Tunnel oxide passivated contact solar cell and photovoltaic module

Abstract

A tunnel oxide passivated contact solar cell, comprising a first anti-reflection layer, a passivation layer, an electrode emission layer, a silicon substrate layer, a tunnel oxide layer, a polycrystalline silicon-doped stack structure layer, and a second anti-reflection layer that are sequentially stacked. The polycrystalline silicon-doped stack structure layer comprises a first phosphorus-doped polycrystalline silicon layer, a phosphorus-carbon co-doped polycrystalline silicon layer, a second phosphorus-doped polycrystalline silicon layer, and a phosphorus-hydrogen co-doped polycrystalline silicon layer that are sequentially stacked. The first phosphorus-doped polycrystalline silicon layer is in contact with the tunnel oxide layer.

Description

Tunneling oxide passivation contacts for solar cells and photovoltaic modules

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 24, 2023, with application number 202321961965.8 and application name “Tunneling Oxide Passivated Contact Solar Cells and Photovoltaic Modules”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of solar cells, and in particular to tunnel oxide layer passivation contact solar cells and photovoltaic modules. Background Art

[0003] At present, compared with traditional crystalline silicon cells, tunneling oxide passivated solar cells (TOPCon) with higher photoelectric conversion efficiency are more valued by the market. In the prior art, the tunneling passivation structure in the above-mentioned cell is generally composed of a stacked ultra-thin tunneling oxide layer and a single phosphorus-doped polysilicon layer, and the above-mentioned phosphorus-doped polysilicon layer is in contact with the metal electrode to transfer electrons. However, the phosphorus-doped polysilicon layer has a parasitic absorption effect, which will affect the photoelectric conversion efficiency of TOPCon; in addition, the back of the existing TOPCon is only passivated by the tunneling oxide passivation contact structure to achieve the back passivation of the cell, and the effect is limited. Therefore, there is an urgent need to provide a solar cell with a new tunneling passivation contact structure to improve the above-mentioned problems.

[0004] Summary of the Invention

[0005] In view of this, the present application provides a tunneling oxide layer passivation contact solar cell having a stacked structure layer of doped polycrystalline silicon, which has high photoelectric conversion efficiency.

[0006] In a first aspect, the present application provides a tunneling oxide layer passivated contact solar cell, comprising a first anti-reflection layer, a passivation layer, an electrode emission layer, a silicon base layer, a tunneling oxide layer, a stacked structure layer of doped polysilicon, and a second anti-reflection layer stacked in sequence;

[0007] The doped polysilicon stacked structure layer includes a first phosphorus-doped polysilicon layer, a phosphorus-carbon co-doped polysilicon layer, a second phosphorus-doped polysilicon layer, and a phosphorus-hydrogen co-doped polysilicon layer stacked in sequence; the first phosphorus-doped polysilicon layer is in contact with the tunneling oxide layer.

[0008] The first phosphorus-doped polysilicon layer and the tunneling oxide layer form a tunneling passivation structure. At the same time, the phosphorus-carbon co-doped polysilicon layer can reduce the absorption rate of the stacked polysilicon layer to visible light and infrared light and the parasitic absorption effect, thereby improving the photoelectric conversion efficiency of the battery while ensuring electron transmission; and it has good electrical conductivity. The second phosphorus-doped polysilicon layer located between the phosphorus-carbon co-doped polysilicon layer and the phosphorus-hydrogen co-doped polysilicon layer can prevent the doping elements between the two layers from diffusing into each other, making the battery easy to manufacture and ensuring its long-term stability. The phosphorus-hydrogen co-doped polysilicon layer has a passivation effect, which can improve the photoelectric conversion efficiency of the battery. Therefore, the solar cell provided in the embodiment of the present application can have high photoelectric conversion efficiency, high stability and long service life.

[0009] In the embodiment of the present application, the thickness of the stacked structure layer of doped polysilicon is in the range of 50nm-176nm.

[0010] In the embodiment of the present application, the thickness of the stacked structure layer of doped polysilicon is in the range of 78nm-114nm.

