5 It is a structural schematic diagram of a groove pattern of a printing mold according to an embodiment of the present invention.

[0045] Figure 6 It is a structural schematic diagram of filling a single - layer paste into a printing mold according to an embodiment of the present invention;

[0046] Figure 7 It is a structural schematic diagram of filling multiple - layer paste into a printing mold according to an embodiment of the present invention;

[0047] Figures 8 to 10 It is a structural schematic diagram of a roller - type sintering furnace according to an embodiment of the present invention;

[0048] Figure 11 is a schematic structural view of a chain sintering furnace according to an embodiment of the present invention;

[0049] As shown in the figure, it includes: 10, printing mold; 11, groove, 111, fine grid groove, 112, main grid groove, 113, pad groove; 12, flange;

[0050] 20, carrier, 21, carrier table, 22, electromagnet, 221, positive pole of electromagnet, 222, negative pole of electromagnet;

[0051] 30, printing slurry, 31, first printing slurry layer, 32, second printing slurry layer;

[0052] 40, solar cell;

[0053] 50, adsorbent;

[0054] 60, sintering furnace, 61, conveying roller, 611, first conveying roller, 612, second conveying roller, 62, chain conveying device, 63, heat preservation layer. Detailed implementation manners

[0055] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] In the description of the present invention, it should be understood that unless otherwise specified and limited, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0057] In addition, unless otherwise specified and limited, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0058] In the present invention, unless otherwise specified or limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the present invention, unless otherwise specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0060] The present invention provides a method for preparing a solar cell electrode, comprising:

[0061] S11 Cover the printing mold 10 on the solar cell 40. Wherein, a groove 11 for the electrode pattern to be printed is provided on the side of the printing mold 10 that contacts the solar cell, and the groove 11 is filled with printing paste 30;

[0062] S12 Sinter the solar cell 40. Wherein, during sintering, the printing mold 10 and the carrier 20 of the solar cell 40 or the adsorber 50 under the solar cell 40 are magnetically adsorbed.

[0063] Specifically, referring to Figures 1 to 3 , which is a schematic diagram of the process of the method for preparing a solar cell electrode of the present invention. Wherein, Figure 1 is a schematic diagram of the printing mold covering the solar cell; Figure 2 is a schematic diagram during the sintering process. In the figure, the printing paste has a certain shrinkage; Figure 3 is a schematic diagram after the printing mold is removed from the solar cell after sintering is completed. At this time, the electrode preparation of the solar cell is completed.

[0064] By using the method of the present invention, the printing mold and the carrier or adsorber under the solar cell are magnetically adsorbed, so that the printing mold and the surface of the solar cell are in good contact, ensuring good contact between the printing paste in the groove and the surface of the solar cell.

[0065] Using the method of the present invention, during sintering, the organic components in the printing paste will volatilize and cause slight shrinkage, and sinter into the solar cell to form an ohmic contact. After sintering, the formed electrode will be separated from the groove of the printing mold.

[0066] For the method for preparing the solar cell electrode of the present invention, the printing mold and the carrier or the adsorbent can be magnetically adsorbed. Specifically, at least one of the printing mold and the carrier or the adsorbent has magnetism, the other has magnetism or can be magnetically adsorbed. It can be understood that at least one of the printing mold and the carrier or the adsorbent includes a magnetic member such as a magnet, and the other includes a magnetic member such as a magnet or has a magnetic substance such as iron that can be adsorbed by the magnet.

[0067] As a preferred embodiment, the printing mold of the present invention is a magnetic substance or contains a magnetic substance. More specifically, the printing mold is a light plate with a magnetic substance, such as a light steel plate, which has a certain stiffness, good workability and a certain elasticity.

[0068] The carrier or the adsorbent of the present invention is provided with a magnet or an electromagnet, which can adsorb the printing mold. Preferably, the carrier or the adsorbent is provided with an electromagnet, and the printing mold can be magnetically adsorbed or the magnetic adsorption can be released by energizing or de-energizing.

