Mixed glass powder and preparation method thereof, nickel-containing front main grid slurry for TOPCon and preparation method of nickel-containing front main grid slurry

Abstract

The invention provides mixed glass powder and a preparation method thereof, nickel-containing front main grid slurry for TOPCon and a preparation method of the nickel-containing front main grid slurry. The mixed glass powder comprises first glass powder and second glass powder, the first glass powder is a Pb-Si-B-Te glass powder system, and the second glass powder is a B-Si-Zn glass powder system; by taking the first glass powder as a metering base number, the first glass powder comprises 20 to 70 weight percent of PbO, 1 to 30 weight percent of SiO2, 0 to 20 weight percent of B2O3, 0 to 10 weight percent of TeO2 and 0 to 10 weight percent of R2O; the second glass powder is used as a metering base number, the second glass powder comprises 0-70 wt% of B2O3, 0-70 wt% of SiO2, 5-30 wt% of ZnO and 0-10 wt% of R2O, and the R2O is one or more of alkali metal oxides of Na2O, Li2O and K2O. By replacing part of silver powder in front main grid slurry with base metal, under the condition that excessive solid content is not reduced, new glass and an organic system are matched, and performance and cost are balanced, so that the TOPCon solar cell is better adapted to current TOPCon cell application scenarios.

Description

Technical Field

[0001] This invention belongs to the technical field of conductive pastes for solar cells, and particularly relates to a mixed glass powder and its preparation method, and a nickel-containing front grid paste for TOPCon and its preparation method. Background Technology

[0002] The photovoltaic industry continues to evolve towards higher efficiency and lower costs. N-type TOPCon cells, with their high conversion efficiency and compatibility with existing PERC production lines, have become the mainstream technology in the market. However, TOPCon cells face significant cost challenges in the metallization process: unlike PERC cells which only use silver paste on the front side, TOPCon cells require silver paste on both sides, resulting in an increase of approximately 50% in silver paste consumption, reaching as high as 10 mg / W. Silver paste accounts for 50%-60% of the non-silicon cost of the cell. Based on the current silver price (7000-8000 RMB / kg), the cost of silver paste per watt is approximately 0.07-0.08 RMB. With the continued rise in silver prices and the development of TOPCon cells towards thinner and more efficient wafers, reducing the cost of paste has become an urgent need for the industry.

[0003] In the metallization process of photovoltaic cells, the busbar paste is the core conductive structure on the cell surface, undertaking the crucial functions of current collection and transmission. With the trend of cost reduction in TOPCon cells, the busbar is also evolving towards "narrower linewidth and lower silver content." While maintaining the busbar structure, paste formulation innovation focuses on reducing silver content and improving interface performance. The key technological breakthrough lies in the innovation of the glass powder system. As the binder phase in the paste, the composition of glass powder directly affects the passivation layer etching behavior and contact resistance. However, while existing low-solids busbar pastes can reduce silver consumption by 10-20%, they face significant technical bottlenecks and mass production challenges. Their welding reliability and mechanical properties decrease, and electrical performance is also somewhat sacrificed. They are only suitable for cost-sensitive applications with less stringent requirements for efficiency and reliability, and cannot be widely adopted. Therefore, in the method of replacing silver powder with base metal powder, there is an urgent need for a front-side busbar paste that can balance cost and performance and is better adapted to current TOPCon cell applications. Summary of the Invention

