A two-component organic vehicle, its preparation method and use

Abstract

The application relates to the technical field of solar cells, in particular to a two-component organic carrier and a preparation method and application thereof, the organic carrier comprises A component and B component, preparation raw materials of the A component comprise a first resin base, a first solvent, a first thixotropic agent and a first auxiliary agent; preparation raw materials of the B component comprise a second resin base, a second solvent, a second thixotropic agent and a second auxiliary agent; preparation raw materials of the first resin base comprise polyvinyl butyral resin and first cellulose; and preparation raw materials of the second resin base comprise polyvinyl butyral resin and second cellulose. The prepared organic carrier is tested, the single consumption range of the organic carrier can be controlled within 20%, with the decrease of the single consumption, the machine welding tension and the aging tension are both stabilized above 3N, and the requirements of the reliability of the tension of the crystalline silicon solar cell piece can be met.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a two-component organic carrier, its preparation method, and its application. Background Technology

[0002] In recent years, driven by the trend of carbon neutrality and energy structure transformation, crystalline silicon solar cells have experienced rapid growth, leading to increasingly fierce market competition. To stand out in this competitive market and maintain strong product competitiveness, crystalline silicon solar cell manufacturers have placed particular emphasis on improving efficiency and reducing costs. Electrode paste, an indispensable component in the metallization process of crystalline silicon solar cells, is the second most expensive material after silicon wafers, accounting for approximately 10% of the cost of crystalline silicon solar cells and even exceeding 30% of the non-silicon cost. Therefore, electrode paste has become a key focus for crystalline silicon solar cell manufacturers. Improving efficiency and reducing costs in the main grid electrode silver paste has become a direction for the development of main grid electrode paste technology. Cost reduction in main grid electrode silver paste mainly involves reducing solid content and unit consumption. However, simply reducing solid content and unit consumption may increase the risk of reliability failure in crystalline silicon solar cells. Therefore, it is necessary to develop a main grid electrode silver paste for crystalline silicon solar cells with a reasonable unit cost (i.e., a fixed solid content range) and controllable unit consumption range while meeting reliability requirements, to meet the needs of crystalline silicon solar cell manufacturers.

[0003] Chinese patent CN109897389A discloses an organic carrier for silver paste on the front side of crystalline silicon solar cells and its preparation method. The organic carrier is prepared by a mixture of resin, solvent and additives and used in the silver paste on the front side of silicon solar cells. The silver paste printing line width can be less than 40 μm and the aspect ratio is greater than 0.4, which is more conducive to improving the efficiency of crystalline silicon cells. However, this formula has high unit consumption in practical applications and cannot achieve a balance between unit consumption and tensile strength. Summary of the Invention

[0004] To address the need for controllable consumption range, the first aspect of this invention provides a two-component organic carrier, comprising component A and component B. The raw materials for preparing component A include: a first resin base, a first solvent, a first thixotropic agent, and a first auxiliary agent; the raw materials for preparing component B include: a second resin base, a second solvent, a second thixotropic agent, and a second auxiliary agent.

[0005] The raw materials for preparing the first resin base material include: polyvinyl butyral resin and first cellulose; the raw materials for preparing the second resin base material include: polyvinyl butyral resin and second cellulose.

[0006] In some embodiments, the viscosity of the polyvinyl butyral resin is 3-500 mPa·s, and it is preferably sourced from Kuraray.

[0007] In some embodiments, the raw materials for preparing component A, by weight percentage, include: 12-30% of a first resin base, 60-85% of a first solvent, 3-8% of a first thixotropic agent, and 0-2% of a first auxiliary agent; the raw materials for preparing component B include: 12-30% of a second resin base, 60-85% of a second solvent, 3-8% of a second thixotropic agent, and 0-2% of a second auxiliary agent.

[0008] In some embodiments, the weight ratio of component A to component B is (2-11):(2-11).

[0009] In some embodiments, the raw materials for preparing the first resin base material, by weight, include: 10-20 parts of polyvinyl butyral resin and 10-150 parts of first cellulose; the raw materials for preparing the second resin base material include: 10-20 parts of polyvinyl butyral resin and 10-150 parts of second cellulose.

[0010] In some embodiments, the first cellulose includes at least one of cellulose acetate butyrate, cellulose acetate propionate, methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, and carboxymethylcellulose.

