Glass powder for back paste of PERC cell and preparation method and application thereof

Abstract

The present application relates to the technical field of solar cell back electrode paste, especially to the field of IPC C03C12, and more particularly to a glass powder for PERC cell back paste, a preparation method and application thereof.The glass powder comprises glass powder A and glass powder B.The glass powder A comprises the following components: SiO2, CuO, MnO2, B2O3, Bi2O3, TiO2, WO3, Cr2O3 and BaCO3.The glass powder B comprises the following components: SiO2, CuO, B2O3, PbO, TiO2, TeO2, WO3, Cr2O3 and AlF3.By optimizing the types and contents of raw materials of the glass powder, the weight ratio of the glass powder A and the glass powder B is (0.8-1.2):(0.2-0.6), and after machine soldering aging, the decrease of the tensile value can be controlled within 10% (730 DEG C) and 6% (780 DEG C).

Description

Technical Field

[0001] This invention relates to the field of solar cell back electrode paste technology, particularly to the field of IPC C03C12, and more specifically, to a glass powder for PERC cell back electrode paste, its preparation method and application. Background Technology

[0002] As silicon material production expansion drives upstream cost reduction, the cost advantage of photovoltaic power generation as a low-cost power generation method becomes more prominent. To further reduce the cost of photovoltaic cells and increase output, the silver content and wet weight of PERC back-side silver paste are continuously decreasing. This brings new challenges to the tensile strength, aging tensile strength, and reliability of PERC back-side silver paste. To ensure qualified mechanical welding aging tensile strength, the glass powder in the PERC back-side silver paste needs to partially etch the passivation film on the back of the cell to provide a suitable tensile strength value. On the other hand, the degree of corrosion of the passivation film should not affect the cell's on-state voltage and other electrical performance parameters, and it should be able to adapt to a wide sintering temperature window. These technical problems urgently need to be solved.

[0003] CN102855961B discloses a paste for forming the back electrode of a solar cell and its preparation method. By using glass powder with a softening point of 400-550℃, glass powder with a softening point of 370-400℃, and glass powder with a softening point of 550-590℃, the paste can adapt to different sintering conditions and broaden the sintering temperature range in the high-temperature zone. However, it cannot solve the problems of insufficient welding tensile strength and welding aging tensile strength at lower sintering temperatures. Summary of the Invention

[0004] The first aspect of the present invention provides a glass powder for the back slurry of a PERC battery, comprising: glass powder A and glass powder B, wherein glass powder A comprises the following components: SiO2, CuO, MnO2, B2O3, Bi2O3, TiO2, WO3, Cr2O3 and BaCO3; and glass powder B comprises the following components: SiO2, CuO, B2O3, PbO, TiO2, TeO2, WO3, Cr2O3 and AlF3.

[0005] The glass powder A comprises the following components: 20-50 parts SiO2, 5-30 parts CuO, 2-26 parts MnO2, 2-16 parts B2O3, 20-40 parts Bi2O3, 1-10 parts TiO2, 0.2-8 parts WO3, 0.8-6 parts Cr2O3, and 0.5-4 parts BaCO3.

[0006] By weight, the glass powder A comprises the following components: 25-45 parts SiO2, 8-25 parts CuO, 3-20 parts MnO2, 2-10 parts B2O3, 25-38 parts Bi2O3, 2-10 parts TiO2, 0.5-6 parts WO3, 1-4 parts Cr2O3, and 0.8-3 parts BaCO3.

[0007] By weight, the glass powder B comprises the following components: 20-50 parts SiO2, 5-30 parts CuO, 3-15 parts B2O3, 10-35 parts PbO, 2-20 parts TiO2, 2-12 parts TeO2, 0.5-10 parts WO3, 1-8 parts Cr2O3, and 1-8 parts AlF3.

[0008] By weight, the glass powder B comprises the following components: 25-45 parts SiO2, 10-25 parts CuO, 5-12 parts B2O3, 10-30 parts PbO, 2-15 parts TiO2, 3-10 parts TeO2, 0.5-8 parts WO3, 1-6 parts Cr2O3, and 1-4 parts AlF3.

[0009] The weight ratio of WO3, Cr2O3 and BaCO3 in the glass powder A is 1:(0.7-1):(1.8-2.5).

[0010] Preferably, the weight ratio of WO3, Cr2O3 and BaCO3 in the glass powder A is 1.3:1.2:2.5.

[0011] The weight ratio of WO3, Cr2O3 and AlF3 in the glass powder B is 1:(0.5-0.8):(1.5-2.5).

