Manufacturing method of solar cell and solar cell

Abstract

The invention provides a solar cell manufacturing method and a solar cell, and the method comprises the steps: providing a substrate, and sequentially carrying out the texturing, diffusion, etching and front and back film layer deposition of the substrate, and obtaining a to-be-printed solar cell; paste is printed on at least one surface of the solar cell to be printed, a solar cell to be sintered is obtained, and the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals; the initial grid lines are subjected to multiple times of sintering treatment through laser, the grid lines are formed, each time of sintering treatment comprises the steps that the laser is adopted to movably irradiate the initial grid lines and apply reverse bias voltage to the initial grid lines, the wavelength range of the laser is 1000 nm to 1064 nm, the range of the reverse bias voltage is-30 V to-5 V, a sintering area is formed in each time of sintering treatment, and the width of the sintering area ranges from-30 V to-5 V; orthographic projections of the plurality of sintering areas on the solar cell to be sintered at least cover orthographic projections of the initial grid lines on the solar cell to be sintered.

Description

[0001] Original application information

[0002] This application is a divisional application of the Chinese patent application number 202510239807.9. The application date of the original application is February 28, 2025. The name of the original invention is "Method for manufacturing solar cells and solar cells". The entire content of the original application is incorporated into this application by reference. Technical Field

[0003] The present application relates to the field of solar cells, and in particular to a method for manufacturing a solar cell and a solar cell. Background Art

[0004] During the preparation of the grid of a solar cell, laser sintering is used. During this process, incomplete action or over-sintering is prone to occur, resulting in unsatisfactory sintering effects and affecting the efficiency of the solar cell.

[0005] Therefore, there is an urgent need for a method for manufacturing solar cells that can solve the problem of unsatisfactory sintering effect of solar cells. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for manufacturing a solar cell and a solar cell, so as to solve the problem of unsatisfactory sintering effect of solar cells in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for manufacturing a solar cell is provided, comprising: providing a substrate, and sequentially performing a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed includes two opposite surfaces; printing a paste on at least one of the surfaces of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered includes a plurality of initial grid lines arranged at intervals; performing multiple sintering treatments on each of the initial grid lines using a laser to form grid lines, wherein each sintering treatment includes moving the laser to irradiate the initial grid lines and applying a reverse bias to the initial grid lines, and the wavelength range of the laser is 1000nm to 1064nm, and the range of the reverse bias is -30V to -5V, and each sintering treatment forms a sintering area, and the positive projections of the plurality of sintering areas on the solar cell to be sintered at least cover the positive projections of the initial grid lines on the solar cell to be sintered.

[0008] Optionally, the overlapping area of ​​two adjacent sintering regions is greater than 0 and less than 8.4 mm 2 .

[0009] Optionally, in a first direction, a minimum distance between an edge of the sintering region and an edge of the initial gate line ranges from 0 to 400 μm, wherein the first direction is a direction in which the plurality of initial gate lines are arranged.

[0010] Optionally, in the same grid line, center points of two adjacent sintering regions have a spacing therebetween, and the spacing is greater than 0 and less than 0.5 mm.

[0011] Optionally, the minimum distance between the center point of any one of the sintering regions and the geometric center of the initial grid line is in the range of 0 to 0.25 mm.

[0012] Optionally, a moving direction of each sintering process is the same as an extending direction of the gate lines.

[0013] Optionally, the initial positions of the sintering processes are located at the same end of the initial gate lines.

[0014] Optionally, in a first direction, a maximum width of the sintering region ranges from 80 to 120 μm, wherein the first direction is a direction in which the plurality of initial gate lines are arranged.

[0015] Optionally, the laser is a linear laser beam, the irradiation area formed by the linear laser beam is the sintering area, and the shape of the sintering area includes any one of a rectangle, a circle or an ellipse.

[0016] Optionally, one of the sintering regions includes a plurality of sub-regions arranged along a second direction, and center points of the sub-regions are located on the same straight line, wherein the second direction is an extension direction of the initial gate lines.

[0017] Optionally, the substrate includes a first surface and a second surface relative to each other, and the front and back film deposition on the substrate includes: depositing a tunneling dielectric layer, a doped conductive layer and a first passivation layer in sequence on the first surface of the substrate, and depositing a doped layer and a second passivation layer in sequence on the second surface of the substrate; printing the paste on at least one of the surfaces of the solar cell to be printed to obtain the solar cell to be sintered, including: printing the paste on a side of the second passivation layer away from the doped layer to form the initial grid line; using the laser to perform the sintering treatment on each of the initial grid lines includes: using the laser to perform the sintering treatment on the initial grid line on the second passivation layer, so that part of the paste burns through the second passivation layer in the thickness direction of the substrate to form a gate, wherein one end of the gate is in ohmic contact with the doped layer to form an alloy junction.

