Solar cell and preparation method therefor, and electric apparatus

Abstract

A solar cell (10) and a preparation method therefor, and an electric apparatus (20). The preparation method for the solar cell (10) comprises the following steps: providing a substrate (100), wherein the substrate (100) has a first surface (101) and a second surface (102) opposite the first surface (101); forming a protective material layer on the first surface (101) of the substrate (100), removing part of a protective material from a preset first doped region (103), and preparing a protective layer; and performing first doping on the substrate (100) along the preset first doped region (103), and preparing the substrate (100), which includes the first doped region (103), wherein the width of the first doped region (103) ranges from 15 μm to 30 μm.

Description

Solar cell, preparation method thereof, and electrical device

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202311244504.3, filed on September 25, 2023, entitled “Solar Cells, Methods for Making Them, and Electrical Devices,” the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a solar cell, a preparation method thereof, and an electrical device. Background Art

[0004] The current mainstream solar PERC cells in the market are no longer able to meet the demand for higher energy conversion efficiency and power. Therefore, the concept of TOPCon high-efficiency solar cells emerged in 2013. After continuous research and development, TOPCon cells have now become relatively mature, balancing cost and efficiency. The large-scale mass production of TOPCon cells is considered to have ushered in the first year of N-type cell industrialization, gradually replacing PERC cells in the mainstream market. In terms of the performance of back-passivated contact technology, N-TOPCon cells are more market-worthy than PERC cells. The theoretical conversion efficiency of the cells is higher than that of PERC cells, and their price is approaching that of PERC cells. TOPCon cells are less affected by weather, especially in terms of spectral response, with excellent response to both long and short waves. Compared with PERC cells that only respond to short waves, TOPCon cells have a large range of spectral response, which can ensure continuous power output. They also have advantages such as low attenuation, high bifaciality, and a low temperature coefficient, which significantly increase power generation in terminal power stations.

[0005] The TOPCon cell is a solar cell technology with tunneling oxide passivation contact based on the principle of selective carriers. The cell's advantages stem from the different potential well heights of the valence band and conduction band for holes and electrons, as well as the different effective masses of holes and electrons. The superposition of an ultra-thin oxide tunneling layer and a doped polysilicon layer enables electron tunneling and hole blocking, achieving excellent chemical passivation and field passivation. Traditional TOPCon cells use N-type silicon wafers as a substrate, with full-surface boron diffusion on the front to form a PN junction on the front of the cell. By building a built-in electric field, the excitons are separated into electron-hole pairs. However, under this technological background, even with oxidation annealing, lattice loss on the front of the cell structure is difficult to avoid. This loss also creates a large number of recombination centers, leading to a loss in the cell's open-circuit voltage and a decrease in photoelectric conversion efficiency, affecting cell performance.

[0006] Summary of the Invention

[0007] According to various embodiments of the present application, a solar cell, a method for manufacturing the same, and an electrical device are provided.

[0008] The present application provides a method for preparing a solar cell, comprising the following steps:

[0009] providing a substrate having a first surface and a second surface opposite to the first surface;

[0010] forming a protective material layer on the first surface, and removing a portion of the protective material layer on the predetermined first doped region to prepare a protective layer;

[0011] Performing first doping on the substrate along the preset first doping region to prepare a substrate including the first doping region, wherein the width of the first doping region is 10 μm to 35 μm;

[0012] The protective layer is removed, and a passivation contact structure is prepared on the second surface.

[0013] In one embodiment, before forming the protective material layer, the method further includes: performing a texturing treatment on the substrate.

[0014] In one embodiment, after preparing the protective layer and before preparing the substrate including the first doped region, the method further includes: performing a first cleaning process on the substrate including the protective layer;

[0015] The conditions of the first cleaning treatment include: the composition of the cleaning solution used in the first cleaning treatment includes, by mass percentage, 1% to 6% of a monobasic strong base, 0.5% to 2% of a texturing additive, and 93% to 98.5% of a first solvent;

[0016] The first cleaning process takes 150s to 350s.

[0017] The temperature of the first cleaning treatment is 60°C to 80°C.

[0018] In one embodiment, the material of the protective layer includes one or more of silicon oxide, silicon nitride and photosensitive resin.

