Sintering method of crystalline silicon solar cell, crystalline silicon solar cell and photovoltaic system

Abstract

The invention provides a crystalline silicon solar cell sintering method, a crystalline silicon solar cell and a photovoltaic system, and relates to the technical field of crystalline silicon solar cells. The sintering method of the crystalline silicon solar cell comprises the following steps: preparing a metal grid line on the surface of the crystalline silicon solar cell, and drying and curing the metal grid line to obtain a target cell; sequentially carrying out sintering treatment, light injection treatment and laser sintering treatment on the target battery piece; the temperature peak value of sintering treatment is 850-900 DEG C; the temperature peak value of the light injection treatment is 650-700 DEG C; the silver content of the silver paste used by the main grid line is lower than that of the silver paste used by the fine grid line. The main grid lines are matched with low-silver slurry, the temperature peak value of sintering treatment and the temperature peak value of light injection treatment are controlled, and laser sintering treatment is matched, so that the recrystallization effect of silver particles can be optimized, meanwhile, lattice defects in a silicon wafer can be effectively passivated, formation of high-quality ohmic contact can be promoted, the consumption of silver can be reduced, and the service life of the silicon wafer can be prolonged. And the battery production cost is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon solar cells, and in particular to a sintering method for a crystalline silicon solar cell, a crystalline silicon solar cell and a photovoltaic system. Background Art

[0002] Crystalline silicon solar cells are one of the most common and widely used types of solar cells on the market. Crystalline silicon solar cells have attracted attention for their high energy conversion efficiency, good stability and long service life. In crystalline silicon solar cells, the cost of photovoltaic silver paste accounts for about 10% of the total production cost of the battery. In the screen printing process of crystalline silicon solar cells, the height of the main grid paste electrode (main grid line) after printing is 5μm~15μm, and the width is between 30μm~60μm. The main grid line in crystalline silicon solar cells mainly plays the role of welding and connecting fine grid lines to collect current. Therefore, the cost of the main grid line accounts for a high proportion of the total cost of photovoltaic silver paste.

[0003] At present, under the conventional sintering process, although the main grid paste with low silver content can effectively reduce the production cost of the battery, the reduction in silver content makes it impossible for the metal grid line to maintain good conductivity, resulting in an increase in the contact resistance of the battery cell, thereby reducing the photoelectric conversion efficiency of the solar cell.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a sintering method for a crystalline silicon solar cell, a crystalline silicon solar cell and a photovoltaic system, which matches a low-silver-containing slurry to the main grid line, controls the temperature peak of the sintering treatment and the temperature peak of the light injection treatment, and then cooperates with laser sintering treatment to effectively burn off the organic solvent and adhesive in the low-silver-containing slurry, thereby optimizing the recrystallization effect of silver particles, improving the contact performance of silver particles, and significantly reducing the contact resistance. At the same time, it can effectively passivate the lattice defects inside the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts. On the premise of ensuring the photoelectric conversion efficiency, the silver consumption is effectively reduced, thereby effectively reducing the battery production cost.

[0006] To achieve the above objectives, this application adopts the following technical solutions: A sintering method for a crystalline silicon solar cell, comprising: Prepare metal grid lines on the surface of a crystalline silicon solar cell, dry and solidify the metal grid lines to obtain a target cell; The target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence; the temperature peak of the sintering treatment is 850-900° C.; the temperature peak of the light injection treatment is 650-700° C.; Wherein, the metal grid lines include fine grid lines and main grid lines; the silver content of the silver paste used for the main grid lines is lower than the silver content of the silver paste used for the fine grid lines.

[0007] In some implementation methods, the mass percentage of silver in the silver paste used for the main grid lines is 65-70%; the mass percentage of silver in the silver paste used for the fine grid lines is 90-95%.

[0008] In some embodiments, the peak temperature of the sintering process is 870-900°C.

[0009] In some embodiments, the sintering treatment method includes: the target battery cell is fed into a sintering furnace, and sequentially passes through a drying zone, a binder removal zone, a pre-sintering zone, a sintering zone, and a cooling zone of the sintering furnace; Wherein, the length of the drying zone is 200-400 cm, and the temperature is set at 200-350°C; The length of the debinding zone is 50-200 cm, and the temperature is set at 200-400° C. The length of the pre-sintering zone is 100-300 cm, and the temperature is set at 400-600° C.; The length of the sintering zone is 100-400 cm, and the temperature is set at 600-950° C.; The length of the cooling zone is 100-450 cm, and the temperature is set at 300-950° C.