[0011] In an embodiment of the present application, the thickness of the first phosphorus-doped polysilicon layer is 1.6nm-8nm; the thickness of the phosphorus-carbon co-doped polysilicon layer is 16nm-120nm; the thickness of the second phosphorus-doped polysilicon layer is 1.6nm-8nm; the thickness of the phosphorus-hydrogen co-doped polysilicon layer is 4nm-40nm.

[0012] In an embodiment of the present application, the thickness of the first phosphorus-doped polysilicon layer is 3.2 nm-4.8 nm.

[0013] In the embodiment of the present application, the thickness of the phosphorus and carbon co-doped polysilicon layer is 56 nm-72 nm.

[0014] In an embodiment of the present application, the thickness of the second phosphorus-doped polysilicon layer is 3.2 nm-4.8 nm.

[0015] In the embodiment of the present application, the thickness of the phosphorus and hydrogen co-doped polysilicon layer is 16 nm-32 nm.

[0016] In an embodiment of the present application, the silicon base layer is an N-type silicon layer; the electrode emitter layer is a boron-doped electrode emitter layer; and the material of the tunneling oxide layer is selected from silicon oxide, titanium oxide or aluminum oxide.

[0017] In an embodiment of the present application, the thickness of the tunnel oxide layer is greater than 0 nm and less than or equal to 2 nm.

[0018] In an embodiment of the present application, the thickness of the passivation layer is 5 nm-20 nm, the thickness of the first anti-reflection layer is 10 nm-120 nm, and the thickness of the second anti-reflection layer is 10 nm-120 nm.

[0019] A second aspect of the present application provides a photovoltaic module, comprising the tunneling oxide layer passivation contact solar cell provided in the first aspect of the present application.

[0020] In an embodiment of the present application, the photovoltaic module further includes a front cover, a rear cover, a first encapsulation film, and a second encapsulation film. The front cover is bonded to one side of the tunnel oxide layer passivation contact solar cell via the first encapsulation film, and the rear cover is bonded to the other side of the tunnel oxide layer passivation contact solar cell via the second encapsulation film.

[0021] Due to the tunneling oxide layer passivation contact solar cell, the photovoltaic module has good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. 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.

[0023] FIG1 is a schematic diagram of a cross-sectional structure of a tunnel oxide passivation contact solar cell provided in an embodiment of the present application.

[0024] FIG2 is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application.

[0025] 100-solar cell; 11-first anti-reflection layer; 12-passivation layer; 20-electrode emission layer; 30-silicon base layer; 40-tunneling oxide layer; 50-stacked structure layer of doped polysilicon; 51-first phosphorus-doped polysilicon layer; 52-phosphorus-carbon co-doped polysilicon layer; 53-second phosphorus-doped polysilicon layer; 54-phosphorus-hydrogen co-doped polysilicon layer; 60-second anti-reflection layer; 70-first electrode; 80-second electrode; 1000-photovoltaic module; 1002-front cover; 1004-back cover; 1006-first encapsulation film; 1008-second encapsulation film. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] It should be understood that, in the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0028] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected or indirectly connected through an intermediate medium, and it can be internal communication between two elements or an interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0029] The above disclosure provides many different embodiments or examples for realizing different structures of the embodiments of the present application. In order to simplify the disclosure of the embodiments of the present application, the components and settings of specific examples are described above. Of course, they are merely examples and are not intended to limit the present application. In addition, the embodiments of the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the embodiments of the present application provide examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0030] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0031] In a tunneling oxide passivated contact solar cell (TOPCon), a tunneling passivated contact structure is provided on the back of the cell (the front of the solar cell is the side facing the sunlight, and the backlight side is the back). When sunlight shines on the front of the above-mentioned solar cell, free electrons are formed in the silicon base layer (generally an N-type silicon base layer). The free electrons tunnel through the tunneling oxide layer into the doped polysilicon layer (correspondingly, generally a phosphorus-doped polysilicon layer) for lateral diffusion, and then the free electrons are collected by the electrodes (generally metal electrodes, especially silver electrodes) to realize the transmission of current. However, in the existing TOPCon, the parasitic effect of the phosphorus-doped polysilicon layer will also reduce the photoelectric conversion efficiency of the TOPCon. In order to solve the above problems, the present application provides a solar cell.

