TOPCon battery preparation method and TOPCon battery

Abstract

The invention relates to the technical field of solar cells, and discloses a TOPCon cell preparation method and a TOPCon cell, and the TOPCon cell preparation method comprises the steps: forming a cell layer which is provided with a boron-doped layer and a first passivation layer located on the surface of one side of the boron-doped layer; cleaning and etching the surface of one side, deviating from the boron-doped layer, of the first passivation layer; forming a metal contact layer on the surface of one side, deviating from the boron-doped layer, of the first passivation layer by adopting a laser enhanced contact optimization process; forming a composite dielectric layer on the surface of one side, deviating from the battery layer, of the metal contact layer; and forming a first electrode on the surface of one side, deviating from the metal contact layer, of the composite dielectric layer. The surface of one side, deviating from the boron-doped layer, of the first passivation layer is cleaned, so that the cleanliness of the surface of one side, deviating from the boron-doped layer, of the first passivation layer is improved, and the first passivation layer can be locally damaged by a laser enhanced contact optimization process, so that the metal contact layer is in contact with the boron-doped layer; therefore, the connection stability of the metal contact layer and the boron-doped layer is improved.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to a TOPCon cell preparation method and a TOPCon cell. Background Art

[0002] With the continuous development of solar cell technology, carrier selective passivation contact has become one of the important ways to improve the efficiency of solar cells. Carrier selective passivation contact is the core process of tunnel oxide passivated contact (TOPCon) cells. By preparing a tunnel oxide layer and a doped polysilicon layer on the back of a TOPCon cell, it can not only provide a good interface passivation contact for the back of the cell, but also form an electron selective tunneling structure on the back of the cell, greatly improving the performance of the cell.

[0003] In the preparation process of TOPCon cells, a passivation layer needs to be prepared on the phosphorus-doped layer to reduce carrier recombination losses, and then a front electrode is prepared on the passivation layer through screen printing and sintering processes. However, with the long-term use of TOPCon cells, the interface between the passivation layer and the phosphorus-doped layer is prone to peeling, which leads to increased resistance and affects the efficiency and life of the battery. Summary of the invention

[0004] In view of this, the present invention provides a TOPCon battery preparation method and a TOPCon battery to solve the problem that with the long-term use of the existing TOPCon battery, the interface peeling between the passivation layer and the phosphorus-doped layer is prone to occur, thereby increasing the resistance and affecting the efficiency and life of the battery.

[0005] In a first aspect, the present invention provides a method for preparing a TOPCon battery, comprising:

[0006] forming a battery layer, wherein the battery layer comprises a boron-doped layer and a first passivation layer located on a surface of one side of the boron-doped layer;

[0007] Cleaning and etching a surface of the first passivation layer facing away from the boron-doped layer;

[0008] Forming a metal contact layer on a surface of the first passivation layer facing away from the boron-doped layer by using a laser enhanced contact optimization process;

[0009] forming a composite dielectric layer on a surface of the metal contact layer facing away from the battery layer;

[0010] A first electrode is formed on a surface of the composite dielectric layer facing away from the metal contact layer.

[0011] Beneficial effects: The surface of the first passivation layer away from the boron-doped layer is cleaned to remove grease, dust, and contaminants on the surface of the first passivation layer away from the boron-doped layer, so as to improve the cleanliness of the surface of the first passivation layer away from the boron-doped layer. The surface of the first passivation layer away from the boron-doped layer is etched to remove defects on the surface of the first passivation layer away from the boron-doped layer, so as to improve the flatness of the surface of the first passivation layer away from the boron-doped layer, so as to form a good contact between the metal contact layer and the first passivation layer, so as to improve the adhesion of the metal contact layer on the first passivation layer, and further improve the connection stability between the metal contact layer and the first passivation layer. In addition, the laser enhanced contact optimization process can partially destroy the first passivation layer so that the metal contact layer contacts the boron-doped layer and forms a metal-silicon alloy to improve the connection stability between the metal contact layer and the boron-doped layer, thereby improving the connection fixity between the first passivation layer and the boron-doped layer, and further reducing the interface peeling between the passivation layer, the boron-doped layer and the first passivation layer. In addition, a composite dielectric layer is formed on the surface of the metal contact layer away from the boron-doped layer to improve the mechanical strength and stability of the metal contact layer and reduce the impact of the external environment on the metal contact layer and the battery layer, thereby further reducing the interface peeling between the boron-doped layer and the first passivation layer. By cleaning and etching the surface of the metal contact layer away from the battery layer, the connection stability between the first passivation layer and the boron-doped layer is ensured to be improved.

