Base metal main grid slurry, preparation method thereof and photovoltaic cell

Abstract

The invention provides base metal main grid slurry, a preparation method thereof and a photovoltaic cell. The base metal main grid slurry comprises 3-8 parts by mass of nickel powder, and the surface of the nickel powder is coated with a modified component; 0.5-1 part by mass of first glass powder; 0.5 to 1.5 parts by mass of second glass powder; 13-16 parts by mass of an organic phase; 0.2 to 0.5 part by mass of an organic auxiliary agent; 15-25 parts by mass of a first silver powder; and 45-60 parts by mass of a second silver powder. The base metal nickel is used for replacing part of silver powder, the wettability is improved through surface coating, meanwhile, glass elements are optimized, the glass softening point is reduced, the paste can be sintered at the low temperature, close combination of silver particles is facilitated, and the density and conductivity of a conducting layer are improved. According to the technical scheme, the sintering is compact, the conductivity is slightly higher than that of pure silver paste, and the effects that the efficiency is equal to that of the silver paste and the tension is slightly lower than that of the pure silver paste are achieved.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of battery slurry, and particularly relates to a base metal main grid slurry, a preparation method thereof and a photovoltaic cell. BACKGROUND

[0002] With the rapid development of the photovoltaic industry, there is an increasing demand for high-efficiency and low-cost solar cell modules. As a key material in the manufacturing process of solar cells, the cost of silver paste accounts for an important part of the non-silicon cost of the cell sheet. Silver powder is the first production cost in photovoltaic silver paste. Therefore, with the rise of silver prices, photovoltaic silver paste with low silver content and excellent performance has become the focus of the industry.

[0003] One of the prior arts, Chinese patent application CN 119833200 A, proposes a high-conductivity main grid electrode silver paste, a preparation method and application thereof. By doping silver alloy materials, cost reduction is achieved. However, in the above prior art, there is a problem of low tensile force / high line resistance. Further improvement is needed to meet the problem of basic flatness of tensile force and line resistance of pure silver paste. Moreover, silver-coated base metal is used, which has a complex coating process and is difficult to disperse, and the cost is still high. SUMMARY

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a base metal main grid slurry, a preparation method thereof and a photovoltaic cell.

[0005] In one aspect of the present disclosure, a base metal main grid slurry is provided, comprising:

[0006] 3-8 parts by mass of nickel powder, the surface of the nickel powder being coated with a modified component;

[0007] 0.5-1 parts by mass of a first glass powder;

[0008] 0.5-1.5 parts by mass of a second glass powder;

[0009] 13-16 parts by mass of an organic phase;

[0010] 0.2-0.5 parts by mass of an organic auxiliary agent;

[0011] 15-25 parts by mass of a first silver powder;

[0012] 45-60 parts by mass of a second silver powder.

[0013] Optionally, the modified component comprises one or more of fatty acids and their salts, carbon materials, polyaniline, polypyrrole, and polyvinylpyrrolidone high molecular polymer.

[0014] Optionally, the first glass powder is a Pb-Si-Ti-Zn system glass.

[0015] Optionally, the second glass powder is a Bi-Si-Cu-Mn-V-B system glass.

[0016] Optionally, the organic phase comprises an organic resin and an organic solvent, a dispersant and a thixotropic agent; wherein,

[0017] The organic resin is one or more of ethyl cellulose resin ethyl cellulose, PVB, CAB, acrylic resin, epoxy resin, SEPS;

[0018] The organic solvent is one or more of diethylene glycol butyl ether acetate, butyl carbitol, triethylene glycol methyl ether, alcohol ester twelve, alcohol ester sixteen, diethylene glycol dibutyl ether, tributyl citrate, dimethyl adipate, benzyl benzoate, dimethyl phthalate;

[0019] The dispersant is one or more of ED120, ED420, BYK-111, TDO, Span 85, TEGO Dispers 670, polyester phosphate dispersant;

[0020] The thixotropic agent is one or more of polyamide wax, hydrogenated castor oil.