[0004] In view of this, the present invention provides a mixed glass powder and its preparation method, a nickel-containing front grid paste for TOPCon and its preparation method. By replacing part of the silver powder in the front grid paste with base metal, the performance and cost are balanced by combining new glass and organic system without reducing too much solid content, thereby better adapting to the current TOPCon battery application scenarios.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: The first aspect of the present invention provides a mixed glass powder, comprising a first glass powder and a second glass powder, wherein the first glass powder accounts for 25-75% of the mass fraction of the mixed glass powder, and the second glass powder accounts for 25-75% of the mass fraction of the mixed glass powder; The first glass powder is a Pb-Si-B-Te glass powder system, and the second glass powder is a B-Si-Zn glass powder system. The glass softening point of the first glass powder is lower than that of the second glass powder. Based on the first glass powder as the measurement base, the first glass powder includes: 20-70 wt% PbO, 1-30 wt% SiO2, 0-20 wt% B2O3, 0-10 wt% TeO2, and 0-10 wt% R2O; Based on the second glass powder as the measurement base, the second glass powder includes: 0-70wt% B2O3, 0-70wt% SiO2, 5-30wt% ZnO, and 0-10wt% R2O; R2O is one or more of the alkali metal oxides Na2O, Li2O, and K2O.

[0006] In a preferred embodiment of the present invention, the first glass powder further includes one or more oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony, and the content of the oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony is 1 to 12 wt%.

[0007] In a preferred embodiment of the present invention, the second glass powder further includes one or more oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony, and the content of the oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony is 1 to 30 wt%.

[0008] A second aspect of the present invention provides a method for preparing mixed glass powder, comprising the following steps: S1: Prepare the ingredients according to the proportion of the first glass powder and mix them thoroughly; S2: The mixed ingredients are loaded into a corundum crucible and melted in a lifting furnace at 1100-1350℃ for 1-1.5 hours. After the glass melts and homogenizes, glass material is obtained by high-temperature water quenching or cold rolling pressing. S3: Grind the glass material to obtain glass powder with D50 < 3μm; The second glass powder is also prepared according to steps S1-S3.

[0009] The third aspect of the present invention provides a nickel-containing front-side grid paste for TOPCon, which, by mass fraction, comprises the following components: 78-85 wt% silver powder, 1-3 wt% nickel powder, 1-3 wt% mixed glass powder, and 13-18 wt% organic carrier. Wherein, the mixed glass powder is the mixed glass powder according to any one of claims 1-3.

[0010] In a preferred embodiment of the present invention, the material comprises 81 wt% silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder, 0.4 wt% second glass powder, and 15.4 wt% organic carrier.

[0011] In a preferred embodiment of the present invention, the organic carrier is mainly composed of resin, solvent, thixotropic agent, dispersant and other additives.

[0012] In a preferred embodiment of the present invention, the silver powder is spherical silver powder with an average particle size of 1-2 μm, a D50 of 1-2 μm, a D90 of 1-6 μm, and a tap density of 4-6 g / m³. 3 .

[0013] In a preferred embodiment of the present invention, the nickel powder is spherical nickel powder with an average particle size of 0.5–2 μm, a D50 of 1–3 μm, a D90 of 3–5 μm, and a tap density of 0.6–1.2 g / m³. 3 .

[0014] The fourth aspect of the present invention also provides a method for preparing the nickel-containing front-side main grid paste for TOPCon, comprising the following steps: A1: Mix silver powder, nickel powder, first glass powder, second glass powder and organic carrier according to the specified ratio and stir evenly; A2: Grind the above mixture 6 to 8 times with a three-roll mill, filter and centrifuge to obtain a front grid slurry with a fineness ≤7μm and a viscosity of 30Pa•S to 100Pa•S.

[0015] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art: This invention modifies the glass powder, using a composite glass system of low-softening-point Pb-Si-B-Te and high-softening-point B-Si-Zn auxiliary glass. Its core lies in achieving precise etching of the passivation layer and improved interface stability through a glass softening-point gradient design. The Pb-Si-B-Te (low softening-point) main glass melts preferentially in the low-temperature range, initially etching the SiNx passivation layer to form micro-contact channels, but avoiding excessive etching of the poly layer. The B-Si-Zn (high softening-point) auxiliary glass melts in the high-temperature range, controlling the etching depth and forming a uniform microporous structure on the poly layer surface, promoting tunneling contact between silver / nickel particles and the silicon substrate, and reducing contact resistance. Furthermore, boron (B) enhances the glass's glass-forming ability, forming a good glass layer during sintering; tetra (Te) enhances fluidity, guiding nickel powder to uniformly fill the gaps between silver particles during silver powder sintering and rearrangement, increasing the density of conductive pathways, strengthening the conductive network, and compensating for the increase in resistance caused by the decrease in silver content.

