A sintering furnace and sintering method for TOPCon cells

Abstract

The application belongs to the technical field of solar cell production and manufacturing, and specifically discloses a sintering furnace and a sintering method for TOPCon cells. The sintering furnace comprises a furnace body and a conveying belt arranged along the axial direction of the furnace body. The furnace body is sequentially divided into a sintering zone and a cooling zone in communication according to a process flow. The length of the sintering zone is 140-260 cm, and the sintering zone is divided into 4-6 sintering sub-zones according to a temperature gradient. Infrared heating lamp tubes are arranged at the upper end and the lower end of each sintering sub-zone. The number of infrared heating lamp tubes at the lower end of at least two sintering sub-zones near the cooling zone is greater than the number of infrared heating lamp tubes at the upper end. The sintering furnace provided by the application has a simple structure, a short length, and saves space and energy consumption. The sintering method provided by the application is used for sintering treatment of a TOPCon cell precursor, and the yield rate and photoelectric conversion efficiency of the TOPCon cell are improved.

Description

Technical Field

[0001] This invention relates to the field of solar cell manufacturing technology, specifically to a sintering furnace and sintering method for TOPCon cells. Background Technology

[0002] TOPCon cells, or Tunnel Oxide Passivated Contact cells, are a new type of passivated contact solar cell. Due to their high photoelectric conversion efficiency and the ability to use most current PERC process technologies, they have become the current trend in high-efficiency cell development.

[0003] The general production process of TOPCon batteries includes texturing, boron diffusion, back-side polishing, deposition of ultrathin oxide and polycrystalline silicon, phosphorus diffusion, plasma etching, decoating, alumina coating, PECVD front and back coating, printing, and sintering. The sintering process, as the final step in TOPCon battery production, primarily functions to sinter the metal paste printed on the front and back sides during the printing process, and to solidify all the preceding processes within the sintering stage. The sintering furnace, the site of the sintering process, typically includes a drying zone, a sintering zone, and a cooling zone. The drying and sintering zones are further divided into multiple sub-zones, with the sintering zone often containing around 10 sub-zones. The entire sintering furnace is approximately 10 meters long, exhibiting not only a complex structure and large volume but also significant space and energy consumption. Summary of the Invention

[0004] In view of this, the present invention provides a sintering furnace and sintering method for TOPCon batteries. The sintering furnace has a simple structure, short length, and saves space and energy consumption. By using the sintering method provided by the present invention to sinter the TOPCon battery precursor, the yield and photoelectric conversion efficiency of the TOPCon battery are improved.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a sintering furnace for TOPCon batteries, comprising a furnace body and a conveyor belt arranged along the axial direction of the furnace body. The furnace body is characterized in that it is sequentially divided into a sintering zone and a cooling zone according to the process flow sequence. The length of the sintering zone is 140-260 cm, and it is divided into 4-6 sintering sub-zones according to the temperature gradient. Each sintering sub-zone is provided with infrared heating lamps at its upper and lower ends. In at least two sintering sub-zones closer to the cooling zone, the number of infrared heating lamps at the lower end is greater than the number of infrared heating lamps at the upper end.

[0007] Compared to existing technologies, the sintering furnace for TOPCon batteries provided by this invention eliminates the drying zone, with a sintering zone length of only 140-260 cm. This results in a simpler structure, shorter length, and reduced space and energy consumption. By eliminating the drying zone, the furnace structure is simplified while maintaining the sintering effect on the TOPCon battery precursor. Furthermore, by ensuring that the number of infrared heating lamps at the lower end of at least two sintering sub-zones near the cooling zone is greater than the number at the upper end, the radiant heating temperature at the lower end of the sub-zone is higher than that at the upper end, thus meeting the different sintering temperature requirements of the front and back sides of the TOPCon battery precursor. Based on the above technical solution, the sintering zone is divided into 4-6 sintering sub-zones according to a temperature gradient, and the length of the sintering zone is limited. This makes the temperature more uniform within each sintering sub-zone, and the temperature settings within each sub-zone and the temperature span between each sub-zone more reasonable. This ensures both the sintering effect on the TOPCon battery precursor and reduces the space resource consumption of the sintering furnace. The TOPCon batteries prepared by the sintering furnace provided by this invention have improved yield and photoelectric conversion efficiency.

