Solar cell and preparation method and application thereof

Abstract

The invention discloses a solar cell and a preparation method and application thereof. The preparation method of the solar cell comprises the following steps: preparing a first doped region, an isolation region and a second doped region on the surface of one side of a substrate, wherein the first doped region and the second doped region are electrically isolated by the isolation region; preparing a first passivation layer on the first doped region, the isolation region and the second doped region, and preparing a second passivation layer on the surface of the other side of the substrate; the thickness of the first passivation layer is 0.1-17nm smaller than the thickness of the second passivation layer. According to the solar cell provided by the invention, the passivation structure is optimized through the preparation method, a relatively thin first passivation layer and a relatively thick second passivation layer are arranged, and a proper thickness difference can provide a good passivation effect, and the risk of film explosion caused by stress concentration of the first doped region and the second doped region on the same side can be avoided; therefore, the solar cell is high in conversion efficiency, high in open voltage and large in current density.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a solar cell, its preparation method, and its application. Background Technology

[0002] TBC (TOPCon Back Contact) solar cells are high-efficiency crystalline silicon solar cells that deeply integrate tunneling oxide passivated contact (TOPCon) technology with a back contact (BC) structure. Their core innovation lies in combining a gridless back contact electrode design on the front side with the passivation layer of TOPCon: by introducing an ultra-thin tunneling oxide layer and a phosphorus / boron-doped polycrystalline silicon layer on the back of the cell, the carrier surface recombination rate is significantly reduced. Simultaneously, laser patterning technology enables precise fabrication of the finger-shaped metal electrodes on the back side, effectively reducing optical shading and resistive losses. This promises to achieve higher efficiency and performance, which is crucial for next-generation solar energy solutions.

[0003] Traditional TBC solar cells require passivation on both their light-receiving and back-light-receiving surfaces. However, the passivation structure of traditional TBC solar cells cannot guarantee a good passivation effect or prevent the film from bursting. Summary of the Invention

[0004] Therefore, it is necessary to provide a solar cell that has both good passivation effect and no film explosion, as well as its preparation method and application.

[0005] This application provides a method for preparing a solar cell, comprising the following steps:

[0006] A first doped region, an isolation region, and a second doped region are formed on one side surface of a substrate, wherein the first doped region and the second doped region are electrically isolated by the isolation region;

[0007] A first passivation layer is formed on the first doped region, the isolation region, and the second doped region.

[0008] A second passivation layer is prepared on the other side surface of the substrate;

[0009] The thickness of the first passivation layer is less than the thickness of the second passivation layer, and the difference between the thickness of the second passivation layer and the thickness of the first passivation layer is 0.1 nm to 17 nm.

[0010] In one embodiment, one or both of the following conditions are met:

[0011] (1) The thickness of the first passivation layer is 1 nm to 5 nm;

[0012] (2) The thickness of the second passivation layer is 5nm~19nm.

[0013] In one embodiment, the conditions for preparing the first passivation layer satisfy one or more of the following:

[0014] (1) The preparation temperature is 250℃~450℃;

[0015] (2) The preparation time is 10s~100s;

[0016] (3) The preparation power is 5000w~8000w.

[0017] In one embodiment, the conditions for preparing the second passivation layer satisfy one or more of the following:

[0018] (1) The preparation temperature is 250℃~450℃;

[0019] (2) The preparation time is 100s~300s;

[0020] (3) The preparation power is 5000w~8000w.

[0021] In one embodiment, fabricating a first doped region, an isolation region, and a second doped region on one side surface of the substrate includes the following steps:

[0022] A first tunneling material and a first doping material are sequentially disposed on one side surface of the substrate, and the first tunneling material and the first doping material on the first region for forming the isolation region and the second region for forming the second doped region are removed.

