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CN-122000111-A - Paste for TOPcon battery LECO process and printing method of TOPcon battery front electrode

CN122000111ACN 122000111 ACN122000111 ACN 122000111ACN-122000111-A

Abstract

The invention discloses a paste for TOPcon-battery LECO process and a printing method of TOPcon-battery front electrode, wherein the paste for TOPcon-battery LECO process comprises a first paste and a second paste, the first paste is used for forming seed layer auxiliary grid lines on a silicon wafer, the second paste is used for forming laminated auxiliary grid lines and main grid lines on the silicon wafer, the first paste comprises, based on the total weight of the first paste as 100%, 60-85wt% of silver powder, 1-10wt% of glass powder, 0.1-5wt% of inorganic auxiliary agent and 10-35wt% of organic carrier, and the second paste comprises, based on the total weight of the second paste as 100%, 60-85wt% of structured silver powder, 1-10wt% of nano silver powder, 0-5wt% of active additive, 0.5-5wt% of epoxy resin, 0.1-1wt% of curing agent, 0.1-2wt% of reducing agent and 5-20wt% of organic solvent. The invention reduces the silver consumption and simultaneously maintains the excellent electrical performance of the battery.

Inventors

  • GUAN YULONG
  • CHEN XIAOLONG
  • LIU JIE
  • SHI WEI
  • PEI LEIYU
  • HU XILING
  • ZHANG FAN
  • ZHU SHANJIN

Assignees

  • 上海银浆科技有限公司

Dates

Publication Date
20260508
Application Date
20260122

Claims (10)

  1. 1. The slurry for the TOPcon battery LECO process is characterized by comprising a first slurry and a second slurry, wherein the first slurry is used for forming a seed layer auxiliary grid line on a silicon wafer, and the second slurry is used for forming a laminated auxiliary grid line and a main grid line on the silicon wafer; The total weight of the first slurry is 100%, and the first slurry comprises 60-85wt% of silver powder, 1-10wt% of glass powder, 0.1-5wt% of inorganic auxiliary agent and 10-35wt% of organic carrier; The second paste comprises, based on 100% of the total weight of the second paste, 60-85% by weight of structured silver powder, 1-10% by weight of nano silver powder, 0-5% by weight of active additive, 0.5-5% by weight of epoxy resin, 0.1-1% by weight of curing agent, 0.1-2% by weight of reducing agent and 5-20% by weight of organic solvent.
  2. 2. The paste for a LECO process for TOPcon battery according to claim 1, wherein in the second paste, the structured silver powder comprises at least one of a coated silver powder comprising at least one of silver-coated copper powder, silver-coated aluminum powder, silver-coated nickel powder, and hollow silver powder.
  3. 3. The paste for use in the LECO process for a TOPcon battery as set forth in claim 2, wherein the silver content of the clad silver powder is 5 to 50wt%, based on 100% by weight of the total weight of the clad silver powder.
  4. 4. The paste for a TOPcon battery LECO process according to claim 1, wherein in the second paste, the active additive includes at least one of a metal powder, an inorganic metal salt, and an organic metal compound.
  5. 5. The paste for use in a TOPcon battery LECO process as set forth in claim 4, wherein said reactive additive is at least one selected from the group consisting of metal powders of silver, copper, tin, bismuth, inorganic metal salts and organic metal compounds.
  6. 6. The paste for use in the LECO process for a TOPcon battery according to claim 1, wherein in the first paste, the silver powder includes a first silver powder having a particle diameter D50 of 50nm to 1 μm and a second silver powder having a particle diameter D50 of 1 μm to 3 μm, and the content of the first silver powder is 1 to 10wt% and the content of the second silver powder is 50 to 75wt% based on 100% of the total weight of the first paste.
  7. 7. The paste for use in a TOPcon battery LECO process according to claim 1, wherein in said first paste, said glass frit comprises the following components, based on 100% of the total weight of said glass frit ：40-60wt%PbO、10-15wt%B 2 O 3 、2-6wt%SiO 2 、15-25wt%Bi 2 O 3 、10-15wt%Al 2 O 3 、4-6wt%FeO、1-4wt%ZnO.
  8. 8. A method for printing a TOPcon battery front electrode, which is characterized in that the TOPcon battery LECO process slurry according to any one of claims 1-7 is adopted, the method comprises the step of forming an auxiliary grid line and a main grid line on a silicon wafer, wherein the auxiliary grid line comprises a seed layer auxiliary grid line and a laminated auxiliary grid line which are arranged in sequence from bottom to top, and the specific steps are as follows: S1, printing a first sizing agent on the front surface of a silicon wafer through a first silk screen, and forming a seed layer auxiliary grid line after drying, sintering and light injection; S2, forming a laminated auxiliary grid line and a laminated main grid line by adopting any one of the following processes: printing second sizing agent on the seed layer auxiliary grid line through a second silk screen, and performing post-treatment through drying, curing and LECO processes; Or, carrying out LECO process treatment on the seed layer auxiliary grid line, printing second slurry on the seed layer auxiliary grid line through a second screen, and carrying out drying and curing treatment.
  9. 9. The method for printing a front electrode of TOPcon battery as defined in claim 8, wherein in step S1, the conditions of baking are 200-300 ℃ for 10-30S, 700-800 ℃ for 10-30S, and the height of the sub-grid line of the seed layer is 1-5 μm and the width is 10-30 μm.
  10. 10. The method for printing a front electrode of TOPcon battery as defined in claim 8, wherein in any one of the processes of step S2, the conditions of drying are 100-200 ℃ for 10-30S, 100-200 ℃ for 1-5min, and the height of the laminated sub-grid line is 1-5 μm and the width is 10-30 μm.

