Photovoltaic cell preparation method, photovoltaic cell, laminated cell and photovoltaic cell assembly

Abstract

The invention relates to a photovoltaic cell preparation method, a photovoltaic cell, a laminated cell and a photovoltaic cell module. Providing an initial battery piece; depositing and forming a protective layer on the surface; carrying out laser treatment twice; printing and sintering to form an electrode; and carrying out at least two times of laser-assisted sintering on the electrode. According to the photovoltaic cell preparation method, the protection layer at the first area is removed, the doping concentration at the first area is improved, and at least two times of laser-assisted sintering are combined, so that on one hand, the metal contact area is optimized, the usage amount of silver paste is reduced, the material cost is reduced, and meanwhile, paste contact sintering is enhanced; damage caused by laser grooving doping is removed; and on the other hand, the doping concentration is optimized, the contact resistance is remarkably reduced, the open-circuit voltage and the filling factor are favorably improved, the shading loss is reduced, and the current collection efficiency is ensured, so that the photoelectric conversion efficiency and the reliability of the cell are remarkably improved, the production process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell preparation, and particularly to a method for preparing a photovoltaic cell, a photovoltaic cell, a tandem cell, and a photovoltaic cell module. Background Art

[0002] The Tunnel Oxide Passivated Contact (TOPCon) cell adopts an efficient N-type silicon solar cell technology based on the principle of selective carriers. By preparing an ultrathin silicon oxide layer and a doped polysilicon layer on the back of the N-type silicon substrate, the TOPCon cell forms a passivated contact structure, thereby reducing surface recombination and metal contact recombination, and further improving the conversion efficiency of the cell. Therefore, it is widely used in the field of solar cells.

[0003] However, the TOPCon cell has the problem of relatively large contact resistance, which reduces the current collection efficiency and results in a relatively low overall conversion efficiency of the cell. Summary of the Invention

[0004] In order to solve the problem of relatively large contact resistance existing in photovoltaic cells, it is necessary to provide a method for preparing a photovoltaic cell, a photovoltaic cell, a tandem cell, and a photovoltaic cell module.

[0005] One embodiment of this application is a method for preparing a photovoltaic cell, which includes the steps of:

[0006] Providing an initial cell sheet, the surface of the initial cell sheet has a doped conductive layer, and the surface has a first region and a second region;

[0007] Depositing and forming a protective layer on the surface;

[0008] Performing a first laser treatment on the first region to remove the protective layer at the first region;

[0009] Performing a second laser treatment on the first region to make the doping concentration of the doped conductive layer in the first region higher than that in the second region;

[0010] Printing and sintering the initial cell sheet to form an electrode on the initial cell sheet, and the projection of the electrode on the substrate of the initial cell sheet is located in the first region;

[0011] Performing at least two laser-assisted sinterings on the electrode, wherein the at least two laser-assisted sinterings use lasers with different wavelengths.

[0012] In some embodiments, depositing and forming a protective layer on the surface includes: depositing and forming a passivation and antireflection layer on the surface.

[0013] In some of these embodiments, the surface includes a first side and a second side that are oppositely disposed; and, depositing a passivation and antireflection layer on the surface includes:

[0014] Depositing an aluminum oxide layer and a first silicon nitride layer on the first side;

[0015] Depositing a second silicon nitride layer on the second side.

[0016] In some of these embodiments, green light is used for the first laser treatment and red light is used for the second laser treatment.

[0017] In some of these embodiments, the laser energy density in the first laser treatment is lower than the laser energy density in the second laser treatment;

[0018] The pulse width range in the first laser treatment is greater than the pulse width range in the second laser treatment;

[0019] The laser frequency and scanning speed in the first laser treatment are respectively lower than the laser frequency and scanning speed in the second laser treatment.

[0020] In some of these embodiments, the laser energy density in the first laser treatment is from 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is from 0.5 J / cm² to 1.0 J / cm²; or,

[0021] The pulse width range in the first laser treatment is from 10 ns to 30 ns, and the pulse width range in the second laser treatment is from 1 ns to 10 ns; or,

[0022] The laser frequency range in the first laser treatment is from 10 kHz to 30 kHz, and the scanning speed is from 100 mm / s to 300 mm / s; the laser frequency range in the second laser treatment is from 30 kHz to 50 kHz, and the scanning speed is from 300 mm / s to 500 mm / s.

[0023] In some of these embodiments, in the at least two laser-assisted sinterings, the irradiation time of the first laser-assisted sintering is at least twice the irradiation time of the second laser-assisted sintering.

[0024] In some of these embodiments, in the at least two laser-assisted sinterings, the spot width of the laser is greater than the width of the electrode.

[0025] In some of these embodiments, in the at least two laser-assisted sinterings, green laser light is used for the first laser-assisted sintering and red laser light is used for the second laser-assisted sintering.

[0026] In some of these embodiments, the printing of the initial solar cell is specifically: screen printing the initial solar cell, or laser pattern transfer on the initial solar cell.

[0027] In some of these embodiments, a photovoltaic cell is obtained by using the photovoltaic cell preparation method described in any of the embodiments; wherein, the photovoltaic cell includes:

[0028] A substrate having opposite first and second surfaces;

[0029] An emitter disposed on the first surface of the substrate;

[0030] A first passivation and antireflection layer disposed on the emitter;

[0031] A first electrode electrically connected to the emitter;

[0032] A tunneling layer disposed on the second surface of the substrate;

[0033] A doped polysilicon layer disposed on the tunneling layer;

[0034] A second passivation and antireflection layer disposed on the doped polysilicon layer; and,

[0035] A second electrode electrically connected to the doped polysilicon layer.

[0036] In some of these embodiments, a tandem cell includes a top cell and a bottom cell, the bottom cell is the photovoltaic cell described in any of the embodiments, and the top cell is a perovskite cell.

[0037] In some of these embodiments, a photovoltaic cell module includes the photovoltaic cell described in any of the embodiments.

[0038] In some of these embodiments, a photovoltaic cell module includes a photovoltaic cell obtained by using the photovoltaic cell preparation method described in any of the embodiments.

[0039] In some of these embodiments, a photovoltaic cell module includes the tandem cell described in any of the embodiments.