[0018] In order to achieve the above object, according to one aspect of the present invention, a solar cell is provided. The solar cell is obtained by processing using any one of the above methods.

[0019] Optionally, the solar cell includes: a substrate having a first surface and a second surface relative to each other; a tunneling dielectric layer located on the first surface; a doped conductive layer located on a side of the tunneling dielectric layer away from the substrate; a first passivation layer located on a side of the doped conductive layer away from the tunneling dielectric layer; a doped layer located on the second surface; a second passivation layer located on a side of the doped layer away from the substrate; and a gate located on a surface of the second passivation layer away from the doped layer and in contact with the doped layer.

[0020] The beneficial effects of this application are as follows:

[0021] An embodiment of the present application provides a method for manufacturing a solar cell and a solar cell. The method for manufacturing a solar cell includes: first, providing a substrate, and performing a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition on the substrate in sequence to obtain a solar cell to be printed, and the solar cell to be printed includes two opposite surfaces; then, printing a slurry on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, and the solar cell to be sintered includes a plurality of initial grid lines arranged at intervals; finally, using a laser to perform multiple sintering treatments on each initial grid line to form a grid line, wherein each sintering treatment includes using a laser to move and irradiate the initial grid line and applying a reverse bias to the initial grid line, and the wavelength range of the laser is 1000nm~1064nm, and the range of the reverse bias is -30V~-5V. Each sintering treatment forms a sintering area, and the positive projections of the multiple sintering areas on the solar cell to be sintered at least cover the positive projections of the initial grid line on the solar cell to be sintered. In this solution, after completing the texturing, diffusion, etching, front and back film deposition and printing slurry of the solar cell to obtain the solar cell to be sintered, the initial grid line is sintered multiple times, so that the next sintering process can sinter again to compensate for the incomplete sintering phenomenon caused by the previous sintering process, thereby solving the under-firing problem that occurs during one sintering process; in addition, the use of the above-mentioned laser wavelength can not only ensure the absorption efficiency of the initial grid line and further improve the sintering effect, but also ensure the sintering depth and further achieve high-precision sintering. The use of the above-mentioned reverse bias can not only further reduce the recombination probability of carriers, but also further reduce the risk of damaging the solar cell. This application solves the technical problem of unsatisfactory sintering effect of solar cells in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 A schematic diagram of a process for manufacturing a solar cell according to an embodiment of the present application is shown;

[0024] Figure 2 A schematic structural diagram of a solar cell to be printed according to an embodiment of the present application is shown;

[0025] Figure 3 Shown in Figure 2 Schematic diagram of the structure of the solar cell to be sintered by printing the paste based on the present invention;

[0026] Figure 4 Shown in Figure 3 Schematic diagram of the structure of a solar cell obtained by multiple sintering processes based on the above;

[0027] Figure 5 A schematic structural diagram of a top view of a solar cell according to an embodiment of the present application is shown.

[0028] The above drawings include the following reference numerals:

[0029] 100, first passivation layer; 101, doped conductive layer; 102, tunneling dielectric layer; 103, substrate; 104, doped layer; 105, second passivation layer; 106, initial gate line; 107, gate; 108, sintering area; H1, predetermined distance. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0033] As introduced in the background art, the sintering effect of solar cells in the prior art is not ideal. In order to solve the above technical problems, the present application proposes a method for manufacturing a solar cell and a solar cell.

[0034] Figure 1 FIG is a flow chart of a method for manufacturing a solar cell according to an embodiment of the present application. Figure 1 Shown, including:

[0035] Step S201, providing a substrate, and sequentially performing texturing treatment, diffusion treatment, etching treatment, and front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed includes two opposite surfaces;

[0036] During the manufacturing process of solar cells, texturing treatment can remove the mechanical damage layer on the surface of the substrate, increase the surface area, reduce the reflectivity and remove impurities. The velvet structure formed after texturing treatment can be a pyramid structure or an irregular concave-convex structure. Diffusion treatment can further form a PN junction on the substrate. For N-type silicon substrates, a layer of phosphosilicate glass is formed on the surface of the substrate during the diffusion process. It should be noted that this film layer will be removed in the subsequent etching process. Etching treatment is used to remove the edge conductive layer and phosphosilicate glass formed during the diffusion process to prevent the PN junction from short-circuiting. The front and back film deposition treatment is used to deposit passivation films and anti-reflection films on the front and back of the cell, thereby further improving the cell efficiency. For example, the front film layer can be made of silicon nitride material to reduce reflection and passivate the surface. The back film layer can be made of materials such as aluminum oxide and silicon nitride for passivation and reducing back recombination.