[0019] In one embodiment, the method for removing the protective layer includes performing a second cleaning process on the substrate including the first doped region;

[0020] The conditions of the second cleaning treatment include: using a hydrofluoric acid aqueous solution with a mass percentage of 40% to 80% for cleaning for 150 seconds to 350 seconds.

[0021] In one embodiment, the surface concentration of the first doped region is 10 19 ~3×10 20, the square resistance is 40Ω~170Ω.

[0022] In one embodiment, after preparing the passivation contact structure, the method further includes: preparing a stacked first passivation layer and a first anti-reflection layer on the first surface, and preparing a second anti-reflection layer on the passivation contact structure.

[0023] In one embodiment, after preparing the first passivation layer, the first anti-reflection layer and the second anti-reflection layer, the method further includes: preparing a first electrode that penetrates the first passivation layer and the first anti-reflection layer and is connected to the first doped region, and preparing a second electrode that penetrates the second anti-reflection layer and is connected to the passivation contact structure.

[0024] The present application also provides a solar cell manufactured according to the above-mentioned manufacturing method.

[0025] The present application also provides an electrical device, comprising the solar cell as described above as a power source.

[0026] The details of one or more embodiments of the present application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to better describe and illustrate the embodiments and / or examples of the inventions disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed inventions, the presently described embodiments and / or examples, and any of the best modes currently understood for these inventions.

[0028] FIG1 is a schematic diagram of a solar cell structure according to a specific example of the present application.

[0029] FIG2 is a top view of a first surface before preparing a passivation contact structure according to a specific example of the present application, wherein (a) is a first doped region having a velvet structure, and (b) is a first surface having a velvet structure.

[0030] FIG3 is a schematic structural diagram of a solar cell and an electrical device in one embodiment of the present application.

[0031] Explanation of the reference numerals: 10: solar cell; 100: substrate; 1101: tunneling oxide layer; 1102: doped polysilicon layer; 110: passivation contact structure; 120: first passivation layer; 130: first anti-reflection layer; 140: second anti-reflection layer; 150: first electrode; 160: second electrode; 101, first surface; 102, second surface; 103, first doped region; 20, electrical device. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0033] In addition, 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0034] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0035] When describing positional relationships, unless otherwise specified, when an element, such as a layer, film, or substrate, is referred to as being "on" another layer, it can be directly on the other layer or intervening layers may also be present. Furthermore, when a layer is referred to as being "under" another layer, it can be directly under or one or more intervening layers may also be present. It will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers or one or more intervening layers may also be present.

[0036] Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless a clear limiting term such as “only,” “consisting of,” etc. is used.

[0037] Unless mentioned otherwise, terms in the singular may include plural forms and should not be construed as having one number.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] The present application provides a method for preparing a solar cell 10, comprising the following steps:

[0040] A substrate 100 is provided, wherein the substrate 100 has a first surface 101 and a second surface 102 opposite to the first surface 101;

[0041] forming a protective material layer on the first surface 101 and removing a portion of the protective material layer on the predetermined first doped region 103 to prepare a protective layer;

[0042] Performing first doping on the substrate along a predetermined first doping region 103 to prepare a substrate including the first doping region 103 , wherein the width of the first doping region 103 is 10 μm to 35 μm;

[0043] The protective layer is removed, and a passivation contact structure 110 is formed on the second surface 102 .

[0044] Furthermore, the width of the first doped region may be, but is not limited to, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 24 μm, 26 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 34 μm or 35 μm. In one embodiment, the width of the first doped region is 15 μm to 30 μm.

[0045] In a specific example, before forming the protective material layer, the method further includes: performing a texturing process on the substrate.

[0046] The texturing treatment performed on the substrate may be, but is not limited to, performing the texturing treatment on one or both of the first surface and the second surface of the substrate. Preferably, the texturing treatment is performed on the first surface of the substrate.

[0047] It can be understood that the composition of the texturing liquid includes, by mass percentage, 0.6% to 2.0% of a monobasic strong base, 0.3% to 1.0% of a texturing additive and 97% to 99% of a second solvent. The texturing treatment time is 350s to 550s, and the texturing treatment temperature is 70°C to 85°C.

[0048] In a specific example, the material of the protective layer includes one or more of silicon oxide, silicon nitride, and photosensitive adhesive.