[0032] Referring to Figure 1, an embodiment of the present application provides a tunneling oxide layer passivation contact solar cell 100, including a first anti-reflection layer 11, a passivation layer 12, an electrode emission layer 20, a silicon base layer 30, a tunneling oxide layer 40, a doped polysilicon stacked structure layer 50, and a second anti-reflection layer 60 stacked in sequence.

[0033] The doped polysilicon stacked structure layer 50 includes a first phosphorus-doped polysilicon layer 51, a phosphorus-carbon co-doped polysilicon layer 52, a second phosphorus-doped polysilicon layer 53, and a phosphorus-hydrogen co-doped polysilicon layer 54, which are stacked in sequence. The first phosphorus-doped polysilicon layer 51 is in contact with the tunneling oxide layer 40. That is, the first phosphorus-doped polysilicon layer 51 is located on the surface of the tunneling oxide layer 40 facing away from the silicon base layer 30. Electrons pass through the tunneling oxide layer 40, sequentially through the first phosphorus-doped polysilicon layer 51, the phosphorus-carbon co-doped polysilicon layer 52, and the second phosphorus-doped polysilicon layer 53, before reaching the phosphorus-hydrogen co-doped polysilicon layer 54. Electrons then diffuse laterally in the phosphorus-hydrogen co-doped polysilicon layer 54 to be collected by the electrodes, completing photoelectric conversion.

[0034] When sunlight shines on the front of the above-mentioned solar cell, the free electrons formed in the silicon base layer 30 move through the tunneling oxide layer 40 to the first phosphorus-doped polysilicon layer 51. The first phosphorus-doped polysilicon layer 51 and the tunneling oxide layer 40 are tunneling passivation structures commonly used in the field. The first phosphorus-doped polysilicon layer 51 can also cause the energy band on the surface of the silicon wafer to bend, greatly promoting the probability of electron tunneling. At the same time, the phosphorus-carbon co-doped polysilicon layer 52 can reduce the absorption rate and parasitic absorption effect of the doped polysilicon stacked structure layer 50 to visible light and infrared light, thereby improving the photoelectric conversion efficiency of the battery while ensuring electron transmission. In addition, the phosphorus-carbon co-doped polysilicon layer 52 has a lower resistivity, which can improve the electronic conductivity of the doped polysilicon stacked structure layer 50. The second phosphorus-doped polysilicon layer 53, located between the phosphorus-carbon co-doped polysilicon layer 52 and the phosphorus-hydrogen co-doped polysilicon layer 54, prevents interdiffusion of doping elements within the phosphorus-carbon co-doped polysilicon layer 52 and the phosphorus-hydrogen co-doped polysilicon layer 54 (e.g., element diffusion during the cell fabrication process), and prevents the elements within the two layers from interfering with each other. The hydrogen atoms within the phosphorus-hydrogen co-doped polysilicon layer 54 can saturate dangling bonds on the surface of silicon atoms, resulting in a passivation effect on the layer. This enhances the interface passivation between the doped polysilicon stacked structure layer 50 and the second anti-reflection layer 60, passivating polysilicon surface defects to reduce photogenerated electron recombination, thereby further improving the cell's photoelectric conversion efficiency.