[0069] See Figure 1 , as an embodiment, the carrier 20 is provided with a carrier table 21 and an electromagnet 22. Figure 1 In, an electromagnet 22 is arranged below the carrier table 21. The solar cell 40 is placed on the carrier table 21, the printing mold 10 covers the solar cell 40, and the electromagnet 22 can be turned on to adsorb the printing mold 10. The present invention is not limited to this, and the electromagnet 22 can also be arranged on the upper part or the middle part of the carrier table 21.

[0070] For the method for preparing the solar cell electrode provided by the present invention, the printing mold is made of a material with a certain stiffness, good workability and a certain elasticity, such as a light steel plate. Its certain stiffness and workability can be used to process grooves with a larger aspect ratio to carry the printing paste. And during the sintering process, the light steel plate can provide support for the printing paste. Even if the aspect ratio of the printed grid line is large, it will not cause the collapse of the grid line, so that grid lines with a higher aspect ratio can be prepared.

[0071] See Figure 4 and Figure 5 , where Figure 4 is a schematic structural diagram of the cross-section of the groove of the printing mold. Figure 5It is a top view schematic diagram of a printing mold. For the printing mold 10 of the present invention, a groove 11 for the electrode pattern to be printed is provided on one side. The groove 11 is used to carry the paste 30 to be printed. A plurality of grooves 11 are arranged according to the grid line pattern to form the electrode pattern to be printed. As a common printing pattern for solar cell wafers, the groove is a plurality of parallel strip-shaped grooves. After the printing paste is filled into the groove and prepared according to the method of the present invention, fine grids of the solar cell wafer are formed. This application is not limited to this, and it can also be applied to main grids, etc.

[0072] Furthermore, for the method for preparing a solar cell electrode provided by the present invention, the groove 11 of the printing mold 10 includes at least one of a main grid groove 112, a fine grid groove 111, and a pad groove 113. Among them, Figure 5 For the shown printing mold, which simultaneously includes a main grid groove 112, a fine grid groove 111, and a pad groove 113, the printing paste can be filled in all the grooves. When preparing the battery grid lines, for the case with a main grid, fine grids, and pads, the electrode preparation can be carried out simultaneously. Compared with the prior art, the preparation efficiency and production capacity are greatly improved.

[0073] In this application, the width (at the opening) of the groove corresponding to the fine grid can be 5 - 35 μm, the depth can be 5 - 35 μm, and the depth-to-width ratio can reach 10 - 400%.

[0074] The solar cell wafer is a fragile material. Therefore, the thickness of the printing mold of the present invention should not be too thick. Specifically, its thickness is 50 - 500 μm, which can not only achieve light weight but also facilitate the processing of the groove.

[0075] By using the method of the present invention, there will be no similar edge extension problems in screen printing, no deformation problems, the printing accuracy of the grid lines is higher, and the printing grid line height has good consistency, which has more advantages for the SE alignment of solar cells.

[0076] At the same time, since the printing mold of the present invention is made of a material with a certain stiffness, good processability, and a certain elasticity, the cross-sectional shape of the groove, hereinafter referred to as the groove type, can be designed according to needs. Specifically, the groove type is trapezoidal, triangular, rectangular, arc-shaped, upper trapezoidal and lower triangular, etc. The cross-section of the printed grid line corresponding to it is trapezoidal, triangular, rectangular, arc-shaped, lower trapezoidal and upper triangular, etc. Triangular grid lines or special-shaped grid lines such as lower trapezoidal and upper triangular are very beneficial to improving the power of solar cell modules. Compared with the prior art, the screen printing stencil can only achieve the printing of trapezoid-like grid lines and cannot achieve the printing of other patterns. By using the method of the present invention, the printing of grid lines with the desired cross-sectional shape can be easily completed.