[0010] In some embodiments, the peak temperature of the light injection process is 680-700°C.

[0011] In some embodiments, the method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection zone for light injection treatment; the length of the light injection zone is 600 to 800 cm, and the temperature is set at 530 to 670°C; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 30 to 50 suns.

[0012] In some embodiments, the laser sintering method includes: using laser to irradiate the metal grid line and loading a bias voltage of 15~35V on the metal grid line to sinter the metal grid line; the laser output power is 15~50w, and the laser processing time is 0.8~1.5s.

[0013] In some embodiments, the target cell passes through a sintering zone and a light injection zone in sequence along a specific direction through a transmission device, the target cell undergoes the sintering treatment in the sintering zone, and the target cell undergoes the light injection treatment in the light injection zone; the transmission speed of the transmission device is 15~25m / min.

[0014] The present application also provides a crystalline silicon solar cell, and the metal grid lines of the crystalline silicon solar cell are prepared by the above-mentioned sintering method.

[0015] The present application also provides a photovoltaic system, comprising the above-mentioned crystalline silicon solar cell.

[0016] In the technical solution of the present application, the main grid line is matched with a low-silver content slurry, the temperature peak of the sintering treatment and the temperature peak of the light injection treatment are controlled, and then combined with laser sintering treatment, the organic solvent and adhesive in the low-silver content slurry can be effectively burned off, which can optimize the recrystallization effect of silver particles, improve the contact performance of silver particles, and significantly reduce the contact resistance. At the same time, it can effectively passivate the internal lattice defects of the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts. On the premise of ensuring the photoelectric conversion efficiency, the silver consumption is effectively reduced, thereby effectively reducing the battery production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application. Figure 1 This is a PL analysis chart of the solar cell prepared in Example 3 of the present application.

[0018] Figure 2 This is a PL analysis chart of the solar cell prepared in Comparative Example 3 of the present application.

[0019] Figure 3 This is a PL analysis chart of the solar cell prepared in Comparative Example 4 of the present application. DETAILED DESCRIPTION

[0020] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0021] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0022] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0025] The embodiments of the present application aim to provide a sintering method for a crystalline silicon solar cell, a crystalline silicon solar cell and a photovoltaic system, which match a low-silver-containing slurry to a main grid line, and effectively burn out organic solvents and adhesives in the low-silver-containing slurry by controlling the temperature peak of the sintering process and the temperature peak of the light injection process, thereby optimizing the recrystallization effect of silver particles, improving the contact performance of silver particles, and significantly reducing contact resistance. At the same time, it can effectively passivate the lattice defects inside the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts, effectively reducing the consumption of silver while ensuring the photoelectric conversion efficiency, and thereby effectively reducing the production cost of the battery.

[0026] The present application provides a sintering method for a crystalline silicon solar cell, comprising: Prepare metal grid lines on the surface of a crystalline silicon solar cell, dry and solidify the metal grid lines to obtain a target cell; The target cell is subjected to a sintering process, a light injection process, and a laser sintering process in sequence; the temperature peak of the sintering process is 850-900°C (for example, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C); the temperature peak of the light injection process is 650-700°C (for example, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C); Wherein, the metal grid lines include fine grid lines and main grid lines; the silver content of the silver paste used for the main grid lines is lower than the silver content of the silver paste used for the fine grid lines.

[0027] In an embodiment of the present application, the method for preparing the metal grid lines can be selected from one or more of screen printing, laser transfer, and steel plate printing. The slurry used to prepare the metal grid lines is a silver paste. The metal grid lines can be prepared on the front or back of the crystalline silicon solar cell, or on both the front and back of the crystalline silicon solar cell. The metal grid lines can be prepared as needed and then sent to the sintering process. In an embodiment of the present application, the purpose of effectively reducing the consumption of silver is achieved mainly by reducing the silver content of the silver paste used for the main grid lines. It should be noted that the silver content of the silver paste used for the fine grid lines is the same as that of the traditional process, and the silver content of the silver paste used for the main grid lines is lower than that of the silver paste used for the fine grid lines.