[0023] A second tunneling material and a second doped material are sequentially disposed on one side surface of the substrate. The first tunneling material, the first doped material, the second tunneling material, and the second doped material formed by winding on the other side surface of the substrate are removed. The second tunneling material and the second doped material on the first region and the third region used to form the first doped region are removed. A first doped region comprising a stacked first tunneling layer and a first doped layer, and a second doped region comprising a stacked second tunneling layer and a second doped layer are prepared. The first doped region and the second doped region are electrically isolated by the isolation region.

[0024] In one embodiment, one or both of the following conditions are met:

[0025] (1) The step of preparing a first antireflection layer is included after preparing the first passivation layer and before preparing the second passivation layer;

[0026] (2) After preparing the second passivation layer, the step of preparing the second antireflection layer is also included.

[0027] This application also provides a solar cell prepared according to the above-described preparation method.

[0028] In one embodiment, a first antireflection layer is further provided on the first passivation layer;

[0029] Optionally, a second antireflection layer may also be provided on the second passivation layer.

[0030] In one embodiment, one or more of the following conditions are met:

[0031] (1) The thickness of the first antireflection layer is 70 nm ~ 95 nm;

[0032] (2) The refractive index of the first antireflective layer is 2.05~2.15;

[0033] (3) The thickness of the second antireflection layer is 65nm ~ 85nm;

[0034] (4) The refractive index of the second antireflective layer is 1.90~2.10;

[0035] (5) The materials of the first passivation layer and the second passivation layer are each independently one or more of aluminum oxide, silicon oxide and hydrogenated amorphous silicon.

[0036] This application also provides a photovoltaic module, the power supply device of which includes a solar cell prepared by the above-described preparation method or the above-described solar cell.

[0037] The solar cell provided in this application achieves a passivation structure through an optimized fabrication method. By setting a thinner first passivation layer and a thicker second passivation layer, and with an appropriate thickness difference between the first and second passivation layers, a good passivation effect can be provided. This also avoids the risk of film bursting due to stress concentration in the first and second doped regions on the same side. As a result, this solar cell has high conversion efficiency, high turn-on voltage, and large current density. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 The solar cell is from Example 1.

[0040] Figure 2This is a microscope image of the surface of the first passivation layer in the solar cell of Example 1.

[0041] Figure 3 This is a microscope image of the surface of the first passivation layer in the solar cell of Comparative Example 1.

[0042] Explanation of reference numerals in the attached figures: 110: substrate; 121: first tunneling layer; 122: second tunneling layer; 131: first doped layer; 132: second doped layer; 140: first passivation layer; 150: first antireflection layer; 160: second passivation layer; 170: second antireflection layer; 180: first electrode; 190: second electrode. Detailed Implementation

[0043] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0045] As used herein, the term "and / or" encompasses any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" includes three parallel options: A, B, and "a combination of A and B".

[0046] In this document, unless otherwise stated, "one or more" means any one of the listed items or any combination of the listed items. Similarly, "one or more" and other instances of "one or more" are to be understood in the same way unless otherwise stated.

[0047] In this document, terms such as "further," "even further," "especially," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later. However, they should not be construed as limitations on the preceding technical solution or on the scope of protection of this document. Unless otherwise specified, in this document, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0048] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0049] In this document, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0050] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0051] In this document, when referring to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints (i.e., the minimum and maximum values) of the numerical interval, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, and other numerical interval types.

[0052] In this document, the terms "room temperature" or "normal temperature" generally refer to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0053] In this document, for methods involving multiple steps, unless otherwise explicitly stated herein, there is no strict order constraint on the execution of these steps; they may be executed in any order other than those described. Moreover, any step may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and their execution order is not necessarily sequential, but may be executed in turn, alternately, or simultaneously with other steps or parts of the sub-steps or stages of other steps.

[0054] This application provides a method for preparing a solar cell, comprising the following steps S100~S300:

[0055] S100. A first doped region, an isolation region, and a second doped region are prepared on one side surface of the substrate, and the first doped region and the second doped region are electrically isolated by the isolation region.

