A two-component glass powder for N-type topcon and a preparation method thereof

Abstract

The application relates to the field of TOPCon cells, in particular to a two-component glass powder for N-type TOPCon and a preparation method thereof. The two-component glass powder for N-type TOPCon comprises an A component and a B component; the A component and the B component are both compositions of metal oxides or semi-metal oxides. The two-component glass powder for N-type TOPCon provided in the application has good high-temperature sintering wettability, can provide good ohmic contact and further reduce the metal-induced recombination rate, plays a large role in thin Poly cell wafers, and has very good market prospects.

Description

Technical Field

[0001] This application relates to the field of TOPCon batteries, and more particularly to a two-component glass powder for N-type TOPCon batteries and its preparation method. Background Technology

[0002] Compared to existing solar cell technologies, TOPCon solar cells have gained increasing attention due to their lower contact recombination loss and higher theoretical limit efficiency. TOPCon solar cells achieve this by using ultrathin silicon oxide and heavily doped silicon films for excellent passivation, which causes band bending on the silicon wafer surface, resulting in field passivation. This significantly increases the probability of electron tunneling and reduces contact resistance. Currently, the efficiency of crystalline silicon cells fabricated using TOPCon technology is already above 26%.

[0003] In recent years, to better save manufacturing costs and improve application performance and environment, N-type TOPCon batteries have been continuously developed with the aim of reducing the thickness of the N-Ploy layer. With continuous research, the thickness of the N-Ploy layer has gradually decreased to 70-80 nm, which poses a great challenge to the conductive silver paste and the glass powder materials used in N-type TOPCon batteries. Patent CN115259675A provides a glass powder for N-type TOPCon batteries, the raw materials of which mainly include the Pb-Te-Bi-Si oxide system, and adds tensile strength aids and sintering performance regulating aids. It claims that the glass powder prepared by it has high tensile strength after sintering and can be sintered at 750-850℃; however, the glass powder system prepared by it is still not effective in N-type TOPCon battery systems with thinner N-Ploy layer thickness.

[0004] Therefore, in order to solve the above problems, this application provides a two-component glass powder for N-type TOPCon and its preparation method. Summary of the Invention

[0005] To address the aforementioned problems, the first aspect of this application provides a two-component glass powder for N-type TOPCon, the two-component glass powder comprising component A and component B; wherein component A and component B are both compositions of metal oxides or half-metal oxides.

[0006] As a preferred embodiment, the mass ratio of component A to component B is 2-13:1-2.

[0007] As a preferred embodiment, the mass ratio of component A to component B is 4 to 11:1.

[0008] As a preferred embodiment, the mass ratio of component A to component B is 6:1.

[0009] As a preferred embodiment, component A, by mass, comprises: 30 to 220 parts of metal oxide and 0.1 to 20 parts of half-metal oxide.

[0010] As a preferred embodiment, component B, by mass, comprises: 30-190 parts of metal oxide and 1-35 parts of half-metal oxide.

[0011] As a preferred embodiment, the half-metal oxide is SiO2; the metal oxide is at least one selected from PbO, B2O3, Al2O3, Sb2O3, Bi2O3, SnO2, SeO2, TeO2, ZnO, ZrO2, CuO, MnO2, Cr2O3, WO3, Nb2O5, MoO3, Co2O3, and Fe2O3.

[0012] As a preferred embodiment, the metal oxide further includes at least an alkali metal oxide; the alkali metal oxide is Li₂O or Na₂O.

[0013] As a preferred embodiment, by mass, the metal oxides in component A are 10-60 parts PbO, 10-60 parts TeO2, 1-5 parts ZnO, 4-25 parts WO3, 1-6 parts CuO, 0.1-20 parts SiO2, and 6-20 parts alkali metal oxides.

[0014] As a preferred embodiment, by mass, the metal oxides in component A are 35-60 parts PbO, 18-30 parts TeO2, 2-5 parts ZnO, 5-25 parts WO3, 1-3 parts CuO, 0.1-10 parts SiO2, and 10-14 parts alkali metal oxides.