[0008] In some embodiments, the sintering zone is divided into four sintering sub-zones. The two sintering sub-zones closest to the cooling zone have a greater number of infrared heating lamps at their lower ends than at their upper ends. Specifically, the first sintering sub-zone has a length of 50–100 cm and a temperature set at 580°C–620°C; the second sintering sub-zone has a length of 50–100 cm and a temperature set at 630°C–670°C; the third sintering sub-zone has a length of 20–30 cm and a temperature set at 750°C–810°C; and the fourth sintering sub-zone has a length of 20–30 cm and a temperature set at 870°C–930°C. By defining four sintering sub-zones and specifying the length and adjustable temperature range of each sub-zone, the sintering effect of the sintering furnace on the TOPCon battery precursor is further ensured.

[0009] In some embodiments, the number of infrared heating lamps at both the upper and lower ends of the first and second sintering sub-regions is 5 to 7; the number of infrared heating lamps at the upper end of the third and fourth sintering sub-regions is 5 to 7, and the number of infrared heating lamps at the lower end is 7 to 9; wherein, the infrared heating lamps at both the upper and lower ends within the same sintering sub-region use the same power for radiant heating during the operation of the sintering furnace. By limiting the number of infrared heating lamps at the upper and lower ends, the heating effect of the sintering furnace on the TOPCon battery precursor is further guaranteed.

[0010] In some embodiments, the length of the cooling zone is 70-180cm, including a water-cooled zone and an air-cooled zone, wherein the length of the water-cooled zone is 20-30cm and the length of the air-cooled zone is 50-150cm.

[0011] In some embodiments, at least one air inlet pipe is provided at the upper and lower ends of each sintering sub-region; the sintering region is provided with at least two exhaust pipes.

[0012] A second aspect of the present invention provides a sintering method for a TOPCon battery, comprising the following steps: placing the TOPCon battery precursor to be sintered onto the conveyor belt of a sintering furnace; the TOPCon battery precursor is sintered sequentially through a sintering zone and a cooling zone to obtain a TOPCon battery;

[0013] The sintering zone includes 4 to 6 sintering sub-zones;

[0014] In at least two sintering sub-regions near the cooling zone, the sintering temperature of the back side of the TOPCon battery precursor is 15-20°C higher than that of the front side.

[0015] Compared to existing technologies, this invention sintersects the TOPCon battery precursor sequentially through a sintering zone and a cooling zone to produce the TOPCon battery. This process is faster, more efficient, and improves both the yield and photoelectric conversion efficiency of the produced TOPCon batteries. By setting 4 to 6 sintering sub-zones, both the sintering effect and efficiency are ensured. Furthermore, by setting at least two sintering sub-zones close to the cooling zone, the sintering temperature on the back side of the TOPCon battery precursor is 15 to 20°C higher than the front side, ensuring good ohmic contact on both the front and back sides. At high temperatures, a small number of silver particles penetrate the oxide tunneling layer through the pure silver paste on the back side, resulting in better charge collection and improved filling effect, thereby enhancing the photoelectric conversion efficiency of the TOPCon battery.

[0016] Optionally, the sintering zone includes four sintering sub-zones; the temperature of the first sintering sub-zone is 580℃~620℃, the temperature of the second sintering sub-zone is 630℃~670℃, the temperature of the third sintering sub-zone is 750℃~810℃, and the temperature of the fourth sintering sub-zone is 870℃~930℃; in the third and fourth sintering sub-zones, the sintering temperature at the lower end is 15~20℃ higher than the sintering temperature at the upper end.

[0017] Optionally, the silicon wafer is subjected to texturing, boron diffusion, back-side polishing, deposition of an ultrathin oxide layer and polysilicon, phosphorus diffusion, plasma etching, decoupling, alumina coating, PECVD front and back coating, and printing to obtain the TOPCon battery precursor with metal paste printed on both the front and back sides, wherein the front side is printed with aluminum-containing silver paste and the back side is printed with pure silver paste.