[0040] The above-mentioned photovoltaic cell preparation method, photovoltaic cell, tandem cell, and photovoltaic cell module remove the protective layer at the first region to cooperate with increasing the doping concentration at the first region, combined with at least two laser-assisted sinterings. On the one hand, by optimizing the metal contact region, it is beneficial to reduce the usage amount of silver paste, thereby reducing the material cost, enhancing the contact sintering of the paste, and removing the damage caused by laser grooving doping. On the other hand, the doping concentration is optimized, significantly reducing the contact resistance, which is beneficial to increasing the open-circuit voltage and fill factor, reducing the shading loss at the same time, and ensuring the current collection efficiency. Therefore, the photoelectric conversion efficiency and reliability of the cell are significantly improved, while the production process is simplified and the production cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic flow chart of an embodiment of the photovoltaic cell preparation method described in the present application.

[0043] Figure 2 It is a schematic structural diagram of the initial cell sheet of the first embodiment of the photovoltaic cell described in the present application.

[0044] Figure 3 For Figure 2 a schematic diagram of the first side of the initial cell sheet of the illustrated embodiment.

[0045] Figure 4 For Figure 2 a schematic diagram of the second side of the initial cell sheet of the illustrated embodiment.

[0046] Figure 5 It is a schematic structural diagram of the first embodiment of the photovoltaic cell described in the present application with a doped conductive layer.

[0047] Figure 6 It is a schematic structural diagram of the first embodiment of the photovoltaic cell described in the present application with a protective layer.

[0048] Figure 7 It is a schematic structural diagram of the first embodiment of the photovoltaic cell described in the present application after the first laser treatment.

[0049] Figure 8 It is a schematic structural diagram of the second embodiment of the photovoltaic cell described in the present application with a protective layer.

[0050] Figure 9Schematic diagram of the structure of the second embodiment of the photovoltaic cell of the present application after the first laser treatment.

[0051] Figure 10 Schematic diagram of the structure of the second embodiment of the photovoltaic cell of the present application after at least two laser-assisted sinterings.

[0052] Figure 11 Schematic diagram of the structure of the third embodiment of the photovoltaic cell of the present application.

[0053] Figure 12 Schematic diagram of the structure of the fourth embodiment of the photovoltaic cell of the present application.

[0054] Reference numerals: 100, initial cell; 101, first region; 102, second region; 103, third region; 104, fourth region; 105, fifth region; 106, sixth region; 110, surface; 111, first surface; 112, second surface; 120, doped conductive layer; 121, first doped conductive layer; 122, second doped conductive layer; 130, protective layer; 131, alumina layer; 132, first silicon nitride layer; 133, second silicon nitride layer; 141, first trench; 142, second trench; 143, third trench; 144, fourth trench; 200, photovoltaic cell; 210, substrate; 220, emitter; 230, first passivation and antireflection layer; 240, first electrode; 250, tunneling layer; 260, doped polysilicon layer; 270, second passivation and antireflection layer; 280, second electrode. Detailed implementation manners

[0055] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0056] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used in the description of the present application are only for the purpose of illustration and do not represent the only implementation manner.

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

[0058] In this application, unless otherwise clearly specified and defined, the first feature may be in direct contact with the second feature or in indirect contact with the second feature through an intermediate medium when the first feature is "on" or "under" the second feature. Moreover, when the first feature is "above", "over" or "on top of" the second feature, the first feature may be directly above or diagonally above the second feature, or merely indicate that the first feature has a higher horizontal height than the second feature. When the first feature is "below", "beneath" or "underneath" the second feature, the first feature may be directly below or diagonally below the second feature, or merely indicate that the first feature has a lower horizontal height than the second feature.

[0059] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more of the related listed items.

[0060] In one embodiment of this application, a method for preparing a photovoltaic cell is as Figure 1As shown, it includes the steps of: providing an initial cell, the surface of the initial cell having a doped conductive layer with a first region and a second region; depositing a protective layer on the surface; performing a first laser treatment on the first region to remove the protective layer at the first region; performing a second laser treatment on the first region to make the doping concentration of the doped conductive layer in the first region higher than that in the second region; performing printing and sintering on the initial cell to form an electrode, the projection of the electrode on the substrate of the initial cell being located in the first region; performing at least two laser-assisted sinterings on the electrode, where at least two laser-assisted sinterings use lasers with different wavelengths. In the above photovoltaic cell preparation method, by removing the protective layer at the first region and cooperating with increasing the doping concentration at the first region, combined with at least two laser-assisted sinterings, on the one hand, by optimizing the metal contact region, it is beneficial to reduce the usage amount of silver paste, thereby reducing the material cost, while enhancing the paste contact sintering and removing the damage caused by laser grooving doping; on the other hand, the doping concentration is optimized, significantly reducing the contact resistance, which is beneficial to increasing the open-circuit voltage and the fill factor, while reducing the shading loss and ensuring the current collection efficiency. Therefore, the photoelectric conversion efficiency and reliability of the cell are significantly improved, while simplifying the production process and reducing the production cost.

[0061] In each embodiment, the photovoltaic cell preparation method has the steps of: as Figure 2 shown, providing an initial cell 100, the surface 110 of the initial cell 100 having a first region 101 and a second region 102; as an example, the surface 110 includes a first surface 111 and a second surface 112 arranged opposite to each other; in other embodiments, the surface 110 to be processed is one surface. Combining Figure 3 and Figure 4 , the first region 101 includes a third region 103 located on the first surface 111 and a fifth region 105 located on the second surface 112, and the second region 102 includes a fourth region 104 located on the first surface 111 and a sixth region 106 located on the second surface 112. Figure 3 and Figure 4 shown in the embodiments, the projections of the third region 103 and the fifth region 105 on the substrate 210 of the initial cell 100 do not coincide, and the projections of the fourth region 104 and the sixth region 106 on the substrate 210 also do not coincide. In other embodiments, as Figure 10 shown, the projections of the third region 103 and the fifth region 105 on the substrate 210 of the initial cell 100 coincide, and the projections of the fourth region 104 and the sixth region 106 on the substrate 210 also coincide. As Figure 3 and Figure 4As shown, the first surface 111 and the second surface 112 respectively include a first region 101 and a second region 102 that are spaced apart in the target direction. Among them, the first surface 111 includes a third region 103 and a fourth region 104 that are spaced apart in the target direction, and the second surface 112 includes a fifth region 105 and a sixth region 106 that are spaced apart in the target direction; as an example, the target direction is the length direction of the electrode to be described below. It can be understood that the first surface 111 and the second surface 112 are planes, or at least one of the first surface 111 and the second surface 112 is a surface 110 with a microscopic undulating shape after being processed by a texturing process. Such a design is conducive to flexibly setting the positions of the first region 101 and the second region 102 according to the product design requirements to cooperate with the electrode production process to be described later.