[0049] Specifically, the photosensitive adhesive may be, but is not limited to, one or more of ma-N 400, NR9-6000PY, and N5735-L0 (N244).

[0050] It is understandable that the method for preparing the protective layer may be, but is not limited to, one or more of wet oxygen, dry oxygen, LPCVD or phosphorus diffusion.

[0051] Furthermore, the protective layer is made of silicon oxide. Specifically, the method for preparing the silicon oxide is phosphorus expansion, with a preparation temperature of 500°C to 900°C, a preparation time of 1500s to 5000s, and a preparation pressure of 600mbar to 1024mbar, to obtain silicon oxide with a thickness of 5nm to 20nm.

[0052] Specifically, the thickness of silicon oxide may be, but is not limited to, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, or 20 nm.

[0053] In a specific example, the preparation temperature for preparing the above-mentioned silicon oxide as a protective layer material may be but is not limited to 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C or 900°C, the preparation time may be but is not limited to 1500s, 2000s, 2500s, 3000s, 3500s, 4000s, 4500s or 5000s, and the preparation pressure may be but is not limited to 600mbar, 700mbar, 800mbar, 900mbar, 1000mbar or 1024mbar.

[0054] The protective layer can effectively avoid lattice distortion caused by doping the first surface of the substrate, effectively realize local patterned doping, achieve good ohmic contact, thereby reducing recombination centers and improving battery conversion efficiency.

[0055] In a specific example, a laser method is used to remove part of the protective material layer on the preset first doping area. The laser processing conditions include: rated power of 15w~45w, laser frequency of 300KHz~950KHz, spot size of 10μm~35μm, and virtual-to-real ratio of 0.2:0.5~0.4:0.5.

[0056] Specifically, the rated power of the laser treatment can be, but is not limited to, 15W, 17W, 20W, 22W, 24W, 26W, 28W, 30W, 32W, 34W, 36W, 38W, 40W, 42W or 45W, and the laser frequency can be, but is not limited to, 300KHz, 350KHz, 400KHz, 450KHz, 500KHz, 550KHz, 600KHz, 650KHz, 700KHz, 750KHz, 800KHz, 8 The laser frequency range is 50 kHz, 900 kHz, or 950 kHz. The spot size can be, but is not limited to, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 24 μm, 26 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 34 μm, or 35 μm. The virtual-to-real ratio can be, but is not limited to, 0.2:0.5, 0.25:0.5, 0.3:0.5, or 0.4:0.5. In one embodiment, the rated power is 20 W to 40 W, the laser frequency is 350 kHz to 900 kHz, and the spot size is 15 μm to 30 μm.

[0057] In a specific example, after preparing the protective layer and before preparing the substrate including the first doped region, the method further includes: performing a first cleaning process on the substrate including the protective layer.

[0058] In a specific example, the conditions for the first cleaning treatment include: the composition of the first cleaning liquid includes, by mass percentage: 1% to 6% of a monobasic strong base, 0.5% to 2% of a texturing additive and 93% to 98.5% of a first solvent, the time for the first cleaning treatment is 150s to 350s, and the temperature for the first cleaning treatment is 65°C to 75°C. In one embodiment, 1.4% to 5% of a monobasic strong base, 0.9% to 1.5% of a texturing additive and 93.5% to 98% of a first solvent, the time for the first cleaning treatment is 200s to 300s, and the temperature for the first cleaning treatment is 65°C to 75°C.

[0059] Specifically, the time of the first cleaning treatment may be but is not limited to 200s, 210s, 220s, 230s, 240s, 250s, 260s, 270s, 280s, 290s or 300s, and the temperature of the first cleaning treatment may be but is not limited to 65°C, 66°C, 67°C, 8°C, 9°C, 70°C, 71°C, 72°C, 73°C, 74°C or 75°C.

[0060] In a specific example, the monobasic strong base may include, but is not limited to, one or more of potassium hydroxide and sodium hydroxide. The first solvent and the second solvent are each independently selected from, but are not limited to, water. It is understood that the water here refers to deionized water.

[0061] It can be understood that cleaning here can remove the lattice loss caused by the laser.

[0062] In a specific example, the surface concentration of the first doping region is 1.5×10 19 ~2.5×10 20 , the square resistance is 60Ω~150Ω.