[0016] This invention ensures sufficient etching depth and contact by adjusting the rearrangement and combination of silver powder, nickel powder and glass powder during the sintering process. Compared with pure silver paste with the same solid content, it maintains the same welding performance and electrical performance, and has comparable printing performance, and is suitable for 15-30um stencil openings. Detailed Implementation

[0017] Traditional grid pastes are based on high silver content (>85wt%), achieving a balance between ohmic contact and adhesion through optimized proportions of silver powder, glass powder, and organic carriers. However, as grid line designs evolve from multi-main-brick (MBB) to super-multi-main-brick (SMBB), grid widths have shrunk to below 30μm, placing higher demands on the printability, sintering window, and weld pull strength of the paste. Against this backdrop, grid pastes must balance the dual goals of "cost reduction" and "performance improvement," driving the emergence of a series of innovative technologies.

[0018] There are currently three main directions for cost reduction in busbars: 1. OBB (Busboard-less) technology significantly reduces silver consumption by removing the silver paste layer on the surface of the cell's main grid and instead using solder ribbons to directly connect the fine grid at the module stage. However, this technology is not yet fully mature. OBB technology eliminates the main grid, reducing the single-point welding area by about 90%, which makes it easy for the solder ribbons to detach from the cell. Furthermore, the welding and dispensing process required for OBB technology is prone to grid breakage during welding, and the dispensing precision requirements are high, difficult, and slow, resulting in a low overall yield.

[0019] 2. Low-silver busbar technology significantly reduces the silver paste solids content (70-80%) of the busbar by optimizing the glass composition system and adjusting the etching depth. While this technology drastically reduces silver content, it has a significant impact on process reliability and paste electrical properties. Excessive organic carrier residue in the paste hinders solder wetting, increasing the rate of poor solder joints by 3%-5% and causing module power degradation. Furthermore, excessively low solids content leads to poor conductive network density, increasing bulk resistivity by 15%-20% and reducing fill factor (FF) by 0.5%-1%.

[0020] 3. Copper paste replacement: Copper paste completely replaces silver paste. Although this process reduces the cost of silver, it significantly increases the complexity of the process and environmental costs. Furthermore, the use of copper paste requires consideration of its material stability. Copper atoms can easily damage the PN junction of TOPCon batteries during sintering, and copper is prone to oxidation, which can cause an increase in contact resistance and affect the battery's electrical performance.

[0021] Taking into account the technical defects of the above-mentioned main grid cost reduction technologies, this invention provides a mixed glass powder and its preparation method, as well as a nickel-containing front-side main grid paste for TOPCon and its preparation method. By introducing base metal nickel to replace part of the silver powder, improving the glass and organic component system, and adjusting the rearrangement and combination of silver powder, nickel powder, and glass powder during the sintering process, sufficient etching depth and contact are ensured. Compared with pure silver paste for the same solid content, its welding performance and electrical performance are comparable, its printability is comparable, and it is suitable for 15-30µm stencil openings.