[0062] Combined with Figure 5 , the surface 110 of the initial cell 100 has a doped conductive layer 120. For the embodiment where the surface 110 includes the first surface 111 and the second surface 112, as Figure 5 shown, the doped conductive layer 120 includes a first doped conductive layer 121 located on the first surface 111 and a second doped conductive layer 122 located on the second surface 112. That is, exemplarily, an initial cell 100 is provided. The initial cell 100 includes a first surface 111 and a second surface 112 that are oppositely arranged. It can also be understood that the substrate 210 of the initial cell 100 includes a first surface 111 and a second surface 112 that are oppositely arranged. Both the first surface 111 and the second surface 112 have a doped conductive layer 120. Among them, the first surface 111 has a first doped conductive layer 121, and the second surface 112 has a second doped conductive layer 122; it can also be understood that the substrate 210 is respectively provided with a first doped conductive layer 121 and a second doped conductive layer 122 on its first surface 111 and second surface 112. As an example, the first doped conductive layer 121 is the emitter to be described below, and the second doped conductive layer 122 is the doped polysilicon layer to be described below. Such a design is conducive to preparing the initial cell 100 into a required photovoltaic cell.

[0063] In each embodiment, the method for preparing a photovoltaic cell has the steps: as Figure 6 shown, a protective layer 130 is deposited on the surface 110. In some of these embodiments, depositing a protective layer 130 on the surface includes: depositing a passivation and antireflection layer on the surface, that is, using the passivation and antireflection layer as the protective layer 130. As an example, the protective layer 130 is deposited on the first surface 111 and the second surface 112. For the embodiment where the surface 110 includes the first surface 111 and the second surface 112, Figure 6In the illustrated embodiment, the protective layer 130 includes a first passivation and antireflection layer 230 located on the first doped conductive layer 121, and a second passivation and antireflection layer 270 located on the second doped conductive layer 122. In some embodiments, as Figure 7 shown, the first passivation and antireflection layer 230 includes an alumina layer 131 and a first silicon nitride layer 132, and the second passivation and antireflection layer 270 includes a second silicon nitride layer 133. Such a design is conducive to adapting to the first surface 111 and the second surface 112 at different positions of the finished battery, avoiding waste of materials and affecting the conversion efficiency.

[0064] As an example, depositing and forming a passivation and antireflection layer on the surface 110 includes: depositing and forming an alumina layer 131 and a first silicon nitride layer 132 located on the alumina layer 131 on the first surface 111, that is, depositing and forming an alumina layer 131 on the first surface 111, and depositing and forming a first silicon nitride layer 132 on the alumina layer 131; depositing and forming a second silicon nitride layer 133 on the second surface 112; that is, depositing and forming an alumina layer 131 on the first surface 111, depositing and forming a first silicon nitride layer 132 on the alumina layer 131, and depositing and forming a second silicon nitride layer 133 on the second surface 112. In some embodiments, as Figure 6 shown, depositing and forming a protective layer 130 on the first surface 111 and the second surface 112 of the initial cell 100 specifically includes: depositing and forming an alumina layer 131 on the first surface 111 of the initial cell 100; depositing and forming a first silicon nitride layer 132 on the first surface 111 of the initial cell 100; depositing and forming a second silicon nitride layer 133 on the second surface 112 of the initial cell 100. That is, the protective layer 130 on the first surface 111 includes an alumina layer 131 and a first silicon nitride layer 132, and the protective layer 130 on the second surface 112 includes a second silicon nitride layer 133; for the sake of distinction, the first silicon nitride layer 132 on the first surface 111 can be called the first antireflection layer; the second silicon nitride layer 133 on the second surface 112 can be called the second antireflection layer. Or the alumina layer 131 and the first silicon nitride layer 132 on the first surface 111 are jointly called the first passivation and antireflection layer 230; the second silicon nitride layer 133 on the second surface 112 is called the second passivation and antireflection layer 270. The functions of the first silicon nitride layer 132 and the second silicon nitride layer 133 are to reduce reflection to maximize the incident rate, thereby improving the utilization rate. Moreover, during the formation process of the first silicon nitride layer 132 and the second silicon nitride layer 133, the generated hydrogen atoms can also effectively passivate the substrate 210 of the initial cell 100, that is, the silicon wafer. That is, the first silicon nitride layer 132 and the second silicon nitride layer 133 also have a certain passivation effect and can reduce the carrier recombination on the surface 110 of the silicon wafer.

[0065] With such a design, on the one hand, the first silicon nitride layer 132 and the second silicon nitride layer 133 can effectively reduce the reflectivity of the battery surface 110, enabling more sunlight to enter the battery interior, thereby improving the utilization rate of light, increasing the generation of photo-generated carriers, and further enhancing the photoelectric conversion efficiency of the battery. Moreover, the alumina layer 131, the first silicon nitride layer 132, and the second silicon nitride layer 133 act alone or jointly to further reduce the carrier recombination on the silicon wafer surface 110, improve the lifetime and mobility of carriers, facilitate the separation and transport of photo-generated carriers, and thus increase the open-circuit voltage and fill factor of the battery, further boosting the photoelectric conversion efficiency of the battery. On the other hand, for the first surface 111, the dual passivation effect of the alumina layer 131 and the first silicon nitride layer 132 can effectively protect the first surface 111 of the silicon wafer that receives light, reducing the influence of surface states and impurities, thereby improving the anti-attenuation performance and long-term stability of the photovoltaic battery, and further extending the service life of the photovoltaic battery.