[0037] Figure 2 is a schematic structural diagram of a solar cell to be printed according to an embodiment of the present application, such as Figure 2As shown, the solar cell to be printed includes, from bottom to top, a first passivation layer 100, a doped conductive layer 101, a tunneling dielectric layer 102, a substrate 103, a doped layer 104, and a second passivation layer 105. The two opposing surfaces of the solar cell to be printed are the surface of the first passivation layer 100 facing away from the doped conductive layer 101 and the surface of the second passivation layer 105 facing away from the doped layer 104. For example, the substrate 103 can be an N-type substrate 103 or a P-type substrate 103. Furthermore, in the thickness direction of the solar cell to be printed, both surfaces of the substrate 103 can be used to receive light. Furthermore, the doped layer 104 and the second passivation layer 105 are sequentially disposed on one surface of the substrate 103; and the tunneling dielectric layer 102, the doped conductive layer 101, and the first passivation layer 100 are sequentially disposed on the other surface of the substrate 103. In practical applications, the solar cells to be printed can constitute at least a part of different types of cells such as tunnel oxide passivating contacts (TOPCon) cells and back contact (BC) cells.

[0038] Step S202, printing a paste on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals;

[0039] The printing paste can be processed by at least one of screen printing, gravure printing, letterpress printing, flexographic printing, laser transfer printing, inkjet printing, and 3D printing. The specific area of ​​the printing paste can be set according to actual conditions and is not specifically limited in this application. Figure 3 is a schematic structural diagram of a solar cell to be sintered according to an embodiment of the present application, such as Figure 3 As shown, the paste is printed on the side of the second passivation layer 105 away from the doped layer 104 to obtain the initial gate line 106. The position relationship of the remaining first passivation layer 100, doped conductive layer 101, tunnel dielectric layer 102 and substrate 103 is the same as that of FIG. Figure 2 The same as in , no further description is given here.

[0040] Step S203, performing multiple sintering processes on each of the above-mentioned initial grid lines to form grid lines, wherein each sintering process forms a sintering area, and the orthographic projections of the multiple sintering areas on the above-mentioned solar cell to be sintered at least cover the orthographic projections of the above-mentioned initial grid lines on the above-mentioned solar cell to be sintered, and the overlapping area of ​​two adjacent sintering areas is greater than 0 and less than 8.4mm 2 .

[0041] The above-mentioned sintering process refers to the process of heat treatment so that at least part of the slurry penetrates the corresponding part of the film layer structure on the substrate to form a grid line. In practical applications, the above-mentioned sintering process can achieve local heating and rapid cooling by precisely controlling the energy and irradiation time of the laser, thereby reducing the heat-affected zone and improving the sintering quality and battery performance. The above-mentioned laser can be a line laser emitted by a laser. During the continuous movement of the laser, the irradiation area formed by the linear light beam is the above-mentioned sintering area. During the process of the laser emitting laser, the emitter can emit continuously or at intervals.

[0042] Figure 4 is a schematic structural diagram of a solar cell according to an embodiment of the present application, such as Figure 4 As shown, the initial gate line is sintered. In the thickness direction of the substrate, part of the slurry burns through the second passivation layer 105 to form the gate 107. One end of the gate 107 contacts the doped layer 104 to form an ohmic contact, forming a tiny alloy junction, thereby reducing the contact resistance and improving the electron transmission efficiency. The positional relationship of the remaining first passivation layer 100, doped conductive layer 101, tunnel dielectric layer 102 and substrate 103 is the same as that of the first passivation layer 100. Figure 2 It should be noted that the moving direction of the multiple sintering treatments ( Figure 5 The directions indicated by the arrows in the figure can be the same or opposite. The shapes of the sintering regions include but are not limited to rectangular, circular or elliptical shapes. In addition, multiple sintering regions cover the initial grid lines, which can achieve a good sintering effect.