[0077] Further, in the method for preparing the solar cell electrode of the present invention, before step S11, it further includes S21, the step of filling the printing paste 30 into the groove 11 of the printing mold 10, wherein one or more layers of printing paste are filled into the groove. Refer to Figure 6 and Figure 7 , wherein, Figure 6 FIG. is a schematic structural diagram of filling one layer of printing paste 30 into the groove 11. Figure 7 FIG. is a schematic structural diagram of filling two layers of printing paste into the groove 11. Among them, in the groove 11, the first printing paste layer 31 is filled first, and then the second printing paste layer 32 is filled. After sintering by the method of the present invention, the second printing paste layer contacts the solar cell sheet, and the second printing paste layer is above the first printing paste layer.

[0078] By using the method of the present invention, the printing paste filled in the groove can be multiple layers of printing paste. For example, it can be two or three layers of printing paste. As mentioned above, since the printing mold can process grooves with a larger aspect ratio to carry the printing paste, and during the sintering process, the lightweight steel plate can provide support for the printing paste, it has better advantages for the sintering of this multi-layer printing paste. Multiple layers of paste can be printed, which has a good effect on correspondingly improving the ohmic contact performance of the solar cell and saving the silver paste. For example, the printed lower layer is an aluminum-containing paste, and the upper layer is a silver-containing paste grid line.

[0079] When filling the printing paste into the printing mold, the side of the printing mold with the groove can be placed upward, and the printing paste is scraped into the groove by a squeegee or a filling head. The squeegee or filling head can adopt the squeegee and filling head of the existing technology.

[0080] It should be noted that when filling the printing paste into the groove of the printing mold, the groove is filled with the printing paste. When the printing mold covers the solar cell sheet, the printing paste can fully contact the solar cell sheet.

[0081] By using the method of the present invention, the gas released during sintering can form a certain pressure in the groove, pressing the printing paste downward toward the solar cell sheet, which helps to sinter and form a good ohmic contact.

[0082] In the method for preparing the solar cell electrode provided by the present invention, a flange 12 is provided on the outer edge of the side of the printing mold 10 with the groove. The height of the flange 12 is substantially equal to the thickness of the solar cell sheet 40. Specifically, when the printing mold 10 covers the solar cell sheet, the flange 12 does not contact the solar cell sheet 40 and is placed on the carrier 20 to play a supporting role, and the middle part of the printing mold contacts the solar cell sheet. When the printing mold and the support are magnetically adsorbed, the part with the groove fits on the solar cell sheet, so that the printing paste and the solar cell sheet are in good contact.

[0083] Specifically, the height of the flange is basically equal to or slightly greater than the thickness of the solar cell. In this embodiment, to adapt to the thickness of the solar cell, the height of the flange is 20 - 300 μm. The setting of the flange can cover the warped solar cell (inevitably generating a small amount of warping during the process) when the printing mold is not magnetically attracted. When magnetically attracted, since the thickness of the printing mold is set at 50 - 500 μm and has a certain elasticity, its groove area can also fit well on the solar cell.

[0084] As a specific implementation manner, the carrier of the preparation method of the solar cell electrode provided by the present invention can be a carrier table, and the whole or part of the carrier table is an electromagnet. As Figure 1 shown, an electromagnet is provided at the bottom of the carrier table.

[0085] The preparation method of the solar cell electrode provided by the present invention can adopt the sintering method in a sintering furnace.

[0086] Specifically, referring to Figures 8 to 10 , the sintering furnace 60 is a roller sintering furnace. A conveying device is arranged inside the sintering furnace 60, and the conveying device is a roller conveying device 61. The solar cell enters from one end of the sintering furnace 60 through the conveying device and is output from the other end to complete sintering. Specifically, spaced first rollers 611 and second rollers 612 are respectively arranged in the direction perpendicular to the conveying direction, and a voltage is applied between the two.