[0011] Further, the first cellulose comprises cellulose acetate butyrate and cellulose acetate propionate in a weight ratio of (5-75):(5-75).

[0012] In some embodiments, the viscosity of the first cellulose is 3-500 mPa·s, and it is preferably sourced from Eastman.

[0013] Furthermore, the viscosity of the cellulose acetate butyrate is 5 mPa·s, and it is preferably sourced from Eastman.

[0014] Furthermore, the viscosity of the cellulose acetate propionate is 20 mPa·s, and it is preferably sourced from Eastman.

[0015] In some embodiments, the second cellulose includes at least one of ethyl cellulose, cellulose acetate propionate, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and carboxymethyl cellulose.

[0016] Furthermore, the second cellulose comprises ethyl cellulose and cellulose acetate propionate in a weight ratio of (5-75):(5-75).

[0017] In some embodiments, the viscosity of the second cellulose is 3-500 mPa·s, and it is preferably sourced from Eastman.

[0018] Furthermore, the viscosity of the ethyl cellulose is 5 mPa·s, and it is preferably sourced from Eastman.

[0019] Furthermore, the viscosity of the cellulose acetate propionate is 20 mPa·s, and it is preferably sourced from Eastman.

[0020] The applicant discovered that by adjusting the ratio of components A and B in this invention, the unit consumption can be further reduced. In particular, the cellulose acetate butyrate and cellulose acetate propionate of component A are compounded in a weight ratio of (5-75):(5-75), and combined with the ethyl cellulose and cellulose acetate propionate of component B in a weight ratio of (5-75):(5-75). On the one hand, this can enhance the compatibility of cellulose-polyvinyl butyral resin-silver particles in silver paste. On the other hand, it can also significantly reduce the unit consumption. This may be because cellulose acetate butyrate, cellulose acetate propionate, and ethyl cellulose with specific viscosities can form a viscosity gradient in the system, which is beneficial to reducing the unit consumption. Furthermore, the specific groups of the three can interact better with polyvinyl butyral resin with specific parameters. Compared with cellulose carrying other types of groups, it is more conducive to reducing the unit consumption in this system while maintaining good tensile strength.

[0021] In some embodiments, the first solvent and the second solvent each include at least one of diethylene glycol monobutyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, tristearate glyceryl alcohol, terpineol, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, triethylene glycol butyl ether, and tripropylene glycol methyl ether.

[0022] Furthermore, both the first solvent and the second solvent comprise diethylene glycol monobutyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, with a weight ratio of (25-45):(25-45):(15-30):(15-30).

[0023] The applicant discovered that the choice of solvent in the system has a significant impact on the quality of the silver paste. Existing solvents often have relatively concentrated boiling points, leading to complete evaporation and the appearance of bubbles and pores on the silver paste surface. During the investigation, the applicant unexpectedly found that using a blend of the four solvents mentioned above in this system resulted in a silver paste with better film formation, a more uniform and delicate film surface, and minimized the problems of pores and bubbles on the film surface. The reason for this is likely that the four solvents can evaporate in a gradient during film formation, resulting in a more uniform evaporation process and degree. This improves film quality while balancing unit consumption and tensile strength, thus largely solving the problem of low tensile strength caused by low unit consumption that has long plagued existing technologies.

[0024] In some embodiments, the first thixotropic agent and the second thixotropic agent each include at least one of hydrogenated castor oil, polyamide wax, polyurea, fumed silica, and modified polyamide wax.

[0025] Furthermore, both the first thixotropic agent and the second thixotropic agent comprise hydrogenated castor oil and polyamide wax.

[0026] Hydrogenated castor oil can be purchased from Aladdin.

[0027] Polyamide wax can be purchased from Kusumoto Chemical Co., Ltd.

[0028] In some embodiments, the first and second additives include additives commonly used in the art, including but not limited to dispersants, leveling agents, and adhesion promoters.

[0029] A second aspect of the present invention provides a method for preparing a two-component organic carrier, the method comprising: adding a first solvent and a first additive to a first reaction vessel, mixing them thoroughly, adding a first resin base, continuing to mix them thoroughly, and then adding a first thixotropic agent to obtain component A; adding a second solvent and a second additive to a second reaction vessel, mixing them thoroughly, adding a second resin base, continuing to mix them thoroughly, and then adding a second thixotropic agent to obtain component B; and mixing component A and component B in a certain proportion and adding silver particles to obtain conductive silver paste.

