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

Abstract

The present application relates to a method for preparing photovoltaic cells, photovoltaic cells, stacked cells and photovoltaic cell modules. An initial cell is provided; a protective layer is deposited on the surface; two laser treatments are performed; printing and sintering are performed to form electrodes; and the electrodes are subjected to at least two laser-assisted sinterings. The above-mentioned method for preparing photovoltaic cells, by removing the protective layer at the first area and increasing the doping concentration at the first area, is combined with at least two laser-assisted sinterings. On the one hand, by optimizing the metal contact area, it is beneficial to reduce the amount of silver paste used, thereby reducing material costs, while 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, which significantly reduces the contact resistance, is beneficial to increasing 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 cell, simplifying the production process and reducing the production cost.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cell preparation, and in particular to a photovoltaic cell preparation method, a photovoltaic cell, a stacked cell, and a photovoltaic cell assembly. Background Art

[0002] Tunnel Oxide Passivated Contact (TOPCon) cells utilize a high-efficiency N-type silicon solar cell technology based on the principle of selective carriers. TOPCon cells utilize an ultra-thin silicon oxide layer and a doped polysilicon layer on the backside of an N-type silicon substrate to create a passivated contact structure. This reduces surface recombination and metal-contact recombination, thereby improving the cell's conversion efficiency. Consequently, they are widely used in the solar cell field.

[0003] However, TOPCon batteries have the problem of large contact resistance, which reduces the current collection efficiency and leads to low overall conversion efficiency of the battery. Summary of the Invention

[0004] In order to solve the problem of large contact resistance of photovoltaic cells, it is necessary to provide a photovoltaic cell preparation method, a photovoltaic cell, a laminated cell and a photovoltaic cell assembly.

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

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

[0007] Depositing a protective layer on the surface;

[0008] performing a first laser treatment on the first region to remove the protective layer in the first region;

[0009] performing a second laser treatment on the first region so that the doping concentration of the doped conductive layer in the first region is higher than the doping concentration of the doped conductive layer in the second region;

[0010] Printing and sintering the initial cell to form electrodes on the initial cell, wherein a projection of the electrodes on the substrate of the initial cell is located in the first area;

[0011] The electrode is subjected to at least two laser-assisted sintering processes, wherein the at least two laser-assisted sintering processes use lasers of different wavelengths.

[0012] In some embodiments, depositing a protective layer on the surface includes depositing a passivation anti-reflection layer on the surface.

[0013] In some embodiments, the surface includes a first surface and a second surface disposed opposite to each other; and depositing a passivation anti-reflection layer on the surface includes:

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

[0015] A second silicon nitride layer is deposited on the second surface.

[0016] In some embodiments, the first laser treatment uses green light, and the second laser treatment uses red light.

[0017] In some 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 the scanning speed in the first laser treatment are respectively lower than the laser frequency and the scanning speed in the second laser treatment.

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

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

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

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

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

[0025] In some embodiments, in the at least two laser-assisted sintering steps, a green laser is used for the first laser-assisted sintering step, and a red laser is used for the second laser-assisted sintering step.

[0026] In some embodiments, printing the initial battery cell specifically includes screen printing the initial battery cell or laser pattern transfer printing the initial battery cell.

[0027] In some embodiments, a photovoltaic cell is prepared using the photovoltaic cell preparation method described in any embodiment; wherein the photovoltaic cell comprises:

[0028] A substrate having a first surface and a second surface opposite to each other;

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

[0030] A first passivation anti-reflection layer is provided 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 anti-reflection layer is disposed on the doped polysilicon layer; and

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

[0036] In some embodiments, a tandem cell includes a top cell and a bottom cell, wherein the bottom cell is the photovoltaic cell according to any one of the embodiments, and the top cell is a perovskite cell.

[0037] In some embodiments, a photovoltaic cell assembly includes the photovoltaic cell according to any one of the embodiments.

[0038] In some embodiments, a photovoltaic cell assembly includes a photovoltaic cell produced by the photovoltaic cell production method described in any embodiment.

[0039] In some embodiments, a photovoltaic cell assembly includes the stacked cell according to any one of the embodiments.

[0040] The above-mentioned photovoltaic cell preparation method, photovoltaic cell, stacked cell and photovoltaic cell assembly, by removing the protective layer in the first area and increasing the doping concentration in the first area, combined with at least two laser-assisted sintering, on the one hand, by optimizing the metal contact area, it is beneficial to reduce the use of silver paste, thereby reducing material costs, while enhancing the contact sintering of the paste and removing the damage caused by laser grooving doping; on the other hand, it optimizes the doping concentration, significantly reduces the contact resistance, is beneficial to increase the open circuit voltage and fill factor, while reducing shading loss and ensuring current collection efficiency, thereby significantly improving the photoelectric conversion efficiency and reliability of the battery, while simplifying the production process and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

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

[0044] Figure 3 for Figure 2 A schematic diagram of the first side of the initial battery cell of the illustrated embodiment.