[0012] In an optional embodiment, the cleaning process includes ultrasonic cleaning, chemical cleaning, and plasma cleaning;

[0013] The etching process includes ion etching and wet etching.

[0014] The cleanliness of the surface of the first passivation layer away from the boron doping layer is maximized by ultrasonic cleaning, chemical cleaning, and plasma cleaning, and the flatness of the surface of the first passivation layer away from the boron doping layer is maximized by wet etching and dry etching.

[0015] In an optional embodiment, after forming a metal contact layer on a surface of the first passivation layer facing away from the boron-doped layer by a laser enhanced contact optimization process, and before forming a composite dielectric layer on a surface of the metal contact layer facing away from the battery layer, the process further includes:

[0016] A surface of the metal contact layer facing away from the battery layer is cleaned.

[0017] The surface of the metal contact layer facing away from the battery layer is cleaned to remove grease, dust and pollutants on the surface of the metal contact layer facing away from the battery layer to improve the cleanliness of the surface of the metal contact layer facing away from the battery layer. The surface of the metal contact layer facing away from the battery layer is etched to remove defects on the surface of the metal contact layer facing away from the battery layer to improve the flatness of the surface of the metal contact layer facing away from the battery layer, so that the metal contact layer forms good contact with the composite dielectric layer, thereby improving the adhesion of the composite dielectric layer on the metal contact layer, and further improving the connection stability between the composite dielectric layer and the metal contact layer.

[0018] In an optional embodiment, after forming the composite dielectric layer on the surface of the metal contact layer facing away from the battery layer, and before forming the first electrode on the surface of the composite dielectric layer facing away from the metal contact layer, the method further includes:

[0019] Under nitrogen or argon atmosphere, the battery layer, the metal contact layer and the composite layer are heat treated, wherein the heat treatment temperature is 350° C.-500° C. and the heat treatment time is 10-120 min.

[0020] Through heat treatment, the metal contact layer and the composite dielectric layer are chemically bonded, so that a good interface bonding is formed between the metal contact layer and the composite dielectric layer, and the stability of the metal contact layer and the composite dielectric layer is improved. It can also reduce defects in the composite dielectric layer and improve the performance and reliability of TOPCon.

[0021] In an optional embodiment, after the heat treatment, the battery layer, the metal contact layer and the composite layer are subjected to pressure treatment, the pressure treatment temperature is 150° C., the pressure is 100-500 MPa, and the pressure treatment time is 4-300 s.

[0022] Through pressure treatment, the metal contact layer and the composite dielectric layer are formed into a more compact assembly.

[0023] In an optional embodiment, after the pressure treatment, the battery layer, the metal contact layer and the composite layer are plasma cleaned.

[0024] In an optional embodiment, the material of the metal contact layer includes one or more of silver, aluminum, copper, and gold, and the composite dielectric layer includes one or more of aluminum oxide, silicon oxide, and barium titanate.

[0025] In an optional embodiment, the battery layer includes a second electrode, a first aluminum oxide layer, a first silicon nitride layer, phosphorus-doped polysilicon, a tunneling oxide layer, an N-type silicon substrate, a boron-doped layer, a second aluminum oxide layer, and a second silicon nitride layer stacked in sequence.

[0026] In a second aspect, the present invention provides a TOPCon battery prepared using the above-mentioned TOPCon battery preparation method.

[0027] The TOPCon cell reduces the interface peeling between the passivation layer and the boron-doped layer and the first passivation layer, thereby extending the life of the TOPCon cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 It is a schematic diagram of the structure of the battery layer in the preparation of the TOPCon battery according to an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of the battery layer and the metal contact layer in the preparation of the TOPCon battery according to an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the structure of the battery layer, the metal contact layer, and the composite dielectric layer in the preparation of the TOPCon battery according to an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the structure of a battery layer, a metal contact layer, a composite dielectric layer and a first electrode in the preparation of a TOPCon battery according to an embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 100, battery layer; 101, second electrode; 102, second passivation layer; 1021, aluminum oxide layer; 1022, silicon nitride layer; 103, phosphorus-doped polysilicon layer; 104, tunneling oxide layer; 105, N-type silicon substrate; 106, boron-doped layer; 107, first passivation layer;

[0035] 200, metal contact layer;

[0036] 300, composite dielectric layer;

[0037] 400. First electrode. DETAILED DESCRIPTION

[0038] 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.