[0030] A third aspect of the present invention provides an application of a two-component organic carrier in the preparation of silver paste for the main grid electrode of crystalline silicon solar cells.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. This invention uses three specific types of cellulose and polyvinyl butyral resin with specific parameters to form a compound. Compared with cellulose carrying other types of groups, this compound is more conducive to reducing unit consumption in this system while maintaining good tensile strength.

[0033] 2. By using four specific solvents in combination, the silver paste prepared in this invention has a good film-forming effect, a more uniform and delicate film surface, and minimizes the problems of pores and bubbles on the film surface.

[0034] 3. Compared with the single-component carriers in the prior art, the viscosity and consumption range of this invention can be adjusted, which can better meet the needs of downstream production enterprises.

[0035] 4. The organic carrier prepared by the present invention has been tested and its unit consumption range can be controlled within 20%. As the unit consumption decreases, the welding tensile force and aging tensile force are both stable above 3N, which can meet the tensile reliability requirements of crystalline silicon solar cells.

[0036] 5. The raw materials for preparation of this invention are simple and readily available, the preparation process is easy to operate, the product cost is low, and it has a higher cost performance, which can provide more economic benefits to enterprises and has extremely high economic value and application prospects. Detailed Implementation

[0037] Example 1

[0038] A two-component organic carrier comprises component A and component B. Component A is prepared from the following raw materials: a first resin base, a first solvent, a first thixotropic agent, and a first auxiliary agent. Component B is prepared from the following raw materials: a second resin base, a second solvent, a second thixotropic agent, and a second auxiliary agent, as detailed in Table 1. The sources of the raw materials are the same as those described in the invention description.

[0039] Table 1

[0040]

[0041]

[0042] A method for preparing a two-component organic carrier, the method comprising: adding a first solvent and a first auxiliary agent to a first reaction vessel, mixing them, adding a first resin base, mixing them further, and adding a first thixotropic agent to obtain component A; adding a second solvent and a second auxiliary agent to a second reaction vessel, mixing them, adding a second resin base, mixing them further, and adding a second thixotropic agent to obtain component B.

[0043] Example 2

[0044] A two-component organic carrier is described in the same way as in Example 1, with the differences shown in Table 2.

[0045] Table 2

[0046]

[0047]

[0048] A method for preparing a two-component organic carrier, the specific implementation method is the same as in Example 1.

[0049] Comparative Example 1

[0050] A two-component organic carrier, the specific implementation method is the same as in Example 1, except that the first cellulose and the second cellulose both contain 0 parts of cellulose acetate propionate.

[0051] Comparative Example 2

[0052] A two-component organic carrier is described in the same manner as in Example 1, except that hydroxymethyl cellulose is used instead of cellulose acetate butyrate in the first cellulose and hydroxypropyl cellulose is used instead of ethyl cellulose in the second cellulose. Both hydroxymethyl cellulose and hydroxypropyl cellulose were purchased from Merck Chemicals.

[0053] Comparative Example 3

[0054] A two-component organic carrier, the specific implementation method is the same as in Example 1, except that the first solvent and the second solvent are both a compound of 30 parts of ethylene glycol butyl ether acetate, 30 parts of ethylene glycol ethyl ether acetate and 15 parts of triethylene glycol butyl ether.

[0055] Comparative Example 4

[0056] A two-component organic carrier, the specific implementation method is the same as in Example 1, except that ethylene glycol butyl ether acetate is used instead of diethylene glycol butyl ether acetate in both the first solvent and the second solvent.

[0057] Experimental Example

[0058] The two-component organic carriers prepared in Examples 1-2 and Comparative Examples 1-4 were used to prepare silver paste for the main grid electrode of crystalline silicon solar cells according to the proportions in Table 3. The glass powder was purchased from Guangdong Nanhai Qiming Guangda Technology Co., Ltd., the silver powder from Suzhou Yinrui, and the solvent, diethylene glycol monobutyl ether, was purchased from Shanghai Panhua.