[0045] Figure 4 for Figure 2 A schematic diagram of the second side of the initial battery cell of the illustrated embodiment.

[0046] Figure 5 This is a schematic structural diagram of the photovoltaic cell having a doped conductive layer according to the first embodiment of the present application.

[0047] Figure 6 This is a schematic structural diagram of the photovoltaic cell with a protective layer according to the first embodiment of the present application.

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

[0049] Figure 8 This is a schematic structural diagram of a second embodiment of the photovoltaic cell described in this application having a protective layer.

[0050] Figure 9This is a schematic structural diagram of the second embodiment of the photovoltaic cell described in this application after the first laser treatment.

[0051] Figure 10 This is a schematic structural diagram of the second embodiment of the photovoltaic cell described in this application after at least two laser-assisted sintering steps.

[0052] Figure 11 This is a schematic structural diagram of the third embodiment of the photovoltaic cell described in this application.

[0053] Figure 12 This is a schematic structural diagram of the fourth embodiment of the photovoltaic cell described in this application.

[0054] Figure 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 side; 112, second side; 120, doped conductive layer; 121, first doped conductive layer; 122, second doped conductive layer; 130, protective layer; 131, aluminum oxide 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 anti-reflection layer; 240, first electrode; 250, tunneling layer; 260, doped polysilicon layer; 270, second passivation anti-reflection layer; 280, second electrode. DETAILED DESCRIPTION

[0055] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to 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 may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

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

[0058] In this application, unless otherwise expressly specified or limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or that the first feature and the second feature are indirectly in contact through an intermediate medium. Furthermore, a first feature being “above,” “above,” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below,” “below,” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level 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 art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments 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 relevant listed items.

[0060] In one embodiment of the present application, a method for preparing a photovoltaic cell is as follows: Figure 1As shown, it includes the following steps: providing an initial cell, wherein the surface of the initial cell has a doped conductive layer, and the surface has a first area and a second area; depositing a protective layer on the surface; performing a first laser treatment on the first area to remove the protective layer at the first area; performing a second laser treatment on the first area to make the doping concentration of the doped conductive layer in the first area higher than the doping concentration of the doped conductive layer in the second area; printing and sintering the initial cell to form an electrode on the initial cell, wherein the projection of the electrode on the substrate of the initial cell is located in the first area; performing at least two laser-assisted sintering on the electrode, wherein the at least two laser-assisted sinterings use lasers of different wavelengths. The above-mentioned photovoltaic cell preparation method, by removing the protective layer in the first area and increasing the doping concentration in the first area, combined with at least two laser-assisted sintering, on the one hand, optimizes the metal contact area, which is beneficial to reduce the use of silver paste, thereby reducing material costs, while enhancing the paste contact sintering and removing the damage caused by laser grooving doping; on the other hand, it optimizes the doping concentration, significantly reduces the contact resistance, is beneficial to increase the open circuit voltage and fill factor, while reducing shading loss and ensuring current collection efficiency, thereby significantly improving the photoelectric conversion efficiency and reliability of the battery, while simplifying the production process and reducing production costs.

[0061] In each embodiment, the photovoltaic cell preparation method comprises the following steps: Figure 2 As shown, an initial cell 100 is provided, and a surface 110 of the initial cell 100 has 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 disposed opposite to each other; in other embodiments, the processed surface 110 is a single surface. 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 In the embodiment shown, the projections of the third region 103 and the fifth region 105 on the substrate 210 of the initial cell 100 do not overlap, and the projections of the fourth region 104 and the sixth region 106 on the substrate 210 do not overlap. Figure 10 As shown, the projections of the third region 103 and the fifth region 105 on the substrate 210 of the initial cell 100 overlap, and the projections of the fourth region 104 and the sixth region 106 on the substrate 210 also overlap. Figure 3 and Figure 4As shown, the first surface 111 and the second surface 112 respectively include a first area 101 and a second area 102 spaced apart along the target direction, wherein the first surface 111 includes a third area 103 and a fourth area 104 spaced apart along the target direction, and the second surface 112 includes a fifth area 105 and a sixth area 106 spaced apart along 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 morphology after being processed by a texturing process. Such a design is conducive to flexibly setting the positions of the first area 101 and the second area 102 according to product design requirements to cooperate with the electrode production process to be described below.

[0062] Combine Figure 5 , the surface 110 of the initial cell 100 has a doped conductive layer 120, and for an embodiment in which the surface 110 includes a first surface 111 and a second surface 112, as shown in FIG. Figure 5 As 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. Specifically, for example, an initial cell 100 is provided. The initial cell 100 includes a first surface 111 and a second surface 112 disposed opposite each other. Alternatively, the substrate 210 of the initial cell 100 includes a first surface 111 and a second surface 112 disposed opposite each other. Both the first surface 111 and the second surface 112 have doped conductive layers 120, wherein the first surface 111 has the first doped conductive layer 121 and the second surface 112 has the second doped conductive layer 122. Alternatively, the substrate 210 has the first doped conductive layer 121 and the second doped conductive layer 122 disposed on its first surface 111 and second surface 112, respectively. By way of example, the first doped conductive layer 121 is an emitter, which will be described below, and the second doped conductive layer 122 is a doped polysilicon layer, which will be described below. This design facilitates the preparation of the initial cell 100 into the desired photovoltaic cell.