[0028] In the embodiment of the present application, the purpose of drying after preparing the metal grid lines on the surface of the crystalline silicon solar cell is to volatilize part of the organic solvent in the silver paste, so that the metal grid lines are close to or reach a solid state, and the target cell is obtained, and then the metal grid lines are sintered. The drying step is only to remove part of the organic solvent, so the temperature of the drying step can be set according to the actual situation, as long as it can volatilize part of the organic solvent in the silver paste.

[0029] In the embodiment of the present application, the main grid line is matched with a low-silver content paste. By controlling the temperature peak of the sintering process and the temperature peak of the light injection process, the organic solvent and the adhesive in the low-silver content paste are effectively burned out, which can optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, and significantly reduce the contact resistance. At the same time, it can effectively passivate the internal lattice defects of the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts. On the premise of ensuring the photoelectric conversion efficiency, the silver consumption is effectively reduced, thereby effectively reducing the production cost of the battery.

[0030] In an optional embodiment, the mass percentage of silver in the silver paste used for the main grid line is 65~70% (for example, 65%, 66%, 67%, 68%, 69%, 70%); the mass percentage of silver in the silver paste used for the fine grid line is 90~95% (for example, 90%, 91%, 92%, 93%, 94%, 95%).

[0031] In the embodiment of the present application, the silver content in the silver paste used for the main grid line is continuously reduced, which can certainly continuously reduce the production cost of the battery, but too low a silver content in the main grid line will reduce the photoelectric conversion efficiency. Therefore, the silver content in the silver paste used for the fine grid line and the main grid line is reasonably controlled, which can not only effectively reduce the production cost of the battery, but also further improve the photoelectric conversion efficiency of the solar cell. In addition, the mass percentage of silver in the silver paste specifically refers to the content of silver powder, and the purity of the silver powder is required to be above 99.99%, that is, the mass percentage of impurities in the silver powder is below 0.01%.

[0032] In an optional embodiment, the peak temperature of the sintering treatment is 870-900°C (for example, 870°C, 880°C, 890°C, 900°C). The peak temperature of the sintering treatment refers to the highest temperature point reached during the sintering process, that is, the peak temperature is the highest point on the sintering curve. The peak temperature of the sintering treatment can affect the phase change, growth and pore closure of the silver particles. Optimizing the peak temperature of the sintering treatment can optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, significantly reduce the contact resistance, and further improve the photoelectric conversion efficiency of the solar cell.

[0033] In an optional embodiment, the sintering treatment method includes: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 200-400 cm (for example, 200 cm, 250 cm, 300 cm, 350 cm, 400 cm), and the temperature is set at 200-350°C (for example, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C); The length of the debinding zone is 50-200 cm (for example, 50 cm, 100 cm, 150 cm, 200 cm), and the temperature is set at 200-400°C (for example, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C); The length of the pre-sintering zone is 100-300 cm (e.g., 100 cm, 150 cm, 200 cm, 250 cm, 300 cm), and the temperature is set at 400-600° C. (e.g., 400° C., 450° C., 500° C., 550° C., 600° C.); The sintering zone has a length of 100-400 cm (e.g., 100 cm, 150 cm, 200 cm, 250 cm, 300 cm, 350 cm, 400 cm), and a temperature set at 600-950° C. (e.g., 600° C., 650° C., 700° C., 750° C., 800° C., 850° C., 900° C., 950° C.); The length of the cooling zone is 100~450cm (for example, 100cm, 150cm, 200cm, 250cm, 300cm, 350cm, 400cm, 450cm), and the temperature is set at 300~950℃ (for example, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃).

[0034] In the embodiments of the present application, the process parameters of each sintering zone of the sintering furnace are optimized. On the one hand, the organic solvent and adhesive in the low-silver-containing slurry can be further removed. On the other hand, the recrystallization effect of the silver particles can be further optimized, the contact performance of the silver particles can be improved, the contact resistance can be significantly reduced, and the internal lattice defects of the silicon wafer can be effectively passivated. The defect suppression is obvious, thereby promoting the formation of high-quality ohmic contact, and further improving the photoelectric conversion efficiency of the solar cell.

[0035] In an optional embodiment, the temperature peak of the light injection treatment is 680-700°C (for example, 680°C, 685°C, 690°C, 695°C, 700°C). During light injection assisted sintering, the temperature peak of the light injection treatment is controlled, and the illumination and temperature peaks simultaneously affect the phase change, growth, and pore closure of the silver particles, further optimizing the recrystallization effect of the silver particles, improving the contact performance of the silver particles, significantly reducing the contact resistance, and further improving the photoelectric conversion efficiency of the solar cell.

