Passivated contact solar cell and method of making same

Abstract

The application relates to the field of photovoltaic technology and discloses a passivated contact solar cell and a preparation method thereof. The preparation method comprises the following steps: providing a substrate layer with opposite first and second surfaces; forming an oxide layer on the first surface of the substrate layer; performing laser sintering treatment on the surface of the oxide layer; forming a first doped layer on the oxide layer after the laser sintering treatment; forming a second doped layer on the second surface of the substrate layer; forming a first electrode connected with the first doped layer on the first surface side of the substrate layer; and forming a second electrode connected with the second doped layer on the second surface side of the substrate layer. In the application, the laser sintering treatment on the oxide layer realizes accurate optimization of the surface of the oxide layer, improves the surface and interface characteristics, further reduces the surface recombination rate of the oxide layer and the substrate layer and the first doped layer, improves the carrier lifetime, and thus the photoelectric conversion efficiency and stability of the cell are improved, and the power generation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a passivated contact solar cell and its preparation method. Background Technology

[0002] Tunnel oxide passivated contact (TOPCon) solar cells are high-efficiency solar cells based on N-type silicon materials. Compared to traditional solar cells, TOPCon cells can further improve the photoelectric conversion efficiency and reduce costs. The key feature of TOPCon cells is the fabrication of an ultrathin silicon oxide layer and a doped polycrystalline silicon layer on the back of an N-type silicon wafer to form a tunnel oxide passivated contact structure. This effectively reduces metal-to-metal recombination, thereby increasing the cell's open-circuit voltage and short-circuit current.

[0003] In the field of photovoltaic cell technology, a crucial factor affecting cell efficiency is the recombination of electron-hole pairs. In related technologies, the tunneling oxide layer is easily damaged during the polycrystalline silicon layer doping and electrode sintering processes on the back side of TOPCon cells. This makes it difficult to precisely control the thickness and quality of the tunneling oxide layer, leading to an accelerated surface recombination rate and reduced carrier lifetime. Consequently, this affects the quality of the electrode ohmic contact and the formation of the back-side field, ultimately resulting in a decrease in the cell's photoelectric conversion efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a passivated contact solar cell and its preparation method to solve the problem that the thickness and quality of the tunneling silicon oxide layer in existing cells are difficult to control precisely, which leads to an accelerated surface recombination rate of the tunneling oxide layer, a reduced carrier lifetime, and thus affects the photoelectric conversion efficiency of the cell.

[0005] In a first aspect, the present invention provides a method for preparing a passivated contact solar cell, comprising:

[0006] A base layer is provided, the base layer having opposing first and second surfaces;

[0007] An oxide layer is formed on the first surface of the substrate layer;

[0008] The surface of the oxide layer is subjected to laser sintering treatment;

[0009] A first doped layer is formed on the oxide layer after laser sintering.

[0010] A second doped layer is formed on the second surface of the substrate layer;

[0011] A first electrode is formed on one side of the first surface of the substrate layer, and a second electrode is formed on one side of the second surface of the substrate layer. The first electrode is connected to the first doped layer, and the second electrode is connected to the second doped layer.

[0012] Beneficial Effects: In the method for fabricating passivated contact solar cells of the present invention, after forming an oxide layer on one side of the back of the cell, specifically on the first surface of the substrate layer, the formed oxide layer is subjected to laser sintering. Laser sintering, on the one hand, makes the oxide layer surface smoother and cleaner, reducing impurities and defects, and improving the surface and internal quality of the oxide layer; on the other hand, the sintered oxide layer has a good interface, allowing the introduction and distribution of dopants in the first doped layer to more precisely match the specific area treated by the laser, improving the uniformity and depth control accuracy of doping, which helps in the precise formation of the first doped layer and achieves more refined electrical performance regulation. In summary, laser sintering of the oxide layer achieves precise optimization of the oxide layer surface, improves surface and interface characteristics, thereby reducing the surface recombination rate between the oxide layer and the substrate layer and the first doped layer, increasing carrier lifetime, and thus improving the photoelectric conversion efficiency and stability of the cell, ultimately increasing power generation efficiency.

[0013] In one alternative embodiment, laser sintering of the oxide layer surface includes: scanning the entire surface of the oxide layer with a laser beam to sinter the oxide layer.

[0014] Beneficial effects: By rationally planning the scanning path and overlapping areas of the laser beam, repeated and precise scanning, along with accurate control of laser parameters, ensures uniform processing of the entire oxide layer. Combined with real-time monitoring and feedback mechanisms, parameters such as laser beam power and application time are adjusted to precisely control the thickness of the entire oxide layer. Simultaneously, combining laser beam scanning with laser sintering methods such as ion implantation and diffusion enables highly precise doping control, ensuring PN junction performance and improving battery output current and efficiency. Localized heating and scanning coverage reduce energy loss from overall heating, improving material thermal efficiency. With the same energy input, more efficient processing can be completed, reducing energy consumption, lowering production costs, and contributing to optimized production efficiency.