[0063] In each embodiment, the photovoltaic cell preparation method comprises the following steps: Figure 6 As shown, a protective layer 130 is deposited on the surface 110. In some embodiments, the protective layer 130 is deposited on the surface, including: depositing a passivation anti-reflection layer on the surface, that is, using the passivation anti-reflection 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 in which the surface 110 includes the first surface 111 and the second surface 112, Figure 6In the embodiment shown, the protective layer 130 includes a first passivation anti-reflection layer 230 located on the first doped conductive layer 121, and a second passivation anti-reflection layer 270 located on the second doped conductive layer 122. In some embodiments, such as Figure 7 As shown, the first passivation anti-reflection layer 230 includes an aluminum oxide layer 131 and a first silicon nitride layer 132, and the second passivation anti-reflection layer 270 includes a second silicon nitride layer 133. This design is conducive to adapting to the first surface 111 and the second surface 112 in different positions of the finished battery, avoiding material waste and affecting conversion efficiency.

[0064] As an example, the passivation anti-reflection layer is deposited on the surface 110, including: depositing an aluminum oxide layer 131 on the first surface 111 and a first silicon nitride layer 132 on the aluminum oxide layer 131, that is, depositing the aluminum oxide layer 131 on the first surface 111 and depositing the first silicon nitride layer 132 on the aluminum oxide layer 131; depositing the second silicon nitride layer 133 on the second surface 112; that is, depositing the aluminum oxide layer 131 on the first surface 111 and depositing the first silicon nitride layer 132 on the aluminum oxide layer 131, and depositing the second silicon nitride layer 133 on the second surface 112. In some embodiments, such as Figure 6 As shown, a protective layer 130 is deposited on the first side 111 and the second side 112 of the initial cell 100. Specifically, the process includes: depositing an aluminum oxide layer 131 on the first side 111 of the initial cell 100; depositing a first silicon nitride layer 132 on the first side 111 of the initial cell 100; and depositing a second silicon nitride layer 133 on the second side 112 of the initial cell 100. That is, the protective layer 130 on the first side 111 includes the aluminum oxide layer 131 and the first silicon nitride layer 132, and the protective layer 130 on the second side 112 includes the second silicon nitride layer 133. For ease of distinction, the first silicon nitride layer 132 on the first side 111 may be referred to as a first anti-reflection layer; and the second silicon nitride layer 133 on the second side 112 may be referred to as a second anti-reflection layer. Alternatively, the aluminum oxide layer 131 and the first silicon nitride layer 132 on the first surface 111 are collectively referred to as the first passivation anti-reflection layer 230; the second silicon nitride layer 133 on the second surface 112 is referred to as the second passivation anti-reflection layer 270. The first silicon nitride layer 132 and the second silicon nitride layer 133 function to reduce reflection, thereby maximizing the incident rate and thus improving utilization. Furthermore, during the formation of the first silicon nitride layer 132 and the second silicon nitride layer 133, the hydrogen atoms generated can also effectively passivate the substrate 210 of the initial cell 100, i.e., the silicon wafer. This means that the first silicon nitride layer 132 and the second silicon nitride layer 133 also have a certain passivation effect, which can reduce carrier recombination on the silicon wafer surface 110.

[0065] Such a design, on the one hand, can effectively reduce the reflectivity of the cell surface 110, allowing more sunlight to enter the interior of the cell, thereby improving light utilization, increasing the generation of photogenerated carriers, and thus improving the photovoltaic conversion efficiency of the cell. In addition, the aluminum oxide layer 131, the first silicon nitride layer 132, and the second silicon nitride layer 133, acting alone or in combination, further reduce carrier recombination on the silicon wafer surface 110, improve the carrier lifetime and mobility, and facilitate the separation and transmission of photogenerated carriers, thereby improving the open circuit voltage and fill factor of the cell, and further improving the photovoltaic conversion efficiency of the cell. On the other hand, for the first surface 111, the dual passivation effect of the aluminum oxide layer 131 and the first silicon nitride layer 132 can effectively protect the first surface 111 of the silicon wafer surface 110 that receives light, reduce the influence of surface states and impurities, thereby improving the anti-attenuation performance and long-term stability of the photovoltaic cell, and thus extending the service life of the photovoltaic cell.