[0036] In an optional embodiment, the method of light injection treatment includes: sending the target cell piece that has undergone sintering treatment into a light injection zone for light injection treatment; the length of the light injection zone is 600 to 800 cm, and the temperature is set at 530 to 670°C; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 30 to 50 suns.

[0037] In the embodiments of the present application, optimizing the process parameters of the light injection zone can further optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, significantly reduce the contact resistance, promote the formation of high-quality ohmic contact, and further improve the photoelectric conversion efficiency of the solar cell.

[0038] In an optional embodiment, the laser sintering method includes: using laser to irradiate the metal grid line and loading a bias voltage of 15~35V on the metal grid line to sinter the metal grid line; the laser output power is 15~50w, and the laser processing time is 0.8~1.5s.

[0039] In the embodiment of the present application, after sintering treatment and light injection treatment, laser sintering treatment is performed to optimize the laser sintering treatment process parameters, which plays a role in strengthening the sintering effect, can further improve the contact performance of silver particles, reduce contact resistance, and further improve the photoelectric conversion efficiency of solar cells.

[0040] In an optional embodiment, the target cell passes through a sintering zone and a light injection zone in sequence along a specific direction through a transmission device, the target cell undergoes the sintering treatment in the sintering zone, and the target cell undergoes the light injection treatment in the light injection zone; the transmission speed of the transmission device is 15~25m / min.

[0041] In the embodiment of the present application, the transmission speed is optimized to control the residence time of the target cell in each sintering area, which is convenient for burning out the organic solvent and adhesive in the low-silver-containing slurry, ensuring the recrystallization effect of the silver particles, and optimizing the sintering quality of the metal grid line, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0042] The following specific examples further illustrate the present application, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the methods, steps or conditions of the present application are within the scope of the present application.

[0043] Example 1 A method for preparing a TOPCon battery, comprising: (1) Cleaning and texturing: Clean the silicon wafer to remove the damage on the edge after cutting and surface impurities. Texturing treatment forms a surface pyramid structure to obtain a silicon wafer with a velvet surface.

[0044] (2) Boron diffusion: Boron is diffused into the silicon wafer with a velvet surface at a high temperature to form a PN junction, thereby obtaining a boron-diffused silicon wafer.

[0045] (3) Removal of BSG and alkali polishing: Use HF (hydrofluoric acid) solution to remove BSG (borosilicate glass) of the boron-diffused silicon wafer, and then perform an alkali polishing step to obtain an alkali-polished silicon wafer.

[0046] (4) Poly deposition: depositing an ultra-thin oxide layer and a polysilicon layer on the back side of the alkali-polished silicon wafer to obtain a silicon wafer having a polysilicon layer.

[0047] (5) Phosphorus diffusion and annealing: An N+ layer is formed on the back of the silicon wafer with the polysilicon layer, and phosphorus is doped to form a passivation contact structure to obtain a passivated silicon wafer. The passivated silicon wafer is annealed at a temperature of 900° C. for 2 minutes to obtain an annealed silicon wafer.

[0048] (6) Removal of PSG and RCA (Radio Corporation of America Clean) cleaning: The annealed silicon wafer is subjected to a PSG cleaning process and then to an RCA cleaning process to remove surface residues and obtain a cleaned cell.

[0049] (7) Passivation: depositing an aluminum oxide film layer on the front side of the cleaned cell to form a passivation layer, thereby obtaining a passivated cell.

[0050] (8) Silicon nitride film deposition: a silicon nitride film is deposited on the front surface of the passivated cell to obtain a cell with an anti-reflection film.

[0051] (9) Screen printing: 9.1) Print four layers of paste on the surface of the cell with the anti-reflection film by screen printing technology to form metal grid lines, dry at 80°C, solidify the metal grid lines, and obtain the target cell; specifically, first print a first layer of paste to form fine grid lines, which are responsible for collecting the current on the surface of the cell and transmitting it to the main grid lines; then print a second layer of paste to form fine grid lines, which are used to collect the current on the surface of the cell and improve the cell efficiency; then print a third layer of paste to form main grid lines, which are thicker and are responsible for collecting and transmitting the current from the fine grid lines to the outside of the cell; finally print a fourth layer of paste to form fine grid lines, which are used to collect the current on the surface of the cell and improve the cell efficiency; the mass percentage of silver in the silver paste used for the main grid lines (the third layer of paste) is 65%; the mass percentage of silver in the silver paste used for the fine grid lines (the first layer of paste, the second layer of paste, and the fourth layer of paste) is 90%.