[0056] S200: A first passivation layer is prepared on the first doped region, the isolation region, and the second doped region.

[0057] S300. Prepare a second passivation layer on the other side surface of the substrate;

[0058] The thickness of the first passivation layer is less than the thickness of the second passivation layer, and the difference between the thickness of the second passivation layer and the thickness of the first passivation layer is 0.1 nm to 17 nm.

[0059] The solar cell provided in this application achieves a passivation structure through an optimized fabrication method. By setting a thinner first passivation layer and a thicker second passivation layer, and with an appropriate thickness difference between the first and second passivation layers, a good passivation effect can be provided. This also avoids the risk of film bursting due to stress concentration in the first and second doped regions on the same side. As a result, this solar cell has high conversion efficiency, high turn-on voltage, and large current density.

[0060] In a specific example, fabricating a first doped region, an isolation region, and a second doped region on one side surface of the substrate includes the following steps:

[0061] A first tunneling material and a first doping material are sequentially disposed on one side surface of the substrate, and the first tunneling material and the first doping material on the first region used to form the isolation region and the second region used to form the second doping region are removed.

[0062] A second tunneling material and a second doped material are sequentially disposed on one side surface of the substrate. The first tunneling material, the first doped material, the second tunneling material, and the second doped material formed by winding on the other side surface of the substrate are removed. The second tunneling material and the second doped material on the first region and the third region used to form the first doped region are removed. A first doped region comprising a stacked first tunneling layer and a first doped layer, and a second doped region comprising a stacked second tunneling layer and a second doped layer are prepared. The first doped region and the second doped region are electrically isolated by an isolation region.

[0063] Furthermore, the preparation method of the first doped region, the isolation region, and the second doped region includes the following steps:

[0064] S110. A first tunneling material and a first intrinsic polysilicon are sequentially deposited on one side surface of the substrate, and a first element is doped into the first intrinsic polysilicon to prepare a first tunneling layer, a first doped layer and a first doped glass layer.

[0065] S120: Remove the first doped glass layer on one side surface of the substrate, a portion of the first tunneling layer and a portion of the first doped layer on the first region for forming the isolation region and the second region for forming the second doped region, and prepare the first doped region;

[0066] S130. Once again, deposit the second tunneling material and the second intrinsic polysilicon sequentially on the same side surface of the substrate, dope with the second element, and prepare the second tunneling layer, the second doped layer and the second doped glass layer.

[0067] S140: Remove the second doped glass layer and a portion of the second tunneling layer and a portion of the second doped layer on the first region and the third region used to form the first doped region from the surface of one side of the substrate to prepare the second doped region and the isolation region.

[0068] S150, Remove the plating formed on the other side surface of the substrate.

[0069] Understandably, due to equipment or process limitations, while the first doped region and the corresponding material of the second doped region are formed on the same side surface of the substrate, the corresponding material will also be formed on the other side surface of the substrate, which can be removed as needed.

[0070] Furthermore, after removing the wrap-around plating and before step S200, step S160 is also included: texturing the surface of the isolation area and texturing the surface of the substrate that does not have an isolation area.

[0071] Furthermore, the method for removing part of the first doped layer and part of the second doped layer can be, but is not limited to, laser removal. Specifically, it can be, but is not limited to, using a green or ultraviolet picosecond laser with a laser power of 50W to 150W.

[0072] In a specific example, the method for preparing the first passivation layer may be, but is not limited to, chemical vapor deposition, and further, chemical vapor deposition may be, but is not limited to, plasma-enhanced chemical vapor deposition.

[0073] Furthermore, the preparation temperature of the first passivation layer is 250℃~450℃; specifically, the preparation temperature of the first passivation layer may be, but is not limited to, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃ or 450℃.

[0074] In a specific example, the preparation time for the first passivation layer is 10s to 100s; specifically, the preparation time for the first passivation layer can be, but is not limited to, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s or 100s.

