Passivated contact solar cell and method of making same

Abstract

The invention relates to the technical field of photovoltaics, and discloses a passivation contact solar cell and a preparation method thereof. The preparation method comprises the following steps: providing a substrate layer with a first surface and a second surface which are opposite; 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 doping layer on the oxide layer after laser sintering treatment; forming a second doping layer on the second surface of the substrate layer; and forming a first electrode connected with the first doping layer on one side of the first surface of the substrate layer, and forming a second electrode connected with the second doping layer on one side of the second surface of the substrate layer. According to the invention, the laser sintering treatment is carried out on the oxide layer to realize accurate optimization of the surface of the oxide layer and improve the surface and interface characteristics, so that the surface recombination rate of the oxide layer and the substrate layer and the first doping layer is reduced, the service life of a carrier is prolonged, the photoelectric conversion efficiency and stability of the cell are improved, and the power generation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaics, and in particular to a passivated contact solar cell and a preparation method thereof. Background Art

[0002] Tunnel Oxide Passivated Contact (TOPcon) is a high-efficiency solar cell based on N-type silicon material. Compared with traditional solar cells, TOPCon can further improve the photoelectric conversion efficiency of solar cells and reduce costs. The characteristics of TOPCon are: a layer of ultra-thin silicon oxide and doped polysilicon layer is prepared on the back of the N-type silicon wafer to form a tunnel oxide passivated contact structure, which effectively reduces metal contact recombination and thus improves the open circuit voltage and short circuit current of the battery.

[0003] In the field of photovoltaic cell technology, an important factor affecting the improvement of cell efficiency is the recombination of electron-hole pairs. In the related technology, during the process of polysilicon layer doping and electrode sintering preparation on the back of TOPCon cells, the tunneling oxide layer is easily damaged, making it difficult to accurately control the thickness and quality of the tunneling silicon oxide layer, resulting in an accelerated recombination rate on the surface of the tunneling oxide layer and a reduced carrier lifetime, thereby affecting the electrode ohmic contact quality of the cell and the formation of the back surface field, and ultimately resulting in a decrease in the photoelectric conversion efficiency of the cell. Summary of the invention

[0004] In view of this, the present invention provides a passivated contact solar cell and a method for preparing the same, so as to solve the problem that the thickness and quality of the tunneling silicon oxide layer in the existing cell are difficult to accurately control, resulting in an accelerated recombination rate on the surface of the tunneling oxide layer and a reduced carrier lifetime, thereby affecting 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] providing a substrate layer having opposing first and second surfaces;

[0007] forming an oxide layer on the first surface of the base layer;

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

[0009] forming a first doping layer on the laser sintered oxide layer;

[0010] forming a second doping layer on the second surface of the base layer;

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

[0012] Beneficial effects: In the preparation method of the passivated contact solar cell of the present invention, after the oxide layer is formed on the back side of the battery, specifically on the first surface of the substrate layer, the formed oxide layer is subjected to laser sintering treatment. On the one hand, laser sintering can make the surface of the oxide layer smoother and cleaner, reduce impurities and defects in the oxide layer, and improve the surface and internal quality of the oxide layer; on the other hand, the oxide layer interface after sintering is good, so that the introduction and distribution of the dopant of the first doping layer can be more accurately matched with the specific area after laser treatment, improve the uniformity of doping and the accuracy of depth control, help to accurately form the first doping layer, and achieve more precise electrical performance control. 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 of the oxide layer with the substrate layer and the first doping layer, and increases the carrier lifetime, thereby improving the photoelectric conversion efficiency and stability of the battery, and thus improving the power generation efficiency.

[0013] In an optional embodiment, performing laser sintering on the surface of the oxide layer includes: performing laser beam scanning on the entire surface of the oxide layer to sinter the oxide layer.

[0014] Beneficial effects: After rationally planning the scanning path and overlapping area of ​​the laser beam, repeated, precise scanning and precise control of laser parameters ensure that the entire oxide layer can be treated evenly, and combined with real-time monitoring and feedback mechanisms, the power, action time and other parameters of the laser beam are adjusted to achieve the purpose of accurately controlling the thickness of the entire oxide layer. At the same time, the laser sintering method of laser beam scanning combined with doping methods such as ion implantation and diffusion can achieve high-precision doping control, ensure the performance of the PN junction, and improve the output current and efficiency of the battery. The local heating and scanning coverage method can reduce the energy loss of overall heating and improve the thermal efficiency of the material. Under the same energy input, more effective processing can be completed, thereby reducing energy consumption, reducing production costs, and helping to optimize production efficiency.