[0087] When the carrier 20, the solar cell 40, and the printing mold 10 are conveyed into the sintering furnace 60 and move on the roller conveying device 61, the positive electrode 221 and the negative electrode 222 of the electromagnet 22 under the carrier table 21 respectively fall on the first roller 611 and the second roller 612. Therefore, it can be ensured that during the conveying in the sintering furnace, that is, during the sintering process, the electromagnet always remains in an energized and magnetic state, that is, the printing mold and the carrier always remain in a magnetically attracted state. After sintering is completed, it is output from the sintering furnace, and the printing mold can be separated from the battery sheet.

[0088] Based on the above description, a method for preparing grid lines on a solar cell provided by the present invention includes the following steps:

[0089] S31 Fill the printing paste 30 into the groove 11 of the printing mold 10;

[0090] S32 Place the printing mold 10 with the groove side facing down and cover it on the solar cell 40 placed on the carrier 20;

[0091] S33 Send the carrier 20, the solar cell 40, and the printing mold 10 into the sintering furnace 60 for sintering. During sintering, the electromagnet of the carrier is in an open state;

[0092] S34 Sends the carrier 20, the solar cell 40, and the printing die 10 out of the sintering furnace;

[0093] S35 Removes the printing die 10 from the solar cell 40.

[0094] In the method for preparing a solar cell electrode provided by the present invention, the sintering furnace is a chain-type or roller-type sintering furnace, and a chain-type or roller-type conveying device is arranged inside the sintering furnace. The solar cell enters from one end of the sintering furnace through the conveying device and is output from the other end to complete sintering. In this embodiment, the carrier does not enter the sintering furnace, and the printing die is magnetically attracted by an adsorbing member (electromagnet) arranged below the conveying device in the sintering furnace.

[0095] Specifically, referring to Figure 10 , taking the chain-type sintering furnace as an example, an adsorbing member 50 (electromagnet) is arranged below the chain-type conveying device 62 and is always in an energized and magnetic state. The solar cell 40 and the printing die 10 are conveyed through the chain-type conveying device 62 in the sintering furnace. When transported above the adsorbing member 50, the printing die 10 will be magnetically attracted and tightly attached to the surface of the solar cell 40 to complete the sintering process; after sintering, it is output from the sintering furnace 60, and the printing die 10 can be separated from the solar cell 40.

[0096] Preferably, a heat insulation layer 63, such as an asbestos heat insulation layer, is arranged at the bottom of the sintering furnace between the chain-type conveying device 62 and the electromagnet, which can isolate heat and at the same time the magnetic field can pass through.

[0097] Based on the above description, a method for preparing a grid line of a solar cell provided by the present invention includes the following steps:

[0098] S41 Fills the printing paste 30 into the groove 11 of the printing die 10;

[0099] S42 Places the printing die 10 with the groove 11 facing downwards and covers it on the solar cell 40;

[0100] S43 Sends the solar cell 40 and the printing die 10 into the sintering furnace for sintering. During sintering, the electromagnet of the adsorbing member is in an open state;

[0101] S44 Sends the solar cell 40 and the printing die 10 out of the sintering furnace;

[0102] S45 Removes the printing die 10 from the solar cell 40.

[0103] Those skilled in the art can understand that, generally speaking, in a chain or roller sintering furnace, the temperature is arranged in intervals in the material transfer direction. For example, the temperature from the inlet of the sintering furnace to the middle of the sintering furnace shows a gradually rising trend. In this way, the printing die in the front stage of sintering can be magnetically attracted to the carrier or the adsorbent well, the printing paste and the solar cell form good contact, and the groove keeps the shape of the printing paste for sintering. Even if the printing die becomes paramagnetic and cannot be magnetically attracted due to too high sintering temperature later, it will not affect the sintering effect.

[0104] Those skilled in the art can understand that although the present invention is called printing paste, when the printing paste is filled, it is in a paste state. During sintering, it will shrink. When sintering is completed, it forms an ohmic contact with the solar cell to complete metallization, that is, electrode preparation.