[0035] It can be understood that in order to collect electrons to form current, electrodes (gate lines) are provided on both the front and back sides of the solar cell. In some embodiments of the present application, a first electrode 70 and a second electrode 80 are provided on the first anti-reflection layer 11 and the second anti-reflection layer 60, respectively. The second electrode 80 is in contact with at least the polysilicon layer 54 co-doped with phosphorus and hydrogen. In a specific embodiment of the present application, the first electrode 70 is provided on the first anti-reflection layer 11, including but not limited to the following situations: the first electrode 70 may be located on the surface of the first anti-reflection layer 11; or, the first electrode 70 penetrates / partially buried and does not penetrate the first anti-reflection layer 11 and protrudes relative to the first anti-reflection layer 11. Furthermore, the first electrode 70 may also extend into the passivation layer 12. In the present application, the second electrode 80 is in contact with at least the polysilicon layer 54 co-doped with phosphorus and hydrogen, which may be: the second electrode 80 penetrates the second anti-reflection layer 60 and contacts the polysilicon layer 54 co-doped with phosphorus and hydrogen, but is not limited thereto. In some specific embodiments, the second electrode 80 may further extend from the phosphorus-hydrogen co-doped polysilicon layer 54 toward the first phosphorus-doped polysilicon layer 51, without penetrating the first phosphorus-doped polysilicon layer 51. Depending on actual application requirements, in some specific embodiments of the present application, an end of the second electrode 80 away from the phosphorus-hydrogen co-doped polysilicon layer 54 protrudes relative to the second anti-reflection layer 60, but this application is not limited thereto.

[0036] Generally, during use of a solar cell, the side of the first anti-reflection layer 11 is the front side of the solar cell (facing sunlight), and the side with the tunnel oxide layer passivation contact structure is the back side of the solar cell. Therefore, the first anti-reflection layer 11 is also referred to as the "front anti-reflection layer," and the second anti-reflection layer 60 is also referred to as the "back anti-reflection layer."

[0037] In an embodiment of the present application, the silicon base layer 30 is an N-type silicon layer. The electrode emitter layer 20 is a boron-doped electrode emitter layer. In some embodiments of the present application, the material of the tunneling oxide layer 40 includes, but is not limited to, at least one of silicon oxide, titanium oxide, and aluminum oxide. In some embodiments of the present application, the material of the passivation layer 12 includes, but is not limited to, at least one of silicon oxide, silicon oxynitride, and aluminum oxide. The materials of the first anti-reflection layer 11 and the second anti-reflection layer 60 are each independently selected from at least one of silicon oxide, silicon nitride, and silicon oxynitride. In some specific embodiments, the passivation layer 12 is an aluminum oxide layer, and the first anti-reflection layer 11 and the second anti-reflection layer 60 are both silicon nitride layers. In some specific embodiments, the refractive index of the first anti-reflection layer 11 is different from the refractive index of the second anti-reflection layer 60. The materials of the first electrode 70 and the second electrode 80 are each independently selected from metal materials such as silver and aluminum, but are not limited to these.

[0038] It should be noted that in Figure 1 of the present application, the first anti-reflection layer 11, the passivation layer 12 and the electrode emission layer 20 are wavy. This is only to cater to the pyramid-shaped light-trapping structure formed on one side surface (front) of the silicon base layer due to the texturing process. It is a commonly used drawing style in the field and does not constitute any restriction on the shape of the first anti-reflection layer 11, the passivation layer 12 and the electrode emission layer 20 in the present application.

[0039] In some embodiments of the present application, the doping concentration of phosphorus atoms in the first phosphorus-doped polysilicon layer 51 is 1×10 19 cm -3 ~9×10 21 cm -3 In this way, the probability of electron tunneling can be better promoted, and the resistivity of the first phosphorus-doped polysilicon layer 51 can be reduced. For example, the doping concentration of phosphorus atoms in the first phosphorus-doped polysilicon layer 51 can be, but is not limited to, 1×10 19 cm -3 , 2×10 19 cm -3 , 3×10 19 cm -3 , 4×10 19 cm -3 , 5×10 19 cm -3 , 6×10 19 cm -3 , 8×10 19 cm-3 , 1×10 20 cm -3 , 2×10 20 cm -3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3 , 2×10 21 cm -3 , 5×10 21 cm -3 , 8×10 21 cm -3 , 9×10 21 cm -3 wait.