[0015] In an optional embodiment, 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 pulse laser beam, it helps to achieve instantaneous high temperature in local areas, promote the rapid diffusion of silicon atoms and the rapid formation of an oxide layer.

[0017] In an optional embodiment, the thickness of the oxide layer is in the range of 1 nm to 5 nm.

[0018] Beneficial effect: The thickness of the oxide layer is limited to 1nm to 5nm, which can ensure that the oxide layer has good insulation properties and obtain better battery performance. Too thick an oxide layer may affect the performance of the battery, such as reducing the current density; too thin an oxide layer may not provide sufficient protection, causing the battery to be easily damaged.

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

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

[0021] In an optional embodiment, after forming an oxide layer on the first surface of the base layer and before laser sintering the surface of the oxide layer, it also includes: forming a passivation layer on the surface of the oxide layer facing away from the base layer, and forming a first doping layer on the passivation layer.

[0022] Beneficial effect: After the oxide layer is formed on the base layer, a passivation layer is coated on the oxide layer. On the one hand, it 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 doping layer, promotes the accuracy of the formation of the first doping layer, and improves the doping efficiency.

[0023] In an optional embodiment, the first electrode and the first doping layer are connected on the first surface side of the substrate layer by laser sintering; the second electrode and the second doping layer are connected on the second surface side of the substrate layer by laser sintering.

[0024] Beneficial effect: Laser sintering is used to achieve precise bonding of the first electrode and the first doping layer, as well as precise bonding of the second electrode and the second doping layer, to form a good ohmic contact, which is helpful for current extraction and improves photoelectric conversion efficiency.

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

[0026] A first anti-reflection layer is formed on the first doping layer, and a second anti-reflection layer is formed on the second doping layer; a first electrode passes through the first anti-reflection layer to connect with the first doping layer, and a second electrode passes through the second anti-reflection layer to connect with the second doping layer.

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

[0028] In a second aspect, the present invention also provides a passivated contact solar cell, which is prepared by the above-mentioned passivated contact solar cell preparation method, and includes: a substrate layer, an oxide layer, a first doping layer, a second doping layer, a first electrode and a second electrode, the substrate layer having a first surface and a second surface relative to each other; the oxide layer is arranged on the first surface of the substrate layer; the first doping layer is arranged on the side surface of the oxide layer away from the substrate layer; the second doping layer is arranged on the second surface of the substrate layer; the first electrode is arranged on one side of the first surface of the substrate layer and is connected to the first doping layer, and the second electrode is arranged on one side of the second surface of the substrate layer and is connected to the second doping layer.

[0029] Beneficial effects: The passivated contact solar cell of the present invention has an oxide layer with a precise and uniform thickness before being treated with laser sintering. On the one hand, laser sintering makes the surface of the oxide layer smoother and cleaner, reduces impurities and defects in the oxide layer, and improves the surface and internal quality of the oxide layer. On the other hand, the oxide layer has a good interface after sintering, so that the introduction and distribution of dopants in the first doping layer can be more accurately matched with the specific area treated with the laser, ensuring the uniformity and precise depth of doping in the first doping layer, thereby achieving more precise electrical performance control. In summary, the oxide layer after laser sintering has a high-quality surface, a low surface recombination rate with the substrate layer and the first doping layer, and a long carrier lifetime, which helps to improve the photoelectric conversion efficiency and stability of the battery, thereby improving the power generation efficiency.

[0030] In an optional implementation, it also includes:

[0031] a first anti-reflection layer and a second anti-reflection layer, wherein the first anti-reflection layer is disposed on the first doped layer, and the first electrode passes through the first anti-reflection layer and is connected to the first doped layer; and the second anti-reflection layer is disposed on the second doped layer, and the second electrode passes through the second anti-reflection layer and is connected to the second doped layer;

[0032] The passivation layer is arranged on the first surface of the base layer or on the surface of the oxide layer facing away from the base layer.