[0015] In one alternative implementation, the laser beam comprises an infrared pulse beam with a wavelength of 1064 nm.

[0016] Beneficial effects: By precisely controlling the focus and power of the 1064nm wavelength infrared pulsed laser beam, it is helpful to achieve instantaneous high temperature in local areas, promote the rapid diffusion of silicon atoms and the rapid formation of oxide layers.

[0017] In one alternative embodiment, the thickness of the oxide layer ranges from 1 nm to 5 nm.

[0018] Beneficial effects: Limiting the oxide layer thickness to 1nm–5nm ensures good insulation properties and results in better battery performance. An excessively thick oxide layer may negatively impact battery performance, such as reducing current density; an excessively thin oxide layer may not provide sufficient protection, making the battery more susceptible to damage.

[0019] In one alternative embodiment, after providing the substrate layer and before forming an oxide layer on the first surface of the substrate layer, the method further includes: forming a passivation layer on the first surface of the substrate layer, wherein the oxide layer is formed on the passivation layer.

[0020] Beneficial effects: Before forming the oxide layer, a passivation layer is first coated on the first surface of the substrate, which helps to enhance the adhesion between the oxide layer and the substrate, and also helps to improve the density of the oxide layer material during the subsequent laser sintering process.

[0021] In one alternative embodiment, after forming an oxide layer on a first surface of the substrate layer and before performing laser sintering on the surface of the oxide layer, the method further includes: forming a passivation layer on a side surface of the oxide layer opposite to the substrate layer, wherein a first doped layer is formed on the passivation layer.

[0022] Beneficial effects: After forming an oxide layer on the substrate, a passivation layer is coated on the oxide layer. On the one hand, this helps to improve the density of the oxide layer material during the subsequent laser sintering process. On the other hand, it improves the interface quality between the oxide layer and the first doped layer, promotes the accuracy of the formation of the first doped layer, and improves the doping efficiency.

[0023] In one alternative embodiment, a first electrode and a first doped layer are connected on one side of the first surface of the substrate by laser sintering; a second electrode and a second doped layer are connected on one side of the second surface of the substrate by laser sintering.

[0024] Beneficial effects: Using laser sintering to achieve precise bonding between the first electrode and the first doped layer, as well as between the second electrode and the second doped layer, forms a good ohmic contact, which helps current conduction and improves photoelectric conversion efficiency.

[0025] In one optional embodiment, after forming a second doped layer on the second surface of the substrate layer and forming a first electrode on one side of the first surface of the substrate layer, and before forming a second electrode on one side of the second surface of the substrate layer, the method further includes:

[0026] A first antireflection layer is formed on a first doped layer, and a second antireflection layer is formed on a second doped layer; a first electrode passes through the first antireflection layer and is connected to the first doped layer, and a second electrode passes through the second antireflection layer and is connected to the second doped layer.

[0027] Beneficial effects: The first and second anti-reflective layers help reduce sunlight reflection on the back and sides of the battery, thereby improving the battery's absorption of sunlight and effectively improving power generation quality.

[0028] Secondly, the present invention also provides a passivated contact solar cell, which is prepared by the above-described method for preparing a passivated contact solar cell, comprising: a substrate layer, an oxide layer, a first doped layer, a second doped layer, a first electrode, and a second electrode. The substrate layer has a first surface and a second surface opposite to each other. The oxide layer is disposed on the first surface of the substrate layer. The first doped layer is disposed on the side of the oxide layer opposite to the substrate layer. The second doped layer is disposed on the second surface of the substrate layer. The first electrode is disposed on the first surface of the substrate layer and connected to the first doped layer, and the second electrode is disposed on the second surface of the substrate layer and connected to the second doped layer.

[0029] Beneficial Effects: The passivated contact solar cell of this invention features a precisely thick and uniform oxide layer without laser sintering treatment. Laser sintering, on the one hand, makes the oxide layer surface smoother and cleaner, reducing impurities and defects and improving the surface and internal quality of the oxide layer; on the other hand, the sintered oxide layer has a good interface, allowing the introduction and distribution of dopants in the first doped layer to more precisely match the specific areas treated by laser, ensuring the uniformity and precise depth of doping in the first doped layer, thereby achieving more refined control of electrical performance. In summary, the oxide layer after laser sintering has a high-quality surface, low recombination rate with the substrate layer and the first doped layer, and long carrier lifetime, which helps to improve the photoelectric conversion efficiency and stability of the cell, thereby increasing power generation efficiency.

[0030] In one alternative implementation, it further includes:

[0031] A first antireflection layer and a second antireflection layer are provided. The first antireflection layer is disposed on a first doped layer, and a first electrode passes through the first antireflection layer and is connected to the first doped layer. The second antireflection layer is disposed on a second doped layer, and a second electrode passes through the second antireflection layer and is connected to the second doped layer.

[0032] The passivation layer is disposed on the first surface of the substrate or on the side surface of the oxide layer facing away from the substrate.