[0052] 9.2) The target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, and the target cell is subjected to the sintering treatment in the sintering area and the light injection treatment in the light injection area; the transmission speed of the transmission device is 15m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 850℃; the peak temperature of the light injection treatment is 650℃; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 200 cm, and the temperature is set at 200°C; The length of the debonding zone is 50 cm, and the temperature is set at 200°C; The length of the pre-sintering zone is 100 cm, and the temperature is set at 400° C. The length of the sintering zone is 100 cm and the temperature is set at 600°C; The length of the cooling zone is 100 cm, and the temperature is set at 300°C.

[0053] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 600 cm, and the temperature is set at 530° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 30 suns.

[0054] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 15V on the metal grid line to sinter the metal grid line; the laser output power is 15W, and the laser processing time is 0.8s.

[0055] Example 2 The TOPCon battery of Example 2 was prepared by referring to the preparation method of Example 1, except that: Step (9) in Example 2 is: screen printing: 9.1) Print four layers of paste on the surface of the cell with the anti-reflection film by screen printing technology to form metal grid lines, dry at 80°C, solidify the metal grid lines, and obtain the target cell; specifically, first print a first layer of paste to form fine grid lines, which are responsible for collecting the current on the surface of the cell and transmitting it to the main grid lines; then print a second layer of paste to form fine grid lines, which are used to collect the current on the surface of the cell and improve the cell efficiency; then print a third layer of paste to form main grid lines, which are thicker and are responsible for collecting and transmitting the current from the fine grid lines to the outside of the cell; finally print a fourth layer of paste to form fine grid lines, which are used to collect the current on the surface of the cell and improve the cell efficiency; the mass percentage of silver in the silver paste used for the main grid lines (the third layer of paste) is 70%; the mass percentage of silver in the silver paste used for the fine grid lines (the first layer of paste, the second layer of paste, and the fourth layer of paste) is 95%.

[0056] 9.2) The target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, and the target cell is subjected to the sintering treatment in the sintering area and the light injection treatment in the light injection area; the transmission speed of the transmission device is 25m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 900℃; the peak temperature of the light injection treatment is 700℃; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 400 cm, and the temperature is set at 350°C; The length of the debinding zone is 200 cm, and the temperature is set at 400°C; The length of the pre-sintering zone is 300 cm, and the temperature is set at 600° C. The length of the sintering zone is 400 cm and the temperature is set at 950°C; The length of the cooling zone is 450 cm, and the temperature is set at 800°C.

[0057] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection zone for light injection treatment; the length of the light injection zone is 800 cm, and the temperature is set at 670° C.; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 50 suns.

[0058] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 35V on the metal grid line to sinter the metal grid line; the laser output power is 50W, and the laser processing time is 1.5s.

[0059] Example 3 The TOPCon battery of Example 3 was prepared by referring to the preparation method of Example 1, except that: Step (9) in Example 3 is: screen printing: 9.1) Print four layers of paste on the surface of the cell with the anti-reflection film by screen printing technology to form metal grid lines, dry at 80°C, solidify the metal grid lines, and obtain the target cell; specifically, first print a first layer of paste to form fine grid lines, which are responsible for collecting the current on the surface of the cell and transmitting it to the main grid lines; then print a second layer of paste to form fine grid lines, which are used to collect the current on the surface of the cell and improve the cell efficiency; then print a third layer of paste to form main grid lines, which are thicker and responsible for transmitting the current to the main grid lines. The current is collected from the fine grid lines and transmitted to the outside of the battery; finally, a fourth paste is printed to form fine grid lines to collect current on the surface of the battery and improve battery efficiency; the silver paste used for the main grid lines (the third paste) is a silver paste with a solid content of 85%, and the mass percentage of silver in the silver paste used for the main grid lines is 68%; the silver paste used for the fine grid lines is BSL paste (back silver paste), and the mass percentage of silver in the silver paste used for the fine grid lines (the first paste, the second paste, and the fourth paste) is 90%.