Description

Paste for TOPcon battery LECO process and printing method of TOPcon battery front electrode Technical Field The invention relates to the technical field of solar cells, in particular to paste for a TOPcon battery LECO process and a printing method of a TOPcon battery front electrode. Background In the current background of the rapid development of the photovoltaic industry, TOPCon (tunnel oxide passivation contact) cells are highly advanced technology in the photovoltaic field. The battery structure is innovated, and excellent passivation effect is realized by preparing an ultrathin tunneling oxide layer and a doped polysilicon layer on the back surface of the battery. This greatly reduces the surface recombination rate and improves minority carrier lifetime, thus significantly improving the open circuit voltage of the cell. The photovoltaic cell has outstanding photoelectric conversion efficiency, and can generate more electric energy under the same illumination condition compared with the traditional photovoltaic cell technology. The efficient conversion capability enables TOPCon cells to obtain higher generated power in a limited installation area, and the method has great advantages in large photovoltaic power stations or distributed photovoltaic systems. In addition, TOPCon batteries have better process compatibility, and can be upgraded and reformed on the existing photovoltaic production line, thereby providing convenience for large-scale industrial production and forcefully promoting the development of the photovoltaic industry towards high efficiency. However, the continued expansion of photovoltaic power production has led to a dramatic increase in the amount of silver paste used as a critical conductive material. Under the influence of scarcity of global silver resources and price rising, the silver paste cost becomes one of the core bottlenecks for restricting the cost reduction and efficiency improvement of the photovoltaic industry. Therefore, the industry is highly in need of effectively reducing the dependence on noble metal silver by a low silver solution under the premise of ensuring the battery performance. Disclosure of Invention Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a battery that can reduce the amount of silver consumption while maintaining excellent electrical performance. The invention provides TOPcon battery LECO process slurry, which comprises a first slurry and a second slurry, wherein the first slurry is used for forming a seed layer auxiliary grid line on a silicon wafer, and the second slurry is used for forming a laminated auxiliary grid line and a main grid line on the silicon wafer; The total weight of the first slurry is 100%, and the first slurry comprises 60-85wt% of silver powder, 1-10wt% of glass powder, 0.1-5wt% of inorganic auxiliary agent and 10-35wt% of organic carrier; The second paste comprises, based on 100% of the total weight of the second paste, 60-85% by weight of structured silver powder, 1-10% by weight of nano silver powder, 0-5% by weight of active additive, 0.5-5% by weight of epoxy resin, 0.1-1% by weight of curing agent, 0.1-2% by weight of reducing agent and 5-20% by weight of organic solvent. Further, in the second paste, the structured silver powder includes at least one of a coated silver powder and a hollow silver powder, and the coated silver powder includes at least one of silver-coated copper powder, silver-coated aluminum powder, and silver-coated nickel powder. Further, the silver content in the coated silver powder is 5 to 50wt% based on 100% by weight of the total weight of the coated silver powder. Further, in the second slurry, the reactive additive includes at least one of a metal powder, an inorganic metal salt, and an organic metal compound. Further, the active additive is at least one selected from the group consisting of metal powders of silver, copper, tin, bismuth, inorganic metal salts, and organic metal compounds. Further, in the first paste, the silver powder includes a first silver powder having a particle diameter D50 of 50nm to 1 μm and a second silver powder having a particle diameter D50 of 1 μm to 3 μm, and the content of the first silver powder is 1 to 10wt% and the content of the second silver powder is 50 to 75wt% based on 100% of the total weight of the first paste. Further, in the first paste, the glass frit comprises the following components based on 100% of the total weight of the glass frit ：40-60wt%PbO、10-15wt%B2O3、2-6wt%SiO2、15-25wt%Bi2O3、10-15wt%Al2O3、4-6wt%FeO、1-4wt%ZnO. The invention also provides a printing method of TOPcon front electrode of battery, which adopts the paste for TOPcon battery LECO process, the method comprises the steps of forming an auxiliary grid line and a main grid line on a silicon wafer, the auxiliary grid line comprises a seed layer auxiliary grid line and a la