[0033] Beneficial effects: The first anti-reflection layer and the second anti-reflection layer help to reduce the reflection of sunlight on the back and back of the battery, thereby improving the battery's absorption of sunlight and effectively improving the quality of power generation; the passivation material adsorbed on the surface of the substrate layer or the surface of the oxide layer forms a compact passivation layer after laser sintering, which can significantly improve the photoelectric conversion efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

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

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

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

[0039] Figure 5 is a schematic structural diagram of forming a second doping layer on the second surface of the base layer according to an embodiment of the present invention;

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

[0041] Figure 7 is a schematic structural diagram of forming a first anti-reflection layer and a second anti-reflection layer according to an embodiment of the present invention;

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

[0043] Description of reference numerals:

[0044] 1. Base layer; 11. First surface; 12. Second surface; 2. Oxide layer; 3. First doping layer; 4. Second doping layer; 5. First electrode; 6. Second electrode; 7. First anti-reflection layer; 8. Second anti-reflection layer. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only some structures related to the present invention are shown in the accompanying drawings, rather than all structures. In the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified for the purpose of clear expression, and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary, and may be deviated due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs. 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. In addition, if one layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0046] refer to Figures 1 to 7 , this embodiment provides a method for passivating contact solar cells, Figure 1 FIG. 1 is a schematic flow chart of a method for preparing a passivated contact solar cell according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0047] Step S101 : providing a base layer 1 , wherein the base layer 1 has a first surface 11 and a second surface 12 opposite to each other.

[0048] For example, the base layer 1 can be a single crystal silicon wafer or a polycrystalline silicon wafer. The single crystal silicon wafer generally has a higher photoelectric conversion efficiency and is suitable for the manufacture of high-performance batteries, while the polycrystalline silicon wafer has a lower cost and is suitable for large-scale production. After selecting a suitable silicon wafer, the silicon wafer is cleaned and surface treated to serve as the base layer 1. Figure 2 The lower surface of the substrate layer 1 serves as the first surface 11, that is, the back side of the battery; and the upper surface serves as the second surface 12, that is, the front side of the battery.

[0049] Step S102 , forming an oxide layer 2 on the first surface 11 of the base layer 1 .

[0050] For example, a thin layer of silicon oxide may be formed on the first surface 11 of the base layer 1 by thermal oxidation to form a good tunneling oxide layer 2, such as Figure 3 shown.

[0051] Step S103 , performing laser sintering on the surface of the oxide layer 2 .

[0052] The formed thin silicon oxide is sintered using a high-energy laser beam, and the high temperature generated by the laser is used to cause the silicon atoms to migrate and redistribute inside the silicon oxide, so as to improve the structure and performance of the silicon oxide. That is, by precisely controlling the focus and power of the laser beam, instantaneous high temperature in a local area is achieved to promote the diffusion of silicon atoms in the oxide layer 2 and on the contact surface between the oxide layer 2 and the substrate layer 1, so that a uniform oxide layer 2 is quickly formed.

[0053] Step S104, forming a first doping layer 3 on the oxide layer 2 after the laser sintering process.

[0054] On the sintered oxide layer 2, a dopant is introduced by ion implantation, diffusion, chemical vapor deposition or solution treatment, and the dopant may be phosphorus ions or boron ions, so as 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 polysilicon layer, such as Figure 4 As shown. Ion implantation is specifically to implant doping elements into the target material (such as silicon material) through high-energy ions to form a doping layer. Ion implantation can achieve high-precision doping control; diffusion method is specifically to place the doping elements on the surface of the target material, and then heat it at high temperature to promote the diffusion of the doping elements into the target material; chemical vapor deposition is specifically to use the vapor deposition method to introduce the doping elements into the target material in gaseous form; solution treatment is specifically to use chemical solutions to introduce specific doping feeds into the target material.

[0055] Step S105 , forming a second doping layer 4 on the second surface 12 of the base layer 1 .

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

[0057] The first doping layer 3 and the second doping layer 4 enable the P-type and N-type semiconductor materials to form a PN junction for separating photogenerated carriers. Through doping, the conductivity of the semiconductor structure is enhanced, which can effectively enhance the efficiency and output current of the battery. In this embodiment, N-type doped silicon is used as the base layer 1, and an N+ doped first doping layer 3 and a P+ doped second doping layer 4 are formed on both sides to improve the conductivity and passivation effect. Through the precise control of the doping layer, the photoelectric conversion efficiency of the battery is limited and improved to achieve higher energy output.

[0058] Step S106 , forming a first electrode 5 on the first surface 11 of the substrate layer 1 , and forming a second electrode 6 on the second surface 12 of the substrate layer 1 , wherein the first electrode 5 is connected to the first doping layer 3 , and the second electrode 6 is connected to the second doping layer 4 .