[0012] Preferably, the weight ratio of WO3, Cr2O3 and AlF3 in the glass powder B is 2:1.2:3.5.

[0013] The weight ratio of glass powder A to glass powder B is (0.8-1.2):(0.2-0.6).

[0014] Preferably, the weight ratio of glass powder A to glass powder B is (0.8-1):(0.4-0.6).

[0015] More preferably, the weight ratio of glass powder A to glass powder B is 1:0.4.

[0016] The applicant's research found that by optimizing the types and content of glass powder raw materials, a wider sintering window (730-780℃) and stable aging tensile strength during sintering machine welding were achieved. This may be because the two types of glass powder used have specific glass transition (Tg) temperature ranges (e.g., Figure 1 The glass powder A shown has a Tg of 614.21℃. Figure 2 The glass powder B shown has a Tg of 762.25℃, balancing the conflicting requirements of backplane passivation layer corrosion and hoist welding tensile strength on the glass powder's activity. Further research revealed that when the weight ratio of glass powder A to glass powder B is (0.8-1.2):(0.2-0.6), the decrease in welding tensile strength during 780℃ sintering can be controlled within 6%. It's possible that glass powder A functions at lower temperatures, enabling the transport of various functional components in the slurry to the surface of the semiconductor substrate. However, excessive glass powder A content at high temperatures can damage the system, hindering the physical and chemical reactions between various powder particles at high temperatures, and also corroding the backplane film.

[0017] The applicant's research found that the weight ratio of WO3, Cr2O3, and BaCO3 in glass powder A is 1:(0.7-1):(1.8-2.5), which improves the tensile strength during machine welding aging after sintering at 740℃. This is likely because WO3 has a strong polarization ability in glass, creating a strong ionic field that easily attracts anions, making the glass more prone to crystallization and altering its properties. Simultaneously, the addition of a specific proportion of AlF3 to glass powder B also improves both the tensile strength during machine welding aging at 740℃ and the photoelectric conversion efficiency.

[0018] A second aspect of this invention provides a method for preparing glass powder for the back slurry of PERC batteries, comprising the following steps:

[0019] Step 1: Put all the components of glass powder A and glass powder B into a mixer and mix them thoroughly;

[0020] Step 2: Load the well-mixed raw materials into a crucible, then place the crucible into a box-type resistance furnace, heat the resistance furnace to 1300-1600℃ and keep it at a constant temperature for 30-60 minutes to obtain a uniform glass melt.

[0021] Step 3: Pour the molten glass into a stainless steel container with a stirrer and containing deionized water and quench it to obtain glass fragments;

[0022] Step 4: Place the obtained glass fragments into a constant temperature drying oven at 100-120℃ and dry for 2-3 hours;

[0023] Step 5: Grind the dried glass shards using a planetary ball mill for 0.5-1 hour, then further grind them using an air jet mill.

[0024] That's it.

[0025] Preferably, the D50 particle size of the milled material is 1.0-2.5 μm.

[0026] A third aspect of the present invention provides a back slurry for a PERC battery, wherein the slurry comprises, by weight, 0.5-2 parts glass powder, 60-64 parts microcrystalline silver powder, and 30-45 parts organic carrier.

[0027] Preferably, the slurry comprises: 1-2 parts glass powder, 60-64 parts microcrystalline silver powder, and 34.4-39 parts organic carrier.

[0028] Preferably, the microcrystalline silver powder includes YRS series silver powder (Suzhou Yinrui).

[0029] The organic carrier, by mass percentage, comprises: 1-4% ethyl cellulose, 1-5% resin, 50-70% terpineol, 10-30% diethylene glycol methyl ether, 10-18% butyl carbolic acid acetate, and 0.5-2% lecithin.

[0030] Preferably, the organic carrier comprises, by mass percentage: 2.5% ethyl cellulose, 2% resin, 60% terpineol, 20% diethylene glycol methyl ether, 14.5% butyl carbolic acid acetate, and 1% lecithin.

[0031] The preparation of the PERC battery back slurry includes the following steps: mixing glass powder, microcrystalline silver powder and organic carrier, stirring evenly with a V-type mixer, and then grinding on a three-roll mill to obtain the final product.

[0032] Beneficial effects:

[0033] 1. By optimizing the types and content of raw materials for glass powder, the two types of glass powder used have suitable glass transition temperature ranges, balancing the requirements of glass powder activity on the two contradictory aspects of backplate passivation layer corrosion and lifting machine welding pull force, and have a wide sintering window (730-780℃).