[0018] In some embodiments, the conveyor belt speed is 7500–8500 mm / min. By limiting the conveyor belt speed, it is ensured that the TOPCon battery precursor can be fully sintered without over-burning. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of the sintering furnace for TOPCon batteries in an embodiment of the present invention;

[0021] Among them, 10-sintering zone, 11-first sintering sub-zone, 12-second sintering sub-zone, 13-third sintering sub-zone, 14-fourth sintering sub-zone, 16-infrared heating lamp tube, 17-air inlet duct, 18-air outlet duct, 20-cooling zone. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] The sintering furnace provided by this invention is used for the sintering process of TOPCon battery precursors. The silicon wafer undergoes sequential processes including texturing, boron diffusion, back-side polishing, deposition of an ultrathin oxide layer and polycrystalline silicon, phosphorus diffusion, plasma etching, decoupling, alumina coating, PECVD front and back-side coating, and printing, resulting in a TOPCon battery precursor with metal paste printed on both sides. During the research and testing of TOPCon batteries, the inventors discovered that the performance of TOPCon batteries is not ideal when sintering is performed in a uniform temperature field.

[0024] Further analysis reveals that the main reason for the difference lies in the composition of the metal paste on the back and front of the TOPCon battery front substrate. The front of the TOPCon battery front substrate uses aluminum-containing silver paste, and due to the addition of aluminum, the eutectic point of the silicon-aluminum alloy is around 595℃. The back substrate, however, uses pure silver paste, and the eutectic point of the silicon-silver alloy is around 720℃. During sintering, aluminum can quickly penetrate into the silicon to form ohmic contacts. Therefore, the temperature required for the aluminum-containing silver paste to form ohmic contacts with the front boron diffusion layer during sintering is low. If the temperature is too high, aluminum will penetrate into the battery, causing over-burning, which increases contact recombination and reduces battery efficiency. Conversely, the back of the TOPCon battery front substrate uses pure silver paste, which requires a higher temperature to form ohmic contacts with the back phosphorus diffusion layer during sintering. If the temperature is too low, under-burning will occur, increasing contact resistance and reducing battery fill, thus affecting battery efficiency.

[0025] Existing sintering furnaces have multiple zones, including drying, sintering, and cooling zones, and the drying and sintering zones are further divided into several temperature zones, resulting in a complex structure. Furthermore, the temperature at the top and bottom of each temperature zone is the same, which cannot meet the different sintering temperature requirements of the different metal pastes on the front and back sides of the TOPCon battery precursor.

[0026] The TOPCon battery sintering furnace provided in this embodiment of the invention includes a furnace body and a conveyor belt arranged along the axial direction of the furnace body. The furnace body is characterized in that it is sequentially divided into a sintering zone 10 and a cooling zone 20 according to the process flow. The length of the sintering zone 10 is 140-260cm, and it is divided into 4-6 sintering sub-zones according to the temperature gradient. Each sintering sub-zone is provided with infrared heating lamps 16 at both the upper and lower ends. In at least two sintering sub-zones near the cooling zone 20, the number of infrared heating lamps at the lower end is greater than the number of infrared heating lamps at the upper end.

[0027] Existing sintering furnaces typically include a drying zone, a sintering zone, and a cooling zone arranged sequentially according to the process flow. The drying zone usually consists of 2-3 sections, with a controlled temperature of 350℃ to 450℃. Through extensive experimentation, the inventors discovered that omitting the drying zone in a traditional sintering furnace does not affect the sintering effect of TOPCon cells. Research revealed that this is primarily because TOPCon cells use an N-type substrate with an ultra-thin oxide layer and phosphorus-doped polycrystalline silicon for passivation on the back side. Only silver grid lines need to be printed on the back side, requiring a small amount of silver paste (only 0.05g-0.07g / piece). This invention has been verified through extensive experimentation. By adjusting the sintering process, the TOPCon cell precursor can be sintered directly without drying. The TOPCon cell sintering furnace provided by this invention includes a sintering zone and a cooling zone arranged sequentially according to the process flow, eliminating the drying zone. This simplifies the furnace structure while ensuring the sintering effect on the TOPCon cell precursor.