[0021] Optionally, the organic auxiliary agent is one or more of antioxidant 1010, triethanolamine, BHT.

[0022] Optionally, the median particle size of the first silver powder is 0.4-0.6 μm, and the tap density is 4.5-5.5 g / cm 3 .

[0023] Optionally, the median particle size of the second silver powder is 0.8-1.0 μm, and the tap density is 5.5-6.5 g / cm 3 .

[0024] Another aspect of the present disclosure provides a preparation method of a base metal busbar paste, the preparation method comprising:

[0025] Obtaining surface-modified nickel powder;

[0026] Dispersing the organic phase, the organic auxiliary agent, the first glass powder, the second glass powder and the nickel powder under ultrasonic conditions, and preparing a glass paste through three-roll processing;

[0027] Adding the first silver powder and the second silver powder to the glass paste, and obtaining the base metal busbar paste as described above through dispersing and three-roll processing.

[0028] Another aspect of the present disclosure provides a photovoltaic cell, the photovoltaic cell comprising the base metal busbar paste as described above.

[0029] The disclosure provides a base metal main grid paste, a preparation method thereof and a photovoltaic cell. The base metal main grid paste comprises 3-8 parts by mass of nickel powder, the surface of the nickel powder being coated with a modified component; 0.5-1 part by mass of first glass powder; 0.5-1.5 parts by mass of second glass powder; 13-16 parts by mass of organic phase; 0.2-0.5 parts by mass of organic auxiliary agent; 15-25 parts by mass of first silver powder; and 45-60 parts by mass of second silver powder. The disclosure replaces part of the silver powder with nickel, improves the wettability by surface coating, optimizes the glass element, reduces the glass softening point, enables the paste to be sintered at a lower temperature, helps the close combination between silver particles, improves the density and conductivity of the conductive layer, thereby reducing the thermal damage to the substrate, achieving sintering density, and the conductivity being slightly greater than that of pure silver paste, the efficiency being the same as that of silver paste, and the tensile force being slightly lower than that of pure silver paste. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The flowchart of the preparation method of the base metal main grid paste is shown in the specific embodiment of the disclosure. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the disclosure, the disclosure will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the disclosure and are part of the embodiments of the disclosure, but not all the embodiments. Based on the embodiments of the disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the disclosure.

[0032] In one aspect of the disclosure, a base metal main grid paste is provided, comprising 3-8 parts by mass of nickel powder, the surface of the nickel powder being coated with a modified component; 0.5-1 part by mass of first glass powder; 0.5-1.5 parts by mass of second glass powder; 13-16 parts by mass of organic phase; 0.2-0.5 parts by mass of organic auxiliary agent; 15-25 parts by mass of first silver powder; and 45-60 parts by mass of second silver powder.

[0033] In the base metal main grid paste provided in the embodiment, part of the silver powder is replaced with nickel, and the wettability is improved by surface coating of the modified component, the glass element is optimized, the glass softening point is reduced, the paste can be sintered at a lower temperature, the close combination between silver particles is helped, the density and conductivity of the conductive layer are improved, thereby reducing the thermal damage to the substrate, achieving sintering density, and the conductivity being slightly greater than that of pure silver paste, the efficiency being the same as that of silver paste, and the tensile force being slightly lower than that of pure silver paste.

[0034] In some preferred embodiments, the modified components coating the nickel powder surface include one or more of fatty acids and their salts (e.g., C16 fatty acids), carbon materials (e.g., amorphous carbon or graphite carbon powder), polyaniline (PANI), polypyrrole (PPy), polyvinylpyrrolidone (PVP), and other high molecular weight polymers. Coating the nickel powder surface reduces its surface energy, enhances its compatibility with the organic phase, prevents agglomeration, ensures uniform dispersion of the nickel powder in the slurry, reduces defects in conductive channels, and improves conductivity.

[0035] In some other preferred embodiments, the first glass powder is a Pb-Si-Ti-Zn system glass. This glass powder has a low glass transition temperature, which is beneficial for low-temperature sintering, helps the bonding between silver particles, improves the density and mechanical strength of the conductive layer, and can isolate air to prevent nickel powder oxidation, while reducing damage to the silicon wafer and maintaining a high on-state voltage.