[0043] In the above embodiment, a method for manufacturing a solar cell is provided, first, a substrate is provided, and the substrate is subjected to a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition in sequence to obtain a solar cell to be printed, and the solar cell to be printed includes two opposite surfaces; then, a slurry is printed on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, and the solar cell to be sintered includes a plurality of initial grid lines arranged at intervals; finally, each initial grid line is subjected to a plurality of sintering treatments to form a grid line, wherein each sintering treatment forms a sintering area, and the orthographic projections of the plurality of sintering areas on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered, and the overlapping area of ​​two adjacent sintering areas is greater than 0 and less than 8.4 mm 2In this solution, after completing the texturing, diffusion, etching, front and back film deposition and printing slurry of the solar cell to obtain the solar cell to be sintered, the initial grid line is sintered multiple times. In this way, the next sintering process can sinter again to compensate for the incomplete sintering phenomenon caused by the previous sintering process, thereby solving the under-sintering problem that occurs during the first sintering process. In addition, since the multiple sintering areas obtained by the multiple sintering processes can cover the initial grid line, and the overlapping area of ​​the two adjacent sintering areas is greater than 0 and less than 8.4mm 2 On the basis of avoiding the problem of under-firing, the problem of over-firing can be further prevented, the sintering effect of solar cells can be improved, and the technical problem of unsatisfactory sintering effect of solar cells in the prior art can be solved.

[0044] In a first direction, the minimum distance between the edge of the sintering region and the edge of the initial grid lines ranges from 0 to 400 μm, wherein the first direction is the direction in which the plurality of initial grid lines are arranged. Setting the minimum distance between the edge of the sintering region and the edge of the initial grid lines can further prevent the light spot from completely covering the grid lines during the sintering process, further avoiding excessive sintering caused by local overheating. Furthermore, the sintering region can be precisely controlled, avoiding unnecessary energy waste, further improving sintering efficiency, and reducing costs.

[0045] like Figure 5 As shown, the minimum distance between the edge of the sintering region 108 and the edge of the initial gate line 106 is a predetermined distance H1. The predetermined distance H1 can be any value within the above range. For example, the minimum distance between the edge of the sintering region 108 and the edge of the initial gate line 106 can be 100 μm, 200 μm, 300 μm and 400 μm.

[0046] In the same grid line, the center points of two adjacent sintering regions are separated by a distance greater than 0 and less than 0.5 mm. This design ensures proper separation between the center portions of the sintering regions, further preventing excessive fusion of the sintering regions, and thus further improving the sintering effect.

[0047] In this embodiment, the interval between the center points of two adjacent sintering regions in the same gate line may be any value, such as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0048] The minimum distance between the center point of any of the sintering regions and the geometric center of the initial grid lines ranges from 0 to 0.25 mm. This configuration can further precisely control the distance between the center point of the sintering region and the geometric center of the initial grid lines, further ensuring a uniform distribution of the sintering regions and thereby further improving the photoelectric conversion efficiency of the solar cell.

[0049] In practical applications, the minimum distances between the center points of the multiple sintering regions formed on the same grid line and the geometric center of the initial grid line may be the same or different. Those skilled in the art may set the same minimum distance or different minimum distances based on actual conditions. The minimum distance between the center point of any of the above sintering regions and the geometric center of the above initial grid line may be any value within the above range, for example, 0.1 mm, 0.15 mm, 0.2 mm, and 0.25 mm.

[0050] The movement direction of each of the above-mentioned sintering processes is the same as the extension direction of the above-mentioned grid lines. Since the laser is emitted by a laser, the movement direction of the above-mentioned sintering process can be regarded as the movement direction of the laser. The movement direction of the above-mentioned laser is the same as the extension direction of the grid lines. Compared with the method where the movement direction of the laser intersects the extension direction of the grid lines, a larger area on the grid lines can be sintered, thereby further improving the efficiency of the sintering process.

[0051] In practical applications, the moving directions of the above-mentioned sintering processes may be the same, that is, the moving direction of each sintering process is from the first end of the grid line to the second end of the grid line along the extension direction. The moving directions of the above-mentioned sintering processes may be opposite, that is, the moving direction of the previous sintering process is from the first end of the grid line to the second end of the grid line along the extension direction, and the moving direction of the next sintering process is from the second end of the grid line to the first end of the grid line along the extension direction. The second processing method can save the time of the laser moving from the second end of the grid line to the first end of the grid line along the extension direction in the next sintering process, and can further improve the efficiency of the sintering process.