[0033] Beneficial effects: The first and second antireflective layers help reduce sunlight reflection on the back and sides of the battery, thereby improving the battery's absorption of sunlight and effectively improving power generation quality; the passivation material adsorbed on the surface of the substrate or oxide layer forms a dense passivation layer after laser sintering, which can significantly improve the photoelectric conversion efficiency of the battery. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of the method for preparing a passivated contact solar cell according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the base layer structure according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of forming an oxide layer on the first surface of the substrate layer according to an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of forming a first doped layer on the oxide layer according to an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the structure of forming a second doped layer on the second surface of the substrate layer according to an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the structure for forming the first electrode and the second electrode according to an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of the structure of the first antireflection layer and the second antireflection layer according to an embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of the structure of a passivated contact solar cell according to an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Substrate layer; 11. First surface; 12. Second surface; 2. Oxide layer; 3. First doped layer; 4. Second doped layer; 5. First electrode; 6. Second electrode; 7. First antireflection layer; 8. Second antireflection layer. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, not all structures. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of the invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, and some details are enlarged for clarity, and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from actual practices due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Additionally, if one layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component can be "below" that other layer / component.

[0046] refer to Figures 1 to 7 This embodiment provides a method for passivating contact solar cells. Figure 1 This is a schematic flowchart of a method for fabricating a passivated contact solar cell according to an embodiment of the present invention, as shown below. Figure 1 As shown, the process includes the following steps:

[0047] Step S101, a base layer 1 is provided, the base layer 1 having a first surface 11 and a second surface 12 opposite to each other.

[0048] For example, substrate 1 can be a monocrystalline silicon wafer or a polycrystalline silicon wafer. Monocrystalline silicon wafers typically have higher photoelectric conversion efficiency and are suitable for manufacturing high-performance batteries, while polycrystalline silicon wafers are lower in cost and suitable for large-scale production. After selecting a suitable silicon wafer, it is cleaned and surface-treated to serve as substrate 1. (Reference) Figure 2 The lower surface of the substrate 1 serves as the first surface 11, which is the back of the battery; the upper surface serves as the second surface 12, which is the front of the battery.

[0049] Step S102: An oxide layer 2 is formed on the first surface 11 of the substrate layer 1.

[0050] For example, a thin silicon oxide layer can be formed on the first surface 11 of the substrate layer 1 using a thermal oxidation method to form a well-tunneling oxide layer 2, such as... Figure 3 As shown.

[0051] Step S103: Laser sintering treatment is performed on the surface of oxide layer 2.

[0052] A high-energy laser beam is used to sinter the formed thin silicon oxide layer. The high temperature generated by the laser promotes the migration and redistribution of silicon atoms within the silicon oxide, thereby improving its structure and properties. In other words, by precisely controlling the focus and power of the laser beam, instantaneous high temperatures are achieved in localized areas to promote the diffusion of silicon atoms in the oxide layer 2 and at the contact surface between the oxide layer 2 and the substrate layer 1, resulting in the rapid formation of a uniform oxide layer 2.

[0053] Step S104: A first doped layer 3 is formed on the oxide layer 2 after laser sintering.

[0054] On the sintered oxide layer 2, a dopant is introduced through methods such as ion implantation, diffusion, chemical vapor deposition, or solution treatment. The dopant can be phosphorus ions or boron ions to form an N-type or P-type first doped layer 3 on the oxide layer 2. In this embodiment, the first doped layer 3 is a polycrystalline silicon layer. Figure 4 As shown. Ion implantation specifically involves injecting dopant elements into a target material (such as silicon) using high-energy ions to form a doped layer. Ion implantation enables highly precise doping control. Diffusion specifically involves placing dopant elements on the surface of the target material and then heating it at high temperatures to induce the dopant elements to diffuse into the interior of the target material. Chemical vapor deposition specifically involves using vapor deposition methods to introduce dopant elements into the target material in a gaseous form. Solution processing specifically involves using chemical solutions to introduce specific dopant feedstocks into the target material.

[0055] Step S105: A second doped layer 4 is formed on the second surface 12 of the substrate layer 1.

[0056] Similarly, on the second surface 12 of the substrate 1, a dopant is introduced through methods such as ion implantation, diffusion, chemical vapor deposition, or solution treatment. The dopant can also be phosphorus or boron, to form an N-type or P-type first doped layer 3 on the second surface 12 of the substrate 1, such as... Figure 5 As shown, the first doped layer 3 and the second doped layer 4 are, respectively, an N-type doped layer and a P-type doped layer. In this embodiment, the substrate 1 is an N-type silicon wafer, so the first doped layer 3 is a phosphorus-diffused N+ doped layer, and the second doped layer 4 is a boron-doped P+ doped layer.

[0057] The first doped layer 3 and the second doped layer 4 enable the P-type and N-type semiconductor materials to form a PN junction for separating photogenerated carriers. Doping enhances the conductivity of the semiconductor structure, effectively increasing the battery's efficiency and output current. In this embodiment, N-type doped silicon serves as the substrate layer 1, with an N+-doped first doped layer 3 and a P+-doped second doped layer 4 formed on either side to improve conductivity and passivation. Precise control of the doped layers limits the increase in the battery's photoelectric conversion efficiency, achieving higher energy output.