[0066] In each embodiment, the photovoltaic cell manufacturing method comprises the following steps: performing a first laser treatment on the first region 101 to remove the protective layer 130 in the first region 101; as an example, after removing the protective layer 130 in the first region 101, a groove is formed on the doped conductive layer 120 at the location of the original protective layer 130 to facilitate subsequent processing. Figure 8 As shown, the first laser treatment is performed on the third area 103 of the first surface 111 to remove the first passivation anti-reflection layer 230 in the third area 103, forming a first groove 141, and retaining the first passivation anti-reflection layer 230 in the fourth area 104; the first laser treatment is performed on the fifth area 105 of the second surface 112 to remove the second passivation anti-reflection layer 270 in the fifth area 105, forming a second groove 142, and retaining the second passivation anti-reflection layer 270 in the sixth area. Or as Figure 9 As shown, the third region 103 of the first surface 111 is subjected to a first laser treatment to remove the aluminum oxide layer 131 and the first silicon nitride layer 132 in the third region 103, forming a third groove 143, and retaining the aluminum oxide layer 131 and the first silicon nitride layer 132 in the fourth region 104; the fifth region 105 of the second surface 112 is subjected to a first laser treatment to remove the second silicon nitride layer 133 in the fifth region 105, forming a fourth groove 144, and retaining the second silicon nitride layer 133 in the sixth region. This design removes the protective layer 130 in the first region 101 through the first laser treatment process, creating conditions for high-concentration doping and electrode printing in the subsequent second laser process, thereby helping to improve the electrode contact effect, thereby reducing the contact resistance, and thus improving the current collection efficiency.

[0067] In some embodiments, the first region 101 is subjected to a second laser treatment so that the doping concentration of the doped conductive layer 120 in the first region 101 is higher than the doping concentration of the doped conductive layer 120 in the second region 102. As an example, the first laser treatment of the first region 101 includes: performing a first laser treatment on the first region 101 of the first surface 111 and the second surface 112 to remove the protective layer 130 of the first surface 111 and the second surface 112 at the first region 101; as an example, performing a 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, removes the protective layer 130 in the first region 101 through the first laser treatment process, thereby creating conditions for high-concentration doping and electrode printing in the subsequent second laser process, which helps to form better quality electrode contacts, thereby reducing contact resistance and improving 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 the doping concentration of the second region 102. This differentiated doping concentration design, combined with the subsequent processing 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 cell 100, the photovoltaic cell preparation method uses a laser process to selectively perform two laser treatments on the front and back surfaces, including adding a laser process to groove the front surface of the cell before printing; as an example, adding a laser process to groove the front surface of the cell before screen printing. The first laser treatment removes the protective layer 130 in the first area 101 of the first surface 111 and the second surface 112, that is, removes part of the film layer on the front and back surfaces. Exemplarily, for an embodiment having an aluminum oxide layer 131, the first laser treatment removes the aluminum oxide layer 131 in the first area 101 of the first surface 111; for an embodiment having a first silicon nitride layer 132 and a second silicon nitride layer 133, the first laser treatment removes the first silicon nitride layer 132 in the first area 101 of the first surface 111, and removes the second silicon nitride layer 133 in the first area 101 of the second surface 112. This is conducive to coordinating with subsequent processes to perform high-concentration doping in these first areas 101. As an example, the second laser treatment makes the doping concentration of the first region 101 higher than the doping concentration of the second region 102. This design, on the one hand, uses a laser process to groove the front of the cell before screen printing, removing the protective layer 130 in the first region 101, creating conditions for subsequent high-concentration doping and electrode printing, which is conducive to improving the electrode contact state, thereby further reducing the contact resistance. On the other hand, the second laser treatment is performed through the laser process to increase the doping concentration of the first region 101. As mentioned above, this differentiated doping concentration design, combined with the subsequent processing 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 increasing the photoelectric conversion efficiency of the battery. On the other hand, by precisely removing the protective layer 130 in the first region 101 through the laser process, the doping area and the electrode printing area can be more accurately controlled, reducing the waste of conductive materials such as silver paste, thereby reducing production costs. On the other hand, the laser process can effectively repair the damage caused by the laser grooving and doping process, improving the stability and reliability of the battery and extending the service life of the battery.

[0069] As an example, the front and back of the cell are lasered twice after back coating and before screen printing. The first laser treatment is the initial laser doping, which can also be called the initial laser doping. First, the initial laser is performed on a local area of ​​the cell to remove part of the passivation layer of the front and back film layers for preliminary doping to form a preliminary high-concentration doping area. This step can use green or red laser, and the appropriate wavelength is selected according to specific needs. The second laser treatment is the second laser doping, which 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 doped area. The two doping can use the same or different wavelengths of lasers to achieve more precise control.