[0075] In a specific example, the fabrication power for the first passivation layer is 5000W to 8000W. Specifically, the fabrication power for the first passivation layer can be, but is not limited to, 5000W, 5500W, 6000W, 6500W, 7000W, 7500W, or 8000W.

[0076] In a specific example, the preparation temperature for the second passivation layer is 250℃~450℃; specifically, the preparation temperature for the second passivation layer may be, but is not limited to, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, or 450℃.

[0077] In a specific example, the preparation time for the second passivation layer is 100s to 300s; specifically, the preparation time for the second passivation layer can be, but is not limited to, 100s, 150s, 200s, 250s or 300s.

[0078] In a specific example, the fabrication power for the second passivation layer is 5000W to 8000W. Specifically, the fabrication power for the second passivation layer can be, but is not limited to, 5000W, 5500W, 6000W, 6500W, 7000W, 7500W, or 8000W.

[0079] In one specific example, the step of preparing a first antireflection layer is included after preparing the first passivation layer and before preparing the second passivation layer.

[0080] In a specific example, the temperature for preparing the first antireflection layer is 400℃~600℃, the time is 900s~1500s, the SiH4 flow rate is 800~3000sccm, the NH3 flow rate is 7000~15000sccm, and the power is 10000w~15000w.

[0081] Specifically, the temperature for fabricating the first antireflective layer can be, but is not limited to, 400℃, 450℃, 500℃, 550℃, or 600℃, and the time can be, but is not limited to, 900s, 1000s, 1100s, 1200s, 1300s, 1400s, or 1500s. The power can be, but is not limited to, 10000W, 11000W, 12000W, 13000W, 14000W, or 15000W.

[0082] In one specific example, the preparation of the second passivation layer is followed by the preparation of the second antireflection layer.

[0083] In a specific example, the temperature for preparing the second antireflection layer is 400℃~600℃, the time is 700s~1000s, the SiH4 flow rate is 800~3000sccm, the NH3 flow rate is 7000~15000sccm, and the power is 10000w~17000w.

[0084] Specifically, the temperature for fabricating the second antireflective layer can be, but is not limited to, 400℃, 450℃, 500℃, 550℃, or 600℃, and the time can be, but is not limited to, 700s, 800s, 900s, or 1000s. The power can be, but is not limited to, 10000W, 11000W, 12000W, 13000W, 14000W, 15000W, 16000W, or 17000W.

[0085] This application provides a method for fabricating a solar cell with reduced film bursting. It employs a tubular PECVD method to deposit alumina in stages, resulting in a thicker alumina layer on the front side, significantly enhancing the passivation effect of the pyramidal textured surface. The thinner alumina layer on the back side provides some passivation to the textured surface of the isolation zone, without causing the boron-doped and phosphorus-doped polycrystalline silicon layers to burst. The TBC solar cell and its fabrication method provided in this application exhibit excellent passivation contact performance, high conversion efficiency, high on-state voltage, and high current density. Furthermore, the solar cell and its fabrication method utilize a combined tubular PECVD method to deposit alumina and silicon nitride, eliminating a separate ALD process, simplifying the process flow, and making it suitable for mass production.

[0086] In a specific example, the thickness of the first passivation layer is 1 nm to 5 nm; specifically, the thickness of the first passivation layer may be, but is not limited to, 1 nm, 2 nm, 3 nm, 4 nm or 5 nm.

[0087] In a specific example, the thickness of the second passivation layer is 5nm to 19nm; specifically, the thickness of the second passivation layer may be, but is not limited to, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 4nm, 5nm, 6nm, 17nm, 18nm or 19nm.

[0088] In one specific example, the materials of the first passivation layer and the second passivation layer are each independently one or more of aluminum oxide, silicon oxide, and hydrogenated amorphous silicon.

[0089] In a specific example, it also includes a first antireflection layer disposed on the first passivation layer and a second antireflection layer disposed on the second passivation layer.