[0052] In some embodiments, the initial position of each of the above-mentioned sintering treatments is located at the same end of the above-mentioned initial grid line. During the laser processing process, as time goes by, due to the influence of thermal effects, changes in material surface transformation, and changes in processing accuracy and efficiency, the sintering effect will change significantly with time. In the early stage, it can usually improve the surface state of the material and processing accuracy, but as time goes on, heat accumulation and energy overload may cause the surface quality of the material to deteriorate, the microstructure to deteriorate, and the processing efficiency to decrease. Therefore, the initial position of each of the above-mentioned sintering treatments is the same, which can ensure that the sintering effect of each sintering treatment is as similar as possible, ensure the uniformity of the sintering treatment of each sintering area, and further improve the sintering effect.

[0053] In still other embodiments, in a first direction, the maximum width of the sintering region ranges from 80 to 120 μm, wherein the first direction is the direction in which the plurality of initial grid lines are arranged. Setting the maximum width of the sintering region can significantly reduce the heat-affected zone, thereby minimizing thermal deformation and residual stress during the sintering process, further avoiding material damage caused by overheating, and further improving the sintering accuracy during the sintering process. In addition, the size setting of the sintering region can further accurately control the width, height, and depth of the melt track, thereby further achieving higher geometric accuracy.

[0054] In practical applications, the maximum width of the sintered region may be any value within the above range. For example, the maximum width of the sintered region may be 80 μm, 90 μm, 100 μm, 110 μm, and 120 μm.

[0055] In some specific applications, each of the above-mentioned sintering processes includes: using a laser to move and irradiate the above-mentioned initial grid lines, and applying a reverse bias to the above-mentioned initial grid lines, wherein the wavelength range of the above-mentioned laser is 1000nm~1064nm, and the range of the above-mentioned reverse bias is -30V~-5V. The use of the above-mentioned laser wavelength can not only ensure the absorption efficiency of the initial grid lines and further improve the sintering effect, but also ensure the sintering depth and further achieve high-precision sintering. The use of the above-mentioned reverse bias can not only further reduce the recombination probability of carriers, but also further reduce the risk of damaging solar cells.

[0056] In practical applications, the reverse bias voltage and wavelength range of the laser can be any value within the above range. For example, the wavelength of the laser can be 1000 nm, 1020 nm, 1040 nm, and 1064 nm, and the reverse bias voltage can be -30 V, -25 V, -20 V, -15 V, -10 V, and -5 V. Furthermore, the reverse bias voltage and wavelength range of the laser can be flexibly set according to actual usage requirements.

[0057] In another embodiment of the present application, one of the above-mentioned sintering areas includes a plurality of sub-areas arranged along a second direction, and the center points of the above-mentioned sub-areas are located on the same straight line, wherein the above-mentioned second direction is the extension direction of the above-mentioned initial grating lines. In the case where the laser emits light beams at intervals, a plurality of sub-areas with intervals are formed during the continuous movement of the laser, and the plurality of sub-areas constitute the above-mentioned sintering area. In other words, during the continuous movement of the laser, the above-mentioned arrangement can further improve the uniformity of the sintering effect by moving in a straight line along the extension direction of the initial grating lines.

[0058] The above-mentioned technical solution of the present application can be used for full back electrode contact cells with busbar-free technology (0BB, Zero Busbar) or multi-busbar technology (MBB, MULTI-BUSBAR), full back electrode contact cells (IBC, Interdigitated Back Contact), full back contact cell solar cells (ABC, All Back Contact), composite passivated back contact cells (HPBC, Hybrid Passivated Back Contact), emitter back passivated cells (PERC, Passivated Emitter and Rear Cell), tunneling oxide passivated contact cells (TOPcon, Tunnel Oxide Passivated Contact), TOPcon-IBC cells, crystalline silicon heterojunction solar cells (HJT, Heterojunction with Intrinsic Thin-layer), perovskite stacked cells, flexible cells and other photovoltaic cells.

[0059] The embodiment of the present application further provides a solar cell as described above, wherein the solar cell is manufactured by any one of the above-mentioned methods for manufacturing a solar cell. Figure 4 As shown, the solar cell comprises:

[0060] A substrate 103 having a first surface and a second surface opposite to each other;

[0061] The substrate 103 may be an N-type substrate 103 or a P-type substrate 103. In addition, in the thickness direction of the solar cell to be printed, both the first surface and the second surface of the substrate 103 may be used to receive light.