[0040] In some embodiments of the present application, the phosphorus-carbon co-doped polysilicon layer 52 has a doping concentration of phosphorus atoms of 1×10 19 cm -3 ~9×10 21 cm -3 ; The doping concentration of carbon atoms is 1×10 17 cm -3 ~5×10 21 cm -3 By controlling the doping concentrations of phosphorus atoms and carbon atoms in the phosphorus-carbon co-doped polysilicon layer 52 within the above range, the parasitic absorption effect of the doped polysilicon stacked structure layer 50 can be more effectively reduced, and the resistivity can be more fully reduced, thereby further improving the photoelectric conversion efficiency of the solar cell. For example, the doping concentration of phosphorus atoms in the phosphorus-carbon co-doped polysilicon layer 52 can be, but is not limited to, 1×10 19 cm -3 , 2×10 19 cm -3 , 3×10 19 cm -3 , 4×10 19 cm -3 , 6×10 19 cm -3 , 8×10 19 cm -3 , 1×10 20 cm -3 , 2×10 20 cm-3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3 , 2×10 21 cm -3 , 5×10 21 cm -3 , 8×10 21 cm -3 , 9×10 21 cm -3 For example, in the phosphorus-carbon co-doped polysilicon layer 52, the doping concentration of carbon atoms may be, but is not limited to, 1×10 17 cm -3 , 5×10 17 cm -3 , 8×10 17 cm -3 , 1×10 18 cm -3 , 5×10 18 cm -3 , 8×10 18 cm -3 , 1×10 19 cm -3 , 5×10 19 cm -3 , 8×10 19 cm -3 , 1×10 20 cm -3 , 2×10 20 cm -3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 6×10 20 cm -3 , 7×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3, 2×10 21 cm -3 , 3×10 21 cm -3 , 4×10 21 cm -3 wait.

[0041] In some embodiments of the present application, the doping concentration of phosphorus atoms in the second phosphorus-doped polysilicon layer 53 (phosphorus-doped polysilicon layer) is 1×10 19 cm -3 ~9×10 21 cm -3 In this way, it can not only isolate the mixed layer of doped atoms, but also help ensure the performance of the battery. For example, in the second phosphorus-doped polysilicon layer 53, the doping concentration of phosphorus atoms can be, but is not limited to, 1×10 19 cm -3 , 2×10 19 cm -3 , 3×10 19 cm -3 , 4×10 19 cm -3 , 6×10 19 cm -3 , 8×10 19 cm -3 , 1×10 20 cm -3 , 2×10 20 cm -3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3 , 2×10 21 cm -3 , 5×10 21 cm -3 , 8×10 21 cm -3 , 9×10 21 cm -3 In the embodiment of the present application, the doping concentration of phosphorus atoms in the second phosphorus-doped polysilicon layer 53 may be the same as that of the first phosphorus-doped polysilicon layer 51 , or may be different.

[0042] In some embodiments of the present application, the phosphorus-hydrogen co-doped polysilicon layer 54 has a doping concentration of phosphorus atoms of 1×10 19 cm -3 ~9×10 21 cm -3 ; The doping concentration of hydrogen atoms is 1×10 17 cm -3 ~5×10 21 cm -3 By controlling the contents of phosphorus atoms and hydrogen atoms within the above range, the phosphorus-hydrogen co-doped polysilicon layer 54 can achieve better passivation effect and better electronic conductivity. For example, the phosphorus-hydrogen co-doped polysilicon layer 54 may have a doping concentration of phosphorus atoms of, but not limited to, 1×10 19 cm -3 , 2×10 19 cm -3 , 3×10 19 cm -3 , 4×10 19 cm -3 , 6×10 19 cm -3 , 8×10 19 cm -3 , 1×10 20 cm -3 , 2×10 20 cm -3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 6×10 20 cm -3 , 7×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3 , 2×10 21 cm -3 , 5×10 21 cm -3 , 8×10 21 cm -3 , 9×10 21 cm -3 For example, in the phosphorus-hydrogen co-doped polysilicon layer 54, the doping concentration of hydrogen atoms may be, but is not limited to, 1×10 17 cm -3 , 5×1017 cm -3 , 8×10 17 cm -3 , 1×10 18 cm -3 , 5×10 18 cm -3 , 8×10 18 cm -3 , 1×10 19 cm -3 , 5×10 19 cm -3 , 8×10 19 cm -3 , 1×10 20 cm -3 , 2×10 20 cm -3 , 3×10 20 cm -3 , 4×10 20 cm -3 , 5×10 20 cm -3 , 6×10 20 cm -3 , 7×10 20 cm -3 , 8×10 20 cm -3 , 9×10 20 cm -3 , 1×10 21 cm -3 , 2×10 21 cm -3 , 5×10 21 cm -3 wait.