[0066] In each embodiment, the method for preparing a photovoltaic battery has the steps of: performing a first laser treatment on the first region 101 to remove the protective layer 130 at the first region 101; as an example, after removing the protective layer 130 at the first region 101, a trench is formed at the position of the original protective layer 130 on the doped conductive layer 120 to facilitate subsequent processing steps. As Figure 8 shown, a first laser treatment is performed on the third region 103 of the first surface 111 to remove the first passivation and antireflection layer 230 at the third region 103, forming a first trench 141, and the first passivation and antireflection layer 230 at the fourth region 104 is retained; a first laser treatment is performed on the fifth region 105 of the second surface 112 to remove the second passivation and antireflection layer 270 at the fifth region 105, forming a second trench 142, and the second passivation and antireflection layer 270 at the sixth region is retained. Or as Figure 9 shown, a first laser treatment is performed on the third region 103 of the first surface 111 to remove the alumina layer 131 and the first silicon nitride layer 132 at the third region 103, forming a third trench 143, and the alumina layer 131 and the first silicon nitride layer 132 at the fourth region 104 are retained; a first laser treatment is performed on the fifth region 105 of the second surface 112 to remove the second silicon nitride layer 133 at the fifth region 105, forming a fourth trench 144, and the second silicon nitride layer 133 at the sixth region is retained. With such a design, through the first laser treatment process, the protective layer 130 at the first region 101 is removed, creating conditions for high-concentration doping and electrode printing in the subsequent second laser process treatment, thereby helping to improve the electrode contact effect, further reducing the contact resistance, and thus increasing the current collection efficiency.

[0067] In some of these embodiments, a second laser treatment is performed on the first region 101 to make the doping concentration of the doped conductive layer 120 in the first region 101 higher than the doping concentration of the doped conductive layer 120 in the second region 102. As an example, performing the first laser treatment on the first region 101 includes: performing the first laser treatment on the first region 101 of the first surface 111 and the second surface 112 to remove the protective layer 130 on the first surface 111 and the second surface 112 at the first region 101; as an example, performing the second laser treatment on the first region 101 of the first surface 111 and the second surface 112 to make the doping concentration of the doped conductive layer 120 in the first region 101 higher than the doping concentration of the doped conductive layer 120 in the second region 102. Such a design, on the one hand, through the first laser treatment process, removes the protective layer 130 at the first region 101, creating conditions for high-concentration doping and electrode printing in the subsequent second laser process treatment, which helps to form a better-quality electrode contact, thereby reducing the contact resistance and improving the current collection efficiency. On the other hand, the design of the second laser treatment process makes the doping concentration of the first region 101 higher than that of the second region 102. This differential doping concentration design, combined with the subsequent treatment processes of the first electrode 240 and the second electrode 280, can significantly reduce the contact resistance, thereby increasing the open-circuit voltage and fill factor of the battery, and further improving the photoelectric conversion efficiency of the battery.

[0068] As an example, before printing and sintering the initial solar cell 100, the photovoltaic cell manufacturing method uses a laser process to selectively perform two lasers on the front and back sides respectively, including adding a laser process before printing to groove the front side of the solar cell; as an example, adding a laser process before screen printing to groove the front side of the solar cell. The first laser treatment removes the protective layer 130 at the first region 101 on the first surface 111 and the second surface 112, that is, removes part of the film layers on the front and back sides. Exemplarily, for an embodiment with an alumina layer 131, the first laser treatment removes the alumina layer 131 at the first region 101 on the first surface 111; for an embodiment with a first silicon nitride layer 132 and a second silicon nitride layer 133, the first laser treatment removes the first silicon nitride layer 132 at the first region 101 on the first surface 111, and removes the second silicon nitride layer 133 at the first region 101 on the second surface 112. This is beneficial for cooperating with subsequent processes to perform high-concentration doping in these first regions 101. As an example, the second laser treatment makes the doping concentration in the first region 101 higher than that in the second region 102. Such a design, on the one hand, grooving the front side of the solar cell before screen printing through the laser process, removing the protective layer 130 at the first region 101, creates conditions for subsequent high-concentration doping and electrode printing, is beneficial for improving the electrode contact state, and thus further reduces the contact resistance. On the other hand, through the laser process for the second laser treatment, the doping concentration in the first region 101 is increased. As before, this design of differential doping concentration, combined with the subsequent treatment processes of the first electrode 240 and the second electrode 280, can significantly reduce the contact resistance, thereby increasing the open-circuit voltage and fill factor of the solar cell, and further improving the photoelectric conversion efficiency of the solar cell. On the further hand, by precisely removing the protective layer 130 at the first region 101 through the laser process, the doping region and the electrode printing region can be more accurately controlled, reducing the waste of conductive materials such as silver paste, and thus reducing the production cost. On yet another hand, the laser process can effectively repair the damage caused during the laser grooving doping process, improve the stability and reliability of the solar cell, and extend the service life of the solar cell.

[0069] As an example, before screen printing after backside coating, two lasers are respectively performed on the front and back sides of the solar cell. The first laser treatment, namely the initial laser doping, can also be called the initial laser doping. First, the initial laser is used to remove part of the passivation layer on the front and back film layers in a local area of the solar cell for preliminary doping, forming a preliminary high-concentration doping region. This step can use green or red laser, and the appropriate wavelength is selected according to specific requirements. The second laser treatment, namely the second laser doping, can also be called the second laser doping. On the basis of the initial doping, the second laser doping is performed to further optimize the uniformity and depth of the doping region. The two dopings can use lasers with the same or different wavelengths to achieve more precise control.

[0070] In some of these embodiments, the first laser treatment uses green light, and the second laser treatment uses red light; that is, the first laser treatment uses green laser light, and the second laser treatment uses red laser light. That is to say, in this embodiment, the laser wavelengths used in the first laser treatment and the second laser treatment are set differently. As an example, the first laser treatment uses green light with a wavelength of 495 nanometers to 570 nanometers to achieve a shallower doping depth and high-precision local doping. The high energy density of the green laser can quickly activate the dopant. The second laser treatment uses red light with a wavelength of 620 nanometers to 1100 nanometers to achieve a deeper doping depth and a more uniform doping distribution. The low energy density and deep penetration ability of the red laser can reduce surface damage. Exemplarily, the first laser treatment uses green light with a wavelength of 532 nm, and the second laser treatment uses red light with a wavelength of 1064 nm. Such a design, on the one hand, through the laser process combined with green light for the first laser treatment, not only helps to effectively repair the damage caused to the first region 101 during the laser grooving doping process, improving the stability and reliability of the battery, but also helps to achieve high-precision local doping with a shallower doping depth in the first region 101; on the other hand, through the laser process for the second laser treatment, the doping concentration in the first region 101 is further increased, which helps to reduce the contact resistance of the photovoltaic cell, and thus helps to increase the open-circuit voltage and fill factor of the photovoltaic cell, so the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0071] As an example, the initial laser doping usually uses a lower energy density to form a preliminary high-concentration doping region. The second laser doping uses a higher energy density to further optimize the doping depth and uniformity. The initial laser doping usually uses a longer pulse width to ensure sufficient diffusion time for the dopant. The second laser doping uses a shorter pulse width to achieve more precise local heating and doping. The initial laser doping usually uses a lower frequency and a slower scanning speed to ensure that the exposure time of each laser point is long enough. The second laser doping uses a higher frequency and a faster scanning speed to improve production efficiency.