[0058] In step S106, a first electrode 5 is formed on one side of the first surface 11 of the substrate layer 1, and a second electrode 6 is formed on one side of the second surface 12 of the substrate layer 1. The first electrode 5 is connected to the first doped layer 3, and the second electrode 6 is connected to the second doped layer 4.

[0059] Electrode materials are typically chosen from metallic materials with good electrical conductivity and stable chemical properties. For example, in this embodiment, the first electrode 5 is made of aluminum, which is low-cost and easy to process, while the second electrode 6 is made of gold, which has excellent electrical conductivity. The electrode structures can be configured in different shapes and sizes. In this embodiment, the first electrode 5 is configured as a strip structure, with multiple electrodes arranged on one side of the back of the substrate layer 1 to improve current collection efficiency; the second electrode 6 is configured as a mesh structure to maximize light absorption without blocking light.

[0060] In the passivated contact solar cell fabrication method provided in this embodiment, after forming an oxide layer 2 on one side of the back of the cell, specifically on the first surface 11 of the substrate layer 1, the formed oxide layer 2 is subjected to laser sintering. Laser sintering, on the one hand, makes the surface of the oxide layer 2 smoother and cleaner, reducing impurities and defects, and improving the surface and internal quality of the oxide layer 2; on the other hand, the sintered oxide layer 2 has a good interface, allowing the introduction and distribution of dopants in the first doped layer 3 to more precisely match the specific area treated by the laser, improving the uniformity and depth control accuracy of doping, which helps in the precise formation of the first doped layer 3 and achieves more refined electrical performance regulation. In summary, the laser sintering treatment of the oxide layer 2 achieves precise optimization of the oxide layer 2 surface, improves surface and interface characteristics, thereby reducing the surface recombination rate of the oxide layer 2 with the substrate layer 1 and the first doped layer 3, increasing carrier lifetime, and thus improving the photoelectric conversion efficiency and stability of the cell, thereby increasing power generation efficiency.

[0061] In this embodiment, the aforementioned base layer 1 includes:

[0062] Step S1011: Provide the initial base layer.

[0063] For example, the initial substrate layer is an untreated monocrystalline or polycrystalline silicon wafer.

[0064] Step S1012 involves cleaning and drying the initial substrate layer, including: degreasing the initial substrate layer; performing a first deionized water cleaning on the degreased initial substrate layer; acid washing on the initial substrate layer after the first deionized water cleaning; performing a second deionized water cleaning on the acid-washed substrate layer; and drying the initial substrate layer to obtain substrate layer 1.

[0065] In this embodiment, the initial substrate layer is cleaned using a standard silicon wafer cleaning process, such as RAC cleaning, to remove surface contaminants. Specifically, the initial substrate layer is degreased by immersing it in a degreasing agent, such as SC-1 cleaning solution (a mixture of ammonia, hydrogen peroxide, and deionized water), to remove organic contaminants. After cleaning with deionized water, an acid such as hydrofluoric acid is applied to remove silicon oxide from the wafer surface, providing a clean silicon surface. Finally, after rinsing the wafer again with deionized water, nitrogen gas is used to dry the wafer, preventing watermarks from forming on the clean silicon surface, ultimately resulting in a clean and contaminant-free silicon wafer.

[0066] Step S1013 involves surface treatment of the initial substrate layer after cleaning and drying, including: roughening the surface of the initial substrate layer; and passivating the surface of the initial substrate layer.

[0067] Specifically, surface roughening treatment involves using chemical or mechanical methods to roughen the silicon wafer surface, increasing light scattering and improving light absorption rate; passivation treatment involves using passivating agents (such as silanes or nitrides) to form a thin film on the silicon wafer surface, reducing the surface recombination rate and improving carrier lifetime.

[0068] In this embodiment, before forming other structural layers on the substrate layer 1, the substrate layer 1 material is first subjected to various fine cleaning, drying, surface roughening and passivation processes to remove impurities and oxides from the silicon wafer surface, reduce silicon wafer surface defects, improve carrier lifetime, and ensure the cleanliness and high-quality surface of the silicon wafer when used as the substrate layer 1.

[0069] In addition, after the above-mentioned cleaning, drying and surface treatment of silicon wafers, before proceeding to the next process, the clean silicon wafers should be wrapped with special materials such as anti-static bags to avoid secondary contamination, and then stored in a clean environment to maintain the cleanliness of the substrate layer 1.

[0070] In this embodiment, step S102 above uses thermal oxidation to form an oxide layer 2 on the first surface 11 of the substrate layer 1. Specifically, it includes:

[0071] Step S1021: Place the treated clean substrate layer 1 in a high-temperature furnace. In this embodiment, a quartz boat high-temperature furnace is used to avoid contamination.