[0060] 9.2) The target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, and the target cell is subjected to the sintering treatment in the sintering area and the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870℃; the peak temperature of the light injection treatment is 680℃; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0061] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0062] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0063] Example 4 The TOPCon battery of Example 4 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 4 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 500 cm, and the temperature is set at 150°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0064] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0065] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0066] Example 5 The TOPCon battery of Example 5 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 5 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 250 cm, and the temperature is set at 450°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0067] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0068] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0069] Example 6 The TOPCon battery of Example 6 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 6 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 400 cm and the temperature is set at 650° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0070] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0071] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0072] Example 7 The TOPCon battery of Example 7 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 7 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 500 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0073] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0074] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0075] Example 8 The TOPCon battery of Example 8 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 8 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 70 cm, and the temperature is set at 450°C.

[0076] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0077] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0078] Example 9 The TOPCon battery of Example 9 was prepared according to the preparation method of Example 3, except that: Step 9.2) in Example 9 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0079] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection zone for light injection treatment; the length of the light injection zone is 500 cm, and the temperature is set at 690° C.; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 60 suns.

[0080] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0081] Example 10 The TOPCon battery of Example 10 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 10 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0082] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection zone for light injection treatment; the length of the light injection zone is 900 cm, and the temperature is set at 500° C.; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 20 suns.

[0083] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0084] Embodiment 11 The TOPCon battery of Example 11 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 11 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0085] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0086] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 10V on the metal grid line to sinter the metal grid line; the laser output power is 60W, and the laser processing time is 1.2s.

[0087] Example 12 The TOPCon battery of Example 12 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 12 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0088] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0089] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 40V on the metal grid line to sinter the metal grid line; the laser output power is 10W, and the laser processing time is 1.2s.

[0090] Example 13 The TOPCon battery of Example 13 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 13 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 10m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0091] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0092] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0093] Embodiment 14 The TOPCon battery of Example 14 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Example 14 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 30m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0094] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0095] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0096] Comparative Example 1 The TOPCon battery of Comparative Example 1 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Comparative Example 1 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 750°C; the peak temperature of the light injection treatment is 600°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0097] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0098] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0099] Comparative Example 2 The TOPCon battery of Comparative Example 2 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Comparative Example 2 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 950°C; the peak temperature of the light injection treatment is 750°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0100] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0101] The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 25V on the metal grid line to sinter the metal grid line; the laser output power is 30W, and the laser processing time is 1.2s.

[0102] Comparative Example 3 The TOPCon battery of Comparative Example 3 was prepared by referring to the preparation method of Example 3, except that: Step 9.2) in Comparative Example 3 is: the target cell passes through the sintering area and the light injection area in sequence along a specific direction through a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; the transmission speed of the transmission device is 20m / min; the target cell is subjected to sintering treatment and light injection treatment in sequence to prepare a TOPCon cell. The peak temperature of the sintering treatment is 870°C; the peak temperature of the light injection treatment is 680°C; the metal grid lines include fine grid lines and main grid lines; The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 300 cm, and the temperature is set at 250°C; The length of the debinding zone is 100 cm, and the temperature is set at 300°C; The length of the pre-sintering zone is 200 cm, and the temperature is set at 500° C. The length of the sintering zone is 300 cm and the temperature is set at 750°C; The length of the cooling zone is 250 cm, and the temperature is set at 450°C.

[0103] The method of light injection treatment includes: sending the target cell piece that has been sintered into a light injection area for light injection treatment; the length of the light injection area is 700 cm, and the temperature is set at 580° C.; the light source of the light injection area is LED lighting, and the light injection radiation intensity is 40 suns.

[0104] Comparative Example 4 The TOPCon battery of Comparative Example 4 was prepared by referring to the preparation method of Example 3, except that: Step (9) in Comparative Example 4 is: printing four layers of paste on the surface of the cell with the anti-reflection film by screen printing technology to form metal grid lines, drying at 80°C to solidify the metal grid lines, and obtaining the target cell; specifically, first printing a first layer of paste to form fine grid lines, which are responsible for collecting the current on the cell surface and transmitting it to the main grid lines; then printing a second layer of paste to form fine grid lines, which are used to collect the current on the cell surface and improve the cell efficiency; then printing a third layer of paste to form the main grid lines, which are thicker and are responsible for collecting and transmitting the current from the fine grid lines to the outside of the cell; finally printing a fourth layer of paste to form fine grid lines, which are used to collect the current on the cell surface and improve the cell efficiency; the silver paste used for the main grid lines and the silver paste used for the fine grid lines are both BSL pastes (back silver pastes), that is, the mass percentage of silver in the first, second, third and fourth pastes is 90%. Finally, the target cell is sintered according to the conventional sintering process.