[0036] In some other preferred embodiments, the second glass powder is a Bi-Si-Cu-Mn-VB system glass. The strong reducing power of V reduces the oxidized nickel powder, while B improves the wettability of the glass powder on the silicon wafer. This glass powder also has a low glass transition temperature and can break down oxides on the nickel surface, promoting the formation of nickel-silicon alloys and increasing tensile strength.

[0037] In some other preferred embodiments, the organic phase includes organic resins and organic solvents, dispersants and thixotropic agents.

[0038] As a further preferred embodiment, the organic resin is one or more of ethyl cellulose resin, PVB, CAB, acrylic resin, epoxy resin, and SEPS.

[0039] As a further preferred embodiment, the organic solvent is one or more of diethylene glycol butyl ether acetate, butyl carbitol, triethylene glycol methyl ether, dodecyl alcohol ester, hexadecyl alcohol ester, diethylene glycol dibutyl ether, tributyl citrate, dimethyl adipate, benzyl benzoate, and dimethyl phthalate.

[0040] As a further preferred option, the dispersant is one or more of ED120, ED420, BYK-111, TDO, Span 85, TEGODispers 670, and polyester phosphate dispersants.

[0041] As a further preferred option, the thixotropic agent is one or more of polyamide wax and hydrogenated castor oil.

[0042] This embodiment achieves full wetting of organic powder through the synergistic effect of multiple organic resins, providing good thixotropy and leveling properties for screen printing paste, while ensuring the adhesion of the paste to the silicon wafer, and ensuring the fullness and flatness of the grid lines and pads after screen printing.

[0043] In some preferred embodiments, the organic additive is an antioxidant. This organic additive is one or more of antioxidant 1010, triethanolamine, and BHT. It captures free radicals at high temperatures, blocking the chain reaction of nickel powder oxidation. Furthermore, it provides long-term protection during the initial stages of drying and sintering, preventing the formation of insulating nickel oxide from the nickel powder, achieving high-temperature resistance during sintering, making its conductivity close to that of pure silver paste, and reducing costs.

[0044] In some other preferred embodiments, the median particle size of the first silver powder is 0.4-0.6 μm, and the tap density is 4.5-5.5 g / cm³. 3 These small-particle silver powders fill the gaps between large particles, increasing the density of conductive channels, optimizing the conductive network, and reducing line resistance.

[0045] In some other preferred embodiments, the median particle size of the second silver powder is 0.8-1.0 μm, and the tap density is 5.5-6.5 g / cm³. 3 This large-particle-size silver powder can provide the main conductive path, reduce electron transport impedance, and the particle size distribution forms a "skeleton-filler" structure, reducing contact resistance, improving conductivity, and making the paste performance close to that of pure silver paste.

[0046] like Figure 1 As shown, one aspect of this disclosure provides a method S100 for preparing a base metal grid paste, specifically including the following steps S110 to S130:

[0047] S110, Obtain surface-modified nickel powder.

[0048] Specifically, the modified components for coating the nickel powder surface include one or more of fatty acids and their salts, carbon materials (amorphous carbon / graphite carbon powder), polyaniline (PANI), polypyrrole (PPy), polyvinylpyrrolidone (PVP), and other high molecular weight polymers. The specific coating process is not specifically limited. For example, in some preferred embodiments, the nickel powder surface is pretreated by cleaning, the coating material is dissolved in an organic solvent to form a coating solution, the treated nickel powder is added to the coating solution, and after stirring, centrifugation, filtration, and drying, the modified nickel powder is obtained (mainly suitable for surface coating agents of PPy, PVP, PANI, fatty acids and their salts). In some preferred embodiments, the nickel powder surface is pretreated by cleaning, and the pretreated nickel powder is mixed uniformly with carbon material (graphite carbon powder / carbon nanotubes) at a mass ratio of 40-100:1. The mixture is then ball-milled for 60-180 minutes at a speed of 200-350 rpm. The weight ratio of nickel powder to zirconium beads (1-3 mm in diameter) is 1:1-6. After ball milling, the mixture is sieved to obtain coated nickel powder with a D50 of 1.5-2.5 μm. The modified material can effectively adsorb and coat the nickel powder surface, thus preventing nickel powder oxidation.