[0043] In some embodiments of the present application, the thickness of the first phosphorus-doped polysilicon layer 51 is 1.6 nm to 8.0 nm. For example, the thickness of the first phosphorus-doped polysilicon layer 51 may be, but is not limited to, 1.6 nm, 2 nm, 3 nm, 3.5 nm, 4 nm, 4.2 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 7 nm, 8 nm, etc. In some specific embodiments, the thickness of the first phosphorus-doped polysilicon layer 51 is 3.2 nm to 4.8 nm. Controlling the thickness of the first phosphorus-doped polysilicon layer 51 within the above range is beneficial to the tunneling effect of electrons and also helps to further reduce the parasitic absorption effect.

[0044] In some embodiments of the present application, the thickness of the phosphorus-carbon co-doped polysilicon layer 52 is 16nm-120nm. In some specific embodiments, the thickness of the phosphorus-carbon co-doped polysilicon layer 52 is 56nm-72nm. For example, the thickness of the phosphorus-carbon co-doped polysilicon layer 52 can be, but is not limited to, 16nm, 20nm, 30nm, 40nm, 50nm, 55nm, 56nm, 60nm, 65nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, etc. Controlling the thickness of the phosphorus-carbon co-doped polysilicon layer 52 within the above range can further ensure that the parasitic absorption effect of the battery is weak, thereby helping to ensure a high photoelectric conversion efficiency of the battery.

[0045] In some embodiments of the present application, the thickness of the second phosphorus-doped polysilicon layer 53 is 1.6nm-8.0nm. For example, the thickness of the second phosphorus-doped polysilicon layer 53 may be, but is not limited to, 1.6nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, etc. In some specific embodiments, the thickness of the second phosphorus-doped polysilicon layer 53 is 3.2nm-4.8nm. Controlling the thickness of the second phosphorus-doped polysilicon layer 53 within the above range can not only achieve a better isolation effect, but also help to ensure that the parasitic absorption effect of the doped polysilicon stacked structure layer 50 as a whole is small, and also help to control the overall thickness of the solar cell to be thinner. In the embodiment of the present application, the thickness of the second phosphorus-doped polysilicon layer 53 may be the same as or different from the thickness of the first phosphorus-doped polysilicon layer 51.

[0046] In some embodiments of the present application, the thickness of the phosphorus-hydrogen co-doped polysilicon layer 54 is 4 nm to 40 nm. For example, the thickness of the phosphorus-hydrogen co-doped polysilicon layer 54 can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 28 nm, 30 nm, 32 nm, 35 nm, 40 nm, etc. In some specific embodiments, the thickness of the phosphorus-hydrogen co-doped polysilicon layer 54 can be 16 nm to 32 nm. This allows the overall thickness of the solar cell to be kept relatively thin while also enhancing the cell's passivation effect.

[0047] In some embodiments of the present application, the thickness of the doped polysilicon stacked structure layer 50 is in the range of 50nm-176nm. In some specific embodiments, the thickness of the doped polysilicon stacked structure layer 50 is in the range of 78nm-114nm. For example, the thickness of the doped polysilicon stacked structure layer 50 can be 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 78nm, 80nmn, 82nm, 85nm, 90nm, 92nm, 95nm, 98nm, 100nm, 105nm, 110nm, 112nm, 114nm, 118nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 175nm, etc.

[0048] In some embodiments of the present application, the thickness of the tunnel oxide layer 40 is greater than 0 nm and less than or equal to 2 nm.