[0072] Step S1022: Perform high-temperature oxidation treatment on the substrate layer 1.

[0073] The high-temperature furnace is heated to the required high temperature, typically 800°C to 1200°C. Oxygen or steam is introduced into the high-temperature furnace to carry out the oxidation reaction. Common oxidation methods include oxidation using pure oxygen or steam oxidation to increase the oxidation rate. The oxidation time is controlled according to the required oxide layer 2 thickness and growth rate to form the target oxide layer 2. The thickness of the oxide layer 2 is usually related to time and temperature, and the growth rate can be determined experimentally.

[0074] Step S1023: Cool the oxide layer 2 grown by oxidation.

[0075] After oxidation is complete, the temperature is slowly lowered to avoid thermal stress causing the silicon wafer to crack.

[0076] Step S1024: Post-process the cooled oxide layer 2.

[0077] Post-processing specifically includes annealing and inspection. Annealing refers to annealing the oxide layer 2 under a nitrogen atmosphere to improve the quality of the oxide layer 2 and reduce internal stress. Afterwards, techniques such as elliptic polarization are used to inspect the thickness and quality of the oxide layer 2.

[0078] In this embodiment, an oxide layer 2 is formed on the surface of the substrate layer 1 by thermal oxidation, which can effectively reduce the interface defects between the substrate layer 1 and the oxide layer 2, thereby reducing the recombination rate of charge carriers and improving the photoelectric conversion efficiency. The oxide layer 2 can prevent direct contact between the metal electrode and the silicon material, reducing the possibility of corrosion and reaction.

[0079] In one embodiment, step S103, laser sintering treatment of the surface of oxide layer 2, includes: laser beam scanning treatment of the entire surface of oxide layer 2 to sinter oxide layer 2.

[0080] Laser sintering is typically performed locally. In this embodiment, multiple repeated, precise scans and accurate control of laser parameters are used to process and control the thickness of the entire silicon oxide layer. Furthermore, by rationally planning the scanning path and overlapping areas of the laser beam, uniform processing of the entire oxide layer 2 is ensured. Combined with a real-time monitoring and feedback mechanism, parameters such as laser beam power and application time are adjusted to precisely control the thickness of the entire oxide layer 2. Simultaneously, this laser beam scanning sintering method, combined with doping methods such as ion implantation and diffusion, enables highly precise doping control, ensuring the performance of the PN junction and improving the battery's output current and efficiency.

[0081] Compared to traditional sintering, the laser sintering in this embodiment has a faster reaction speed. The localized heating and scanning coverage methods reduce overall heating energy loss, improving the thermal efficiency of the material. With the same energy input, more efficient processing can be completed, thereby reducing energy consumption, lowering production costs, and helping to optimize production efficiency. The specific power and sintering time of laser sintering will vary depending on the material and equipment. Generally, the power range of laser sintering is between tens of watts and hundreds of watts, and the sintering time varies from a few seconds to tens of seconds. Specific parameters need to be adjusted based on experimental results and process requirements.

[0082] Specifically, in this embodiment, the laser beam is selected as an infrared pulsed beam with a wavelength of 1064nm. The 1064nm wavelength infrared pulsed laser beam is emitted by an infrared pulsed laser. By precisely controlling the laser's focus and power, it helps to achieve instantaneous high temperatures in a local area, promoting the rapid diffusion of silicon atoms and the rapid formation of oxide layer 2.

[0083] Furthermore, the thickness of the oxide layer 2 after laser sintering ranges from 1 nm to 5 nm.

[0084] This thickness range ensures that oxide layer 2 has good insulation properties. An excessively thick oxide layer 2 may affect battery performance, such as reducing current density; an excessively thin oxide layer 2 may not provide sufficient protection, making the battery susceptible to damage. Therefore, controlling the thickness of oxide layer 2 within the range of 1nm to 5nm can balance these factors and achieve better battery performance.

[0085] In an alternative embodiment, after providing the substrate layer 1 in step S101 and before forming the oxide layer 2 on the first surface 11 of the substrate layer 1 in step S102, the method further includes: forming a passivation layer on the first surface 11 of the substrate layer 1, wherein the oxide layer 2 is formed on the passivation layer.

[0086] That is, before forming oxide layer 2, a passivation material, such as silicon oxide or silicon carbide, is first coated on the first surface 11 of substrate layer 1 to form a passivation layer with passivation cross-linking effect (not shown in the figure). Coating with passivation material helps to enhance the adhesion between oxide layer 2 and substrate layer 1, and also helps to improve the density of oxide layer 2 material during subsequent laser sintering.

[0087] In another alternative embodiment, after forming oxide layer 2 on the first surface 11 of substrate layer 1 in step S102, and before performing laser sintering treatment on the surface of oxide layer 2 in step S103, the method further includes forming a passivation layer on the side surface of oxide layer 2 facing away from substrate layer 1, and forming a first doped layer 3 on the passivation layer.