[0049] Step S110 of this embodiment can reduce the activation energy of the nickel powder surface, improve the compatibility of nickel powder with organic matter, and improve dispersion.

[0050] S120. The organic phase, organic additives, first glass powder, second glass powder and nickel powder are dispersed under ultrasonic conditions and then processed by three-roll milling to prepare glass slurry.

[0051] It should be noted that the content and specific composition of each component in step S120 can be referred to the above description, and will not be repeated here.

[0052] Step S120 of this embodiment can improve the conductivity of the slurry by allowing the silver particles to be more tightly packed together through microwave-ultrasound combined treatment, forming more conductive channels. Simultaneously, the microstructural changes that may occur during the treatment also contribute to improved conductivity, such as increasing the contact area between silver particles and reducing contact resistance.

[0053] S130. First silver powder and second silver powder are added to the glass slurry, and after dispersion treatment and three-roll processing, the base metal grid slurry described above is obtained.

[0054] It should be noted that the content and specific parameters of the first and second silver powders in step S120 can be referred to the previous description and will not be repeated here.

[0055] The preparation process of this embodiment is simple. By coating the surface of nickel powder and mixing glass powder and silver powder separately, the quality, performance stability and consistency of the slurry can be improved.

[0056] In another aspect of this disclosure, a photovoltaic cell is proposed, which includes the base metal grid paste described above. The paste serves as the grid electrode of the cell and is firmly connected to the cell by welding to ensure the long-term reliability of the module. It is used to collect photocurrent and transmit it to an external circuit.

[0057] The base metal gate paste will be further explained below with reference to specific embodiments:

[0058] Example 1

[0059] As shown in Table 1, the base metal grid paste of this example comprises: 3 parts by mass of nickel powder I, the surface of which is coated with graphite carbon powder; 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 15.5 parts by mass of organic phase; 0.5 parts by mass of organic additive; 20.5 parts by mass of first silver powder; and 59 parts by mass of second silver powder.

[0060] Further, the slurry preparation method of this embodiment includes: obtaining surface-modified nickel powder I; dispersing 15.5 parts by mass of organic phase, 0.5 parts by mass of organic additive, 0.5 parts by mass of first glass powder, 1 part by mass of second glass powder and 3 parts by mass of nickel powder I under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by mass of first silver powder and 59 parts by mass of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0061] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.4 Ω / cm, the welding tensile strength was 2.966 N, and the Eta was 26.237%.

[0062] Example 2

[0063] As shown in Table 1, the base metal grid paste of this example comprises: 5 parts by mass of nickel powder I, the surface of which is coated with graphite carbon powder; 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 15.5 parts by mass of organic phase; 0.5 parts by mass of organic additive; 20.5 parts by mass of first silver powder; and 57 parts by mass of second silver powder.

[0064] Further, the slurry preparation method of this embodiment includes: obtaining surface-modified nickel powder I; dispersing 15.5 parts by mass of organic phase, 0.5 parts by mass of organic additive, 0.5 parts by mass of first glass powder, 1 part by mass of second glass powder and 5 parts by mass of nickel powder I under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by mass of first silver powder and 57 parts by mass of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0065] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.66 Ω / cm, the welding tensile strength was 2.456 N, and the Eta was 26.231%.

[0066] Example 3

[0067] As shown in Table 1, the base metal grid paste of this example comprises: 5 parts by mass of nickel powder II, the surface of which is coated with PVP; 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 15.5 parts by mass of organic phase; 0.5 parts by mass of organic additive; 20.5 parts by mass of first silver powder; and 57 parts by mass of second silver powder.