[0034] 2. The weight ratio of glass powder A to glass powder B is (0.8-1.2):(0.2-0.6), and the decrease in tensile strength value during aging in the 780℃ sintering machine can be controlled within 6%.

[0035] 3. The weight ratio of WO3, Cr2O3 and BaCO3 in the glass powder A is 1:(0.7-1):(1.8-2.5), which can effectively improve the photoelectric conversion efficiency, reaching 23.25%.

[0036] 4. The weight ratio of WO3, Cr2O3, and AlF3 in the glass powder B is 2:1.2:3.5, which can simultaneously improve...

[0037] The tensile strength and photoelectric conversion efficiency of machine welding aging at 730℃.

[0038] Instruction manual illustrations

[0039] Figure 1 This is the thermal analysis diagram of glass powder A2.

[0040] Figure 2 This is the thermal analysis diagram of glass powder B2. Detailed Implementation

[0041] A glass powder for the back slurry of a PERC battery is comprising glass powder A and glass powder B. The components of glass powder A are shown in Table 1, namely A1, A2 and A3, and the components of glass powder B are shown in Table 2, namely B1, B2 and B3.

[0042] Table 1

[0043] Components (parts by weight) A1 A2 A3 <![CDATA[SiO2]]> 25 30 35 CuO 15.5 15.5 15.5 <![CDATA[MnO2]]> 6 6 6 <![CDATA[B2O3]]> 2.5 2.5 2.5 <![CDATA[Bi2O3]]> 33 33 33 <![CDATA[TiO2]]> 5.2 5.2 5.2 <![CDATA[WO3]]> 0 1.3 1.8 <![CDATA[Cr2O3]]> 0 1.2 1.7 <![CDATA[BaCO3]]> 2.5 2.5 2.5

[0044] Table 2

[0045] Components (parts by weight) B1 B2 B3 <![CDATA[SiO2]]> 30 34.5 38 CuO 20.5 20.5 20.5 <![CDATA[B2O3]]> 6.5 6.5 6.5 PbO 17.5 17.5 17.5 <![CDATA[TiO2]]> 8.3 8.3 8.3 <![CDATA[TeO2]]> 5.2 5.2 5.2 <![CDATA[WO3]]> 0 2 2.5 <![CDATA[Cr2O3]]> 0 1.2 1.8 <![CDATA[AlF3]]> 0 3.5 5

[0046] In Example 1, the glass powders are A2 and B2, and the weight ratio of A1 to B1 is 1:0.4.

[0047] In Example 2, the glass powder consists of A1 and B1, and the weight ratio of A1 to B1 is 1:0.4.

[0048] In Example 3, the glass powders are A1 and B2, and the weight ratio of A1 to B2 is 1:0.4.

[0049] In Example 4, the glass powders are A1 and B3, and the weight ratio of A1 to B3 is 1:0.4.

[0050] In Example 5, the glass powders are A2 and B2, and the weight ratio of A1 to B1 is 0.4:1.

[0051] In Example 6, the glass powders are A2 and B3, and the weight ratio of A2 to B3 is 1:0.4.

[0052] The glass powder in Example 7 is A3 and B3, and the weight ratio of A3 to B3 is 1:0.4.

[0053] A method for preparing glass powder for the back slurry of PERC batteries comprises the following steps:

[0054] Step 1: Put all the components of glass powder A and glass powder B into a mixer and mix them thoroughly;

[0055] Step 2: Put the well-mixed raw materials into a crucible, then put the crucible into a box-type resistance furnace, heat the resistance furnace to 1500℃ and keep it at a constant temperature for 30 minutes to obtain a uniform glass melt.

[0056] Step 3: Pour the molten glass into a stainless steel container with a stirrer and containing deionized water and quench it to obtain glass fragments;

[0057] Step 4: Place the obtained glass fragments in a 120℃ constant temperature drying oven and dry for 3 hours;

[0058] Step 5: The dried glass shards are ball-milled for 1 hour using a planetary ball mill, and then ground by an air jet mill until the D50 particle size is 1.7 μm.

[0059] A PERC battery back slurry, by weight, comprises 1.4 parts glass powder, 62 parts microcrystalline silver powder, and 36.6 parts organic carrier.

[0060] The microcrystalline silver powder is model YRS-P182 (Suzhou Yinrui).

[0061] The organic carrier, by mass percentage, comprises: 2.5% ethyl cellulose, 2% acrylic resin (Shanghai Kaizhi New Material Technology Co., Ltd.), 60% terpineol, 20% diethylene glycol methyl ether, 14.5% butyl carbolic acid acetate, and 1% lecithin.