[0039] In the preparation process of TOPCon cells, a passivation layer needs to be prepared on the phosphorus-doped layer to reduce carrier recombination losses, and then a front electrode is prepared on the passivation layer through screen printing and sintering processes. However, with the long-term use of TOPCon cells, the interface between the passivation layer and the phosphorus-doped layer is prone to peeling, which leads to increased resistance and affects the efficiency and life of the battery.

[0040] Therefore, the embodiment of the present invention provides a TOPCon battery preparation method, by cleaning and etching the surface of the metal contact layer 200 away from the battery layer 100, so as to ensure and further improve the connection stability between the first passivation layer 107 and the boron doped layer 106, the laser enhanced contact optimization process can partially destroy the first passivation layer 107, so that the metal contact layer 200 is in contact with the boron doped layer 106, and form a metal silicon alloy to improve the connection stability between the metal contact layer 200 and the boron doped layer 106. Thereby, the connection fixity between the first passivation layer 107 and the boron doped layer 106 is improved, and the interface peeling between the passivation layer and the boron doped layer 106 and the first passivation layer 107 is reduced.

[0041] A TOPCon battery preparation method provided in an embodiment of the present invention is as follows: Figure 1 and Figure 4 As shown, the following steps are included:

[0042] S101, such as Figure 1As shown, a battery layer 100 is formed;

[0043] The specific steps of forming the battery layer 100 include:

[0044] S1011, providing an N-type silicon substrate 105, and performing double-sided texturing on the N-type silicon substrate 105 using an alkaline solution.

[0045] Specifically, the N-type silicon substrate 105 is single crystal silicon doped with pentavalent elements, and the alkaline solution is sodium hydroxide, potassium hydroxide, hydrogen peroxide or other common alkaline solutions. It should be noted that the texturing is mainly to make the silicon react chemically with the alkaline solution through the anisotropic corrosion characteristics in the alkaline solution to form a pyramid-shaped velvet structure on both the front and back sides of the N-type silicon substrate 105, so that the N-type silicon substrate produces a light trapping effect, thereby increasing the absorption of sunlight, reducing the light reflectivity of the front side of the N-type silicon substrate 105, increasing the short-circuit current, and improving the photoelectric conversion capacity.

[0046] S1012 , performing a boron diffusion doping process on the front surface of the N-type silicon substrate 105 to form a boron doped layer 106 , and forming a PN junction with the N-type silicon substrate 105 .

[0047] Specifically, boron is a pentavalent element, and its diffusion into the N-type silicon substrate 105 will introduce additional electron holes, thereby changing the conductive properties of the N-type silicon substrate 105. Through the boron diffusion process, boron atoms can enter the interior of the silicon wafer to form a boron diffusion layer to achieve the regulation of the conductivity and resistivity of the N-type substrate layer. The boron diffusion process first coats a thin film on the front of the N-type silicon substrate 105, usually using silicon dioxide as the film material. The function of this film is to prevent boron atoms from directly diffusing from the front of the N-type silicon substrate 105 to the interior, ensuring that the boron atoms can be evenly distributed on the film; the N-type silicon substrate 105 coated with the film is placed in a diffusion furnace, and the boron source (such as boron tribromide, boron chloride) is evaporated or sublimated by heating. The generated boron atoms are heated to a certain temperature by the diffusion source, pass through the film and diffuse into the N-type silicon substrate 105 to form a boron diffusion layer.

[0048] S1013, forming a tunneling oxide layer 104 and a phosphorus-doped polysilicon layer 103 on the back side of the N-type silicon substrate 105;

[0049] Specifically, a tunnel oxide layer 104 is deposited on the back of the N-type silicon substrate 105 by using a vapor deposition process. The material of the tunnel oxide layer 104 is silicon dioxide, and the thickness of the tunnel oxide layer 104 is 1-2 nm. A phosphorus-doped polysilicon layer 103 is deposited on the surface of the tunnel oxide layer 104 away from the N-type silicon substrate 105 by using a vapor deposition process. The phosphorus-doped polysilicon layer 103 is laser crystallized by using a laser.