[0070] In some embodiments, green light is used for the first laser treatment and red light is used for the second laser treatment; that is, green laser light is used for the first laser treatment and red laser light is used for the second laser treatment. That is, in this embodiment, the laser wavelengths used for 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 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 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. For example, 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, uses a laser process in conjunction with green light for the first laser treatment, which is not only conducive to effectively repairing the damage caused to the first region 101 during the laser grooving and doping process, thereby improving the stability and reliability of the battery, but also facilitates high-precision local doping at a shallow doping depth in the first region 101; on the other hand, the second laser treatment through the laser process further increases the doping concentration of the first region 101, thereby facilitating the reduction of the contact resistance of the photovoltaic cell, and further facilitating the improvement of the open circuit voltage and fill factor of the photovoltaic cell, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0071] For example, the initial laser doping typically uses a lower energy density to form a preliminary high-concentration doped area. The second laser doping uses a higher energy density to further optimize the doping depth and uniformity. The initial laser doping typically 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 typically 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 embodiments, 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; and the laser frequency and scanning speed in the first laser treatment are lower than the laser frequency and scanning speed in the second laser treatment, respectively. In some embodiments, the laser energy density in the first laser treatment is 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is 0.5 J / cm² to 1.0 J / cm²; in some embodiments, the pulse width in the first laser treatment is 10 ns to 30 ns, and the pulse width in the second laser treatment is 1 ns to 10 ns; in some embodiments, the laser frequency in the first laser treatment is 10 kHz to 30 kHz, and the scanning speed is 100 mm / s to 300 mm / s; and the laser frequency in the second laser treatment is 30 kHz to 50 kHz, and the scanning speed is 300 mm / s to 500 mm / s. In some embodiments, the laser energy density in the first laser treatment is 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is 0.5 J / cm² to 1.0 J / cm²; the pulse width in the first laser treatment is in the range of 10 ns to 30 ns, and the pulse width in the second laser treatment is in the range of 1 ns to 10 ns; the laser frequency in the first laser treatment is in the range of 10 kHz to 30 kHz, and the scanning speed is in the range of 100 mm / s to 300 mm / s; the laser frequency in the second laser treatment is in the range of 30 kHz to 50 kHz, and the scanning speed is in the range of 300 mm / s to 500 mm / s. The remaining embodiments are similar and will not be described in detail.

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

[0074] Such a design, on the one hand, achieves high-concentration doping by improving doping, that is, by laser grooving, high-concentration doping is performed in the first area, such as the metal grid line contact area, 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, only performing high-concentration doping in the first area, such as the metal grid line contact area, can avoid the negative effects of high-concentration doping on the entire battery surface, such as increasing surface recombination losses, that is, it is beneficial to avoid increasing surface recombination losses. On the other hand, due to the reduced contact resistance, the recombination loss of carriers can be reduced, thereby increasing the open circuit voltage, which is beneficial to improving electrical performance. On the other hand, by improving doping and combining at least two laser-assisted sintering, it is beneficial to optimize the electrical performance of the metal contact area, improve the fill factor, and further improve the overall efficiency of the photovoltaic cell; at the same time, the amount of silver paste used can be reduced, thereby reducing material costs. Among them, the fill factor reflects the current and voltage output capabilities of the battery under actual working conditions. This embodiment uses two laser dopings on the front and back sides respectively. By reducing the series resistance and optimizing the electrode contact, it can significantly improve the fill factor of the photovoltaic cell, thereby improving the overall performance of the photovoltaic cell and significantly improving the overall photoelectric conversion efficiency of the photovoltaic cell.

[0075] In each embodiment, the photovoltaic cell preparation method comprises the steps of: printing and sintering the initial cell 100, and forming electrodes on the initial cell 100; it is understood that the initial cell 100 before printing and sintering can also be called a cell intermediate or a cell semi-finished product. Figure 10 As shown, as an example, the initial cell 100 is printed and sintered to form a first electrode 240 located on the first surface 111 and a second electrode 280 located on the second surface 112 on the initial cell 100; it can be understood that, Figure 10 As shown, a first electrode 240 is formed on the first doped conductive layer 121 located on the first surface 111, and a second electrode 280 is formed on the second doped conductive layer 122 located on the second surface 112. In some embodiments, printing the initial cell 100 is specifically performed by screen printing the initial cell 100, or performing laser pattern transfer on the initial cell 100 to print a conductive paste onto the silicon wafer surface 110 to form 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, also known as laser transfer printing, uses a high-power laser beam to perform high-speed pattern scanning to accurately transfer the paste to the cell surface 110, thereby completing the preparation of the grid lines and the electrodes.

[0076] In some embodiments, combined Figure 2 and Figure 10 The electrodes include 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 electrodes include 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. By way of example, the length direction of the first electrode 240 is the direction in which the first electrode 240 extends in terms of length, and the length direction of the second electrode 280 is the direction in which the second electrode 280 extends in terms of length. In some embodiments, the projection of the electrodes on the substrate 210 of the initial cell 100 is located in the first region 101. For the first electrode 240, its projection onto the substrate 210 of the initial cell 100 is located in the third region 103 of the first side 111. For the second electrode 280, its projection onto the substrate 210 of the initial cell 100 is located in the fifth region 105 of the second side 112. In some embodiments, the width of the first electrode 240 is different from the width of the second electrode 280. This design, by positioning the electrode projection within the first region 101 of the initial cell 100, allows the electrode to precisely align with the laser-treated high-doping concentration region, further reducing contact resistance, improving electrical performance between the electrode and the silicon wafer, and enhancing current collection efficiency. Furthermore, the ability to differ in width between the first and second electrodes 240, 280 provides greater flexibility in battery design. For example, the electrode widths can be adjusted based on the specific needs and design requirements of the battery to optimize the battery's current collection and transmission efficiency, thereby improving overall battery performance. Furthermore, this design allows for flexible adjustment of the electrode layout and dimensions in different embodiments based on specific process conditions and battery performance targets. This allows the method to better adapt to different types of photovoltaic cell manufacturing processes, improving the process's versatility and adaptability. Furthermore, by precisely controlling the layout and size of the electrodes, materials can be more efficiently utilized, reducing waste of conductive materials like silver paste, thereby lowering production costs.