[0022] A mixed glass powder includes a first glass powder and a second glass powder. The first glass powder accounts for 25-75% of the total mass fraction of the mixed glass powder, and the second glass powder accounts for 25-75% of the total mass fraction of the mixed glass powder. This includes, but is not limited to, the first glass powder accounting for 75%, 65%, 55%, 45%, 35%, or 25% of the total mass fraction of the mixed glass powder, and the second glass powder accounting for 25%, 35%, 45%, 55%, 65%, or 75% of the total mass fraction of the mixed glass powder. The first glass powder is a Pb-Si-B-Te glass powder system, and the second glass powder is a B-Si-Zn glass powder system. The glass softening point of the first glass powder is lower than that of the second glass powder. Based on the first glass powder as the measurement base, the first glass powder includes: 20-70 wt% PbO, 1-30 wt% SiO2, 0-20 wt% B2O3 or H3BO3, 0-10 wt% TeO2, and 0-10 wt% R2O. Based on the second glass powder as the measurement base, the second glass powder includes: 0-70wt% B2O3, 0-70wt% SiO2, 5-30wt% ZnO, and 0-10wt% R2O; R2O is one or more of the alkali metal oxides Na2O, Li2O, and K2O.

[0023] Furthermore, the average particle size of the two glass powders is 1–3 μm, and the softening point is 300–550 °C.

[0024] Furthermore, the proportion of PbO in the first glass powder can be 20, 30, 40, 50, 55, 60, or 70 wt%, the proportion of SiO2 in the first glass powder can be 1, 10, 16, 20, 25, or 30 wt%, the proportion of B2O3 or H3BO3 in the first glass powder can be 5, 10, 15, or 20 wt%, the proportion of TeO2 in the first glass powder can be 2, 4, 6, 8, or 10 wt%, and the proportion of R2O in the first glass powder can be 2, 4, 6, 8, or 10 wt%. The proportions of B2O3 in the second glass powder can be 10, 20, 30, 40, 50, 60, or 70 wt%, the proportions of SiO2 in the second glass powder can be 10, 20, 30, 40, 50, 60, or 70 wt%, the proportions of ZnO in the second glass powder can be 5, 15, 20, 25, or 30 wt%, and the proportions of R2O in the second glass powder can be 2, 4, 5, 8, or 10 wt%.

[0025] In a preferred embodiment of the present invention, the first glass powder further includes one or more of oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony, and the content of the oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony is 1 to 12 wt%, for example, containing 2 wt% zinc oxide and 10 wt% Cu2O.

[0026] In a preferred embodiment of the present invention, the second glass powder further includes one or more oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony, wherein the content of the oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony is 1-30 wt%. For example, the second glass powder may also include 35 wt% Bi₂O and 35 wt% Te₂O.

[0027] A second aspect of the present invention provides a method for preparing mixed glass powder, comprising the following steps: S1: Prepare the ingredients according to the proportion of the first glass powder. The weight of each component is calculated and weighed by weight percentage. The ingredients are then fully mixed in the mixer. S2: The mixed ingredients are loaded into a corundum crucible and melted in a lifting furnace at 1100-1350℃ for 1-1.5 hours. After the glass melts and homogenizes, glass material is obtained by high-temperature water quenching or cold rolling pressing. S3: The glass material is dry-milled using a planetary ball mill at a speed of 300–650 r / min for 1–4 h. It is then further wet-milled using a horizontal ball mill with alcohol as the solvent at a speed of 100–300 r / min for 10–30 h. After drying, glass powder with D50 < 3 μm is obtained. Similarly, the second glass powder is prepared according to steps S1-S3.

[0028] The third aspect provides a nickel-containing front-side grid paste for TOPCon, which, by mass fraction, includes the following components: 78-85 wt% silver powder, 1-3 wt% nickel powder, 1-3 wt% mixed glass powder, and 13-18 wt% organic carrier.

[0029] Furthermore, the nickel-containing front-side grid paste comprises 81 wt% silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder, 0.4 wt% second glass powder, and 15.4 wt% organic carrier.

[0030] For example, the organic carrier mainly consists of resin, solvent, thixotropic agent, dispersant, and other additives. For instance, the organic carrier can be composed of one or more of the following: ethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, acrylic resin, oleic acid, stearic acid, polyethylene glycol, polyvinyl butyral, dimethyl adipate, triphosphate, epoxy resin, dodecyl alcohol ester, butyl carbitol acetate, diethylene glycol dibutyl ether, etc.