[0062] The preparation of the PERC battery back slurry is carried out by the following steps: mixing glass powder, microcrystalline silver powder and organic carrier, stirring evenly with a V-type mixer, and then grinding on a three-roll mill to obtain the final product.

[0063] Performance testing methods

[0064] The paste prepared in the examples was screen-printed onto a single-crystal silicon substrate (166mm × 166mm), ensuring that the wet weight of the paste printed on the substrate was 3.6 mg / cm³. 2 After drying, the silicon substrate is sintered at peak temperatures of 730°C and 780°C; after exiting the furnace, it is mechanically welded using a stringer to obtain the finished PERC battery.

[0065] Mechanical welding tensile test method: After mechanical welding with a string welding machine, the tensile values ​​before and after aging and at different temperatures are tested to obtain the force when the welding strip is pulled off; Test instrument: Horizontal battery cell welding strip peeling tensile tester (Lianbitop LN8506); Mechanical welding aging conditions: Oven temperature 150℃, drying time 30min.

[0066] IV test (efficiency value, photoelectric conversion): The test was conducted using a single-flash simulator. The IV test conditions were: light intensity: 1000W / m². 2 Spectrum: AM 1.5; Temperature: 25℃; Test method according to 1SUN standard. Test instrument: Halm IV tester (Halm GmbH, Germany).

[0067] The test results are shown in Table 3.

[0068] Performance test data

[0069] Table 3

[0070]

Claims

1. A glass powder for the back slurry of a PERC battery, characterized in that, include: Glass powder A and glass powder B, by weight, wherein glass powder A comprises the following components: 20-50 parts SiO2, 5-30 parts CuO, 2-26 parts MnO2, 2-16 parts B2O3, 20-40 parts Bi2O3, 1-10 parts TiO2, 0.2-8 parts WO3, 0.8-6 parts Cr2O3, and 0.5-4 parts BaCO3; and glass powder B comprises the following components: 20-50 parts SiO2, 5-30 parts CuO, 3-15 parts B2O3, 10-35 parts PbO, 2-20 parts TiO2, 2-12 parts TeO2, 0.5-10 parts WO3, 1-8 parts Cr2O3, and 1-8 parts AlF3. The weight ratio of WO3, Cr2O3 and BaCO3 in the glass powder A is 1:(0.7-1):(1.8-2.5). The weight ratio of glass powder A to glass powder B is (0.8-1.2):(0.2-0.6).

2. The glass powder for the back slurry of a PERC battery according to claim 1, characterized in that, By weight, the glass powder A comprises the following components: 25-45 parts SiO2, 8-25 parts CuO, 3-20 parts MnO2, 2-10 parts B2O3, 25-38 parts Bi2O3, 2-10 parts TiO2, 0.5-6 parts WO3, 1-4 parts Cr2O3, and 0.8-3 parts BaCO3.

3. The glass powder for the back slurry of a PERC battery according to claim 2, characterized in that, By weight, the glass powder B comprises the following components: 25-45 parts SiO2, 10-25 parts CuO, 5-12 parts B2O3, 10-30 parts PbO, 2-15 parts TiO2, 3-10 parts TeO2, 0.5-8 parts WO3, 1-6 parts Cr2O3, and 1-4 parts AlF3.

4. A method for preparing glass powder for the back slurry of a PERC battery according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Put all the components of glass powder A and glass powder B into a mixer and mix them evenly; Step 2: Load the well-mixed raw materials into a crucible, then place the crucible into a box-type resistance furnace, heat the resistance furnace to 1300-1600℃ and keep it at a constant temperature for 30-60 minutes to obtain molten glass. Step 3: Pour the molten glass into a stainless steel container with a stirrer containing deionized water and quench it to obtain glass fragments; Step 4: Place the obtained glass fragments into a constant temperature drying oven at 100-120℃ and dry for 2-3 hours; Step 5: Grind the dried glass shards using a planetary ball mill for 0.5-1 hour, and then grind them using an air jet mill to obtain the final product.

5. The method for preparing glass powder for the back slurry of a PERC battery according to claim 4, characterized in that, The D50 particle size of the milled material is 1.0-2.5 μm.

6. The application of a glass powder for the back slurry of a PERC battery according to any one of claims 1-3, characterized in that, The paste, applied to the back of PERC batteries, comprises, by weight: 0.5-2 parts of glass powder as described in any one of claims 1-3, 60-64 parts of microcrystalline silver powder, and 30-45 parts of organic carrier.

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