[0105] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a solar cell electrode, characterized in that: It includes the following steps: S11 Cover the printing mold on the solar cell, wherein, on the side of the printing mold contacting the solar cell, a groove for the electrode pattern to be printed is provided, and the groove is filled with printing paste. S12 Sinter the solar cell, wherein, during sintering, the printing mold and the carrier of the solar cell or the adsorbing member below the solar cell are magnetically adsorbed. Wherein, at least one of the printing mold and the carrier or the adsorbing member includes a magnetic member, and the other includes a magnetic member or has magnetic substances.

2. The preparation method of the solar cell electrode according to claim 1, characterized in that: A magnet is provided on the carrier, or the adsorbing member is a magnet, and the printing mold has magnetic substances or is a magnetic member.

3. The preparation method of the solar cell electrode according to claim 2, wherein: The carrier includes a carrier table and an electromagnet.

4. The manufacturing method of the solar cell electrode according to claim 3, wherein: It includes the following steps: S31 Fill the printing paste into the groove of the printing mold. S32 Place the printing mold with the groove side down and cover it on the solar cell placed on the carrier. S33 Send the carrier, the solar cell, and the printing mold into a sintering furnace for sintering. During sintering, the electromagnet is in an on state. S34 Send the carrier, the solar cell, and the printing mold out of the sintering furnace. S35 Remove the printing mold from the solar cell.

5. The manufacturing method of the solar cell electrode according to claim 4, characterized in that: The sintering furnace is a roller sintering furnace, and a roller conveyor device is provided inside the sintering furnace. The solar cell enters from one end of the sintering furnace through the conveyor device and exits from the other end to complete sintering. Wherein, in the direction perpendicular to the conveying direction, a spaced first roller and a second roller are respectively provided, and a voltage is applied between the two. When the carrier, the solar cell, and the printing mold are conveyed into the sintering furnace and move on the roller conveyor device, the positive and negative poles of the electromagnet on the carrier respectively fall on the first roller and the second roller, so that the electromagnet remains in an on state.

6. The preparation method of the solar cell electrode according to claim 2, wherein: It includes the following steps: S41 Fill the printing paste into the groove of the printing mold. S42 Place the printing mold with the groove side down and cover it on the solar cell. S43 Send the solar cell and the printing mold into a sintering furnace for sintering. During sintering, the electromagnet of the adsorbing member under the conveyor device of the sintering furnace is in an on state. S44 Send the solar cell and the printing mold out of the sintering furnace. S45 Remove the printing mold from the solar cell.

7. The method for preparing a solar cell electrode according to claim 6, characterized in that: The sintering furnace is a chain or roller sintering furnace, and a chain or roller conveyor device is provided inside the sintering furnace. The solar cell enters from one end of the sintering furnace through the conveyor device and exits from the other end to complete sintering. Wherein, an electromagnet is provided under the conveyor device as the adsorbing member.

8. The preparation method of the solar cell electrode according to any one of claims 1 to 7, characterized in that: The groove of the printing mold includes at least one of a sub-grid groove, a main-grid groove, and a pad groove.

9. The method for preparing a solar cell electrode according to claim 8, wherein: The width of the groove of the printing mold corresponding to the fine grid is 5 - 35 μm, the depth is 5 - 35 μm, and the depth-to-width ratio is 10 - 400%.

10. The preparation method of the solar cell electrode according to claim 8, characterized in that: The thickness of the printing mold is 50 - 500 μm.

11. The preparation method of the solar cell electrode according to claim 8, characterized in that: The cross-sectional shape of the groove is trapezoidal, triangular, rectangular, arc-shaped, upper trapezoidal and lower triangular, and the cross-section of the printed grid line corresponding to it is trapezoidal, triangular, rectangular, arc-shaped or lower trapezoidal and upper triangular.

12. The preparation method of the solar cell electrode according to claim 8, characterized in that: A flange is provided on the outer edge of the side of the printing mold having the groove, and the height of the flange is greater than or equal to the thickness of the cell.

13. The preparation method of the solar cell electrode according to claim 1, wherein: Before step S11, it further includes S21, the step of filling the printing paste into the groove of the printing mold, wherein one layer or multiple layers of printing paste are filled into the groove.

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