[0062] A tunneling dielectric layer 102 is located on the first surface;

[0063] A tunneling dielectric layer 102 is disposed on the first surface, i.e., the back side of substrate 103. Tunneling dielectric layer 102 chemically passivates the back side of substrate 103. Specifically, by saturating dangling bonds on the back side of substrate 103, the density of defect states on the back side of substrate 103 is reduced, and the number of recombination centers on the surface of substrate 103 is reduced, thereby reducing the carrier recombination rate. In some embodiments, the material of tunneling dielectric layer 102 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and magnesium fluoride.

[0064] The doped conductive layer 101 is located on a side of the tunnel dielectric layer 102 away from the substrate 103;

[0065] The doped conductive layer 101 and the tunneling dielectric layer 102 form a passivation contact structure, which can form a band bending on the backlit surface of the substrate 103, thereby achieving selective carrier transport. The material of the doped conductive layer 101 may include at least one of amorphous silicon, polycrystalline silicon, and silicon carbide. The doped conductive layer 101 may be doped with the same type of doping element as the substrate 103. For example, if the doping type of the substrate 103 is P-type, the doping type in the doped conductive layer 101 may also be P-type; if the doping type of the substrate 103 is N-type, the doping type in the doped conductive layer 101 may also be N-type.

[0066] A first passivation layer 100 is located on a side of the doped conductive layer 101 away from the tunnel dielectric layer 102;

[0067] In practical applications, a PECVD method can be used to form a first passivation layer 100 on a side of the doped conductive layer 101 away from the tunnel dielectric layer 102. The first passivation layer 100 can effectively passivate the back surface of the substrate 103, reduce the defect state density on the back surface of the substrate 103, and effectively inhibit carrier recombination on the back surface of the substrate 103. The material of the first passivation layer 100 can include at least one of silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride.

[0068] a doping layer 104 located on the second surface;

[0069] The doping type of the doping layer 104 is opposite to the doping type of the substrate 103 , and the doping layer 104 forms a PN junction with the substrate 103 . In some embodiments, the material of the doping layer 104 can be the same as that of the substrate 103 .

[0070] A second passivation layer 105 is located on a side of the doped layer 104 away from the substrate 103;

[0071] The second passivation layer 105 can achieve a good anti-reflection effect, reduce the reflection of incident light from the front of the substrate 103, and improve the utilization rate of incident light by the substrate 103. The material of the second passivation layer 105 can include at least one of silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride.

[0072] The gate 107 is located on a surface of the second passivation layer 105 away from the doping layer 104 and is in contact with the doping layer 104 .

[0073] The gate electrode is manufactured by sintering the initial gate line, and partially burning the slurry through the second passivation layer 105 in the thickness direction of the substrate.

[0074] The solar cell in the above embodiment is manufactured by the above solar cell manufacturing method. In the manufacturing method, first, a substrate is provided, and the substrate is subjected to a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition in sequence to obtain a solar cell to be printed, and the solar cell to be printed includes two opposite surfaces; then, a slurry is printed on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, and the solar cell to be sintered includes a plurality of initial grid lines arranged at intervals; finally, each initial grid line is subjected to a plurality of sintering treatments to form a grid line, wherein each sintering treatment forms a sintering area, and the orthographic projections of the plurality of sintering areas on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered, and the overlapping area of ​​two adjacent sintering areas is greater than 0 and less than 8.4 mm 2 In this solution, after completing the texturing, diffusion, etching, front and back film deposition and printing slurry of the solar cell to obtain the solar cell to be sintered, the initial grid line is sintered multiple times. In this way, the next sintering process can sinter again to compensate for the incomplete sintering phenomenon caused by the previous sintering process, thereby solving the under-sintering problem that occurs during the first sintering process. In addition, since the multiple sintering areas obtained by the multiple sintering processes can cover the initial grid line, and the overlapping area of ​​the two adjacent sintering areas is greater than 0 and less than 8.4mm 2 On the basis of avoiding the problem of under-firing, the problem of over-firing can be further prevented, the sintering effect of solar cells can be improved, and the technical problem of unsatisfactory sintering effect of solar cells in the prior art can be solved.

[0075] The solar cell of the present application will be described in detail below with reference to specific embodiments and comparative examples.

[0076] Example

[0077] This embodiment provides a method for manufacturing a solar cell, comprising:

[0078] Providing a substrate, and sequentially performing texturing treatment, diffusion treatment, etching treatment, and front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed includes two opposite surfaces;

[0079] Printing a paste on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals;

[0080] Each of the initial grid lines is subjected to multiple sintering processes to form grid lines, wherein each sintering process forms a sintering region, and the orthographic projections of the multiple sintering regions on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered, and the overlapping area of ​​two adjacent sintering regions is greater than 0 and less than 8.4 mm 2 .