[0105] The TOPCon cells prepared in the above examples and comparative examples were subjected to photoelectric tests, and the test results are shown in Table 1 below.

[0106] Table 1 (Sintering efficiency improvement data of Examples 1-14 and Comparative Examples 1-3 were obtained by taking Comparative Example 4 as a reference.)

[0107] In the above table, Qty (pieces) refers to the number of batteries, that is, 20 batteries are taken for photoelectric testing in each embodiment, and the average value is taken. The test data is shown in Table 1 above. Eta refers to the photoelectric conversion efficiency of the battery, Voc refers to the open circuit voltage of the solar cell, Isc refers to the short circuit current, FF refers to the fill factor, and unit consumption refers to the consumption of silver in the third slurry. Taking Example 1 as an example, Eta (%) in the above table = -0.001, which specifically means that the photoelectric conversion efficiency of the battery in Example 1 decreases by 0.001% relative to Comparative Example 4; FF (%) = 0.07, which specifically means that the fill factor of the battery in Example 1 increases by 0.07% relative to Comparative Example 4; Voc (V) = -0.0002, which specifically means that the open circuit voltage of the battery in Example 1 decreases by 0.0002V relative to Comparative Example 4; Unit consumption (g) = -0.003, which specifically means that the consumption of silver in the third slurry in Example 1 decreases by 0.003g relative to Comparative Example 4.

[0108] Referring to the detection data of the above-mentioned Examples 1-14, it can be known that for the main grid line matching low-silver content paste, by controlling the temperature peak of the sintering treatment and the temperature peak of the light injection treatment, the organic solvent and the adhesive in the low-silver content paste can be effectively burned off, which can optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, and significantly reduce the contact resistance. At the same time, it can effectively passivate the internal lattice defects of the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts. On the premise of ensuring the photoelectric conversion efficiency, the silver consumption is effectively reduced, thereby effectively reducing the production cost of the battery.

[0109] With reference to the detection data of the above-mentioned Example 3 and Examples 4-8, it can be known that optimizing the process parameters of each sintering zone of the sintering furnace can, on the one hand, further remove the organic solvent and adhesive in the low-silver-containing slurry, and on the other hand, further optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, significantly reduce the contact resistance, and effectively passivate the internal lattice defects of the silicon wafer, with obvious defect suppression, thereby promoting the formation of high-quality ohmic contact, and further improving the photoelectric conversion efficiency of the solar cell.

[0110] Referring to the detection data of the above-mentioned Example 3 and Examples 9-10, it can be seen that optimizing the process parameters of the light injection zone can further optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, significantly reduce the contact resistance, promote the formation of high-quality ohmic contact, and further improve the photoelectric conversion efficiency of the solar cell.

[0111] With reference to the detection data of the above-mentioned Example 3 and Examples 11-12, it can be known that after sintering treatment and light injection treatment, laser sintering treatment is performed to optimize the laser sintering treatment process parameters, which plays a role in strengthening the sintering effect, can further improve the contact performance of silver particles, reduce contact resistance, and further improve the photoelectric conversion efficiency of solar cells.

[0112] With reference to the detection data of the above-mentioned Example 3 and Examples 13-14, it can be seen that optimizing the transmission speed plays a role in controlling the residence time of the target battery cell in each sintering area, which facilitates the burning of organic solvents and adhesives in the low-silver-containing slurry, ensures the recrystallization effect of the silver particles, and can optimize the sintering quality of the metal grid line, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0113] Figure 1 This is a PL (photoluminescence) analysis diagram of the solar cell prepared in Example 3 of the present application; Figure 2 This is a PL (photoluminescence) analysis diagram of the solar cell prepared in Comparative Example 3 of the present application; Figure 3 This is a PL (photoluminescence) analysis diagram of the solar cell prepared in Comparative Example 4 of this application. Figure 1-Figure 3 , analysis shows that the solar cell prepared in Example 3 ( Figure 1), which is brighter than the solar cell prepared in Comparative Example 3 and the solar cell prepared in Comparative Example 4; it can be seen that the solar cell prepared by the method of the embodiment can effectively passivate the lattice defects inside the silicon wafer while ensuring the photoelectric conversion efficiency, and the defects are significantly suppressed.