[0031] The silver powder is spherical with an average particle size of 1–2 μm, a D50 of 1–2 μm, a D90 of 1–6 μm, and a tap density of 4–6 g / m³. 3 .

[0032] In a preferred embodiment of the present invention, the nickel powder is spherical nickel powder with an average particle size of 0.5–2 μm, a D50 of 1–3 μm, a D90 of 3–5 μm, and a tap density of 0.6–1.2 g / m³. 3 By adjusting the particle size of the silver powder, using blends of silver powders with different particle sizes can further improve the density of the conductive network and the roughness of the pad points in the silver paste, thereby affecting the electrical properties and solderability.

[0033] The fourth aspect of the present invention also provides a method for preparing the nickel-containing front-side main grid paste for TOPCon, comprising the following steps: A1: Mix silver powder, nickel powder, first glass powder, second glass powder and organic carrier according to the specified ratio and stir evenly; A2: Grind the above mixture 6 to 8 times with a three-roll mill, filter and centrifuge to obtain a front grid slurry with a fineness ≤7μm and a viscosity of 30Pa•S to 100Pa•S.

[0034] The following detailed description, in conjunction with specific embodiments, provides a further detailed explanation of the mixed glass powder and its preparation method, as well as the nickel-containing front-side gate paste for TOPCon and its preparation method. The advantages and features of the present invention will become clearer from the following description.

[0035] Example 1 This embodiment illustrates two types of glass powder, as shown in Tables 1 and 2 below: Table 1 Table 2 The preparation method of the above-mentioned glass powder is as follows: S1: After weighing the raw materials according to Table 1 or 2 above, mix the raw materials thoroughly and evenly in the mixer; S2: The mixed raw materials are loaded into a corundum crucible and melted in a lifting furnace at 1100-1350℃ for 1-1.5 hours. After the glass melts and homogenizes, glass material is obtained by high-temperature water quenching or cold rolling pressing. S3: The glass material is dry-milled using a planetary ball mill at a speed of 300–650 r / min for 1–4 h. It is then further wet-milled using a horizontal ball mill with alcohol as the solvent at a speed of 100–300 r / min for 10–30 h. After drying, glass powder with a D50 of 1–3 μm is obtained.

[0036] Example 2 TOPCon uses nickel-containing front-side grid paste SY-1, which includes: 81 wt% conductive silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder ZB-1, 0.4 wt% second glass powder FB-1, and 15.4 wt% organic phase, wherein the organic phase is commercially available and is mainly an activated mixture of terpineol, ethyl cellulose, polyurethane, epoxy resin, and silane coupling agent.

[0037] Example 3 TOPCon uses nickel-containing front-side grid paste SY-2, which includes: 81 wt% conductive silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder ZB-2, 0.4 wt% second glass powder FB-1, and 15.4 wt% organic phase, wherein the organic phase is commercially available and is mainly an activation mixture of terpineol, ethyl cellulose, polyurethane, epoxy resin, and silane coupling agent.

[0038] Example 4 TOPCon uses nickel-containing front-side grid paste SY-3, which includes: 81 wt% conductive silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder ZB-1, 0.4 wt% second glass powder FB-2, and 15.4 wt% organic phase, wherein the organic phase is commercially available and is mainly an activated mixture of terpineol, ethyl cellulose, polyurethane, epoxy resin, and silane coupling agent.

[0039] The silver powders in Examples 2, 3, and 4 are spherical silver powders with an average particle size of 1-2 μm, a D50 of 1-2 μm, a D90 of 1-6 μm, and a tap density of 4-6 g / m³. 3 Nickel powder, specifically spherical nickel powder, with an average particle size of 0.5-2 μm, a D50 of 1-3 μm, a D90 of 3-5 μm, and a specific surface area of ​​0.6-1.2 m². 2 / g.