[0028] Secondly, existing sintering furnaces use the same temperature at both ends of each temperature zone, which cannot meet the different sintering temperature requirements of the different metal pastes on the front and back sides of the TOPCon battery precursor. Currently, the same sintering temperature is typically used for both the front and back sides of the TOPCon battery precursor, with the temperature set as a compromise between the front and back sides. This results in poor sintering performance and affects the battery's photoelectric conversion efficiency. Some studies have also attempted to sinter the front and back sides of the TOPCon battery precursor separately, requiring an additional sintering furnace. This not only increases equipment and space requirements and wastes energy but also easily leads to battery contamination, affecting sintering efficiency. The inventors discovered that if the temperature difference between the upper and lower heating surfaces is controlled by changing the power of the heating lamps, the infrared heating depth cannot guarantee the temperature difference between the front and back sides of the TOPCon battery precursor due to changes in the optimal matching wavelength of infrared radiation, resulting in poor sintering performance. This invention sets different numbers of infrared heating lamps 16 at the upper and lower ends of at least two sintering sub-zones near the cooling zone 20. By changing the distribution density of the infrared heating lamps 16 at the upper and lower ends of the sintering sub-zones, the different sintering temperature requirements of the different metal pastes on the front and back sides of the TOPCon battery precursor are met. The infrared heating lamp tube 16 heats the object by infrared radiation. During the sintering process, the radiation intensity received on the back side of the TOPCon battery front body is greater than that on the front side. Therefore, the temperature on the back side is higher than that on the front side. The method is simple and easy to operate.

[0029] Finally, existing sintering furnaces typically include around 10 temperature zones in their sintering zone to ensure the sintering effect of the TOPCon battery precursor. Through extensive experimentation, the inventors discovered that, based on the aforementioned technical solution, dividing the sintering zone into 4-6 sub-zones according to temperature gradients not only ensures the sintering effect of the TOPCon battery precursor but also achieves rational utilization of space and energy. Too few sub-zones can easily lead to uneven temperature distribution within the sintering zone and incomplete sintering of the TOPCon battery precursor. Furthermore, excessively large temperature ranges between sub-zones and rapid temperature changes between different sub-zones can negatively impact the sintering effect. Conversely, too many sub-zones would result in a waste of space and energy.

[0030] In some embodiments, the sintering zone 10 is divided into four sintering sub-zones; the number of infrared heating lamps at the lower end of the two sintering sub-zones near the cooling zone 20 is greater than the number of infrared heating lamps at the upper end; wherein, the length of the first sintering sub-zone 11 is 50-100cm, and the temperature is adjustable within the range of 580℃-620℃; the length of the second sintering sub-zone 12 is 50-100cm, and the temperature is adjustable within the range of 630℃-670℃; the length of the third sintering sub-zone 13 is 20-30cm, and the temperature is adjustable within the range of 750℃-810℃; the length of the fourth sintering sub-zone 14 is 20-30cm, and the temperature is adjustable within the range of 870℃-930℃.

[0031] In some embodiments, by limiting the number of upper and lower infrared heating lamps 16, the heating intensity and uniformity of the sintering furnace on the TOPCon battery precursor are further ensured, thereby further guaranteeing the sintering effect. The number of infrared heating lamps at both the upper and lower ends of the first sintering zone 11 and the second sintering zone 12 is 5 to 7; the number of upper infrared heating lamps at the upper end of the third sintering zone 13 and the fourth sintering zone 14 is 5 to 7, and the number of lower infrared heating lamps at the lower end is 7 to 9. The infrared heating lamps at both ends of the same sintering sub-zone use the same power for radiant heating during furnace operation. The number of lower infrared heating lamps in the third sintering zone 13 and the fourth sintering zone 14 is greater than the number of upper infrared heating lamps, which allows the lower heating temperature to be higher than the upper heating temperature, further ensuring the sintering effect of the TOPCon battery precursor.

[0032] This embodiment also provides a sintering method for a TOPCon battery, comprising the following steps: placing the TOPCon battery precursor to be sintered onto the conveyor belt of a sintering furnace; the TOPCon battery precursor is sintered sequentially through a sintering zone 10 and a cooling zone 20 to obtain a TOPCon battery; wherein, the sintering zone 10 includes 4 to 6 sintering sub-zones; in at least two sintering sub-zones near the cooling zone 20, the sintering temperature of the back side of the TOPCon battery precursor is 15 to 20°C higher than the sintering temperature of the front side.