[0088] That is, an oxide layer 2 is formed on the substrate layer 1, and then a passivation material, such as silicon oxide or silicon carbide, is coated on the oxide layer 2 to form a passivation layer with passivation cross-linking effect. At this time, the passivation layer helps to improve the density of the oxide layer 2 material in the subsequent laser sintering process, and at the same time, it improves the interface quality between the oxide layer 2 and the first doped layer 3, promotes the accuracy of the formation of the first doped layer 3, and improves the doping efficiency.

[0089] In this embodiment, after the oxide layer 2 with a passivation layer on one side is formed, a laser heating process is first performed: the oxide layer 2 or the passivation layer is directionally heated by a laser beam, and the wavelength and power of the laser beam are selected according to the material characteristics to produce an ideal thermal effect; then the sintering reaction is completed: the material particles after laser heating gradually soften and fuse to form a dense cross-linked structure. Laser sintering can improve the density of the oxide layer 2, reduce the gaps between particles, and improve the electrical conductivity; finally, the cooling stage: after the laser is turned off, the oxide layer 2 gradually cools down, and the microstructure of the material can be further optimized by controlling the cooling rate.

[0090] Laser beams can precisely position and adjust energy input, resulting in uniform sintering. Localized heating reduces overall energy loss and improves material thermal efficiency. Compared to traditional sintering methods, laser sintering offers faster reaction times, increasing production efficiency. Passivation materials adsorbed on the surface of substrate layer 1 or oxide layer 2 form a dense passivation layer after laser sintering, significantly improving the photoelectric conversion efficiency of the battery. The sintering process also enhances the conductivity of oxide layer 2 and reduces contact resistance, thereby improving the overall performance of the battery.

[0091] Based on the above scheme, this embodiment connects the first electrode 5 and the first doped layer 3 on one side of the first surface 11 of the substrate layer 1 by laser sintering; and connects the second electrode 6 and the second doped layer 4 on one side of the second surface 12 of the substrate layer 1 by laser sintering.

[0092] The above-mentioned laser sintering method achieves precise bonding between the first electrode 5 and the first doped layer 3, as well as between the second electrode 6 and the second doped layer 4, forming a good ohmic contact, which helps current conduction and improves photoelectric conversion efficiency.

[0093] The preparation of the first electrode 5 and the second electrode 6 in this embodiment specifically includes the following steps:

[0094] Step S1061: Clean the silicon wafer having oxide layer 2, first doped layer 3, second doped layer 4 and substrate layer 1.

[0095] The silicon wafer is cleaned using chemical treatments (such as acid pickling) or physical methods (such as ultrasonic cleaning) to remove surface dirt and oxides, ensuring good contact between the first electrode 5 and the second electrode 6 and the silicon wafer.

[0096] Step S1062: Coat the first doped layer 3 and the second doped layer 4 with conductive material.

[0097] For example, the coating method can be screen printing, spray coating, or evaporation / sputtering deposition to form a conductive pattern of the first electrode 5 on the first doped layer 3 and a conductive pattern of the second electrode 6 on the second doped layer 4. Screen printing refers to coating a conductive paste onto the surface of a silicon wafer using screen printing technology to form a conductive pattern; spray coating refers to uniformly spraying conductive material onto the surface of a silicon wafer using a spray method, which can be used to form complex conductive patterns; evaporation / sputtering deposition refers to depositing conductive material onto a silicon wafer in the form of a thin film using vacuum evaporation or sputtering technology.

[0098] Step S1063: Baking and sintering the conductive material.

[0099] The coated silicon wafer is placed in an oven and heated to drive away the solvent, while simultaneously allowing the conductive material particles to bond together and form good contact with the silicon wafer surface.

[0100] In one embodiment, for complex electrode patterns, after step S1063, the method further includes:

[0101] Step S1064: Etch the electrode structure after baking and sintering.

[0102] For cases with complex electrode pattern designs, it is necessary to etch the electrode structure after baking and sintering to remove excess electrode material, thereby forming the desired electrode pattern.

[0103] In addition, after forming the required first electrode 5 and second electrode 6, quality inspection and necessary post-processing are required to ensure the good conductivity, corrosion resistance and bonding strength of the first electrode 5 and second electrode 6 with other materials.

[0104] See Figure 7 After forming the second doped layer 4 on the second surface 12 of the substrate layer 1 in step S105, and before forming the first electrode 5 on the first surface 11 side of the substrate layer 1 and the second electrode 6 on the second surface 12 side of the substrate layer 1 in step S106, the method further includes:

[0105] A first antireflection layer 7 is formed on the first doped layer 3, and a second antireflection layer 8 is formed on the second doped layer 4; a first electrode 5 passes through the first antireflection layer 7 and is connected to the first doped layer 3, and a second electrode 6 passes through the second antireflection layer 8 and is connected to the second doped layer 4.

[0106] For example, in this embodiment, both the first antireflection layer 7 and the second antireflection layer 8 are made of chemically stable silicon nitride material, which can be formed by chemical vapor deposition (CVD) to reduce sunlight reflection on the back of the battery and the back side, thereby improving the battery's absorption of sunlight and effectively improving the power generation quality.