[0040] The preparation methods of the nickel-containing front-side main grid paste for TOPCon in Examples 2, 3, and 4 include: Step 1: Mix the conductive silver powder, nickel powder, glass powder, and organic carrier according to the specified ratio, and stir until homogeneous; Step 2: Grind the above mixture 6-8 times using a three-roll mill, filter and centrifuge to obtain a front grid slurry with a fineness ≤7μm and a viscosity of 30Pa•S~100Pa•S.

[0041] Comparative Example 1 This comparative example provides a control over the above embodiments using commercially available BSL slurry.

[0042] Comparative Example 2 This comparative example is largely the same as Example 1 above. The main difference is that in SY-1, Te2O3 in the first and second glass powders is removed, and the other components and their amounts are increased proportionally by 100% mass ratio. The slurry is designated as BSL-1.

[0043] The N-type TOPCon solar cell samples were obtained by using the pastes SY-1 / 2 / 3 in the examples, the BSL paste in the comparative example, and BSL-1 through the following steps. Step 1: Using a screen printing machine, conventional back grid and back main grid pastes are printed onto the back of the silicon wafer, which is then further dried in a drying oven at a temperature of 250-350℃. Step 2: After drying, the silicon wafer with the back side paste already printed is flipped over and reprinted with the pastes SY-1 / 2 / 3 in the example, BSL paste in the comparative example, and BSL-1 paste in the front side of the silicon wafer using a screen printing machine. After drying in a drying oven, it is then heated and sintered in a sintering furnace at a temperature of 650-800℃ for a peak time of 1-4s to obtain the printed solar cell.

[0044] Step 3: The cells then undergo further passivation using a light-injection annealing device. The peak temperature in the LED illumination area is between 200 and 320°C, and the light intensity is between 10% and 60%. After light-injection passivation, the cells are then irradiated with a high-intensity laser using a LECO laser-assisted sintering device, while a deflection voltage of 10V or higher is applied to obtain the final N-type TOPCon solar cell sample.

[0045] The obtained N-type TOPCon solar cell samples were then subjected to IV efficiency and tensile tests, and the recorded data are shown in Table 3.

[0046] Table 3 The results are shown in Table 3. The TOPCon nickel-containing front-side grid paste SY-1 / -2 used in this embodiment shows a significant improvement in photoelectric conversion efficiency compared to BSL, mainly reflected in the increased on-state voltage. Tensile testing results show that the welding performance of SY-1 / -2 is roughly equal to, but slightly stronger than, that of BSL. Furthermore, a comparison between SY-1 and SY-2 reveals a direct correlation between boron (B) content and on-state voltage; B can improve the glass-forming ability, resulting in a better glass layer during sintering. A comparison between SY-1 and SY-3 shows that the reduction in silicon content increases the corrosiveness of the paste to the silicon wafer, leading to a simultaneous decrease in both on-state voltage and open-factor (FF) of the battery, indicating some damage to the PN junction. Secondly, the test results of the comparative example BSL-1 show that tetrahydropalmatine (Te) also significantly affects the contact ability of the grid paste. Te enhances fluidity, guiding nickel powder to uniformly fill the gaps between silver particles during the silver powder sintering and rearrangement process, increasing the density of the conductive pathway, strengthening the conductive network, and compensating for the increased resistance caused by the decrease in silver content.

[0047] In summary, the nickel-containing front-side grid paste for TOPCon provided in this embodiment of the invention replaces part of the silver powder with base metal nickel. By controlling the distribution and rearrangement of nickel powder on the cell surface through adjustment of glass powder, it provides TOPCon cells with good etching depth and excellent welding pull strength. This ensures that, while reducing the amount of silver used, the electrical and mechanical properties are comparable to or slightly higher than those of conventional commercially available grids, achieving effective cost reduction and efficiency improvement. Simultaneously, nickel can form a NiSi2 alloy layer with silicon during sintering, preventing silver diffusion to the PN junction, reducing the risk of short circuits, and improving the long-term reliability of the battery.