[0068] Further, the slurry preparation method of this embodiment includes: obtaining surface-modified nickel powder II; dispersing 15.5 parts by mass of organic phase, 0.5 parts by mass of organic additive, 0.5 parts by mass of first glass powder, 1 part by mass of second glass powder and 5 parts by mass of nickel powder II under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by mass of first silver powder and 57 parts by mass of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0069] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.46 Ω / cm, the welding tensile strength was 2.885 N, and the Eta was 26.231%.

[0070] Example 4

[0071] As shown in Table 1, the base metal grid paste of this example comprises: 5 parts by mass of nickel powder III, the surface of which is coated with C16 fatty acid; 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 15.5 parts by mass of organic phase; 0.5 parts by mass of organic additive; 20.5 parts by mass of first silver powder; and 57 parts by mass of second silver powder.

[0072] Further, the slurry preparation method of this embodiment includes: obtaining surface-modified nickel powder III; dispersing 15.5 parts by weight of organic phase, 0.5 parts by weight of organic additive, 0.5 parts by weight of first glass powder, 1 part by weight of second glass powder and 5 parts by weight of nickel powder III under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by weight of first silver powder and 57 parts by weight of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0073] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.89 Ω / cm, the welding tensile strength was 2.012 N, and the Eta was 25.892%.

[0074] Comparative Example 1

[0075] As shown in Table 1, the base metal grid paste of this example comprises: 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 16 parts by mass of organic phase; 20.5 parts by mass of first silver powder; and 62 parts by mass of second silver powder.

[0076] Furthermore, the slurry preparation method of this embodiment includes: dispersing 16 parts by mass of organic phase, 0.5 parts by mass of first glass powder, and 1 part by mass of second glass powder under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by mass of first silver powder and 62 parts by mass of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0077] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.33 Ω / cm, the welding tensile strength was 3.069 N, and the Eta was 26.246%.

[0078] Comparative Example 2

[0079] As shown in Table 1, the base metal grid paste of this example comprises: 0.5 parts by mass of first glass powder; 1 part by mass of second glass powder; 15.5 parts by mass of organic phase; 0.5 parts by mass of organic additive; 20.5 parts by mass of first silver powder; and 62 parts by mass of second silver powder.

[0080] Further, the slurry preparation method of this embodiment includes: dispersing 15.5 parts by weight of organic phase, 0.5 parts by weight of organic additive, 0.5 parts by weight of first glass powder, and 1 part by weight of second glass powder under ultrasonic conditions and then preparing a glass slurry with a fineness ≤7μm using a three-roll mill; adding 20.5 parts by weight of first silver powder and 62 parts by weight of second silver powder to the glass slurry, and then dispersing and processing it using a three-roll mill to obtain a finished slurry with a fineness ≤6μm.

[0081] The slurry obtained in this example was used to form a photovoltaic cell. The test performance results are shown in Table 2. The line resistance was 3.26 Ω / cm, the welding tensile strength was 2.987 N, and the Eta was 26.252%.

[0082] It should be noted that the above embodiments are mainly used to illustrate whether the slurry includes nickel powder, and the effect of different contents and different modified components on the nickel powder coating treatment on the slurry. The components and parameters of the first glass powder, the second glass powder, the organic phase, the organic additives, and the first and second silver powders are all the same. For example, the first glass powder is a Pb-Si-Ti-Zn system glass, which includes the following components: PbO 40-70%; SiO2 20-30%; TiO2 5-10%; ZnO 5-8%; WO3 0.2-1%; Al2O3 0.5-2%; D50 controlled at 0.8-2μm; softening point controlled at 350℃-450℃; the second glass powder is a Bi-Si-Cu-Mn-VB system glass, which includes the following components: Bi2O3 35-50%; SiO2 10-20%; CuO 10-20%; MnO2 3~8%; V2O5 0.5~1%; B2O3 3-8%; D50 controlled at 0.8-2μm, softening temperature at 550℃-650℃; the organic phase includes organic resin and organic solvent, dispersant and thixotropic agent, wherein the preparation method of the organic phase includes: mixing and stirring 20wt% butyl carbitol, 40wt% diethylene glycol butyl ether acetate, 10% diethylene glycol dibutyl ether, 5wt% tripropylene glycol methyl ether, 10wt% ethyl cellulose, 3wt% rosin-modified phenolic resin, 4wt% PVB, 2wt% SEPS, 3wt% polyether fatty acid (dispersant) and 3wt% polyamide wax (thixotropic agent), heating and stirring at 80℃ for 2h, dispersing at 1000rpm, and then allowing to stand and cool to obtain the organic phase; the organic additive is antioxidant BHT; the first silver powder is spherical silver powder with a median particle size of 0.4-0.6μm and a tap density of 4.5-5.5g / cm³. 3 The second type of silver powder is spherical, with a median particle size of 0.8-1.0 μm and a tap density of 5.5-6.5 g / cm³. 3 .