[0015] As a preferred embodiment, by mass, the metal oxides in component B are: PbO 5-40 parts, TeO2 10-30 parts, Bi2O3 10-50 parts, ZnO 1-10 parts, WO3 5-30 parts, CuO 1-10 parts, Fe2O3 0.1-6 parts, SiO2 1-35 parts, and alkali metal oxides 1-15 parts.

[0016] As a preferred embodiment, by mass, the metal oxides in component B are: PbO 25-40 parts, TeO2 10-28 parts, Bi2O3 28-30 parts, ZnO 1-10 parts, WO3 5-15 parts, CuO 1-6 parts, Fe2O3 1 part, SiO2 1-35 parts, and alkali metal oxides 1-3 parts.

[0017] As a preferred embodiment, the D of component A 50The average particle size is 1.4–1.8 μm; the D of component B... 50 The average particle size is 1.6–2.1 μm.

[0018] As a preferred embodiment, the D of component A 50 The average particle size is 1.5–1.7 μm; the D of component B. 50 The average particle size is 1.8–2.0 μm.

[0019] As a preferred embodiment, the D of component A 50 The average particle size is 1.6 μm; the D of component B. 50 The average particle size is 1.9 μm.

[0020] As a preferred embodiment, the glass powder D 50 The average particle size is 1.2–3 μm.

[0021] As a preferred embodiment, the glass powder D 50 The average particle size is 1.5–2 μm.

[0022] As a preferred embodiment, the glass transition temperature of component A is 200–600°C; and the glass transition temperature of component B is 350–600°C.

[0023] As a preferred embodiment, the glass transition temperature of component A is 200–400°C; and the glass transition temperature of component B is 450–600°C.

[0024] This application provides a two-component glass powder for N-type TOPCon cells, which exhibits excellent high-temperature sintering wettability, provides good ohmic contact, and further reduces the metal-induced recombination rate. It plays a significant role in thin-film Poly solar cells. The silver paste exhibits good sintering density, demonstrating low contact resistivity and high open-circuit voltage even at relatively low sintering temperatures. The applicant believes that in this application, the Bi-free Pb-Te system in component A, used as the main oxide, combined with the ZnO-WO3-SiO2-CuO auxiliary oxide system, effectively improves the wetting rate of the glass powder at high temperatures and reduces the required wetting temperature, enabling complete wetting at lower temperatures and ensuring ohmic contact performance. On the other hand, component B, using Pb-Te-Bi as the main oxide system and ZnO-WO3-SiO2-CuO-Fe2O3 as the auxiliary oxide system, further enhances the open-circuit voltage in the oxide sintering system, thereby ultimately reducing the absorption of free carriers, given the better wettability of component A.

[0025] The second aspect of this application provides a method for preparing the above-mentioned two-component glass powder for N-type TOPCon, the steps of which include the following steps: (1) accurately weighing component A and component B and mixing them evenly with a stirrer in proportion, and transferring them to a crucible; (2) placing the above crucibles in a sintering furnace at a furnace temperature of 850-1300℃ and holding them at that temperature for 30-80 minutes; (3) pouring the above-mentioned molten glass into a stainless steel double roller mill for dry quenching to obtain corresponding glass sheets; (4) subjecting the above-mentioned glass sheets to coarse grinding and air jet milling to obtain products with the target particle size.

[0026] Beneficial effects:

[0027] 1. The bicomponent glass powder for N-type TOPCon provided in this application has good high-temperature sintering wettability, can provide good ohmic contact and further reduce the metal-induced recombination rate, plays a significant role in thin poly solar cells and has a very good market prospect.

[0028] 2. The two-component glass powder for N-type TOPCon provided in this application can be sintered at a lower temperature and has good sintering density of silver paste. Even when sintered at a relatively low temperature, it has low contact resistivity and high open circuit voltage.