[0049] In some embodiments of the present application, the thickness of the passivation layer 12 is within the range of 5nm-20nm, and the thickness of the first anti-reflection layer 11 and the second anti-reflection layer 60 are each independently within the range of 10nm-120nm. Controlling the thickness of the first anti-reflection layer 11, the passivation layer 12, and the second anti-reflection layer 60 within the above ranges can both ensure optimal cell performance and keep the total thickness of the solar cell relatively thin. For example, the thickness of the passivation layer 12 can be 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, etc. Exemplarily, the thickness of the first anti-reflection layer 11 and the second anti-reflection layer 60 can be independently 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 105nm, 110nm, 115nm, etc.

[0050] In one specific embodiment of the present application, a tunneling oxide passivated contact solar cell includes a first anti-reflection layer 11 (specifically, an 80nm thick silicon nitride layer), a passivation layer 12 (specifically, a 12nm thick aluminum oxide layer), an electrode emitter layer 20, a silicon base layer 30 (specifically, an N-type silicon base layer with a thickness of 130μm), a tunneling oxide layer 40 (specifically, a 1.6nm thick silicon oxide layer), a doped polysilicon stacked structure layer 50, and a second anti-reflection layer 60 (specifically, an 80nm thick silicon nitride layer). The doped polysilicon stacked structure includes a first phosphorus-doped polysilicon layer 51 (5nm thick), a phosphorus-carbon co-doped polysilicon layer 52 (80nm thick), a second phosphorus-doped polysilicon layer 53 (5nm thick), and a phosphorus-hydrogen co-doped polysilicon layer 54 (12nm thick). Furthermore, a first electrode 70 and a second electrode 80 are provided on the first anti-reflection layer 11 and the second anti-reflection layer 60, respectively.

[0051] In some embodiments of the present application, the preparation of a tunnel oxide layer passivation contact solar cell includes:

[0052] S01, pre-treating the silicon wafer raw material;

[0053] S02, forming an electrode emission layer on one surface (front side) of the silicon wafer, and polishing the back side of the silicon wafer to obtain the electrode emission layer and the silicon base layer;

[0054] S03, depositing a tunneling oxide layer on the back side of the silicon wafer using a thermal oxidation process, a thermal nitric acid oxidation process, an ozone oxidation process, or a plasma-assisted nitrous oxide process;

[0055] S04, preparing a stacked structure layer of doped polysilicon on the surface of the tunnel oxide layer;

[0056] S05, preparing a passivation layer on the surface of the electrode emission layer;

[0057] S06, forming a first anti-reflection layer on the surface of the passivation layer; and forming a second anti-reflection layer on the surface of the doped polysilicon stacked structure away from the tunneling oxide layer;

[0058] S07. Prepare the first electrode and the second electrode. Electrode paste is printed on the surfaces of the first anti-reflection layer and the second anti-reflection layer, respectively, and then sintered at high temperature to prepare the first electrode and the second electrode. In some specific embodiments, the printing is screen printing.

[0059] In some embodiments of the present application, in S07, an electrode paste is printed on the surface of the second anti-reflection layer so that the paste burns through the second anti-reflection layer and is sintered at a high temperature to obtain a second electrode, so that the second electrode is in contact with the stacked structure layer of doped polycrystalline silicon to better collect electrons. Specifically, the second electrode is in contact with at least the phosphorus-hydrogen co-doped polycrystalline silicon layer in the stacked structure layer of doped polycrystalline silicon to collect electrons. Furthermore, the second electrode can extend in a direction away from the second anti-reflection layer, extend to any position in the stacked structure layer of doped polycrystalline silicon, and even contact the second phosphorus-doped polycrystalline silicon layer, the phosphorus-carbon co-doped polycrystalline silicon layer, and the first phosphorus-doped polycrystalline silicon layer in sequence, as long as it does not penetrate the stacked structure layer of doped polycrystalline silicon and does not contact the tunneling oxide layer.