[0072] In some of these embodiments, the laser energy density in the first laser treatment is lower than that in the second laser treatment; the pulse width range in the first laser treatment is greater than that in the second laser treatment; the laser frequency and scanning speed in the first laser treatment are respectively lower than those in the second laser treatment. In some of these embodiments, the laser energy density in the first laser treatment is from 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is from 0.5 J / cm² to 1.0 J / cm²; in some of these embodiments, the pulse width range in the first laser treatment is from 10 ns to 30 ns, and the pulse width range in the second laser treatment is from 1 ns to 10 ns; in some of these embodiments, the laser frequency range in the first laser treatment is from 10 kHz to 30 kHz, and the scanning speed is from 100 mm / s to 300 mm / s; the laser frequency range in the second laser treatment is from 30 kHz to 50 kHz, and the scanning speed is from 300 mm / s to 500 mm / s. In some of these embodiments, the laser energy density in the first laser treatment is from 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is from 0.5 J / cm² to 1.0 J / cm²; the pulse width range in the first laser treatment is from 10 ns to 30 ns, and the pulse width range in the second laser treatment is from 1 ns to 10 ns; the laser frequency range in the first laser treatment is from 10 kHz to 30 kHz, and the scanning speed is from 100 mm / s to 300 mm / s; the laser frequency range in the second laser treatment is from 30 kHz to 50 kHz, and the scanning speed is from 300 mm / s to 500 mm / s. The rest of the embodiments are the same by analogy and will not be elaborated.

[0073] As an example, the laser energy density in the first laser treatment is 0.25 J / cm², and the laser energy density in the second laser treatment is 0.8 J / cm²; the pulse width range in the first laser treatment is 18 ns, and the pulse width range in the second laser treatment is 3 ns; the laser frequency range in the first laser treatment is 20 kHz, and the scanning speed is 200 mm / s; the laser frequency range in the second laser treatment is 42 kHz, and the scanning speed is 390 mm / s; the rest of the embodiments are the same by analogy and will not be elaborated.

[0074] In such a design, on the one hand, high-concentration doping is achieved by improving doping, that is, through laser grooving, high-concentration doping is carried out in the first region such as the metal gate line contact region, which can significantly reduce the contact resistance, that is, the series resistance. The increase in doping concentration significantly reduces the contact resistance between the electrode and the silicon wafer, thereby improving the current collection efficiency of the photovoltaic cell. On the other hand, high-concentration doping is only carried out in the first region such as the metal gate line contact region, which can avoid the negative impacts brought by high-concentration doping on the entire cell surface, such as increasing surface recombination losses, that is, it is beneficial to avoid increasing surface recombination losses. On the further hand, due to the reduction of the contact resistance, the recombination loss of carriers can be reduced, thereby increasing the open-circuit voltage, which is further beneficial to improving the electrical performance. On yet another hand, by improving doping and cooperating with at least two laser-assisted sinterings, it is beneficial to optimize the electrical performance of the metal contact region, increase the fill factor, and further improve the overall efficiency of the photovoltaic cell; at the same time, the usage amount of silver paste can be reduced, thereby reducing the material cost. Among them, the fill factor reflects the current and voltage output capabilities of the cell under actual working conditions. In this embodiment, two laser dopings are respectively carried out on the front and back sides. By reducing the series resistance and optimizing the electrode contact, the fill factor of the photovoltaic cell can be significantly increased, thereby improving the overall performance of the photovoltaic cell and significantly increasing the overall photoelectric conversion efficiency of the photovoltaic cell.

[0075] In each embodiment, the method for preparing a photovoltaic cell has the steps of: printing and sintering an initial cell wafer 100 to form electrodes on the initial cell wafer 100; it can be understood that the initial cell wafer 100 before printing and sintering can also be referred to as an intermediate cell wafer or a semi-finished cell wafer. As Figure 10 shown, as an example, the initial cell wafer 100 is printed and sintered to form a first electrode 240 on the first surface 111 and a second electrode 280 on the second surface 112; it can be understood that Figure 10 shown is to form a first electrode 240 on the first doped conductive layer 121 on the first surface 111 and a second electrode 280 on the second doped conductive layer 122 on the second surface 112. In some of these embodiments, the printing of the initial cell wafer 100 specifically includes: screen printing the initial cell wafer 100 or laser pattern transfer printing the initial cell wafer 100 to print the conductive paste onto the silicon wafer surface 110 to form the front and back electrodes, including the first electrode 240 and the second electrode 280. As an example, screen printing uses a screen template to print silver paste onto the front of the silicon wafer and silver paste or aluminum paste onto the back of the silicon wafer. Laser pattern transfer printing (Pattern Transfer Printing), also known as laser transfer printing, is to use a high-power laser beam to perform high-speed graphic scanning to accurately transfer the paste onto the cell surface 110, thereby completing the preparation of the gate lines and the preparation of the electrodes.

[0076] In some of these embodiments, in combination with Figure 2 and Figure 10 , the electrode includes a first electrode 240 located on the first surface 111 and a second electrode 280 located on the second surface 112, and the target direction includes the length direction of the first electrode 240 and the length direction of the second electrode 280. That is, the electrode includes the first electrode 240 and the second electrode 280 of the photovoltaic cell; the first electrode 240 is located on the first surface 111 of the photovoltaic cell, and the second electrode 280 is located on the second surface 112 of the photovoltaic cell; the target direction includes the length direction of the first electrode 240 and the length direction of the second electrode 280. As an example, the length direction of the first electrode 240 is the extending direction of the first electrode 240 in terms of the length index, and the length direction of the second electrode 280 is the extending direction of the second electrode 280 in terms of the length index. In some of these embodiments, the projection of the electrode on the substrate 210 of the initial cell 100 is located in the first region 101. For the first electrode 240, the projection of the first electrode 240 on the substrate 210 of the initial cell 100 is located in the third region 103 of the first surface 111, and for the second electrode 280, the projection of the second electrode 280 on the substrate 210 of the initial cell 100 is located in the fifth region 105 of the second surface 112. In some of these embodiments, the width of the first electrode 240 is set differently from the width of the second electrode 280. Such a design, on the one hand, by setting the projection of the electrode in the first region 101 of the initial cell 100, enables the electrode to accurately correspond to the highly doped concentration region after laser treatment, thereby further reducing the contact resistance, improving the electrical performance between the electrode and the silicon wafer, and enhancing the current collection efficiency. On the other hand, since the widths of the first electrode 240 and the second electrode 280 can be set differently, this provides greater flexibility for cell design. For example, the widths of the electrodes can be adjusted according to the specific requirements and design specifications of the cell to optimize the current collection and transmission efficiency of the cell, and thus improve the overall performance of the cell. On the further hand, this design allows for flexible adjustment of the layout and size of the electrode according to specific process conditions and cell performance goals in different embodiments. This enables the preparation method to better adapt to different types of photovoltaic cell manufacturing processes, improving the versatility and adaptability of the process. On yet another hand, by precisely controlling the layout and size of the electrode, materials can be more effectively utilized, reducing the waste of conductive materials such as silver paste, thereby reducing production costs.