[0081] Comparative Example

[0082] This embodiment provides a method for manufacturing a solar cell, comprising:

[0083] Providing a substrate, and sequentially performing texturing treatment, diffusion treatment, etching treatment, and front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed includes two opposite surfaces;

[0084] Printing a paste on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals;

[0085] Each of the initial grid lines is subjected to a sintering process to form a grid line, wherein the orthographic projection of the sintered area formed by the sintering process on the solar cell to be sintered at least covers the orthographic projection of the initial grid line on the solar cell to be sintered.

[0086] The solar cells manufactured in the above-mentioned embodiment and comparative example were tested for power using a digital source meter instrument. The test results are shown in Table 1.

[0087] Table 1

[0088] Classification Battery conversion efficiency Eta (%) <![CDATA[Open-circuit voltage U oc (V)]]> <![CDATA[Short-circuit current I sc (A)]]> Fill factor FF (%) Example 26.41 0.7403 13.923 85.31 Comparative Example 26.37 0.7405 13.931 85.20

[0089] Before the sintering process, both the comparative example and the embodiment are subjected to the steps of texturing, diffusion, etching, deposition of front and back film layers, and printing slurry to obtain the solar cell to be sintered. The difference is that the comparative example is sintered only once, and the sintered area formed completely covers the initial grid line, while the embodiment is sintered multiple times, and the multiple sintered areas obtained cover the above-mentioned initial grid line, and the overlapping area of ​​two adjacent sintered areas is greater than 0 and less than 8.4mm. 2 As can be seen from Table 1, compared with the comparative example, the conversion efficiency of the solar cell in the embodiment is improved by 0.04%, and the fill factor is improved by 0.11%. This shows that the solar cell produced by the method for manufacturing a solar cell provided in the embodiment of the present application improves the sintering effect while also improving the conversion efficiency.

[0090] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0091] 1. The manufacturing method of the solar cell of the present application comprises the following steps: first, providing a substrate, and sequentially performing a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed comprises two opposite surfaces; then, printing a slurry on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals; finally, performing a sintering treatment on each initial grid line multiple times to form a grid line, wherein each sintering treatment forms a sintering area, and the orthographic projections of the plurality of sintering areas on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered, and the overlapping area of ​​two adjacent sintering areas is greater than 0 and less than 8.4 mm 2 In this solution, after completing the texturing, diffusion, etching, front and back film deposition and printing slurry of the solar cell to obtain the solar cell to be sintered, the initial grid line is sintered multiple times. In this way, the next sintering process can sinter again to compensate for the incomplete sintering phenomenon caused by the previous sintering process, thereby solving the under-sintering problem that occurs during the first sintering process. In addition, since the multiple sintering areas obtained by the multiple sintering processes can cover the initial grid line, and the overlapping area of ​​the two adjacent sintering areas is greater than 0 and less than 8.4mm 2 On the basis of avoiding the problem of under-firing, the problem of over-firing can be further prevented, the sintering effect of solar cells can be improved, and the technical problem of unsatisfactory sintering effect of solar cells in the prior art can be solved.

[0092] 2. The solar cell of the present application is manufactured by the above-mentioned solar cell manufacturing method. In the manufacturing method, first, a substrate is provided, and the substrate is subjected to a texturing treatment, a diffusion treatment, an etching treatment, and a front and back film deposition in sequence to obtain a solar cell to be printed, and the solar cell to be printed includes two opposite surfaces; then, a slurry is printed on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, and the solar cell to be sintered includes a plurality of initial grid lines arranged at intervals; finally, each initial grid line is subjected to a plurality of sintering treatments to form a grid line, wherein each sintering treatment forms a sintering area, and the orthographic projections of the plurality of sintering areas on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered, and the overlapping area of ​​two adjacent sintering areas is greater than 0 and less than 8.4 mm 2In this solution, after completing the texturing, diffusion, etching, front and back film deposition and printing slurry of the solar cell to obtain the solar cell to be sintered, the initial grid line is sintered multiple times. In this way, the next sintering process can sinter again to compensate for the incomplete sintering phenomenon caused by the previous sintering process, thereby solving the under-sintering problem that occurs during the first sintering process. In addition, since the multiple sintering areas obtained by the multiple sintering processes can cover the initial grid line, and the overlapping area of ​​the two adjacent sintering areas is greater than 0 and less than 8.4mm 2 On the basis of avoiding the problem of under-firing, the problem of over-firing can be further prevented, the sintering effect of solar cells can be improved, and the technical problem of unsatisfactory sintering effect of solar cells in the prior art can be solved.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: Providing a substrate, and sequentially performing a texturing process, a diffusion process, an etching process, and front and back film deposition on the substrate to obtain a solar cell to be printed, wherein the solar cell to be printed includes two opposite surfaces; Printing a paste on at least one surface of the solar cell to be printed to obtain a solar cell to be sintered, wherein the solar cell to be sintered comprises a plurality of initial grid lines arranged at intervals; Laser is used to perform multiple sintering treatments on each of the initial grid lines to form grid lines, wherein each sintering treatment includes using laser to move and irradiate the initial grid lines and applying a reverse bias to the initial grid lines, and the wavelength range of the laser is 1000nm~1064nm, and the range of the reverse bias is -30V~-5V. Each sintering treatment forms a sintering area, and the orthographic projections of the multiple sintering areas on the solar cell to be sintered at least cover the orthographic projections of the initial grid lines on the solar cell to be sintered.