[0059] Table 3

[0060]

[0061] Performance testing

[0062] (1) The main grid electrode silver paste prepared in the experimental example was printed on a 182*182mm silicon wafer using a screen printing machine with a printing speed of 400mm / s, a printing pressure of 50N, a screen spacing of 1.50mm, and a return speed of 1000mm / s. The finished crystalline silicon solar cell was then prepared. The unit consumption of the main grid electrode silver paste under the same printing parameters was weighed using an electronic balance. The test results are shown in Table 4.

[0063] (2) The main grid electrode prepared in the experimental example was subjected to mechanical welding tensile test and aging tensile test. Both mechanical welding tensile test and aging tensile test were performed using a Wuxi Autowell string welding machine. The specific process was as follows: welding time 2300ms, heating power 65W, and base plate temperature 100 degrees. The aging conditions for the aging tensile test were as follows: after welding, the electrode was baked at 150 degrees for 30 minutes before the tensile value was tested. The test results are shown in Table 4.

[0064] Table 4

[0065] Single consumption / mg Welding tensile force / N Aging tensile strength / N Experimental Example 1 25.3 3.56 3.65 Experiment Example 2 23.4 3.30 3.33 Experimental Example 3 22.1 3.51 3.17 Experiment Example 4 20.4 3.49 3.04 Experimental Example 5 26.2 3.37 3.29 Experimental Example 6 23.7 3.30 3.04 Experimental Example 7 22.6 3.31 3.28 Experimental Example 8 20.1 3.14 3.25 Experimental Example 9 18.1 2.31 2.35 Experimental Example 10 25.1 3.11 2.25 Experimental Example 11 19.1 2.01 1.86 Experimental Example 12 20.1 3.01 2.75

[0066] (3) The physicochemical properties of the main grid electrode silver paste prepared in the experimental example were tested, and the results are shown in Table 5.

[0067] Viscosity testing conditions were: BRF DV3T viscometer (CPA-52Z, 2.5 rpm, 25℃);

[0068] The testing of organic and inorganic solids content should refer to GB / T-17473.1.

[0069] Table 5

[0070]

[0071]

Claims

1. A two-component organic carrier, characterized in that, The organic carrier comprises component A and component B. By weight percentage, component A comprises: 12-30% first resin base, 60-85% first solvent, 3-8% first thixotropic agent, and 0-2% first auxiliary agent; component B comprises: 12-30% second resin base, 60-85% second solvent, 3-8% second thixotropic agent, and 0-2% second auxiliary agent. By weight, the raw materials for preparing the first resin base material include: 10-20 parts of polyvinyl butyral resin and 10-150 parts of first cellulose; the raw materials for preparing the second resin base material include: 10-20 parts of polyvinyl butyral resin and 10-150 parts of second cellulose. The first cellulose comprises cellulose acetate butyrate and cellulose acetate propionate in a weight ratio of (5-75):(5-75); the second cellulose comprises ethyl cellulose and cellulose acetate propionate in a weight ratio of (5-75):(5-75). Both the first solvent and the second solvent include diethylene glycol monobutyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, with a weight ratio of (25-45):(25-45):(15-30):(15-30). The weight ratio of component A to component B is (2-11):(2-11).

2. The two-component organic carrier according to claim 1, characterized in that, The viscosity of the first cellulose is 3-500 mPa·s.

3. The two-component organic carrier according to claim 1, characterized in that, The viscosity of the second cellulose is 3-500 mPa·s.

4. The two-component organic carrier according to any one of claims 1-3, characterized in that, The first thixotropic agent and the second thixotropic agent each include at least one of hydrogenated castor oil, polyamide wax, polyurea, fumed silica, and modified polyamide wax.

5. A method for preparing a two-component organic carrier according to any one of claims 1-4, characterized in that, The preparation method includes: adding a first solvent and a first additive to a first reaction vessel, mixing them, adding a first resin base, continuing to mix them, and then adding a first thixotropic agent to obtain component A; adding a second solvent and a second additive to a second reaction vessel, mixing them, adding a second resin base, continuing to mix them, and then adding a second thixotropic agent to obtain component B; when using, mixing component A and component B in a certain proportion and adding silver particles to obtain conductive silver paste.

6. The application of a two-component organic carrier according to any one of claims 1-4 in the preparation of silver paste for the main grid electrode of crystalline silicon solar cells.

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