[0063] Furthermore, the surface concentration of the first doping region is 10 19 ~3×10 20 , the square resistance is 40Ω~170Ω, preferably, the surface concentration of the first doped region can be but not limited to 1.5×10 19 , 3×10 19 , 4.5×10 19 , 6×10 19 , 7.5×10 19 , 9×10 19 , 1.05×10 20 , 1.2×10 20 , 1.35×10 20 , 1.5×10 20 , 1.65×10 20 , 1.8×10 20 , 1.95×10 20 , 2.1×10 20 , 2.25×10 20 , 2.4×10 20 or 2.5×10 20 The square resistance may be, but is not limited to, 60Ω, 70Ω, 80Ω, 90Ω, 100Ω, 110Ω, 120Ω, 130Ω, 140Ω, or 150Ω.

[0064] Furthermore, the diffusion temperature in preparing the first doping region is 900° C. to 1100° C., and the diffusion time is 300s to 700s.

[0065] Specifically, the diffusion temperature may be, but is not limited to, 900°C, 950°C, 1000°C, 1050°C or 1100°C, and the diffusion time may be, but is not limited to, 300s, 350s, 400s, 450s, 500s, 550s, 600s, 650s or 700s.

[0066] Furthermore, the protective layer removal method includes performing a second cleaning process on the substrate including the first doped region. In one specific example, the second cleaning process includes cleaning with a 40% to 80% by mass hydrofluoric acid aqueous solution for 150 seconds to 350 seconds. In another embodiment, the second cleaning process includes cleaning with a 50% to 70% by mass hydrofluoric acid aqueous solution for 180 seconds to 300 seconds.

[0067] Specifically, the mass percentage of hydrofluoric acid in the hydrofluoric acid aqueous solution can be but is not limited to 50%, 55%, 60%, 65% or 70%, and the cleaning time can be but is not limited to 180s, 200s, 220s, 240s, 260s, 280s or 300s.

[0068] It can be understood that the cleaning process can not only clean the protective layer but also clean the glass layer generated by preparing the first doped region.

[0069] In a specific example, after preparing the passivation contact structure, the method further includes: preparing a stacked first passivation layer and a first anti-reflection layer on the first surface, and preparing a second anti-reflection layer on the passivation contact structure.

[0070] Furthermore, the material of the first passivation layer can be but is not limited to one or more of aluminum oxide and gallium oxide, and the material of the first anti-reflection layer and the material of the second anti-reflection layer are each independently selected from one or more of silicon nitride, silicon oxynitride layer and silicon oxide layer.

[0071] Furthermore, the passivation contact structure includes a tunneling oxide layer and a doped polysilicon layer stacked in sequence, and the tunneling oxide layer is in contact with the substrate.

[0072] In a specific example, after preparing the first passivation layer, the first anti-reflection layer and the second anti-reflection layer, the method further includes: preparing a first electrode that penetrates the first passivation layer and the first anti-reflection layer and is connected to the first doped region, and preparing a second electrode that penetrates the second anti-reflection layer and is connected to the passivation contact structure.

[0073] The process of the present application is different from that of traditional passivated contact solar cells. For the cell structure, the solution of preparing a local first doping region by optimizing the first surface of the substrate can realize local diffusion of the first doping source in the substrate, thereby avoiding lattice loss on the front side of the solar cell and achieving higher photoelectric conversion of the cell. On the basis of ensuring short current and fill factor, the loss of open circuit voltage caused by lattice distortion on the front side is reduced, thereby improving the conversion efficiency of the cell.

[0074] Referring to FIG3 , the present application also provides a solar cell manufactured according to the above-mentioned manufacturing method.

[0075] Referring to FIG3 , further, an electrical device is provided, including the above-mentioned solar cell as a power source. It can be understood that the above-mentioned electrical device may include but is not limited to transformers, reactors, capacitors, combination electrical appliances, circuit breakers, mutual inductors, lightning arresters, coupling capacitors, transmission lines, power cables, grounding devices, generators, phase regulators, motors, closed busbars and thyristors.

[0076] The following specific examples are provided to further illustrate the solar cell and its preparation method of the present application. Unless otherwise specified, the raw materials involved in the following specific embodiments can all be obtained from commercial sources.