[0050] S1014, a first passivation layer 107 is deposited on the surface of the boron-doped layer 106 facing away from the N-type silicon substrate 105 by a vapor deposition process, and a second passivation layer 102 is deposited on the surface of the phosphorus-doped layer facing away from the N-type silicon substrate 105 by a vapor deposition process. Both the first passivation layer 107 and the second passivation layer 102 may include an aluminum oxide layer 1021 and a silicon nitride layer 1022.

[0051] S102, cleaning and etching the surface of the first passivation layer 107 which is away from the boron-doped layer 106;

[0052] S1021 , chemically cleaning a surface of the first passivation layer 107 that is away from the boron-doped layer 106 .

[0053] Specifically, a mixed solution of sodium hydroxide and deionized water is first used to clean the surface of the first passivation layer 107 away from the boron-doped layer 106 to remove organic pollutants on the surface of the first passivation layer 107, and then a mixed solution of hydrogen peroxide and sulfuric acid is used to clean the surface of the first passivation layer 107 away from the boron-doped layer 106 to remove metal ions and inorganic impurities.

[0054] S1022 , ultrasonically cleaning the surface of the first passivation layer 107 facing away from the boron-doped layer 106 , and removing particles on the surface of the first passivation layer 107 and in micropores on the surface of the first passivation layer 107 by using ultrasonic vibration.

[0055] S1023 , plasma cleaning is performed on a surface of the first passivation layer 107 that is away from the boron-doped layer 106 .

[0056] Specifically, plasma is used to treat the surface of the first passivation layer 107 facing away from the boron-doped layer 106 to further clean the surface of the first passivation layer 107 and increase the surface activity of the first passivation layer 107. The plasma includes oxygen and argon plasma.

[0057] S1024 , etching the surface of the first passivation layer 107 on the side facing away from the boron-doped layer 106 by using an etching process, so as to process the surface of the first passivation layer 107 .

[0058] The surface of the first passivation layer 107 facing away from the boron-doped layer 106 is cleaned to remove grease, dust and pollutants on the surface of the first passivation layer 107 facing away from the boron-doped layer 106, so as to improve the cleanliness of the surface of the first passivation layer 107 facing away from the boron-doped layer 106. The surface of the first passivation layer 107 facing away from the boron-doped layer is etched to remove defects on the surface of the first passivation layer 107 facing away from the boron-doped layer 106, so as to improve the flatness of the surface of the first passivation layer 107 facing away from the boron-doped layer 106, so as to form a good contact between the metal contact layer 200 and the first passivation layer 107, so as to improve the adhesion of the metal contact layer 200 on the first passivation layer 107, and further improve the connection stability between the metal contact layer 200 and the first passivation layer 107.

[0059] S1025, such as Figure 2 As shown, a metal contact layer 200 is formed on a surface of the first passivation layer 107 that is away from the boron-doped layer 106 by using a laser enhanced contact optimization process.

[0060] The material of the metal contact layer 200 includes one or more of aluminum, copper, gold, and silver. The thickness of the metal contact layer 200 is 50nm-300nm. The laser enhanced contact optimization process can partially destroy the first passivation layer 107 so that the metal contact layer 200 contacts the boron doped layer 106 and forms a metal silicon alloy to improve the connection stability and adhesion between the metal contact layer 200 and the boron doped layer 106, and reduce the contact resistance between the metal contact layer 200 and the boron doped layer 106, so that the electron transmission between the metal contact layer 200 and the boron doped layer 106 is improved, thereby improving the charge collection efficiency, and then improving the conversion efficiency of the TOPCon solar cell, the open circuit voltage and the fill factor of the battery.

[0061] The laser enhanced contact optimization process can locally destroy the first passivation layer 107 so that the metal contact layer 200 contacts the boron doped layer 106 and forms a metal silicon alloy to improve the connection stability between the metal contact layer 200 and the boron doped layer 106, thereby improving the connection fixity between the first passivation layer 107 and the boron doped layer 106, and further reducing the interface peeling between the passivation layer and the boron doped layer 106 and the first passivation layer 107.

[0062] S103, cleaning the surface of the metal contact facing away from the battery layer 100;

[0063] S1031 , chemically cleaning the surface of the metal contact layer 200 that is away from the battery layer 100 .