[0090] In a specific example, the thickness of the first antireflection layer is 70 nm to 95 nm; specifically, the thickness of the first antireflection layer may be, but is not limited to, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm or 95 nm.

[0091] In a specific example, the refractive index of the first antireflective layer is 2.05 to 2.15; specifically, the refractive index of the first antireflective layer may be, but is not limited to, 2.05, 2.06, 2.07, 2.08, 2.09, 2.1, 2.11, 2.12, 2.13, 2.14 or 2.15.

[0092] In a specific example, the thickness of the second antireflection layer is 65nm to 85nm; the thickness of the second antireflection layer may be, but is not limited to, 65nm, 70nm, 75nm, 80nm or 85nm.

[0093] In a specific example, the refractive index of the second antireflective layer is 1.90 to 2.10. The refractive index of the second antireflective layer may be, but is not limited to, 1.9, 1.91, 1.92, 1.93, 1.94, 1.95, 1.96, 1.97, 1.98, 1.99, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 2.1.

[0094] It is understood that the aforementioned solar cells may be, but are not limited to, TBC solar cells or Topcon solar cells.

[0095] Furthermore, this application also provides a photovoltaic module whose power supply device includes a solar cell prepared by the above-described preparation method or a solar cell prepared by the above-described method.

[0096] The present application will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0097] In the specific embodiments described below, the measurement parameters of the raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision. "Ambient temperature" refers to 25°C; "atmospheric pressure" refers to 100 kPa or 101 kPa.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] Example 1

[0100] This embodiment provides a solar cell 10, the structure of which is as follows: Figure 1 As shown, the structure includes a substrate 110, a first tunneling layer 121, a second tunneling layer 122, a first doped layer 131, a second doped layer 132, a first passivation layer 140, a first antireflection layer 150, a second passivation layer 160, a second antireflection layer 170, a first electrode 180, and a second electrode 190. The first doped region includes the first tunneling layer 121 and the first doped layer 131, and the second doped region includes the second tunneling layer 122 and the second doped layer 132.

[0101] S1: The silicon wafer serves as the substrate 110, and its surface is polished on both sides.

[0102] S2: First tunneling oxide material silicon oxide and intrinsic polycrystalline silicon material are deposited on both sides, and then a boron source is diffused to form a double-sided boron-doped polycrystalline silicon layer and a BSG layer on both sides of the substrate, wherein the thickness of the boron-doped polycrystalline silicon layer is 300nm and the thickness of the BSG layer is 55nm.

[0103] S3: Laser grooving 1, removing the BSG layer on the second doped region and isolation region on the back side of substrate 110, wherein the laser is a green picosecond laser with a power of 80W.

[0104] S4: Alkali cleaning 1, removes the boron-doped polysilicon layer and the first tunneling oxide material on the second doped region and isolation region on the back side of the substrate 110, and prepares the first tunneling layer 121 and the first doped layer 131.

[0105] S5: Deposit a second tunneling oxide material and an intrinsic polycrystalline silicon material on both sides, and then diffuse a phosphorus source through the back side to form a phosphorus-doped polycrystalline silicon layer and a PSG layer on the back side of the substrate 110, wherein the thickness of the phosphorus-doped polycrystalline silicon layer is 300nm and the thickness of the PSG layer is 60nm.

[0106] S6: Laser grooving 2, removing the PSG layer on the first doped region and isolation region on the back side, wherein the laser is a green picosecond laser with a power of 60W.

[0107] S7: Alkali cleaning 2, removes phosphorus-doped polysilicon material and second tunneling oxide material on the back side first doped region and isolation region, and prepares second tunneling layer 122 and second doped layer 132.

[0108] S8: Etching to remove the boron-doped polysilicon material, the first tunneling oxide material, the phosphorus-doped polysilicon material, and the second tunneling oxide material from the side and front sides.

[0109] S8: Texturing, which creates a pyramidal textured surface in the isolation areas on the front and back of the silicon wafer.