[0077] In each embodiment, the method for preparing a photovoltaic cell has the steps of: performing at least two laser-assisted sinterings on the electrodes of the first surface 111 and the second surface 112, wherein at least two laser-assisted sinterings use lasers of different wavelengths. In some of these embodiments, in at least two laser-assisted sinterings, the irradiation time of the first laser-assisted sintering is at least twice that of the second laser-assisted sintering; for example, the irradiation time of the first laser-assisted sintering is 0.8 seconds, and the irradiation time of the second laser-assisted sintering is 0.4 seconds, that is, the irradiation time of the first laser-assisted sintering is twice that of the second laser-assisted sintering; exemplarily, the irradiation time of the first laser-assisted sintering is 2 to 4 times that of the second laser-assisted sintering. For at least two laser-assisted sinterings, the peak sintering temperature zones for screen sintering are 710°C, 760°C, 810°C, 870°C, 920°C, and the sintering temperature zone is reduced by 5°C to 15°C. At least two laser-assisted sinterings can reduce the laser process irradiation time by 0.1 second to 0.3 second. For example, the higher the peak temperature zone of screen sintering, the more the at least two laser-assisted sinterings reduce the laser process irradiation time; the lower the peak temperature zone of screen sintering, the more the at least two laser-assisted sinterings increase the laser process irradiation time by 0.1 second to 0.3 second. For at least two laser-assisted sinterings, for example, the laser power of the first laser-assisted sintering is 8% to 13%, and the irradiation time is 0.6 second to 0.9 second; the laser power of the second laser-assisted sintering is 3% to 8%, and the irradiation time is 0.3 second to 0.6 second. For example, the first laser-assisted sintering uses a lower energy density to form a preliminary sintering area, and the energy density range is 0.1 J / cm² to 0.3 J / cm². The second laser-assisted sintering uses a higher energy density to further optimize the sintering and the sintering line type, and the energy density range is 0.3 J / cm² to 0.8 J / cm². It can be understood that the lower and higher in this embodiment are compared between the first laser-assisted sintering and the second laser-assisted sintering, and the same will not be elaborated below. For example, the first laser-assisted sintering uses a longer pulse width to ensure sufficient diffusion time for the paste, and the pulse width range is 10 ns to 35 ns. The second laser-assisted sintering uses a shorter pulse width to achieve more precise local heating and sintering. The pulse width range is 1 ns to 15 ns. For example, the first laser-assisted sintering uses a lower frequency and a slower scanning speed to ensure that the exposure time of each laser point is long enough, the frequency range is 10 kHz to 30 kHz, and the scanning speed is 100 mm / s to 300 mm / s. The second laser-assisted sintering uses a higher frequency and a faster scanning speed to improve production efficiency. The frequency range is 35 kHz to 50 kHz, and the scanning speed is 350 mm / s to 550 mm / s. For example, by controlling the power and irradiation time of the laser, the temperature threshold of the electrode is controlled.With such a design, on the one hand, by controlling the power and irradiation time of the laser, the temperature threshold of the electrode can be precisely controlled, which is conducive to ensuring that the electrode reaches the optimal sintering temperature during the sintering process, thus achieving good contact between the electrode and the silicon wafer, and at the same time avoiding damage or thermal stress to the silicon wafer due to excessive temperature. On the other hand, LECO laser-assisted sintering can provide rapid and concentrated heat energy, enabling the electrode material to reach the sintering temperature in a short time and achieving rapid sintering, which is conducive to reducing the diffusion and oxidation of materials during the sintering process, improving the conductivity and adhesion of the electrode, and thus optimizing the sintering quality of the electrode. On the further hand, by precisely controlling the sintering temperature and optimizing the sintering quality of the electrode, precise control of the sintering process is achieved, which is conducive to reducing the thermal damage to the silicon wafer during the sintering process, improving the mechanical stability and reliability of the battery, and at the same time reducing the contact resistance between the electrode and the silicon wafer, increasing the current collection efficiency and fill factor of the battery, and thus improving the overall performance of the battery.

[0078] In some of these embodiments, in at least two laser-assisted sinterings, the spot width of the laser used in the laser-assisted sintering is greater than the width of the electrode, that is, the spot width of the laser irradiated on the electrode is greater than the width of the electrode. For the embodiments where the spot width of the laser irradiated on the electrode is greater than the width of the electrode, with such a design, on the one hand, it can ensure that the entire area of the electrode and the edge part of the electrode can be fully sintered, and this design helps to improve the adhesion and conductivity of the electrode edge, further optimizing the overall performance of the electrode. On the other hand, by coordinating the control of the spot width and power of the laser, it can ensure that the electrode is uniformly sintered across the entire width, reducing sintering non-uniformity, improving the consistency and reliability of the electrode; at the same time, combined with the laser-assisted sintering technology, the laser parameters can be flexibly adjusted according to different battery designs and process requirements to achieve a better sintering effect, thus improving the flexibility and adaptability of the process.

[0079] In some of these embodiments, in at least two laser-assisted sinterings, the first laser-assisted sintering uses green laser, and the second laser-assisted sintering uses red laser. As an example, each laser-assisted sintering is LECO laser-assisted sintering. Using the auxiliary LECO laser, two laser-assisted sinterings are respectively carried out on the front and back main fine grids. The first is green sintering, and the second is red sintering, reducing the usage amount of silver paste, enhancing the contact sintering of the paste, and removing the damage caused by laser grooving doping. Exemplarily, the first laser-assisted sintering uses a green laser with a wavelength of 495 nanometers to 570 nanometers; the second laser-assisted sintering uses a red laser with a wavelength of 620 nanometers to 1100 nanometers. As an example, in each relevant embodiment, the red laser is not limited to the visible range of the naked eye.