[0114] In summary, the present application matches the main grid line with a low-silver content paste, and effectively burns out the organic solvent and adhesive in the low-silver content paste by controlling the temperature peak of the sintering treatment and the temperature peak of the light injection treatment, which can optimize the recrystallization effect of the silver particles, improve the contact performance of the silver particles, and significantly reduce the contact resistance. At the same time, it can effectively passivate the internal lattice defects of the silicon wafer, and the defects are significantly suppressed, thereby promoting the formation of high-quality ohmic contacts. On the premise of ensuring the photoelectric conversion efficiency, it effectively reduces the consumption of silver, thereby effectively reducing the production cost of the battery.

[0115] The present application also provides a crystalline silicon solar cell (not shown), and the metal grid lines of the crystalline silicon solar cell are prepared by the above-mentioned sintering method.

[0116] The embodiment of the present application can provide a photovoltaic system, including the crystalline silicon solar cell in any of the above embodiments. The advantages of the above-mentioned crystalline silicon solar cell are also possessed by the photovoltaic system, which will not be repeated here. The above-mentioned photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0117] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0118] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0119] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0120] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A sintering method for a crystalline silicon solar cell, characterized in that: include: Prepare metal grid lines on the surface of a crystalline silicon solar cell, dry and solidify the metal grid lines to obtain a target cell; The target cell is subjected to sintering treatment, light injection treatment, and laser sintering treatment in sequence; the temperature peak of the sintering treatment is 850-900° C.; the temperature peak of the light injection treatment is 650-700° C.; Wherein, the metal grid lines include fine grid lines and main grid lines; the silver content of the silver paste used for the main grid lines is lower than the silver content of the silver paste used for the fine grid lines.

2. The method according to claim 1, characterized in that The mass percentage of silver in the silver paste used for the main grid lines is 65-70%; the mass percentage of silver in the silver paste used for the fine grid lines is 90-95%.

3. The method according to claim 1, characterized in that: The peak temperature of the sintering process is 870-900°C.

4. The method according to any one of claims 1 to 3, characterized in that The sintering treatment method comprises: the target battery cell is sent into a sintering furnace, and sequentially passes through a drying area, a binder removal area, a pre-sintering area, a sintering area, and a cooling area of ​​the sintering furnace; Wherein, the length of the drying zone is 200-400 cm, and the temperature is set at 200-350°C; The length of the debinding zone is 50-200 cm, and the temperature is set at 200-400° C. The length of the pre-sintering zone is 100-300 cm, and the temperature is set at 400-600° C.; The length of the sintering zone is 100-400 cm, and the temperature is set at 600-950° C.; The length of the cooling zone is 100-450 cm, and the temperature is set at 300-950° C.

5. The method according to claim 1, characterized in that: The peak temperature of the light injection treatment is 680-700°C.

6. The method according to claim 1, characterized in that The method of light injection treatment includes: sending the target battery cell that has been sintered into a light injection zone for light injection treatment; the length of the light injection zone is 600-800 cm, and the temperature is set at 530-670°C; the light source of the light injection zone is LED lighting, and the light injection radiation intensity is 30-50 suns.

7. The method according to claim 1, characterized in that The laser sintering method includes: irradiating the metal grid line with laser, and loading a bias voltage of 15-35V on the metal grid line to sinter the metal grid line; the laser output power is 15-50W, and the laser processing time is 0.8-1.5s.

8. The method according to claim 1, characterized in that: The target cell passes through the sintering area and the light injection area in sequence along a specific direction by a transmission device, the target cell is subjected to the sintering treatment in the sintering area, and the target cell is subjected to the light injection treatment in the light injection area; The transmission speed of the transmission device is 15-25 m / min.

9. A crystalline silicon solar cell, characterized in that: The metal grid lines of the crystalline silicon solar cell are prepared by the sintering method according to any one of claims 1 to 8.

10. A photovoltaic system, characterized in that: Comprising the crystalline silicon solar cell as claimed in claim 9.

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