[0060] The present invention also provides a photovoltaic module 1000, comprising the solar cell provided in the present invention. Referring to FIG2 , the photovoltaic module 1000 further comprises a front cover 1002, a rear cover 1004, a first encapsulating film 1006, and a second encapsulating film 1008. The front cover 1002 is bonded to one side of the tunnel oxide layer passivation contact solar cell 100 via the first encapsulating film 1006. The rear cover 1004 is bonded to the other side of the tunnel oxide layer passivation contact solar cell 100 via the second encapsulating film 1008.

[0061] Due to the solar cell provided by the present application, the photovoltaic module 1000 has good market competitiveness.

[0062] The above is an exemplary embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made thereto without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A tunnel oxide passivation contact solar cell (100), characterized in that: It comprises a first anti-reflection layer (11), a passivation layer (12), an electrode emission layer (20), a silicon base layer (30), a tunneling oxide layer (40), a doped polysilicon stacked structure layer (50), and a second anti-reflection layer (60) which are stacked in sequence; The doped polysilicon stacked structure layer (50) comprises a first phosphorus-doped polysilicon layer (51), a phosphorus-carbon co-doped polysilicon layer (52), a second phosphorus-doped polysilicon layer (53), and a phosphorus-hydrogen co-doped polysilicon layer (54) stacked in sequence; the first phosphorus-doped polysilicon layer (51) is in contact with the tunneling oxide layer (40).

2. The tunnel oxide passivation contact solar cell (100) according to claim 1, characterized in that: The thickness of the doped polysilicon stacked structure layer (50) is in the range of 50nm-176nm.

3. The tunnel oxide passivation contact solar cell (100) according to claim 1 or 2, characterized in that: The thickness of the doped polysilicon stacked structure layer (50) is in the range of 78 nm to 114 nm.

4. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 3, characterized in that: The thickness of the first phosphorus-doped polysilicon layer (51) is 1.6nm-8nm; the thickness of the phosphorus-carbon co-doped polysilicon layer (52) is 16nm-120nm; the thickness of the second phosphorus-doped polysilicon layer (53) is 1.6nm-8nm; and the thickness of the phosphorus-hydrogen co-doped polysilicon layer (54) is 4nm-40nm.

5. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 4, characterized in that: The thickness of the first phosphorus-doped polysilicon layer (51) is 3.2 nm-4.8 nm.

6. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 5, characterized in that: The thickness of the phosphorus and carbon co-doped polysilicon layer (52) is 56nm-72nm.

7. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 6, characterized in that: The thickness of the second phosphorus-doped polysilicon layer (53) is 3.2 nm-4.8 nm.

8. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 7, characterized in that: The thickness of the phosphorus and hydrogen co-doped polysilicon layer (54) is 16nm-32nm.

9. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 8, characterized in that: The silicon base layer (30) is an N-type silicon layer; the electrode emission layer (20) is a boron-doped electrode emission layer (20); and the material of the tunneling oxide layer (40) is selected from silicon oxide, titanium oxide or aluminum oxide.

10. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 9, characterized in that: The thickness of the tunnel oxide layer (40) is greater than 0 nm and less than or equal to 2 nm.

11. The tunnel oxide passivation contact solar cell (100) according to any one of claims 1 to 10, characterized in that: The thickness of the passivation layer (12) is 5nm-20nm, the thickness of the first anti-reflection layer (11) is 10nm-120nm, and the thickness of the second anti-reflection layer (60) is 10nm-120nm.

12. A photovoltaic module (1000), characterized in that: The photovoltaic module (1000) comprises the tunneling oxide layer passivated contact solar cell (100) according to any one of claims 1 to 11.

13. The photovoltaic module (1000) according to claim 12, characterized in that: The photovoltaic module (1000) further comprises a front cover plate (1002), a rear cover plate (1004), a first packaging film (1006) and a second packaging film (1008); the front cover plate (1002) is bonded to one side of the tunnel oxide layer passivation contact solar cell (100) via the first packaging film (1006), and the rear cover plate (1004) is bonded to the other side of the tunnel oxide layer passivation contact solar cell (100) via the second packaging film (1008).

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