[0077] Example 1

[0078] This embodiment provides a solar cell and a method for manufacturing the same, comprising the following steps:

[0079] An N-type substrate is provided, and a first surface of the N-type substrate is subjected to a texturing treatment, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 2.0% sodium hydroxide, 0.3% texturing additive, and 97.7% water; the texturing treatment time is 550 seconds; and the texturing treatment temperature is 85° C.;

[0080] A phosphorus expansion tube was placed to grow a double-sided silicon oxide layer at a temperature of 900°C, a time of 5000s, and a pressure of 1024mbar, resulting in a 20nm silicon oxide layer.

[0081] Laser windowing was performed on the silicon wafer after the oxide layer was grown to remove part of the protective material layer on the preset first doped region. The laser rated power was 40W, the frequency was 900KHz, the spot size was 30μm, and the virtual-to-real ratio was 0.3:0.5.

[0082] The laser-windowed silicon wafer is placed on a texturing machine for the first cleaning. The cleaning solution contains 5% sodium hydroxide, 1.4% texturing additive, and 93.6% water. The reaction temperature is 75°C and the reaction time is 300 seconds. The wafer is then cleaned with HCl solution to remove any residual alkaline cleaning solution.

[0083] The cleaned silicon wafer was subjected to boron diffusion at a diffusion temperature of 1050°C, a diffusion time of 700s, a surface concentration of 2.5e20, and a sheet resistance of 60Ω.

[0084] The silicon wafer after boron diffusion was cleaned of BSG and protective layer, and then a second cleaning was performed. The cleaning conditions included: 70% by mass HF aqueous solution for 300 seconds;

[0085] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0086] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0087] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0088] Example 2

[0089] This embodiment provides a solar cell and a method for manufacturing the same, comprising the following steps:

[0090] An N-type substrate is provided, and a texturing treatment is performed on a first surface of the N-type substrate, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 0.6% sodium hydroxide, 1.0% texturing additive, and 98.4% water; a texturing treatment time of 350 seconds; and a texturing treatment temperature of 70° C.;

[0091] A phosphorus expansion tube was placed to grow a double-sided silicon oxide layer at a temperature of 500°C, a time of 1500s, and a pressure of 600mbar, resulting in a 5nm silicon oxide layer.

[0092] After the oxide layer is grown, the silicon wafer is laser windowed to remove part of the protective material layer on the preset first doped region. The laser rated power is 20W, the frequency is 350KHz, the spot size is 15μm, and the virtual-to-real ratio is 0.2:0.5.

[0093] The laser-windowed silicon wafer is placed on a texturing machine for the first cleaning. The cleaning solution contains 1.5% sodium hydroxide, 0.9% texturing additive, and 97.6% water. The reaction temperature is 65°C and the reaction time is 200 seconds. The wafer is then cleaned with HCl solution to remove any residual alkaline cleaning solution.

[0094] The cleaned silicon wafer was subjected to boron diffusion at a diffusion temperature of 950°C, a diffusion time of 300s, a surface concentration of 1.5e19, and a sheet resistance of 150Ω.

[0095] The silicon wafer after boron diffusion was cleaned from BSG and protective layer, and then cleaned for the second time. The cleaning conditions included: 50% by mass HF aqueous solution for 180 seconds;

[0096] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0097] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0098] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0099] Example 3

[0100] This embodiment provides a solar cell and a method for manufacturing the same, comprising the following steps:

[0101] An N-type substrate is provided, and a texturing treatment is performed on a first surface of the N-type substrate, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 1.4% sodium hydroxide, 0.4% texturing additive, and 98.2% water; a texturing treatment time of 450 seconds; and a texturing treatment temperature of 80° C.;

[0102] A phosphorus expansion tube was placed to grow a double-sided silicon oxide layer at a temperature of 750°C, a time of 3000 seconds, and a pressure of 800 mbar, resulting in a 12 nm silicon oxide layer.

[0103] After the oxide layer is grown, the silicon wafer is laser windowed to remove part of the protective material layer on the preset first doped region. The laser has a rated power of 20W, a frequency of 350KHz, a spot size of 20μm, and a virtual-to-real ratio of 0.4:0.5.

[0104] The laser-windowed silicon wafer is placed in a texturing machine for the first cleaning. The cleaning solution contains 3% sodium hydroxide, 1.1% texturing additive, and 95.9% water. The reaction temperature is 72°C and the reaction time is 250 seconds. The wafer is then cleaned with HCl solution to remove any residual alkaline cleaning solution.