[0029] 3. The two-component glass powder for N-type TOPCon provided in this application, by distinguishing the glass transition temperatures between component A and component B, can ensure that the silver paste has appropriate wettability during high-temperature sintering, effectively guaranteeing the integrity of sintering, thereby further ensuring various properties such as low contact resistance and high open circuit resistance.

[0030] 4. The two-component glass powder for N-type TOPCon provided in this application uses a Bi-free Pb-Te system as the main oxide in component A, and the auxiliary oxide system of ZnO-WO3-SiO2-CuO can effectively improve the wetting speed of the glass powder at high temperature and reduce the temperature requirement for wetting, so that it can achieve complete wetting at a lower temperature and ensure ohmic contact performance.

[0031] 5. The two-component glass powder for N-type TOPCon provided in this application has Pb-Te-Bi as the main oxide system in component B and ZnO-WO3-SiO2-CuO-Fe2O3 as the auxiliary oxide system. Under the premise that component A has better wettability, it can further work together to improve the open circuit voltage in the oxide sintering system, thereby ultimately reducing the absorption of free carriers. Detailed Implementation

[0032] Example 1

[0033] Example 1 provides a two-component glass powder for N-type TOPCon, the two-component glass powder comprising component A and component B; the mass ratio of component A to component B is 6:1.

[0034] By mass, component A includes: 40 parts PbO, 25 parts TeO2, 5 parts ZnO, 25 parts WO3, 2 parts CuO, 1 part SiO2, and 2 parts Li2O.

[0035] By mass, component B includes: 40 parts PbO, 5 parts TeO2, 10 parts Bi2O3, 10 parts ZnO, 15 parts WO3, 6 parts CuO, 0 parts Fe2O3, 9 parts SiO2, and 5 parts Li2O.

[0036] Component A of D 50 The average particle size is 1.6 μm; the D of component B 50 The average particle size is 1.9 μm.

[0037] The glass transition temperature of component A is 320°C; the glass transition temperature of component B is 480°C.

[0038] The second aspect of this embodiment provides a method for preparing the above-mentioned two-component glass powder for N-type TOPCon, the steps of which include the following steps: (1) accurately weighing component A and component B and mixing them evenly with a mixer in proportion, and transferring them to a crucible; (2) placing the above crucibles in a sintering furnace at a furnace temperature of 950°C and holding them at that temperature for 60 minutes; (3) pouring the above-mentioned molten glass into a stainless steel double roller mill for dry quenching to obtain corresponding glass sheets; (4) subjecting the above-mentioned glass sheets to coarse grinding and air jet milling to obtain products with the target particle size.

[0039] Glass powder D 50 The average particle size is 1.8 μm.

[0040] Example 2

[0041] The specific implementation method of this embodiment is the same as that of embodiment 1, except that:

[0042] By mass, component A comprises: 35 parts PbO, 30 parts TeO2, 3 parts ZnO, 15 parts WO3, 2 parts CuO, 5 parts SiO2, and 10 parts Li2O.

[0043] By mass, component B includes: 20 parts PbO, 10 parts TeO2, 30 parts Bi2O3, 8 parts ZnO, 8 parts WO3, 5 parts CuO, 0 parts Fe2O3, 9 parts SiO2, and 10 parts Li2O.

[0044] Example 3

[0045] The specific implementation method of this embodiment is the same as that of embodiment 1, except that:

[0046] By mass, component A includes: 60 parts PbO, 20 parts TeO2, 2 parts ZnO, 5 parts WO3, 2.9 parts CuO, 0.1 parts SiO2, 7 parts Li2O, and 3 parts Na2O.

[0047] By mass, component B includes: 30 parts PbO, 28 parts TeO2, 28 parts Bi2O3, 2 parts ZnO, 5 parts WO3, 1 part CuO, 1 part Fe2O3, 1 part SiO2, 2 parts Li2O, and 3 parts Na2O.