[0059] Electrode materials are usually selected from metal materials with good electrical conductivity and stable chemical properties. For example, in this embodiment, the first electrode 5 is selected from metal aluminum, which is low in cost and easy to process, and the second electrode 6 is selected from metal gold, which has excellent electrical conductivity. The electrode structure can be set to different shapes and sizes. In this embodiment, the first electrode 5 is set to a strip structure, and multiple strips are set on the back side of the substrate layer 1 to improve the current collection efficiency; the second electrode 6 is set to a mesh structure to absorb light to the greatest extent without blocking light.

[0060] In the preparation method of the passivated contact solar cell provided in the present embodiment, after the oxide layer 2 is formed on the back side of the battery, specifically on the first surface 11 of the substrate layer 1, the formed oxide layer 2 is subjected to laser sintering treatment. On the one hand, laser sintering can make the surface of the oxide layer 2 smoother and cleaner, reduce impurities and defects in the oxide layer 2, and improve the surface and internal quality of the oxide layer 2; on the other hand, the oxide layer 2 after sintering has a good interface, so that the introduction and distribution of the dopant of the first doping layer 3 can be more accurately matched with the specific area after laser treatment, improve the uniformity of doping and the depth control accuracy, help the precise formation of the first doping layer 3, and achieve more precise electrical performance regulation. In summary, the laser sintering treatment of the oxide layer 2 realizes the precise optimization of the surface of the oxide layer 2, improves the surface and interface characteristics, and then reduces the surface recombination rate of the oxide layer 2 with the substrate layer 1 and the first doping layer 3, and improves the carrier lifetime, thereby improving the photoelectric conversion efficiency and stability of the battery, thereby improving the power generation efficiency.

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

[0062] Step S1011, providing an initial base layer.

[0063] Exemplarily, the initial base layer is an unprocessed single crystal silicon or multi-crystalline silicon wafer.

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

[0065] In this embodiment, the initial base layer is cleaned using a standard silicon wafer cleaning process, such as RAC cleaning, to remove surface contaminants. The initial base layer is degreased and cleaned by soaking the initial base layer with a degreaser, which can be an SC-1 cleaning solution mixed with ammonia, hydrogen peroxide and deionized water to remove organic contaminants. After cleaning with deionized water, an acid such as hydrofluoric acid is used to remove silicon oxide on the surface of the silicon wafer to provide a clean silicon surface. Finally, after rinsing the silicon wafer with deionized water again, the silicon wafer is blown dry with nitrogen to avoid water marks on the clean silicon surface after cleaning, and finally a clean and pollution-free silicon wafer is obtained.

[0066] Step S1013, performing surface treatment on the cleaned and dried initial base layer, including: performing roughening treatment on the surface of the initial base layer; performing passivation treatment on the surface of the initial base layer.

[0067] Specifically, surface roughening treatment is to roughen the surface of the silicon wafer by chemical or mechanical methods to increase light scattering and improve light absorption rate; passivation treatment is to use a passivating agent (such as silane or nitride) to form a thin film on the surface of the silicon wafer to reduce the surface recombination rate and improve the carrier lifetime.

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

[0069] In addition, after the above-mentioned cleaning, drying and surface treatment of the silicon wafer, before proceeding to the next process, the clean silicon wafer 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 base layer 1.

[0070] In this embodiment, in the above step S102, a thermal oxidation method is used to form an oxide layer 2 on the first surface 11 of the base layer 1. Specifically, the step S102 includes:

[0071] Step S1021, placing the clean substrate layer 1 after treatment in a high temperature furnace. This embodiment uses a quartz boat high temperature furnace to avoid contamination.

[0072] Step S1022: performing high temperature oxidation treatment on the base layer 1.

[0073] Heat the high temperature furnace to the required high temperature, usually 800°C to 1200°C; introduce oxygen or water vapor into the high temperature furnace for oxidation reaction. Common oxidation methods include: using pure oxygen for oxidation, or using water vapor for water vapor oxidation to increase the oxidation rate; according to the required oxide layer 2 thickness and growth rate, control the oxidation time to form the target oxide layer 2. Usually, the thickness of the oxide layer 2 is related to time and temperature, and the growth rate can be determined by experiments.

[0074] Step S1023, cooling the oxidized oxide layer 2.