[0105] The cleaned silicon wafer was subjected to boron diffusion at a diffusion temperature of 1000°C, a diffusion time of 500s, a surface concentration of 7e19, and a sheet resistance of 100Ω.

[0106] The silicon wafer after boron diffusion was cleaned from BSG and protective layer, and then cleaned for the second time. The cleaning conditions included: HF aqueous solution with a mass percentage of 60% for 240 seconds.

[0107] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0108] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0109] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0110] Comparative Example 1

[0111] This comparative example provides a solar cell and a method for preparing the same, comprising the following steps:

[0112] An N-type substrate is provided, and a first surface of the N-type substrate is subjected to a texturing treatment, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 2.0% sodium hydroxide, 0.3% additive, and 97.7% water; the texturing treatment time is 550 seconds; and the texturing treatment temperature is 85° C.;

[0113] Boron diffusion was performed on the silicon wafer at a temperature of 1050°C, a diffusion time of 700s, a surface concentration of 2.5e20, and a sheet resistance of 60Ω.

[0114] The boron-diffused silicon wafer was cleaned with BSG using a 70% by mass HF aqueous solution for 300 seconds.

[0115] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0116] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0117] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0118] Comparative Example 2

[0119] This comparative example provides a solar cell and a method for preparing the same, comprising the following steps:

[0120] An N-type substrate is provided, and a first surface of the N-type substrate is subjected to a texturing treatment, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 0.6% sodium hydroxide, 1.0% additive, and 98.4% water; a texturing treatment time of 350 seconds; and a texturing treatment temperature of 70° C.;

[0121] Boron diffusion is performed on the silicon wafer at a diffusion temperature of 950°C, a diffusion time of 300s, a surface concentration of 1.5e19, and a sheet resistance of 150Ω.

[0122] The boron-diffused silicon wafer was cleaned with BSG under the following cleaning conditions: 50% by mass HF aqueous solution for 180 seconds;

[0123] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0124] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0125] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0126] Comparative Example 3

[0127] This comparative example provides a solar cell and a method for preparing the same, comprising the following steps:

[0128] An N-type substrate is provided, and a texturing treatment is performed on a first surface of the N-type substrate, wherein the texturing treatment conditions include: a first texturing solution having a composition, by mass percentage, of 1.2% sodium hydroxide, 0.5% texturing additive, and 98.2% water; a texturing treatment time of 450 seconds; and a texturing treatment temperature of 80° C.;

[0129] A phosphorus expansion tube was placed to grow a double-sided silicon oxide layer at a temperature of 750°C, a time of 3000 seconds, and a pressure of 800 mbar, resulting in a 12 nm silicon oxide layer.

[0130] After the oxide layer is grown, the silicon wafer is laser windowed to remove part of the protective material layer on the preset first doped region. The laser rated power is 20W, the frequency is 350KHz, the spot size is 40μm, and the virtual-to-real ratio is 0.4:0.5.

[0131] The laser-windowed silicon wafer is placed in a texturing machine. The cleaning solution contains 3% sodium hydroxide, 1.1% texturing additive, and 95.9% water. The reaction temperature is 72°C and the reaction time is 250 seconds. The wafer is then cleaned with HCl solution to remove any residual alkaline cleaning solution.

[0132] The cleaned silicon wafer was subjected to boron diffusion at a diffusion temperature of 1000°C, a diffusion time of 500s, a surface concentration of 7e19, and a sheet resistance of 100Ω.

[0133] The boron-diffused silicon wafer was cleaned of BSG and protective layer using a 60% by mass HF aqueous solution for 240 seconds.

[0134] Prepare a passivation contact structure on the second surface of the N-type substrate;

[0135] Aluminum oxide is formed as a first passivation layer and silicon nitride is formed as a first anti-reflection layer on a first surface of the N-type substrate, and silicon nitride is formed as a second anti-reflection layer on a second surface of the N-type substrate;

[0136] A silver-aluminum electrode penetrating the first passivation layer and the first anti-reflection layer and connected to the first doped region is prepared as the first electrode, and a silver electrode penetrating the second anti-reflection layer and connected to the passivation contact structure is prepared as the second electrode.