[0048] Example 4

[0049] The specific implementation method of this embodiment is the same as that of embodiment 1, except that:

[0050] By mass, component A comprises: 35 parts PbO, 18 parts TeO2, 5 parts ZnO, 8 parts WO3, 10 parts CuO, 10 parts SiO2, 12 parts Li2O, and 2 parts Na2O.

[0051] By mass, component B includes: 28 parts PbO, 10 parts TeO2, 22 parts Bi2O3, 5 parts ZnO, 15 parts WO3, 3 parts CuO, 0 parts Fe2O3, 10 parts SiO2, 6 parts Li2O, and 1 part Na2O.

[0052] Example 5

[0053] The specific implementation method of this embodiment is the same as that of embodiment 1, except that:

[0054] By mass, component A includes: 60 parts PbO, 25 parts TeO2, 3 parts ZnO, 7 parts WO3, 1 part CuO, 2 parts SiO2, and 2 parts Li2O.

[0055] By mass, component B includes: 25 parts PbO, 21 parts TeO2, 21 parts Bi2O3, 1 part ZnO, 10 parts WO3, 4 parts CuO, 1 part Fe2O3, 6 parts SiO2, 12 parts Li2O, and 2 parts Na2O.

[0056] Performance Evaluation

[0057] The conductive silver paste for N-type TOPCon batteries was prepared by using glass powder components A and B, which together accounted for 2.5% of the total mass of the silver paste. The silver paste composition included, by total mass, 88.9% silver powder, 2.5% glass powder (including components A and B), 7.8% organic carrier (ethyl cellulose organic carrier, Maclean), and 0.8% solvent (silicone oil, Aladdin).

[0058] The prepared silver paste and the commercially available N-type TOPCon battery conductive silver paste were screen printed onto N-type TOPCon cells (80nm thin Poly structure), respectively. The cells were then sintered in a sintering furnace at a peak temperature of 710℃. The commercially available N-type TOPCon battery conductive silver paste was compared with the sample. The open circuit voltage (Uoc), series resistance (Rs), fill factor (FF), and conversion efficiency (Eta) were obtained through current-voltage performance testing, and the contact resistivity (ρc) was obtained through TLM testing. The results were averaged 10 times and are shown in Table 1.

[0059] Table 1

[0060]

Claims

1. A two-component glass powder for N-type TOPCon, characterized in that: The two-component glass powder comprises component A and component B; both component A and component B are compositions of metal oxides or half-metal oxides. The metal oxides in component A are: PbO 35-60 parts, TeO2 18-30 parts, ZnO 2-5 parts, WO3 5-25 parts, CuO 1-3 parts, SiO2 0.1-10 parts, and alkali metal oxides 10-14 parts; the metal oxides in component B are: PbO 25-40 parts, TeO2 10-28 parts, Bi2O3 28-30 parts, ZnO 1-10 parts, WO3 5-15 parts, CuO 1-6 parts, Fe2O3 1 part, SiO2 1-35 parts, and alkali metal oxides 1-3 parts. The glass transition temperature of component A is 200~400℃; the glass transition temperature of component B is 450~600℃. The mass ratio of component A to component B is 2~13:1~2.

2. The two-component glass powder for N-type TOPCon according to claim 1, characterized in that: The alkali metal oxide is Li₂O or Na₂O.

3. The two-component glass powder for N-type TOPCon according to claim 2, characterized in that: The D of component A 50 The average particle size is 1.4~1.8 μm; the D of component B... 50 The average particle size is 1.6~2.1μm.

4. A method for preparing a two-component glass powder for N-type TOPCon according to any one of claims 1 to 3, characterized in that: The steps include the following steps: (1) Weigh component A and component B accurately and mix them evenly with a mixer according to the ratio, and transfer them to a crucible; (2) Place the above crucibles in a sintering furnace with a furnace temperature of 850~1300℃ and keep them warm for 30~80 min; (3) Pour the molten glass into a stainless steel double roller mill for dry quenching to obtain the corresponding glass sheets; (4) Perform coarse grinding and air jet milling on the above glass sheets to obtain products with the target particle size.

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