[0033] Optionally, the sintering zone 10 includes four sintering sub-zones; the temperature of the first sintering sub-zone 11 is 580℃~620℃, the temperature of the second sintering sub-zone 12 is 630℃~670℃, the temperature of the third sintering sub-zone 13 is 750℃~810℃, and the temperature of the fourth sintering sub-zone 14 is 870℃~930℃; in the third and fourth sintering sub-zones, the sintering temperature at the lower end is 15~20℃ higher than the sintering temperature at the upper end.

[0034] Compared to existing sintering methods, this invention sintersects the TOPCon battery precursor sequentially through a sintering zone and a cooling zone to produce the TOPCon battery. This method is faster, more efficient, and improves both the yield and photoelectric conversion efficiency of the produced TOPCon batteries. By setting the sintering temperature of the back side of the TOPCon battery precursor 15-20°C higher than the front side in at least two sintering sub-regions near the cooling zone 20, the different sintering temperature requirements of the different metal pastes on the front and back sides of the TOPCon battery precursor are met. This ensures that good ohmic contact can be formed on both the front and back sides of the TOPCon battery precursor. At high temperatures, a small number of silver particles in the pure silver paste on the back side penetrate the oxide tunneling layer, resulting in better charge collection and improved filling, thus achieving better sintering results. Furthermore, by setting a temperature gradient in the two sintering sub-regions near the cooling zone 20, it is ensured that the glass in the metal paste softens sufficiently during sintering and burns through the surface SiN film. The silver in the metal paste enters the silicon to form a silver-silicon alloy, thereby improving the photoelectric conversion efficiency of the TOPCon battery.

[0035] The present invention will be described below with reference to some specific embodiments.

[0036] Figure 1 The TOPCon battery sintering furnace provided in this embodiment of the invention includes a furnace body and a conveyor belt arranged along the axial direction of the furnace body. The furnace body is divided into a sintering zone 10 and a cooling zone 20 in sequence according to the process flow.

[0037] The sintering zone 10 is 190cm long and divided into four sub-zones. The first sub-zone 11 is 70cm long, with six infrared heating lamps 16 at both the top and bottom, and its temperature is adjustable between 580℃ and 620℃. The second sub-zone 12 is also 70cm long, with six infrared heating lamps 16 at both the top and bottom, and its temperature is adjustable between 630℃ and 670℃. The third sub-zone 13 is 25cm long, with six infrared heating lamps 16 at the top and eight at the bottom, and its temperature is adjustable between 750℃ and 810℃. The fourth sub-zone 14 is also 25cm long, with six infrared heating lamps 16 at the top and eight at the bottom, and its temperature is adjustable between 870℃ and 930℃. Within the same sub-zone, the infrared heating lamps 16 at both the top and bottom use the same power for radiant heating during furnace operation. The sintering zone 10 is equipped with two exhaust ducts 18, and each sintering sub-zone is equipped with an air inlet duct 17 at both the upper and lower ends.

[0038] The length of the cooling zone 20 is 100cm, including the water cooling zone 21 and the air cooling zone 22, wherein the length of the water cooling zone 21 is 25cm and the length of the air cooling zone 22 is 70cm.

[0039] Specifically for the sintering method of TOPCon cells, in a specific embodiment, 2000 silicon wafers are taken and subjected to texturing, boron diffusion, back polishing, deposition of an ultra-thin oxide layer and polysilicon, phosphorus diffusion, plasma etching, removal of edge plating, alumina coating, PECVD front and back coating, and printing treatment to obtain a TOPCon cell precursor with metal paste printed on both the front and back. The TOPCon cell precursors are divided into 4 groups, namely G1, G2, G3, and G4. Group G1 is sintered using the sintering furnace and sintering process of the present invention. The sintering processes for G1 to G4 are set as shown in Table 1. Among them, for the drying zone, if provided, the length of the drying zone is 300 cm; in the sintering zone, the lengths of temperature zones 1 and 2 are both 70 cm, and the lengths of temperature zones 3 to 6 are all 25 cm; the length of the cooling zone is 100 cm.