[0110] S9: Alumina is deposited on the back side of a silicon wafer as the first passivation layer 140 and the first antireflection layer 150 using a tubular PECVD combined method. The alumina thickness is 4nm, the deposition temperature is 300℃, the deposition time is 60s, the N2O flow rate is 6000sccm, the TMA flow rate is 55sccm, and the power is 6000w. The first antireflection layer 150 has a thickness of 90nm, a refractive index of 2.13, a deposition temperature of 530℃, a deposition time of 1000s, a SiH4 flow rate of 1200sccm, an NH3 flow rate of 11000sccm, and a power of 13500w.

[0111] S10: Alumina is deposited on the front side of the silicon wafer as the second passivation layer 160 and the second antireflection layer 170 using a tubular PECVD combined method. The alumina thickness is 7nm, the deposition temperature is 300℃, the deposition time is 200s, the N2O flow rate is 6000sccm, the TMA flow rate is 65sccm, and the power is 7000w. The second antireflection layer 170 has a thickness of 78nm, a refractive index of 2.02, a deposition temperature of 530℃, a deposition time of 850s, a SiH4 flow rate of 2000sccm, an NH3 flow rate of 13000sccm, an N2O flow rate of 12000sccm, and a power of 15000w.

[0112] S11: Electrode paste is printed in the first doped region and sintered to form the first electrode 180 and the second electrode 190 in ohmic contact with it, and finally a solar cell 10 is fabricated.

[0113] Example 2

[0114] The method for preparing a solar cell provided in this embodiment differs from that in Embodiment 1 only in that the thickness of the back antireflection layer is 90 nm, the refractive index is 2.20, the time is 800 s, the SiH4 flow rate is 2200 sccm, and the thickness, deposition temperature, NH3 flow rate, and power of the back antireflection layer are the same as in Embodiment 1.

[0115] Comparative Example 1

[0116] This comparative example provides a method for fabricating a solar cell, which is the same as Example 1 except that the thickness of the back alumina is the same as that of the front alumina in Example 1, which is 7 nm. The deposition time, temperature and flow rate are the same as those of the front alumina.

[0117] Comparative Example 2

[0118] This comparative example provides a method for fabricating a solar cell, which is the same as Example 1 except that the thickness of the front alumina is the same as that of the back alumina in Example 1, which is 4 nm. The deposition time, temperature and flow rate are the same as those of the back alumina.

[0119] Comparative Example 3

[0120] The comparative example provides a method for preparing a solar cell, which differs from Example 1 only in that the thickness of the front alumina is 22 nm, while the deposition time, temperature, flow rate, and power of the front antireflection layer are the same as in Example 1.

[0121] Comparative Example 4

[0122] This comparative example provides a method for fabricating a solar cell, which differs from Example 1 only in that the back alumina thickness is 1 nm, the front alumina thickness is 20 nm, and the deposition temperature and flow rate of the back alumina are the same as those of the front alumina.

[0123] The conversion efficiency of the TBC solar cells obtained in Examples 1-2 and Comparative Examples 1-4 was measured using a Halm tester, and the results are shown in Table 1.

[0124] Table 1

[0125]

[0126] It can be seen from the combined examples 1-2 and comparative examples 1-4 that, as Figure 2The image shown is a microscope image of the surface of the first passivation layer in the solar cell of Example 1. The solar cell did not exhibit any film bursting problem.

[0127] Because both the front and back alumina in Comparative Example 1 are relatively thick, such as Figure 3 The white dots shown represent the film bursting phenomenon on the surface of the first passivation layer, aluminum oxide. This deteriorates the passivation effect on the back poly of Comparative Example 1, resulting in lower on-state voltage, short-current current, and fill factor, as well as lower conversion efficiency.

[0128] In Comparative Example 2, both the front and back alumina are relatively thin. There is no film bursting phenomenon on the boron-doped polysilicon and phosphorus-doped polysilicon on the back. However, due to the thin alumina, the field passivation and chemical passivation effects on the front are poor, resulting in low turn-on voltage, short current and fill ratio, and low conversion efficiency in Comparative Example 2.