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

[0076] Step S1024, post-processing the cooled oxide layer 2.

[0077] The post-processing specifically includes annealing and testing. The annealing refers to annealing the oxide layer 2 in a nitrogen atmosphere to improve the quality of the oxide layer 2 and reduce the internal stress. Then, the thickness and quality of the oxide layer 2 are detected using techniques such as ellipsometry.

[0078] In this embodiment, an oxide layer 2 is formed on the surface of the base layer 1 by a thermal oxidation method, which can effectively reduce the interface defects between the base layer 1 and the oxide layer 2, thereby reducing the recombination rate of 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 , performing laser sintering on the surface of the oxide layer 2 includes: performing laser beam scanning on the entire surface of the oxide layer 2 to sinter the oxide layer 2 .

[0080] Laser sintering is usually carried out locally. In this embodiment, the entire silicon oxide layer is processed and the thickness is controlled by repeated, precise scanning and precise control of laser parameters. Furthermore, by rationally planning the scanning path and overlapping area of ​​the laser beam, it is ensured that the entire oxide layer 2 can be uniformly processed, and in combination with real-time monitoring and feedback mechanisms, the power, action time and other parameters of the laser beam are adjusted to achieve the purpose of accurately controlling the thickness of the entire oxide layer 2. At the same time, the laser sintering method of laser beam scanning is combined with doping methods such as ion implantation and diffusion method to achieve high-precision doping control, ensure the performance of the PN junction, and improve the output current and efficiency of the battery.

[0081] Compared with traditional sintering, the laser sintering of this embodiment has a faster reaction speed. The local heating and scanning coverage method can reduce the energy loss of overall heating, improve the thermal efficiency of the material, and complete more effective processing under the same energy input, thereby reducing energy consumption, reducing production costs, and helping to optimize production efficiency. The specific power and sintering time of laser sintering will vary depending on different materials and equipment. Generally speaking, the power range of laser sintering is between tens of watts and hundreds of watts, and the sintering time ranges from a few seconds to tens of seconds. The specific parameters need to be adjusted according to experimental results and process requirements.

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

[0083] Furthermore, the thickness of the oxide layer 2 after laser sintering is in the range of 1 nm to 5 nm.

[0084] This thickness range can ensure that the oxide layer 2 has good insulation properties. An oxide layer 2 that is too thick may affect the performance of the battery, such as reducing the current density; an oxide layer 2 that is too thin may not provide sufficient protection, causing the battery to be easily damaged. Therefore, controlling the thickness of the oxide layer 2 within the range of 1nm to 5nm can balance these factors and obtain better battery performance.

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

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

[0087] In another optional embodiment, after forming the oxide layer 2 on the first surface 11 of the substrate layer 1 in step S102, and before performing laser sintering on the surface of the oxide layer 2 in step S103, it also includes: forming a passivation layer on the surface of the oxide layer 2 facing away from the substrate layer 1, and forming a first doping layer 3 on the passivation layer.

[0088] That is, an oxide layer 2 is formed on the base layer 1, and then a layer of passivation material, such as silicon oxide or silicon carbide, is coated on the oxide layer 2 to form a passivation layer with a passivation cross-linking effect. The passivation layer at this time, on the one hand, helps to improve the density of the oxide layer 2 material in the subsequent laser sintering process, and on the other hand, improves the interface quality of the oxide layer 2 and the first doping layer 3, promotes the accuracy of the formation of the first doping 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 properties 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 increase 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] The laser beam can accurately locate and adjust the energy input to obtain a uniform sintering effect. Through local heating, the energy loss of overall heating is reduced, and the thermal efficiency of the material is improved. Compared with the traditional sintering method, the laser sintering method has a faster reaction speed and helps to improve production efficiency. After laser sintering, the passivation material adsorbed on the surface of the substrate layer 1 or the surface of the oxide layer 2 can form a compact passivation layer, which significantly improves the photoelectric conversion efficiency of the battery. Through the sintering process, the conductivity of the oxide layer 2 is enhanced, the contact resistance is reduced, and the overall performance of the battery is improved.

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

[0092] The laser sintering method is used to achieve precise bonding of the first electrode 5 and the first doping layer 3, and precise bonding of the second electrode 6 and the second doping layer 4, so as to form a good ohmic contact, which is helpful for current extraction and improves the photoelectric conversion efficiency.

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

[0094] Step S1061 , cleaning the silicon wafer having the oxide layer 2 , the first doping layer 3 , the second doping layer 4 and the base layer 1 .