[0048] The embodiments of the present invention have been described in detail above with reference to specific examples, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A mixed glass powder, characterized in that, It includes a first glass powder and a second glass powder, wherein the first glass powder accounts for 25-75% of the mass fraction of the mixed glass powder, and the second glass powder accounts for 25-75% of the mass fraction of the mixed glass powder; The first glass powder is a Pb-Si-B-Te glass powder system, and the second glass powder is a B-Si-Zn glass powder system. The glass softening point of the first glass powder is lower than that of the second glass powder. Based on the first glass powder as the measurement base, the first glass powder includes: 20-70 wt% PbO, 1-30 wt% SiO2, 0-20 wt% B2O3, 0-10 wt% TeO2, and 0-10 wt% R2O; Based on the second glass powder as the measurement base, the second glass powder includes: 0-70wt% B2O3, 0-70wt% SiO2, 5-30wt% ZnO, and 0-10wt% R2O; R2O is one or more of the alkali metal oxides Na2O, Li2O, and K2O.

2. The mixed glass powder according to claim 1, characterized in that, The first glass powder also includes one or more oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony, and the content of the oxides or salts of bismuth, zinc, magnesium, aluminum, calcium, copper, manganese, and antimony is 1 to 12 wt%.

3. The mixed glass powder according to claim 1, characterized in that, The second glass powder also includes one or more of the oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony, and the content of the oxides or salts of titanium, tellurium, magnesium, aluminum, calcium, barium, tungsten, copper, manganese, and antimony is 1 to 30 wt%.

4. A method for preparing the mixed glass powder as described in any one of claims 1-3, characterized in that, Includes the following steps: S1: Prepare the ingredients according to the proportion of the first glass powder and mix them thoroughly; S2: The mixed ingredients are loaded into a corundum crucible and melted in a lifting furnace at 1100-1350℃ for 1-1.5 hours. After the glass melts and homogenizes, glass material is obtained by high-temperature water quenching or cold rolling pressing. S3: The glass material is ground using a planetary ball mill to obtain glass powder with D50 < 3μm; The second glass powder is also prepared according to steps S1-S3.

5. A nickel-containing front-side grid paste for TOPCon, characterized in that, Calculated by mass fraction, it includes the following components: 78-85 wt% silver powder, 1-3 wt% nickel powder, 1-3 wt% mixed glass powder, and 13-18 wt% organic carrier; The mixed glass powder is the mixed glass powder according to any one of claims 1-3.

6. The nickel-containing front-side main grid paste for TOPCon according to claim 5, characterized in that, It includes 81 wt% silver powder, 2 wt% nickel powder, 1.2 wt% first glass powder, 0.4 wt% second glass powder, and 15.4 wt% organic carrier.

7. The nickel-containing front-side main grid paste for TOPCon according to claim 5, characterized in that, The organic carrier is mainly composed of resin, solvent, thixotropic agent, dispersant and other additives.

8. The nickel-containing front-side grid paste for TOPCon according to claim 5, characterized in that, The silver powder is spherical with an average particle size of 1–2 μm, a D50 of 1–2 μm, a D90 of 1–6 μm, and a tap density of 4–6 g / m³. 3 .

9. The nickel-containing front-side main grid paste for TOPCon according to claim 5, characterized in that, The nickel powder is spherical, with an average particle size of 0.5–2 μm, a D50 of 1–3 μm, a D90 of 3–5 μm, and a tap density of 0.6–1.2 g / m³. 3 .

10. A method for preparing a nickel-containing front-side main grid paste for TOPCon as described in any one of claims 5-9, characterized in that, Includes the following steps: A1: Mix silver powder, nickel powder, first glass powder, second glass powder and organic carrier according to the specified ratio and stir evenly; A2: Grind the above mixture 6 to 8 times with a three-roll mill, filter and centrifuge to obtain a front grid slurry with a fineness ≤7μm and a viscosity of 30Pa•S to 100Pa•S.

Images