2. The method for manufacturing a solar cell according to claim 1, wherein: The overlapping area of ​​two adjacent sintered regions is greater than 0 and less than 8.4 mm 2 .

3. The method for manufacturing a solar cell according to claim 1, wherein: In a first direction, a minimum distance between an edge of the sintering region and an edge of the initial gate line ranges from 0 to 400 μm, wherein the first direction is a direction in which the plurality of initial gate lines are arranged.

4. The method for manufacturing a solar cell according to claim 1, wherein: In the same grid line, center points of two adjacent sintering regions are spaced apart, and the space is greater than 0 and less than 0.5 mm.

5. The method for manufacturing a solar cell according to claim 1, wherein: The minimum distance between the center point of any one of the sintering regions and the geometric center of the initial grid line is in the range of 0 to 0.25 mm.

6. The method for manufacturing a solar cell according to claim 1, wherein: The moving direction of each sintering process is the same as the extending direction of the gate line.

7. The method for manufacturing a solar cell according to claim 1, wherein: The initial positions of the sintering processes are located at the same end of the initial grid lines.

8. The method for manufacturing a solar cell according to claim 1, wherein: In a first direction, a maximum width of the sintering region ranges from 80 to 120 μm, wherein the first direction is a direction in which the plurality of initial gate lines are arranged.

9. The method for manufacturing a solar cell according to claim 1, wherein: The laser is a linear laser beam, and the irradiation area formed by the linear laser beam is the sintering area. The shape of the sintering area includes any one of a rectangle, a circle, and an ellipse.

10. The method for manufacturing a solar cell according to claim 1, wherein: One of the sintering regions includes a plurality of sub-regions arranged along a second direction, and the center points of the sub-regions are located on the same straight line, wherein the second direction is the extending direction of the initial gate lines.

11. The method for manufacturing a solar cell according to claim 1, wherein: The substrate comprises a first surface and a second surface opposite to each other, and depositing the front and back film layers on the substrate comprises: depositing a tunnel dielectric layer, a doped conductive layer, and a first passivation layer in sequence on the first surface of the substrate, and depositing a doped layer and a second passivation layer in sequence on the second surface of the substrate; Printing the paste on at least one surface of the solar cell to be printed to obtain the solar cell to be sintered, comprising: printing the paste on a side of the second passivation layer away from the doping layer to form the initial grid line; Using the laser to perform the sintering treatment on each of the initial gate lines includes: using the laser to perform the sintering treatment on the initial gate lines on the second passivation layer, so that part of the slurry burns through the second passivation layer in the thickness direction of the substrate to form a gate, wherein one end of the gate is in ohmic contact with the doping layer to form an alloy junction.

12. A solar cell, characterized in that: The solar cell is obtained by using the solar cell manufacturing method according to any one of claims 1 to 11.

13. The solar cell according to claim 12, wherein: The solar cell comprises: a substrate having opposing first and second surfaces; a tunneling dielectric layer, located on the first surface; a doped conductive layer, located on a side of the tunnel dielectric layer away from the substrate; a first passivation layer, located on a side of the doped conductive layer away from the tunnel dielectric layer; a doping layer located on the second surface; a second passivation layer, located on a side of the doped layer away from the substrate; The gate is located on a surface of the second passivation layer away from the doping layer and is in contact with the doping layer.

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