[0129] In Comparative Examples 3-4, the difference in thickness between the front and back alumina is too large, resulting in poor hydrogen passivation and chemical passivation effects of the back-side doped polycrystalline silicon. This leads to low turn-on voltage, short-current, and fill ratios, as well as low conversion efficiency in Comparative Examples 3-4.

[0130] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a solar cell, characterized in that, Includes the following steps: A first doped region, an isolation region, and a second doped region are formed on one side surface of a substrate, wherein the first doped region and the second doped region are electrically isolated by the isolation region; A first passivation layer is formed on the first doped region, the isolation region, and the second doped region. A second passivation layer is prepared on the other side surface of the substrate; The thickness of the first passivation layer is less than the thickness of the second passivation layer, and the difference between the thickness of the second passivation layer and the thickness of the first passivation layer is 0.1 nm to 17 nm.

2. The method for preparing a solar cell as described in claim 1, characterized in that, One or two of the following conditions must be met: (1) The thickness of the first passivation layer is 1 nm to 5 nm; (2) The thickness of the second passivation layer is 5nm~19nm.

3. The method for preparing a solar cell as described in claim 1 or 2, characterized in that, The conditions for preparing the first passivation layer satisfy one or more of the following: (1) The preparation temperature is 250℃~450℃; (2) The preparation time is 10s~100s; (3) The preparation power is 5000w~8000w.

4. The method for preparing a solar cell as described in claim 1 or 2, characterized in that, The conditions for preparing the second passivation layer must satisfy one or more of the following: (1) The preparation temperature is 250℃~450℃; (2) The preparation time is 100s~300s; (3) The preparation power is 5000w~8000w.

5. The method for preparing a solar cell as described in claim 1 or 2, characterized in that, The fabrication of a first doped region, an isolation region, and a second doped region on one side surface of the substrate includes the following steps: A first tunneling material and a first doping material are sequentially disposed on one side surface of the substrate, and the first tunneling material and the first doping material on the first region for forming the isolation region and the second region for forming the second doped region are removed. A second tunneling material and a second doped material are sequentially disposed on one side surface of the substrate. The first tunneling material, the first doped material, the second tunneling material, and the second doped material formed by winding on the other side surface of the substrate are removed. The second tunneling material and the second doped material on the first region and the third region used to form the first doped region are removed. A first doped region comprising a stacked first tunneling layer and a first doped layer, and a second doped region comprising a stacked second tunneling layer and a second doped layer are prepared. The first doped region and the second doped region are electrically isolated by the isolation region.

6. The method for preparing a solar cell as described in claim 1 or 2, characterized in that, One or two of the following conditions must be met: (1) The step of preparing a first antireflection layer is included after preparing the first passivation layer and before preparing the second passivation layer; (2) After preparing the second passivation layer, the step of preparing the second antireflection layer is also included.

7. A solar cell, characterized in that, A solar cell prepared according to any one of claims 1 to 6.

8. The solar cell as claimed in claim 7, characterized in that, It also includes a first antireflection layer disposed on the first passivation layer; Optionally, a second antireflection layer may also be provided on the second passivation layer.

9. The solar cell as claimed in claim 8, characterized in that, One or more of the following conditions must be met: (1) The thickness of the first antireflection layer is 70 nm ~ 95 nm; (2) The refractive index of the first antireflective layer is 2.05~2.15; (3) The thickness of the second antireflection layer is 65nm ~ 85nm; (4) The refractive index of the second antireflective layer is 1.90~2.10; (5) The materials of the first passivation layer and the second passivation layer are each independently one or more of aluminum oxide, silicon oxide and hydrogenated amorphous silicon.

10. A photovoltaic module, characterized in that, Its power supply device includes a solar cell prepared by any one of claims 1 to 6 or a solar cell as described in any one of claims 7 to 9.

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