[0083] In summary, the line resistance of the nickel-doped sample was slightly higher than that of the comparative pure silver paste, indicating that the nickel-doped paste has excellent conductivity. By using nickel powder coating and a two-component silver powder design, the amount of silver used can be reduced, achieving a balance between cost reduction and performance.

[0084] Table 1. Slurry formulations for each embodiment and comparative example.

[0085]

[0086] Table 2 Test results for each embodiment and comparative example

[0087]

[0088]

[0089] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A base metal main grid paste, characterized by, It comprises: 3-8 parts by mass of nickel powder, the surface of which is coated with a modified component; 0.5-1 part by mass of a first glass powder; 0.5-1.5 parts by mass of a second glass powder; 13-16 parts by mass of an organic phase; 0.2-0.5 parts by mass of an organic auxiliary agent; 15-25 parts by mass of a first silver powder; 45-60 parts by mass of a second silver powder.

2. The base metal main grid paste of claim 1, wherein, The modified component comprises one or more of fatty acids and their salts, carbon materials, polyaniline, polypyrrole, polyvinylpyrrolidone high molecular polymer.

3. The base metal main grid paste of claim 1 wherein, The first glass powder is a glass of Pb-Si-Ti-Zn system.

4. The base metal main grid paste of claim 1 wherein, The second glass powder is a glass of Bi-Si-Cu-Mn-V-B system.

5. The base metal main grid paste of claim 1 wherein, The organic phase comprises organic resin and organic solvent, dispersant and thixotropic agent; wherein, The organic resin is one or more of ethyl cellulose resin ethyl cellulose, PVB, CAB, acrylic resin, epoxy resin, SEPS; The organic solvent is one or more of diethylene glycol butyl ether acetate, butyl carbitol, triethylene glycol methyl ether, alcohol ester twelve, alcohol ester sixteen, diethylene glycol dibutyl ether, tributyl citrate, dimethyl adipate, benzyl benzoate, dimethyl phthalate; The dispersant is one or more of ED120, ED420, BYK-111, TDO, Span 85, TEGO Dispers 670, polyester phosphate dispersant; The thixotropic agent is one or more of polyamide wax, hydrogenated castor oil.

6. The base metal main grid paste of claim 1 wherein, The organic auxiliary agent is one or more of antioxidant 1010, triethanolamine, BHT.

7. The base metal main grid paste of claim 1 wherein, The first silver powder has a median particle size of 0.4-0.6 μm and a tap density of 4.5-5.5 g / cm 3 .

8. The base metal main grid paste of claim 1 wherein, The median particle size of the second silver powder is 0.8-1.0 μm, and the tap density is 5.5-6.5 g / cm 3 .

9. A method of preparing a base metal main grid paste, characterized by, The preparation method comprises: obtaining surface-modified nickel powder; dispersing the organic phase, the organic auxiliary agent, the first glass powder, the second glass powder and the nickel powder under ultrasonic conditions, and preparing a glass paste through three-roll processing; adding the first silver powder and the second silver powder to the glass paste, and obtaining the base metal bus bar paste of any one of claims 1-8 through dispersing and three-roll processing.

10. A photovoltaic cell, characterized by, The photovoltaic cell comprises the base metal bus bar paste of claim 9.

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