[0080] The following continues with an example to illustrate the method for preparing a photovoltaic cell. In some embodiments, the method for preparing a photovoltaic cell includes the steps of: cleaning and texturing, boron diffusion, backside etching, tunneling oxide layer and polysilicon deposition, backside laser, frontside etching RCA (Radio Corporation of America cleaning), atomic layer deposition (ALD) passivation and annealing, frontside alumina deposition, front and backside silicon nitride deposition, two times of front and backside laser doping, screen printing and sintering, two times of front and backside laser-assisted sintering using the laser-enhanced contact optimization (LECO) technique, and half-cut piece (HCP) passivation. As an example, the surface 110 includes a first surface 111 and a second surface 112 that are oppositely arranged; and, the steps of frontside alumina deposition and front and backside silicon nitride deposition are specifically: depositing a protective layer 130 on the first surface 111 and the second surface 112; the steps of two times of front and backside laser doping are specifically: performing a first laser treatment on the first regions 101 of the first surface 111 and the second surface 112 to remove the protective layer 130 on the first surface 111 and the second surface 112 at the first regions 101; performing a second laser treatment on the first regions 101 of the first surface 111 and the second surface 112 to make the doping concentration of the doped conductive layer 120 in the first regions 101 higher than the doping concentration of the doped conductive layer 120 in the second regions 102, that is, making the doping concentration of the first doped conductive layer 121 in the third regions 103 higher than the doping concentration of the first doped conductive layer 121 in the fourth regions 104; and making the doping concentration of the second doped conductive layer 122 in the fifth regions 105 higher than the doping concentration of the second doped conductive layer 122 in the sixth regions 106. As an example, the steps of two times of front and backside LECO laser-assisted sintering are specifically: performing at least two times of laser-assisted sintering on the electrodes of the first surface 111 and the second surface 112, wherein at least two times of laser-assisted sintering use lasers with different wavelengths. As an example, the number of times of laser-assisted sintering is 2 to 4 times. Such a design, on the one hand, by removing the protective layer 130 at the first regions 101, enables the subsequent electrode printing and sintering processes to act more precisely on the target regions, thereby reducing the usage amount of silver paste and lowering the material cost; and this optimized contact region is beneficial to enhancing the contact sintering effect between the paste and the silicon wafer, improving the adhesion and conductivity of the electrodes. On the other hand, by performing a second laser treatment on the first regions 101 to increase the doping concentration of the first regions 101 and making the doping concentration of the first regions 101 higher than the doping concentration of the second regions 102, this design of differential doping concentration can significantly reduce the contact resistance, thereby increasing the open-circuit voltage and fill factor of the cell, and further improving the photoelectric conversion efficiency of the photovoltaic cell.On the other hand, by precisely controlling the doping concentration of the first region 101 and the second region 102 and optimizing the metal contact area, the shading area of the photovoltaic electrode on the surface 110 of the battery can be reduced, the shading loss can be reduced, the current collection efficiency can be ensured, and the conversion efficiency and performance of the photovoltaic cell can be further improved.

[0081] In some embodiments, a photovoltaic cell is prepared by using any photovoltaic cell preparation method of any embodiment. It is understandable that since the photovoltaic cell is prepared by using any photovoltaic cell preparation method of any embodiment, the photovoltaic cell also has the beneficial technical effects corresponding to the photovoltaic cell preparation method, which will not be described in detail here.

[0082] In one embodiment, a photovoltaic cell 200 is Figure 11 As shown, it includes a substrate 210, an emitter 220, a first passivation anti-reflection layer 230, a first electrode 240, a tunneling layer 250, a doped polysilicon layer 260, a second passivation anti-reflection layer 270 and a second electrode 280; the substrate 210 has a first surface 111 and a second surface 112 opposite to each other; the emitter 220 is arranged on the first surface 111 of the substrate 210; the first passivation anti-reflection layer 230 is arranged on the emitter 220; the first electrode 240 is arranged on the emitter 220, and the first electrode 240 is electrically connected to the emitter 220; the tunneling layer 250 is arranged on the second surface 112 of the substrate 210; the doped polysilicon layer 260 is arranged on the tunneling layer 250; the second passivation anti-reflection layer 270 is arranged on the doped polysilicon layer 260; the second electrode 280 is arranged on the doped polysilicon layer 260, and the second electrode 280 is electrically connected to the doped polysilicon layer 260. Figure 10 In the illustrated embodiment, the first electrode 240 is connected to the emitter 220, and the second electrode 280 extends into the doped polysilicon layer 260. The remaining embodiments are similar and will not be described in detail. Such a structural design, as described above, is conducive to reducing the amount of silver paste used, thereby reducing material costs, while enhancing the contact sintering of the paste, and optimizing the doping concentration, significantly reducing the contact resistance, which is conducive to improving the open circuit voltage and filling factor, while reducing the shading loss and ensuring the current collection efficiency, thereby significantly improving the photoelectric conversion efficiency and reliability of the battery.

[0083] As an example, Figure 11As shown, the region where the first electrode 240 is located is the first region 101 of the first surface 111 in the related embodiments of the present application, and the remaining region of the first surface 111 is the second region 102 of the first surface 111; that is, the region where the first electrode 240 is located is the third region 103 of the first surface 111 in the related embodiments of the present application, and the remaining region of the first surface 111 is the fourth region 104 of the first surface 111. The region where the second electrode 280 is located is the first region 101 of the second surface 112 in the related embodiments of the present application; the remaining region of the second surface 112 is the second region 102 of the second surface 112; that is, the region where the second electrode 280 is located is the fifth region 105 of the second surface 112 in the related embodiments of the present application, and the remaining region of the second surface 112 is the sixth region 106 of the second surface 112. Such a design optimizes the first electrode 240 and the second electrode 280 on the two surfaces of the photovoltaic cell 200.