[0095] The silicon wafer is cleaned by chemical treatment (such as acid cleaning) or physical method (such as ultrasonic cleaning) to remove dirt and oxide on the surface, so as to ensure good contact between the first electrode 5 and the second electrode 6 and the silicon wafer.

[0096] Step S1062 , coating a conductive material on the first doping layer 3 and the second doping layer 4 .

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

[0098] Step S1063, baking and sintering the conductive material.

[0099] The coated silicon wafer is placed in a baking oven and heated to drive off the solvent, while allowing the conductive material particles to bond to each other and form good contact with the surface of the silicon wafer.

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

[0101] Step S1064, etching the electrode structure after the baking and sintering process.

[0102] In the case of a more complex electrode pattern design, the electrode structure after baking and sintering needs to be etched to remove excess electrode material to form the desired electrode pattern.

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

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

[0105] A first anti-reflection layer 7 is formed on the first doping layer 3 , and a second anti-reflection layer 8 is formed on the second doping layer 4 ; the first electrode 5 is connected to the first doping layer 3 through the first anti-reflection layer 7 , and the second electrode 6 is connected to the second doping layer 4 through the second anti-reflection layer 8 .

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

[0107] After the passivated contact solar cell of this embodiment is prepared in all structural layers, it is necessary to perform post-processing steps to further improve the performance and reliability of the cell and ensure the stability of the cell. The post-processing steps specifically include:

[0108] Step S1071, performing annealing treatment on 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. The heat treatment eliminates the stress of the electrode material during the coating process, promotes the connection between metal particles, and improves the conductive performance.

[0110] Step S1072, post-cleaning the passivated contact solar cell.

[0111] Exemplarily, chemical cleaning is performed using an appropriate cleaning agent, or physical methods such as deionized water rinsing and ultrasonic cleaning are combined to remove contaminants and unreacted materials on the cell surface to prevent the performance of the passivated contact solar cell from being affected.

[0112] Step S1073, performing surface passivation on the passivated contact solar cell.

[0113] Exemplarily, a protective film (such as silicon oxide, 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 the passivated contact solar cell.

[0114] Step S1074, leveling the passivated contact solar cell.

[0115] The surfaces of the first electrode 5 and the second electrode 6 are firstly flattened by applying a pressing force or coating a thin film, so that the surface of the passivation contact solar cell is flatter, and the contact quality and conductivity are improved.

[0116] Step S1075, performing quality inspection on the passivated contact solar cell.

[0117] Passivated contact solar cells are evaluated using resistance testing, microscopy and other characterization techniques to ensure that the conductivity, contact resistance and corrosion resistance of the passivated contact solar cells meet the standards and ensure the overall performance of the cell.

[0118] Step S1076, assembling and packaging the passivated contact solar cell.

[0119] Use efficient adhesives and encapsulation materials to combine the passivated contact solar cells 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, performing an environmental adaptability test on the passivated contact solar cell.

[0121] High temperature, high humidity, ultraviolet radiation and other tests are carried out to ensure the performance of components with passivated contact solar cells in various usage environments and to evaluate the stability and reliability of passivated contact solar cells under different environmental conditions.

[0122] In the preparation method of the passivated contact solar cell of the present embodiment, the formation of each structural layer is improved and perfected, especially the new laser sintering processing step is directly introduced after the oxide layer 2, so that the entire preparation process is more efficient, accurate and reliable, thereby improving the quality and performance of the finally 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-mentioned passivated contact solar cell preparation method, including: a substrate layer 1, an oxide layer 2, a first doping layer 3, a second doping 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 relative to each other; the oxide layer 2 is arranged on the first surface 11 of the substrate layer 1; the first doping layer 3 is arranged on the side surface of the oxide layer 2 away from the substrate layer 1; the second doping layer 4 is arranged on the second surface 12 of the substrate layer 1; the first electrode 5 is arranged on the side of the first surface 11 of the substrate layer 1 and is connected to the first doping layer 3, and the second electrode 6 is arranged on the side of the second surface 12 of the substrate layer 1 and is connected to the second doping layer 4.