[0040] Table 1

[0041]

[0042] The battery performance of the prepared TOPCon cells in groups G1 to G4 is detected. When the photoelectric conversion efficiency of the TOPCon cell is not less than 22.5%, the TOPCon cell is considered qualified. The photoelectric conversion efficiency takes the average value of the qualified products, and the detection results are shown in Table 2. It can be seen from the detection results that by using the sintering furnace provided by the present invention for sintering and adopting the sintering method provided by the present invention, both the yield rate and the photoelectric conversion efficiency of the prepared TOPCon cells are improved.

[0043] Table 2

[0044] serial number Yield (%) Photoelectric conversion efficiency (%) G1 96 22.92 G2 82 22.35 G3 93 22.61 G4 93 22.63

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, or improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A sintering furnace for TOPCon batteries, comprising a furnace body and a conveyor belt arranged axially along the furnace body, characterized in that, The furnace body is sequentially divided into a connected sintering zone (10) and a cooling zone (20) according to the process flow. The length of the sintering zone (10) is 140~260cm, and it is divided into 4 sintering sub-zones according to the temperature gradient. Each sintering sub-zone is provided with infrared heating lamps (16) at both the upper and lower ends. The number of infrared heating lamps at the lower end of the third sintering sub-zone (13) and the fourth sintering sub-zone (14) is greater than the number of infrared heating lamps at the upper end. The length of the first sintering zone (11) is 50~100cm, and the temperature is set at 580℃~620℃; The length of the second sintering zone (12) is 50~100cm, and the temperature is set at 630℃~670℃; The length of the third sintering zone (13) is 20~30cm, and the temperature is set at 750℃~810℃; The length of the fourth sintering zone (14) is 20~30cm, and the temperature is set at 870℃~930℃; The number of infrared heating lamps at both the upper and lower ends of the first sintering sub-region (11) and the second sintering sub-region (12) is 5 to 7; The number of infrared heating lamps at the upper end of the third sintering sub-region (13) and the fourth sintering sub-region (14) are both 5 to 7, and the number of infrared heating lamps at the lower end are both 7 to 9. In the same sintering zone, the infrared heating lamps at both ends of the upper and lower ends of the sintering furnace use the same power for radiant heating during the operation of the sintering furnace. In the third sintering sub-region (13) and the fourth sintering sub-region (14), the sintering temperature of the back side of the TOPCon battery precursor is 15~20℃ higher than that of the front side.

2. The sintering furnace for TOPCon batteries as described in claim 1, characterized in that, The length of the cooling zone (20) is 70~180cm, including a water cooling zone (21) and an air cooling zone (22), wherein the length of the water cooling zone (21) is 20~30cm, and the length of the air cooling zone (22) is 50~150cm.

3. The sintering furnace for TOPCon batteries as described in claim 1, characterized in that, At least one air inlet pipe (17) is provided at the upper and lower ends of each sintering sub-zone. The sintering zone is equipped with at least two exhaust ducts (18).

4. A sintering method for a TOPCon battery, characterized in that, Includes the following steps: The TOPCon battery precursor to be sintered is placed on the conveyor belt of the sintering furnace; The TOPCon battery precursor is sintered in a sintering zone (10) and a cooling zone (20) in sequence to obtain the TOPCon battery; The sintering zone (10) includes four sintering sub-zones; The number of infrared heating lamps at the lower end of the third sintering zone (13) and the fourth sintering zone (14) is greater than the number of infrared heating lamps at the upper end; The temperature of the first sintering zone (11) is 580℃~620℃, the temperature of the second sintering zone (12) is 630℃~670℃, the temperature of the third sintering zone (13) is 750℃~810℃, and the temperature of the fourth sintering zone (14) is 870℃~930℃. In the third sintering sub-region (13) and the fourth sintering sub-region (14), the sintering temperature of the back side of the TOPCon battery precursor is 15~20℃ higher than that of the front side.

5. The sintering method for TOPCon batteries as described in claim 4, characterized in that, The silicon wafer is sequentially subjected to texturing, boron diffusion, back-side polishing, deposition of an ultrathin oxide layer and polysilicon, phosphorus diffusion, plasma etching, decoupling, alumina coating, PECVD front and back coating, and printing to obtain the TOPCon battery precursor with metal paste printed on both the front and back sides. The front side is printed with aluminum-containing silver paste, and the back side is printed with pure silver paste.

6. The sintering method for TOPCon batteries as described in claim 4, characterized in that, The conveyor belt speed is 7500~8500 mm / min.

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