[0107] After the passivated contact solar cell of this embodiment has completed the fabrication of all structural layers, a post-processing step is required to further improve the performance and reliability of the cell and ensure its stability during use. The post-processing steps specifically include:

[0108] Step S1071: Anneal the passivated contact solar cell.

[0109] Specifically, the structurally complete battery is placed in a high-temperature furnace and annealed for a period of time, usually between 300°C and 500°C. This heat treatment eliminates the stress on the electrode material during the coating process, promotes the connection between metal particles, and improves conductivity.

[0110] Step S1072: Post-cleaning of the passivated contact solar cell.

[0111] For example, chemical cleaning with appropriate cleaning agents, or a combination of physical methods such as deionized water rinsing and ultrasonic cleaning, can be used to remove contaminants and unreacted materials from the battery surface to prevent them from affecting the performance of passivated contact solar cells.

[0112] Step S1073: Perform surface passivation on the passivated contact solar cell.

[0113] For example, a protective film (such as silicon oxide or silicon nitride) is formed on the electrode surface using thin film deposition technology to reduce the surface recombination rate, reduce defects and energy levels on the surfaces of the first electrode 5 and the second electrode 6, and improve the efficiency of passivated contact solar cells.

[0114] Step S1074: Level the passivated contact solar cell.

[0115] The surfaces of the first electrode 5 and the second electrode 6 are first leveled by applying pressure or coating a thin film, making the surface of the passivated contact solar cell smoother and improving the contact quality and conductivity.

[0116] Step S1075: Perform quality inspection on the passivated contact solar cell.

[0117] The passivated contact solar cells are evaluated using resistance testing, microscopic observation, and other characterization techniques to ensure that the conductivity, contact resistance, and corrosion resistance of the passivated contact solar cells meet the standards, thereby ensuring the overall performance of the cells.

[0118] Step S1076: Assemble and encapsulate the passivated contact solar cell.

[0119] Using efficient adhesives and encapsulation materials, passivated contact solar cells are combined with other components (such as photovoltaic materials, glass panels, etc.) to form a complete photovoltaic module, maintaining the sealing and durability of the passivated contact solar cells.

[0120] Step S1077: Conduct environmental adaptability tests on the passivated contact solar cells.

[0121] Tests are conducted under high temperature, high humidity, and ultraviolet radiation to ensure the performance of modules with passivated contact solar cells under various operating environments and to evaluate the stability and reliability of passivated contact solar cells under different environmental conditions.

[0122] In the method for preparing the passivated contact solar cell in this embodiment, the formation of each structural layer is improved and perfected. In particular, a new laser sintering process is introduced directly after the oxide layer 2, making the entire preparation process more efficient, precise and reliable, thereby improving the quality and performance of the final prepared passivated contact solar cell.

[0123] like Figure 8 As shown, this embodiment also provides a passivated contact solar cell, which is prepared by the above-described method for preparing a passivated contact solar cell. It includes: a substrate layer 1, an oxide layer 2, a first doped layer 3, a second doped layer 4, a first electrode 5, and a second electrode 6. The substrate layer 1 has a first surface 11 and a second surface 12 facing each other. The oxide layer 2 is disposed on the first surface 11 of the substrate layer 1. The first doped layer 3 is disposed on the side of the oxide layer 2 facing away from the substrate layer 1. The second doped layer 4 is disposed on the second surface 12 of the substrate layer 1. The first electrode 5 is disposed on one side of the first surface 11 of the substrate layer 1 and connected to the first doped layer 3. The second electrode 6 is disposed on one side of the second surface 12 of the substrate layer 1 and connected to the second doped layer 4.

[0124] The passivated contact solar cell provided in this embodiment features a precisely and uniformly thick oxide layer 2 without laser sintering. Laser sintering, on the one hand, makes the surface of oxide layer 2 smoother and cleaner, reducing impurities and defects and improving the surface and internal quality of oxide layer 2. On the other hand, the interface of the sintered oxide layer 2 is good, allowing the introduction and distribution of dopants in the first doped layer 3 to more precisely match the specific areas treated by laser, ensuring the uniformity and precise depth of doping in the first doped layer 3, thereby achieving more refined control of electrical performance. In summary, the oxide layer 2 after laser sintering has a high-quality surface, a low surface recombination rate with the substrate layer 1 and the first doped layer 3, and a long carrier lifetime, which helps to improve the photoelectric conversion efficiency and stability of the cell, thereby increasing power generation efficiency.

[0125] In one embodiment, the passivated contact solar cell further includes: a first antireflection layer 7, a second antireflection layer 8, and a passivation layer. The first antireflection layer 7 is disposed on the first doped layer 3, and the first electrode 5 passes through the first antireflection layer 7 and is connected to the first doped layer 3. The second antireflection layer 8 is disposed on the second doped layer 4, and the second electrode 6 passes through the second antireflection layer 8 and is connected to the second doped layer 4. The passivation layer is disposed on the first surface 11 of the substrate layer 1 or on the side surface of the oxide layer 2 facing away from the substrate layer 1.