[0064] Specifically, a mixed solution of sodium hydroxide and deionized water is first used to clean the surface of the metal contact layer 200 that is away from the battery layer 100 to remove organic pollutants on the surface of the metal contact layer 200, and then a mixed solution of hydrogen peroxide and sulfuric acid is used to clean the surface of the metal contact layer 200 that is away from the battery layer 100 to remove metal ions and inorganic impurities.

[0065] S1, 32, ultrasonically clean the surface of the metal contact layer 200 facing away from the battery layer 100, and use ultrasonic vibration to remove particles in the metal contact layer 200 and in the micropores on the metal contact surface.

[0066] S1033 , plasma cleaning is performed on the surface of the metal contact layer 200 facing away from the battery layer 100 .

[0067] Specifically, plasma is used to treat the surface of the metal contact layer 200 facing away from the battery layer 100 to further clean the surface of the metal contact and increase the surface activity of the metal contact layer 200. The plasma includes oxygen and argon plasma.

[0068] The surface of the metal contact layer 200 facing away from the battery layer 100 is cleaned to remove grease, dust and pollutants on the surface of the metal contact layer 200 facing away from the battery layer 100, so as to improve the cleanliness of the surface of the first passivation layer 107 facing away from the boron-doped layer 106, so that the composite dielectric layer 300 forms good contact with the metal contact layer 200, so as to improve the adhesion of the composite dielectric layer 300 on the first passivation layer 107, and further improve the connection stability between the composite dielectric layer 300 and the metal contact layer 200. Reduce the interface peeling between the composite dielectric layer 300 and the metal contact layer 200.

[0069] S104, such as Figure 3 As shown, a composite dielectric layer 300 is formed on the surface of the metal contact layer 200 facing away from the battery layer 100 .

[0070] S1041, select the material of the composite dielectric layer 300. The material of the composite dielectric layer 300 includes one or more of aluminum oxide, silicon oxide, and barium titanate. Of course, the composite dielectric layer 300 can also be a polymer film, an oxide film, or other types of dielectric materials. The material of the composite dielectric layer 300 can be selected according to different battery performances. The material of the composite dielectric layer 300 can be aluminum oxide, which has excellent chemical stability, mechanical strength, and insulation properties. The material of the composite dielectric layer 300 can also be nitrogen oxide, and silicon nitride has good insulation, thermal stability, and oxidation resistance. The material of the composite dielectric layer 300 can also be barium titanate, which has a high dielectric constant and is suitable for occasions where capacitor performance is enhanced. When selecting the composite dielectric layer 300, first of all, the composite dielectric layer 300 needs to maintain good chemical stability (not prone to chemical reactions) at the working temperature and working environment of the battery. Secondly, the composite dielectric layer 300 needs to be able to withstand the stress in the battery manufacturing process and environmental changes in long-term use. The composite dielectric layer 300 also needs to have good electrical insulation properties to reduce the risk of short circuits while maintaining low contact resistance. In addition, the material of the composite dielectric layer 300 needs to be compatible with the material of the metal contact layer 200 to avoid performance degradation caused by chemical reactions between the composite dielectric layer 300 and the metal dielectric layer. In addition, the composite dielectric layer 300 has a set dielectric constant that can optimize capacitance and electric field distribution. Finally, the material of the composite dielectric layer 300 needs to form strong adhesion with the material of the metal contact layer 200 to ensure that it does not peel off during manufacturing and use. The material of the composite dielectric layer 300 in this application is aluminum oxide.

[0071] S1042, dissolving the material of the composite dielectric layer 300 in a solvent, which may be an acid solvent, an alkali solvent, or an organic solvent, to form a liquid composite dielectric layer 300 material.

[0072] S1043, using a coating device to evenly coat the liquid composite dielectric layer 300 material on the surface of the metal contact layer 200 facing away from the battery layer 100, and then performing a drying process to solidify the liquid composite dielectric layer 300.

[0073] The coating device may be a spin coating device or a spray coating device.

[0074] As an alternative implementation, the composite dielectric layer 300 may be formed on the surface of the metal contact layer 200 facing away from the battery layer 100 by using a vapor deposition process.