[0084] In one embodiment, a photovoltaic cell 200 is as Figure 12 shown, different from the Figure 11 embodiment shown, in this embodiment, the first passivation and antireflection layer 230 includes an aluminum oxide layer 131 and a first silicon nitride layer 132. The aluminum oxide layer 131 is disposed on the emitter 220, and the first silicon nitride layer 132 is disposed on the aluminum oxide layer 131. As an example, the second passivation and antireflection layer 270 includes a second silicon nitride layer 133. Such a design uses the aluminum oxide layer 131 to enhance the passivation effect of the emitter 220 at the first surface 111, and uses the first silicon nitride layer 132 and the second silicon nitride layer 133 to reduce reflection on the first surface 111 and the second surface 112 respectively. At the same time, the first silicon nitride layer 132 and the second silicon nitride layer 133 also have a certain passivation effect.

[0085] In some of the embodiments, a tandem cell includes a top cell and a bottom cell. The bottom cell is a photovoltaic cell of any embodiment, and the top cell is a perovskite cell. It can be understood that since the tandem cell uses a photovoltaic cell of any embodiment, the tandem cell also has the beneficial technical effects corresponding to the photovoltaic cell, which will not be elaborated here. As an example, the tandem cell further includes a connection layer, that is, an intermediate layer, disposed between the top cell and the bottom cell to improve the carrier transport efficiency and avoid recombination loss. Exemplarily, the top cell is a perovskite cell in the form of a flexible thin film layer.

[0086] In some of these embodiments, a photovoltaic cell module includes a photovoltaic cell of any of the embodiments. In some of these embodiments, a photovoltaic cell module includes a photovoltaic cell obtained by a photovoltaic cell preparation method of any of the embodiments. In some of these embodiments, a photovoltaic cell module includes a tandem cell of any of the embodiments; it can be understood that the tandem cell includes a photovoltaic cell. Similarly, since the photovoltaic cell module uses a photovoltaic cell of any of the embodiments or a photovoltaic cell obtained by a photovoltaic cell preparation method of any of the embodiments, the photovoltaic cell module has the beneficial technical effects corresponding to the photovoltaic cell, which will not be elaborated here.

[0087] As an example, the photovoltaic cell module includes a photovoltaic cell string, a film layer, and a cover plate. The photovoltaic cell string includes at least two photovoltaic cells of any of the embodiments connected to each other; the film layer is disposed on the photovoltaic cell string; the cover plate covers the film layer.

[0088] It should be noted that other embodiments of the present application further include a photovoltaic cell preparation method, a photovoltaic cell, a tandem cell, and a photovoltaic cell module that can be implemented formed by combining the technical features in the above embodiments.

[0089] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered to be within the scope described in this specification.

[0090] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can be made, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application shall be subject to the appended claims.

Claims

1. A method for preparing a photovoltaic cell, characterized in that, Including the steps: Providing an initial cell, the surface of the initial cell having a doped conductive layer, the surface having a first region and a second region; Depositing a protective layer on the surface; Performing a first laser treatment on the first region to remove the protective layer at the first region; Performing a second laser treatment on the first region to make the doping concentration of the doped conductive layer in the first region higher than the doping concentration of the doped conductive layer in the second region; Printing and sintering the initial cell to form an electrode on the initial cell, the projection of the electrode on the substrate of the initial cell being located in the first region; Performing at least two laser-assisted sinterings on the electrode, wherein different wavelengths of lasers are used for the at least two laser-assisted sinterings.

2. The method for preparing a photovoltaic cell according to claim 1, wherein Depositing a protective layer on the surface includes: depositing a passivation and antireflection layer on the surface.

3. The photovoltaic cell preparation method according to claim 2, characterized in that, The surface includes a first surface and a second surface arranged oppositely; and, Depositing a passivation and antireflection layer on the surface includes: Depositing an alumina layer on the first surface and a first silicon nitride layer on the alumina layer; Depositing a second silicon nitride layer on the second surface.

4. The method for preparing a photovoltaic cell according to claim 1, wherein The first laser treatment uses green light, and the second laser treatment uses red light.

5. The method for preparing a photovoltaic cell according to claim 1, wherein The laser energy density in the first laser treatment is lower than the laser energy density in the second laser treatment; The pulse width range in the first laser treatment is greater than the pulse width range in the second laser treatment; The laser frequency and scanning speed in the first laser treatment are respectively lower than the laser frequency and scanning speed in the second laser treatment.

6. The method for preparing a photovoltaic cell according to claim 5, wherein The laser energy density in the first laser treatment is from 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is from 0.5 J / cm² to 1.0 J / cm²; or, The pulse width range in the first laser treatment is from 10 ns to 30 ns, and the pulse width range in the second laser treatment is from 1 ns to 10 ns; or, The laser frequency range in the first laser treatment is from 10 kHz to 30 kHz, and the scanning speed is from 100 mm / s to 300 mm / s; the laser frequency range in the second laser treatment is from 30 kHz to 50 kHz, and the scanning speed is from 300 mm / s to 500 mm / s.

7. The method for preparing a photovoltaic cell according to claim 1, wherein In the at least two laser-assisted sinterings, the irradiation time of the first laser-assisted sintering is at least twice the irradiation time of the second laser-assisted sintering.

8. The method for preparing a photovoltaic cell according to claim 1, wherein, In the at least two laser-assisted sinterings, the spot width of the laser is greater than the width of the electrode.

9. The method for preparing a photovoltaic cell according to claim 1, wherein In the at least two laser-assisted sinterings, the first laser-assisted sintering uses a green laser, and the second laser-assisted sintering uses a red laser.

10. The method for preparing a photovoltaic cell according to claim 1, wherein Performing printing on the initial cell specifically includes: performing screen printing on the initial cell, or performing laser pattern transfer on the initial cell.

11. A photovoltaic cell, characterized in that, Prepared by using the photovoltaic cell preparation method according to any one of claims 1 to 10; wherein, the photovoltaic cell includes: A substrate having opposite first and second surfaces; An emitter provided on the first surface of the substrate; The first passivation and antireflection layer is disposed on the emitter; The first electrode is electrically connected to the emitter; The tunneling layer is disposed on the second surface of the substrate; The doped polysilicon layer is disposed on the tunneling layer; The second passivation and antireflection layer is disposed on the doped polysilicon layer; and, The second electrode is electrically connected to the doped polysilicon layer.

12. A stacked battery, characterized in that, It includes a top cell and a bottom cell, the bottom cell is the photovoltaic cell as described in claim 11, and the top cell is a perovskite cell.

13. A photovoltaic cell module, characterized in that, It includes a photovoltaic cell prepared by the photovoltaic cell preparation method as described in any one of claims 1 to 10, or includes the photovoltaic cell as described in claim 11, or includes the tandem cell as described in claim 12.

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