[0137] As shown in FIG1 , a solar cell 10 structure provided in an embodiment includes a substrate 100, the substrate 100 including a first doped region 103 formed on one side thereof, a passivation contact structure 110 and a second anti-reflection layer 140 formed on a surface of the substrate 100 away from the first doped region 103, the passivation contact structure 110 including a tunneling oxide layer 1101 and a doped polysilicon layer 1102, a first passivation layer 120 and a first anti-reflection layer 130 formed on the other side of the substrate 100, a first electrode 150 in contact with the first doped region 103 in the substrate 100, and a second electrode 160 in contact with the doped polysilicon layer 1102. FIG2 shows a top view of the first surface 101 before forming the passivation contact structure 110, FIG2(a) showing the first doped region 103 having a suede structure, and FIG2(b) showing the first surface 101 having a suede structure. After three batch experiments, the efficiency (Eta), short-circuit current (Isc), open-circuit voltage (Uoc) and fill factor (FF) of the final silicon wafer product cells were tracked, as shown in Table 1 below.

[0138] Table 1: Differences between Examples 1-3 and Comparative Examples 1-3

[0139] Comparing Table 1, the efficiency Eta of the embodiment is improved by 0.01 to 0.08 compared to the comparative example. The main gain is brought by Uoc, which increases by approximately 1.6mV to 2.1mV, but there is a loss of 0.06 in the fill factor FF. This proves that the present application optimizes the battery structure by preparing a localized first doping region on the first surface of the substrate, thereby achieving local diffusion of the first doping source in the substrate, thereby avoiding lattice loss on the front side of the solar cell and achieving higher photoelectric conversion of the battery. On the basis of ensuring short current and fill factor, the loss of open circuit voltage caused by front lattice distortion is reduced, thereby improving the conversion efficiency of the battery.

[0140] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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.

[0141] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent application of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for preparing a solar cell, characterized in that: The following steps are involved: providing a substrate having a first surface and a second surface opposite to the first surface; forming a protective material layer on the first surface, and removing a portion of the protective material layer on the preset first doped region to prepare a protective layer; Performing first doping on the substrate along the preset first doping region to prepare a substrate including the first doping region, wherein the width of the first doping region is 10 μm to 35 μm; The protective layer is removed, and a passivation contact structure is prepared on the second surface.

2. The preparation method according to claim 1, wherein Before forming the protective material layer, the method further includes: performing a texturing process on the substrate.

3. The preparation method according to claim 1, wherein After preparing the protective layer and before preparing the substrate including the first doping region, the method further includes: performing a first cleaning process on the substrate including the protective layer; The conditions of the first cleaning treatment include: the composition of the cleaning solution used in the first cleaning treatment includes, by mass percentage, 1% to 6% of a monobasic strong base, 0.5% to 2% of a texturing additive, and 93% to 98.5% of a first solvent; The first cleaning process takes 150s to 350s. The temperature of the first cleaning treatment is 60°C to 80°C.

4. The preparation method according to claim 1, wherein The material of the protective layer includes one or more of silicon oxide, silicon nitride and photosensitive adhesive.

5. The preparation method according to claim 1, wherein The method for removing the protective layer includes performing a second cleaning process on the substrate including the first doped region; The conditions of the second cleaning treatment include: using a hydrofluoric acid aqueous solution with a mass percentage of 40% to 80% for cleaning for 150s to 350s.

6. The preparation method according to claim 1, wherein The surface concentration of the first doping region is 10 19 ~3×10 20 , the square resistance is 40Ω~170Ω.

7. The preparation method according to any one of claims 1 to 6, wherein: After preparing the passivation contact structure, the method further includes: preparing a stacked first passivation layer and a first anti-reflection layer on the first surface, and preparing a second anti-reflection layer on the passivation contact structure.

8. The preparation method according to claim 7, wherein After preparing the first passivation layer, the first anti-reflection layer and the second anti-reflection layer, the method further includes: preparing a first electrode that penetrates the first passivation layer and the first anti-reflection layer and is connected to the first doped region, and preparing a second electrode that penetrates the second anti-reflection layer and is connected to the passivation contact structure.

9. A solar cell, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. An electrical device, characterized in that: The solar cell according to claim 9 is included as a power source.

Images