[0124] The passivated contact solar cell provided in this embodiment has an oxide layer 2 that has not been subjected to laser sintering and has a precise and uniform thickness. On the one hand, laser sintering makes the surface of the oxide layer 2 smoother and cleaner, reduces impurities and defects in the oxide layer 2, and improves the surface and internal quality of the oxide layer 2. On the other hand, the oxide layer 2 has a good interface after sintering, so that the introduction and distribution of the dopant in the first doping layer 3 can be more accurately matched with the specific area after laser treatment, ensuring the uniformity and precise depth of doping in the first doping layer 3, thereby achieving more precise electrical performance regulation. 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 doping layer 3, and a long carrier lifetime, which helps to improve the photoelectric conversion efficiency and stability of the battery, thereby improving the power generation efficiency.

[0125] In one embodiment, the above-mentioned passivated contact solar cell further includes: a first anti-reflection layer 7, a second anti-reflection layer 8 and a passivation layer, the first anti-reflection layer 7 is arranged on the first doped layer 3, and the first electrode 5 is connected to the first doped layer 3 through the first anti-reflection layer 7; the second anti-reflection layer 8 is arranged on the second doped layer 4, and the second electrode 6 is connected to the second doped layer 4 through the second anti-reflection layer 8; the passivation layer is arranged 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 anti-reflection layer 7 and the second anti-reflection layer 8 help to reduce the reflection of sunlight from the back and back of the battery, thereby improving the battery's absorption of sunlight and effectively improving the quality of power generation; the passivation material adsorbed on the surface of the substrate layer 1 or the surface of the oxide layer 2 forms a compact 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 the battery performance was compared with that of the conventional passivated contact solar cell in the comparative example, and 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] It can be seen from the above table that the open circuit voltage (Uoc), short circuit current (Jsc), fill factor (FF) and power generation efficiency (Efficiency) of the passivated contact solar cell in this embodiment are increased compared with the control battery, that is, the photoelectric conversion performance of the passivated contact solar cell in this embodiment is significantly improved.

[0130] The further functional description of each of the above modules is the same as that of the above corresponding embodiments and will not be repeated here.

[0131] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

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

Claims

1. A method for preparing a passivated contact solar cell, characterized in that: include: providing a substrate layer having opposing first and second surfaces; forming an oxide layer on the first surface of the base layer; Performing laser sintering on the surface of the oxide layer; forming a first doping layer on the oxide layer after the laser sintering process; forming a second doping layer on the second surface of the base layer; A first electrode is formed on one side of the first surface of the base layer, and a second electrode is formed on one side of the second surface of the base layer, wherein 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 treatment on the surface of the oxide layer includes: performing a laser beam scanning treatment on the entire surface of the oxide layer 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 includes 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 base layer and before forming the oxide layer on the first surface of the base layer, the method further includes: forming a passivation layer on the first surface of the base 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 base layer and before performing laser sintering on the surface of the oxide layer, the method further includes: forming a passivation layer on a surface of the oxide layer facing away from the base layer, wherein the first doping 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 doping layer are connected on the first surface side of the base layer by laser sintering; the second electrode and the second doping layer are connected on the second surface side of the base layer by laser sintering.

8. The method for preparing a passivated contact solar cell according to any one of claims 1 to 7, characterized in that: After forming the second doping layer on the second surface of the base layer, and forming the first electrode on the first surface of the base layer, and before forming the second electrode on the second surface of the base layer, the method further includes: A first anti-reflection layer is formed on the first doping layer, and a second anti-reflection layer is formed on the second doping layer; the first electrode is connected to the first doping layer through the first anti-reflection layer, and the second electrode is connected to the second doping layer through the second anti-reflection 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 to 8, characterized in that: include: a substrate layer having opposing first and second surfaces; An oxide layer, disposed on the first surface of the base layer; A first doping layer is disposed on a surface of the oxide layer facing away from the base layer; A second doping layer is disposed on the second surface of the base layer; A first electrode and a second electrode, wherein the first electrode is disposed on a first surface side of the base layer and connected to the first doped layer, and the second electrode is disposed on a second surface side of the base layer and connected to the second doped layer.

10. The passivated contact solar cell according to claim 9, characterized in that: Also includes: a first anti-reflection layer and a second anti-reflection layer, wherein the first anti-reflection layer is disposed on the first doped layer, and the first electrode passes through the first anti-reflection layer and is connected to the first doped layer; The second anti-reflection layer is disposed on the second doped layer, and the second electrode passes through the second anti-reflection layer and is connected to the second doped layer; The passivation layer is arranged on the first surface of the base layer or on the surface of the oxide layer facing away from the base layer.

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