[0077] In various embodiments, the photovoltaic cell manufacturing method includes the steps of performing at least two laser-assisted sintering processes on the electrodes on the first side 111 and the second side 112, wherein the at least two laser-assisted sintering processes utilize lasers of different wavelengths. In some embodiments, during the at least two laser-assisted sintering processes, the irradiation time of the first laser-assisted sintering process is at least twice that of the second laser-assisted sintering process. As an example, the irradiation time of the first laser-assisted sintering process is 0.8 seconds, and the irradiation time of the second laser-assisted sintering process is 0.4 seconds, i.e., the irradiation time of the first laser-assisted sintering process is twice that of the second laser-assisted sintering process. Exemplarily, the irradiation time of the first laser-assisted sintering process is 2 to 4 times that of the second laser-assisted sintering process. For the at least two laser-assisted sintering processes, the peak sintering temperature range for wire mesh sintering is 710°C, 760°C, 810°C, 870°C, and 920°C, and the sintering temperature range is reduced by 5°C to 15°C. The at least two laser-assisted sintering processes can reduce the laser process irradiation time by 0.1 to 0.3 seconds. As an example, the higher the screen sintering peak temperature zone, the lower the screen sintering peak temperature zone, the longer the laser irradiation time of the at least two laser-assisted sintering processes. The lower the screen sintering peak temperature zone, the longer the laser irradiation time of the at least two laser-assisted sintering processes. For at least two laser-assisted sintering processes, as an example, the laser power of the first laser-assisted sintering process is 8% to 13%, and the irradiation time is 0.6 seconds to 0.9 seconds; the laser power of the second laser-assisted sintering process is 3% to 8%, and the irradiation time is 0.3 seconds to 0.6 seconds. As an example, the first laser-assisted sintering process uses a lower energy density to form a preliminary sintering area, and the energy density range is 0.1J / cm² to 0.3J / cm². The second laser-assisted sintering process uses a higher energy density to further optimize sintering and sintering line shape, and the energy density range is 0.3J / cm² to 0.8J / cm². It can be understood that the lower and higher values ​​in this embodiment are compared between the first laser-assisted sintering process and the second laser-assisted sintering process, and the same will be repeated below. As an example, the first laser-assisted sintering uses a longer pulse width to ensure that the slurry has sufficient diffusion time, and the pulse width range is 10ns to 35ns. The second laser-assisted sintering uses a shorter pulse width to achieve more precise local heating and sintering. The pulse width range is 1ns to 15ns. As an 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 10kHz to 30kHz, and the scanning speed is 100mm / s to 300mm / s. The second laser-assisted sintering uses a higher frequency and a faster scanning speed to improve production efficiency. The frequency range is 35kHz to 50kHz, and the scanning speed is 350mm / s to 550mm / s. As an example, the temperature threshold of the electrode is controlled by controlling the power and irradiation time of the laser.Such a design, on the one hand, can precisely control the temperature threshold of the electrode by controlling the power and irradiation time of the laser, which is conducive to ensuring that the electrode reaches the optimal sintering temperature during the sintering process, thereby achieving good contact between the electrode and the silicon wafer, while avoiding damage or thermal stress to the silicon wafer due to excessive temperature. On the other hand, LECO laser-assisted sintering can provide fast and concentrated thermal energy, so that the electrode material reaches the sintering temperature in a short time, achieving rapid sintering, which is conducive to reducing the diffusion and oxidation of the material during the sintering process, improving the conductivity and adhesion of the electrode, and thus optimizing the sintering quality of the electrode. On the other hand, by precisely controlling the sintering temperature and optimizing the electrode sintering quality, precise control of the sintering process is achieved, which is conducive to reducing 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, improving the current collection efficiency and fill factor of the battery, and thus improving the overall performance of the battery.

[0078] In some embodiments, in at least the second laser-assisted sintering, 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 to the electrode is greater than the width of the electrode. For embodiments in which the spot width of the laser irradiated to the electrode is greater than the width of the electrode, such a design can, on the one hand, ensure that the entire area of ​​the electrode and the edge 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 controlling the spot width and power of the laser, it can be ensured that the electrode is uniformly sintered across the entire width, reducing sintering unevenness and improving the consistency and reliability of the electrode; at the same time, combined with laser-assisted sintering technology, the laser parameters can be flexibly adjusted according to different battery designs and process requirements to achieve better sintering effects, thereby improving the flexibility and adaptability of the process.