[0075] The thickness of the composite dielectric layer 300 is generally between 10-100 nm (nanometers). If the thickness of the composite dielectric is greater than 100 nm, it is difficult for the composite dielectric layer 300 to form a good cross-sectional contact with the metal contact layer 200 due to the excessive thickness of the composite dielectric layer 300. If the thickness of the composite layer is less than 10 nm, the insulation of the composite dielectric layer 300 cannot meet the requirements of the TOPCon battery.

[0076] A composite dielectric layer 300 is formed on the surface of the metal contact layer 200 facing away from the boron-doped layer 106 to improve the mechanical strength and stability of the metal contact layer 200 and reduce the impact of the external environment on the metal contact layer 200 and the battery layer 100, thereby further reducing the interface peeling between the passivation layer and the boron-doped layer 106 and the first passivation layer 107.

[0077] S105, heat-treating the battery layer 100, the metal contact layer 200 and the composite layer under a nitrogen or argon atmosphere, wherein the heat-treating temperature is 350° C.-500° C. and the heat-treating time is 10-120 min.

[0078] Specifically, when silver is used as the metal contact layer 200, the temperature of the heat treatment is 400°C-450°C. When aluminum (Al) or copper (Cu) is used, the temperature of the heat treatment is 350°C-400°C to avoid excessive diffusion or oxidation of the metal. The time of the heat treatment depends on the temperature setting and the reactivity of the material. The time of the heat treatment needs to ensure sufficient reaction without causing excessive degradation of the material; the heat treatment process needs to be carried out in an inert atmosphere (such as nitrogen or argon) to prevent oxidation or unnecessary chemical reactions; during the heat treatment process, the heating rate and cooling rate are controlled to be less than 10°C / min to avoid temperature changes causing material stress or structural damage.

[0079] Through heat treatment, the metal contact layer 200 and the composite dielectric layer 300 are chemically bonded, so that a good interface bonding is formed between the metal contact layer 200 and the composite dielectric layer 300, and the stability of the metal contact layer 200 and the composite dielectric layer 300 is improved. In addition, defects in the composite dielectric layer 300 can be reduced, and the performance and reliability of TOPCon can be improved.

[0080] S106, performing pressure treatment on the battery layer 100, the metal contact layer 200 and the composite layer, wherein the pressure treatment temperature is 150°C, the pressure is 100-500 MPa, and the pressure treatment time is 4-300 s.

[0081] Specifically, the pressure during the pressure treatment process can be adjusted according to the material properties of the composite dielectric layer 300 and the battery structure. If the pressure is greater than 500MPa, it is easy to cause damage to the TOPCon battery structure. If the pressure treatment time is less than 4s (seconds), there is not enough time to promote close bonding between the layers. If the pressure treatment time is greater than 300s, it is easy to waste time, resulting in low efficiency of the pressure treatment. When performing pressure treatment, the temperature of the pressure treatment is from room temperature to 150°C to maintain the stability of the material and avoid possible thermal damage. During the pressure treatment process, pressure should be evenly applied to the entire battery surface to ensure consistent bonding in all areas and avoid excessive local stress. Through pressure treatment, the metal contact layer 200 and the composite dielectric layer 300 form a tighter assembly.

[0082] S107, plasma cleaning the battery layer 100, the metal contact layer 200 and the composite layer.

[0083] S108, such as Figure 4 As shown, the first electrode 400 is printed on the surface of the composite dielectric layer 300 away from the metal layer by screen printing, and sintering is performed after printing, the sintering temperature is 760-800°C, and the sintering time is 20-40s. The second electrode 101 is printed on the surface of the second passivation layer 102 away from the phosphorus-doped polysilicon by screen printing, and sintering is performed after printing, the sintering temperature is 760-800°C, and the sintering time is 20-40s. The materials of the first electrode 400 and the second electrode 101 are both silver-copper alloy.