[0126] The first antireflection layer 7 and the second antireflection layer 8 help reduce sunlight reflection on the back of the battery, thereby improving the battery's absorption of sunlight and effectively improving power generation quality. The passivation material adsorbed on the surface of the substrate layer 1 or the oxide layer 2 forms a dense passivation layer after laser sintering, which can significantly improve the photoelectric conversion efficiency of the battery.

[0127] Therefore, the battery in this embodiment was sampled twice and its performance was compared with that of a conventional passivated contact solar cell in the comparative example. The following results were obtained:

[0128] Battery samples Uoc(v) Jsc(A) FF (%) Efficiency (%) Sample 1 0.736 13.402 87.21 26.93 Sample 2 0.739 13.354 86.31 27.08 Comparative Example 0.706 13.218 83.42 23.84

[0129] As shown in the table above, the passivated contact solar cell in this embodiment has increased open-circuit voltage (Uoc), short-circuit current (Jsc), fill factor (FF), and power generation efficiency compared to the comparative cell. In other words, the photoelectric conversion performance of the passivated contact solar cell in this embodiment is significantly improved.

[0130] Further functional descriptions of the above modules are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0131] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0132] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for preparing a passivated contact solar cell, characterized in that, include: A base layer is provided, the base layer having opposing first and second surfaces; An oxide layer is formed on the first surface of the substrate layer, including annealing the oxide layer; One side of the oxide layer has a passivation layer formed of a passivation material; The surface of the oxide layer is subjected to laser sintering treatment, including: laser heating the oxide layer with a passivation material on one side; and completing the sintering reaction to form a dense cross-linked structure. A first doped layer is formed on the oxide layer after laser sintering. A second doped layer is formed on the second surface of the substrate layer; A first electrode is formed on one side of the first surface of the substrate layer, and a second electrode is formed on one side of the second surface of the substrate layer. The first electrode is connected to the first doped layer, and the second electrode is connected to the second doped layer.

2. The method for preparing a passivated contact solar cell according to claim 1, characterized in that, The laser sintering process on the surface of the oxide layer includes: scanning the entire surface of the oxide layer with a laser beam to sinter the oxide layer.

3. The method for preparing a passivated contact solar cell according to claim 2, characterized in that, The laser beam comprises an infrared pulse beam with a wavelength of 1064 nm.

4. The method for preparing a passivated contact solar cell according to claim 3, characterized in that, The thickness of the oxide layer ranges from 1 nm to 5 nm.

5. The method for preparing a passivated contact solar cell according to claim 4, characterized in that, After providing the substrate layer and before forming an oxide layer on the first surface of the substrate layer, the method further includes: forming a passivation layer on the first surface of the substrate layer, wherein the oxide layer is formed on the passivation layer.

6. The method for preparing a passivated contact solar cell according to claim 4, characterized in that, After forming an oxide layer on the first surface of the substrate layer, and before performing laser sintering on the surface of the oxide layer, the method further includes: forming a passivation layer on the side surface of the oxide layer opposite to the substrate layer, wherein the first doped layer is formed on the passivation layer.

7. The method for preparing a passivated contact solar cell according to claim 1, characterized in that, The first electrode and the first doped layer are connected on one side of the first surface of the substrate by laser sintering; the second electrode and the second doped layer are connected on one side of the second surface of the substrate by laser sintering.

8. The method for preparing a passivated contact solar cell according to any one of claims 1-7, characterized in that, After forming a second doped layer on the second surface of the substrate layer, and before forming a first electrode on one side of the first surface of the substrate layer, the method further includes: A first antireflection layer is formed on the first doped layer, and a second antireflection layer is formed on the second doped layer; the first electrode passes through the first antireflection layer and is connected to the first doped layer, and the second electrode passes through the second antireflection layer and is connected to the second doped layer.

9. A passivated contact solar cell, prepared by the method for preparing a passivated contact solar cell according to any one of claims 1-8, characterized in that, include: A base layer having opposing first and second surfaces; An oxide layer is disposed on the first surface of the substrate layer; A first doped layer is disposed on the side surface of the oxide layer opposite to the substrate layer; A second doped layer is disposed on the second surface of the substrate layer; A first electrode and a second electrode, wherein the first electrode is disposed on one side of the first surface of the substrate layer and is connected to the first doped layer, and the second electrode is disposed on one side of the second surface of the substrate layer and is connected to the second doped layer.

10. The passivated contact solar cell according to claim 9, characterized in that, Also includes: A first antireflection layer and a second antireflection layer, wherein the first antireflection layer is disposed on the first doped layer, and the first electrode passes through the first antireflection layer and is connected to the first doped layer; The second antireflection layer is disposed on the second doped layer, and the second electrode passes through the second antireflection layer and is connected to the second doped layer; A passivation layer is disposed on a first surface of the substrate layer or on a side surface of the oxide layer opposite to the substrate layer.

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