[0079] In some embodiments, in 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. As an example, each laser-assisted sintering is LECO laser-assisted sintering, using an auxiliary LECO laser, and performing two laser-assisted sinterings on the front and back main fine grids respectively, the first time is green light sintering and the second time is red light sintering, so as to reduce the amount of silver paste used, enhance the contact sintering of the paste, and remove the damage caused by laser grooving and 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 range visible to the naked eye.

[0080] The following is an example of a method for preparing a photovoltaic cell. In some embodiments, the method for preparing a photovoltaic cell includes the following steps: cleaning and texturing, boron diffusion, back etching, tunneling oxide layer and polysilicon deposition, back laser, front etching RCA (Radio Corporation of America cleaning), atomic layer deposition (ALD) passivation and annealing, front aluminum oxide deposition, front and back silicon nitride deposition, front and back laser doping, screen printing and sintering, front and back laser assisted sintering using laser-enhanced contact optimization (LECO) technology, and half-cut piece (HCP) passivation. As an example, the surface 110 includes a first surface 111 and a second surface 112 arranged opposite to each other; and the front-side aluminum oxide deposition and the front-side and back-side silicon nitride deposition steps are specifically as follows: depositing a protective layer 130 on the first surface 111 and the second surface 112; the front-side and back-side laser doping steps are specifically as follows: performing a first laser treatment on the first area 101 of the first surface 111 and the second surface 112 to remove the protective layer 130 on the first area 101 of the first surface 111 and the second surface 112; performing a second laser treatment on the first area 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 area 101 higher than the doping concentration of the doped conductive layer 120 in the second area 102, that is, the doping concentration of the first doped conductive layer 121 in the third area 103 is higher than the doping concentration of the first doped conductive layer 121 in the fourth area 104; and making the doping concentration of the second doped conductive layer 122 in the fifth area 105 higher than the doping concentration of the second doped conductive layer 122 in the sixth area 106. As an example, the two LECO laser-assisted sintering steps on the front and back sides are specifically as follows: the electrodes on the first side 111 and the second side 112 are subjected to at least two laser-assisted sintering processes, wherein the at least two laser-assisted sintering processes use lasers of different wavelengths. As an example, the number of laser-assisted sintering processes is 2 to 4 times. This design, on the one hand, by removing the protective layer 130 in the first area 101, allows the subsequent electrode printing and sintering processes to act more accurately on the target area, thereby reducing the amount of silver paste used and reducing material costs; and this optimized contact area is conducive to enhancing the contact sintering effect between the paste and the silicon wafer, improving the adhesion and conductivity of the electrode. On the other hand, by performing a second laser treatment on the first area 101, the doping concentration of the first area 101 is increased, so that the doping concentration of the first area 101 is higher than the doping concentration of the second area 102. This differentiated doping concentration design can significantly reduce the contact resistance, thereby improving the open circuit voltage and fill factor of the battery, and further improving the photoelectric conversion efficiency of the photovoltaic cell.On the other hand, by precisely controlling the doping concentrations 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 produced using any of the methods for producing a photovoltaic cell in any of the embodiments. It is understood that since the photovoltaic cell is produced using any of the methods for producing a photovoltaic cell in any of the embodiments, the photovoltaic cell also has the beneficial technical effects corresponding to the method for producing a photovoltaic cell, which will not be described in detail here.

[0082] In one embodiment, a photovoltaic cell 200 such as 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 are not described in detail here. This structural design, as previously described, helps reduce the amount of silver paste used, thereby reducing material costs, while also enhancing paste contact sintering and optimizing the doping concentration, significantly reducing contact resistance, and facilitating increased open-circuit voltage and fill factor. It also reduces shading losses and ensures current collection efficiency, thereby significantly improving the photovoltaic conversion efficiency and reliability of the cell.

[0083] As an example, Figure 11As shown, the area where the first electrode 240 is located is the first area 101 of the first surface 111 in the embodiment of the present application, and the remaining area of ​​the first surface 111 is the second area 102 of the first surface 111. In other words, the area where the first electrode 240 is located is the third area 103 of the first surface 111 in the embodiment of the present application, and the remaining area of ​​the first surface 111 is the fourth area 104 of the first surface 111. The area where the second electrode 280 is located is the first area 101 of the second surface 112 in the embodiment of the present application, and the remaining area of ​​the second surface 112 is the second area 102 of the second surface 112. In other words, the area where the second electrode 280 is located is the fifth area 105 of the second surface 112 in the embodiment of the present application, and the remaining area of ​​the second surface 112 is the sixth area 106 of the second surface 112. This design optimizes the first electrode 240 and the second electrode 280 on both surfaces of the photovoltaic cell 200.