[0084] In a second aspect, the present invention provides a TOPCon battery, such as Figure 4As shown, the TOPCon battery preparation method described above is used to obtain the battery. It includes a second electrode 101, a second passivation layer 102, a phosphorus-doped polysilicon layer 103, a tunneling oxide layer 104, an N-type silicon substrate 105, a boron-doped layer 106, a first passivation layer 107, a metal contact layer 200, a composite dielectric layer 300 and a first electrode 400, wherein the boron-doped layer 106 is located on the front surface of the N-type silicon substrate 105, the tunneling oxide layer 104 is located on the back surface of the N-type silicon substrate 105, the first passivation layer 107 is located on the side surface of the boron-doped layer 106 away from the N-type silicon substrate 105, and the phosphorus-doped polysilicon layer 103 is located on the tunneling oxide layer 104. The surface of the tunnel oxide layer 104 is away from the N-type substrate layer, the second passivation layer 102 is located on the surface of the phosphorus-doped layer away from the tunnel oxide layer 104, the metal contact layer 200 is located on the surface of the first passivation layer 107 away from the boron-doped layer 106, the composite dielectric layer 300 is located on the surface of the metal contact layer 200 away from the first passivation layer 107, the first electrode 400 is located on the surface of the composite dielectric layer 300 away from the metal contact layer 200, and the second electrode 101 is located on the surface of the second passivation layer 102 away from the phosphorus-doped polysilicon. The TOPCon cell reduces the interface peeling between the passivation layer and the boron-doped layer 106 and the first passivation layer 107, thereby extending the life of the TOPCon cell.

[0085] 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.

[0086] 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 TOPCon battery, characterized in that: include: forming a battery layer (100), wherein the battery layer (100) comprises a boron-doped layer (106) and a first passivation layer (107) located on a surface of one side of the boron-doped layer (106); Cleaning and etching the surface of the first passivation layer (107) on one side facing away from the boron-doped layer (106); Using a laser enhanced contact optimization process to form a metal contact layer (200) on a surface of the first passivation layer (107) that is away from the boron doped layer (106); forming a composite dielectric layer (300) on a surface of the metal contact layer (200) facing away from the battery layer (100); A first electrode (400) is formed on a surface of the composite dielectric layer (300) that is away from the metal contact layer (200).

2. The method for preparing a TOPCon battery according to claim 1, characterized in that: The cleaning process includes ultrasonic cleaning, chemical cleaning, and plasma cleaning; The etching process includes ion etching and wet etching.

3. The method for preparing a TOPCon battery according to claim 2, characterized in that: After forming a metal contact layer (200) on a surface of the first passivation layer (107) facing away from the boron-doped layer (106) by using a laser enhanced contact optimization process, and before forming a composite dielectric layer (300) on a surface of the metal contact layer (200) facing away from the battery layer (100), the method further comprises: A cleaning process is performed on a surface of the metal contact layer (200) that is away from the battery layer (100).

4. The method for preparing a TOPCon battery according to any one of claims 1 to 3, characterized in that: After forming a composite dielectric layer (300) on a surface of the metal contact layer (200) facing away from the battery layer (100), and before forming a first electrode (400) on a surface of the composite dielectric layer (300) facing away from the metal contact layer (200), the method further comprises: Under nitrogen or argon atmosphere conditions, the battery layer (100), the metal contact layer (200) and the composite layer are heat treated, wherein the heat treatment temperature is 350° C.-500° C. and the heat treatment time is 10-120 min.

5. The method for preparing a TOPCon battery according to claim 4, characterized in that: After the heat treatment, the method further comprises: The battery layer (100), the metal contact layer (200) and the composite layer are subjected to pressure treatment, wherein the pressure treatment temperature is 150° C., the pressure is 100-500 MPa, and the pressure treatment time is 4-300 s.

6. The method for preparing a TOPCon battery according to claim 5, characterized in that: After the pressure treatment, the battery layer (100), the metal contact layer (200) and the composite layer are plasma cleaned.

7. The method for preparing a TOPCon battery according to claim 1, characterized in that: The thickness of the metal contact layer (200) is 50nm-300nm, and the thickness of the composite dielectric layer (300) is 10-100nm.

8. The method for preparing a TOPCon battery according to claim 1, characterized in that: The material of the metal contact layer (200) includes one or more of silver, aluminum, copper, and gold, and the composite dielectric layer (300) includes one or more of aluminum oxide, silicon oxide, and barium titanate.

9. The method for preparing a TOPCon battery according to claim 1, characterized in that: The battery layer (100) comprises a second electrode (101), a second passivation layer (102), a phosphorus-doped polysilicon layer (103), a tunneling oxide layer (104), an N-type silicon substrate (105), a boron-doped layer (106), and a first passivation layer (107) which are stacked in sequence.

10. A TOPCon battery, characterized in that: The TOPCon battery is prepared by the TOPCon battery preparation method described in any one of claims 1 to 9.

Images