[0084] In one embodiment, a photovoltaic cell 200 such as Figure 12 As shown, Figure 11 The difference from the illustrated embodiment is that, in this embodiment, the first passivation anti-reflection 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 anti-reflection layer 270 includes a second silicon nitride layer 133. In this design, the aluminum oxide layer 131 is used to enhance the passivation effect of the emitter 220 at the first surface 111, while the first silicon nitride layer 132 and the second silicon nitride layer 133 are used 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 embodiments, a tandem cell includes a top cell and a bottom cell, wherein the bottom cell is a photovoltaic cell according to any embodiment, and the top cell is a perovskite cell. It is understood that because the tandem cell utilizes a photovoltaic cell according to any embodiment, it also exhibits the corresponding beneficial technical effects of a photovoltaic cell, which will not be elaborated upon here. As an example, the tandem cell further includes a connecting layer, or intermediate layer, disposed between the top and bottom cells to improve carrier transport efficiency and prevent recombination losses. Exemplarily, the top cell is a perovskite cell in the form of a flexible thin film layer.

[0086] In some embodiments, a photovoltaic cell assembly includes a photovoltaic cell according to any embodiment. In some embodiments, a photovoltaic cell assembly includes a photovoltaic cell produced by the method for producing a photovoltaic cell according to any embodiment. In some embodiments, a photovoltaic cell assembly includes a laminated cell according to any embodiment; it is understood that a laminated cell includes a photovoltaic cell. Similarly, because the photovoltaic cell assembly utilizes the photovoltaic cell according to any embodiment or the photovoltaic cell produced by the method for producing a photovoltaic cell according to any embodiment, the photovoltaic cell assembly has the beneficial technical effects corresponding to the photovoltaic cell, which will not be further described here.

[0087] As an example, the photovoltaic cell assembly includes a photovoltaic cell string, a film layer and a cover plate, the photovoltaic cell string includes at least two connected photovoltaic cells described in any embodiment; the film layer is covered on the photovoltaic cell string; and the cover plate is covered on the film layer.

[0088] It should be noted that other embodiments of the present application also include photovoltaic cell preparation methods, photovoltaic cells, laminated cells and photovoltaic cell modules that can be implemented by combining the technical features in the above embodiments.

[0089] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of patent protection for the present application shall be determined by the appended claims.

Claims

1. A method for preparing a photovoltaic cell, characterized in that: Including steps: Providing an initial cell, wherein a surface of the initial cell has a doped conductive layer, and the surface has 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 in the first region; performing a second laser treatment on the first region so that the doping concentration of the doped conductive layer in the first region is higher than the doping concentration of the doped conductive layer in the second region; Printing and sintering the initial cell to form electrodes on the initial cell, wherein a projection of the electrodes on the substrate of the initial cell is located in the first area; Performing at least two laser-assisted sintering processes on the electrode, wherein the at least two laser-assisted sintering processes use lasers of different wavelengths; 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 the scanning speed in the first laser treatment are respectively lower than the laser frequency and the scanning speed in the second laser treatment.

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

3. The method for preparing a photovoltaic cell according to claim 2, wherein: The surface includes a first surface and a second surface that are oppositely disposed; and Depositing a passivation anti-reflection layer on the surface includes: Depositing an aluminum oxide layer and a first silicon nitride layer on the aluminum oxide layer on the first surface; A second silicon nitride layer is deposited 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 0.1 J / cm² to 0.5 J / cm², and the laser energy density in the second laser treatment is 0.5 J / cm² to 1.0 J / cm²; or The pulse width in the first laser treatment ranges from 10 ns to 30 ns, and the pulse width in the second laser treatment ranges from 1 ns to 10 ns; or The laser frequency range in the first laser treatment is 10kHz to 30kHz, and the scanning speed is 100mm / s to 300mm / s; the laser frequency range in the second laser treatment is 30kHz to 50kHz, and the scanning speed is 300mm / s to 500mm / s.

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

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

8. The method for preparing a photovoltaic cell according to claim 1, wherein: In the at least two laser-assisted sintering processes, a green laser is used for the first laser-assisted sintering process, and a red laser is used for the second laser-assisted sintering process.

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

10. A photovoltaic cell, characterized in that: The photovoltaic cell is prepared by the method for preparing the photovoltaic cell according to any one of claims 1 to 9; wherein the photovoltaic cell comprises: A substrate having a first surface and a second surface opposite to each other; an emitter, disposed on the first surface of the substrate; A first passivation anti-reflection layer is provided on the emitter; a first electrode electrically connected to the emitter; a tunneling layer, disposed on the second surface of the substrate; a doped polysilicon layer, disposed on the tunneling layer; A second passivation anti-reflection layer is disposed on the doped polysilicon layer; and The second electrode is electrically connected to the doped polysilicon layer.

11. A laminated battery, characterized in that: The device comprises a top cell and a bottom cell, wherein the bottom cell is the photovoltaic cell according to claim 10, and the top cell is a perovskite cell.

12. A photovoltaic cell assembly, characterized in that: The photovoltaic cell comprises a photovoltaic cell prepared by the method for preparing a photovoltaic cell according to any one of claims 1 to 9, or comprises a photovoltaic cell according to claim 10, or comprises a stacked cell according to claim 11.

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