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Organic adhesive for aluminum paste of silicon solar cells and preparation method thereof

A technology of silicon solar cells and organic adhesives, applied in the direction of adhesive types, cellulose adhesives, adhesives, etc., can solve the problem of poor uniformity and continuity of back field electrodes, poor film compactness, and lower yields, etc. problems, to achieve the effect of good wetting and dispersing performance, simple process method, and reducing the tendency of agglomeration

Active Publication Date: 2011-09-14
WUXI RUXING TECH DEV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1. The organic binder in the prepared aluminum paste can make the aluminum powder layer and the silicon chip have a certain bonding strength after drying, but the aluminum paste prepared by the organic adhesive is more brittle after drying (before sintering) Strong, large shrinkage rate, easy to add stress to the silicon wafer, resulting in silicon wafer fragmentation, reducing the yield; at the same time, due to its brittleness, the formed aluminum paste film shrinks and the adhesion to the silicon substrate decreases instead. Its bond strength is 4th grade, and the aluminum film will be partially peeled off when it is wiped.
[0007] 2. The dispersion and suspension effect of the above-mentioned organic binder is also not good. After long-term storage of the aluminum paste, the layered settlement of the powder sometimes occurs, and the stability of the aluminum paste is not good, resulting in solidification everywhere on the silicon wafer after screen printing. If the content is inconsistent, the uniformity and continuity of the formed back field electrode is not good, which affects the photoelectric conversion efficiency
[0008] 3. The above-mentioned organic binders often produce more air bubbles during the grinding and stirring process for preparing aluminum paste, resulting in poor film density during printing

Method used

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  • Organic adhesive for aluminum paste of silicon solar cells and preparation method thereof
  • Organic adhesive for aluminum paste of silicon solar cells and preparation method thereof
  • Organic adhesive for aluminum paste of silicon solar cells and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0030] The components of the organic binder are: by mass parts ethyl cellulose 2.8%, acetate butyl cellulose 1.2%, diethylene glycol-ether 24%, dipropylene glycol-methyl ether 32%, diethyl phthalate 8.0%, Propylene Glycol Butyl Ether 30%, Tego Dispers6550.8%, Airex 9001.2%. The above composition is shown in Example 1 in Table 1, and the components in Table 1 are percentages by mass.

[0031] Organic adhesive preparation steps: Put the above components into a stainless steel reaction kettle, heat up with electric heating, start the agitator, and stir at a speed of 80 rpm, and wait for the solution in the reaction kettle to heat up to 140°C and keep the temperature for 2.5 hours. Uniformly mix and fully react in the reaction kettle. After the obtained reactants are cooled, they are filtered with a 200-mesh screen to obtain finished organic adhesives for silicon solar cell aluminum paste. The above-mentioned preparation process conditions are shown in Example 1 in Table 2.

[00...

Embodiment 2- Embodiment 6

[0044] The component amounts of the organic binder, the preparation steps and the test results related to the performance indicators of the organic binder of the present invention are shown in Table 1, Table 2 and Table 3 respectively, and the description of the rest of the process is the same as that of Example 1.

[0045] Table 2

[0046]

[0047] table 3

[0048]

[0049] Note: The bonding strength is grade 1, the bonding strength is better, and the bonding strength decreases with the increase of the grade.

[0050] From the test data of table 3 embodiment 1-6 and comparative example 7-8 as seen:

[0051] The silicon solar cell aluminum paste prepared by the organic binder of the present invention comprising acetobutylcellulose and ethyl cellulose, after drying (before sintering), the fragmentation rate of silicon wafers is significantly reduced, that is, effectively reduced The stress produced on the silicon wafer; and the adhesive strength of the aluminum paste fi...

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Abstract

The invention provides organic adhesive for the aluminum paste of silicon solar cells and a preparation method thereof. The organic adhesive comprises the following components by the weight part: 23% of ethyl cellulose, 1% to 5% of cellulose acetate butyrate, 88% to 94% of organic solvent, 0.2% to 1% of wetting dispersant and 1% to 3% of defoamer with the total amount being 100%. The preparation method comprises the following steps: putting the components into a reaction kettle; heating the components up to the temperature of 120 to 140 DEG C while stirring at the speed of 60 to 80 RPM and holding at a constant temperature for 2 to 4 hours to ensure that the components in the reaction kettle can be evenly stirred and subjected to complete reaction; and cooling the reactant and filtering the reactant with mesh to obtain the final product of the organic adhesive. The aluminum paste prepared from the organic adhesive has the advantages that the dispersibility or the suspensibility thereof is high, the aluminum paste does not laminate or precipitate after long-time storage and the aluminum paste can be uniformly coated so that the solid powder in the dried aluminum powder has the advantages of high adhesive strength and low stress generated on silicon chips.

Description

technical field [0001] The invention relates to crystalline silicon solar cells, in particular to an organic binder for aluminum paste of silicon solar cells and a preparation method thereof. The organic binder exists as a carrier or a dispersion medium in the aluminum paste, endows the paste with suitable fluid properties, can fully wet the aluminum powder and the inorganic binder powder in the aluminum paste, and can be miscible with other additives. Background technique [0002] In the preparation process of crystalline silicon solar cells, the aluminum paste is printed on the back of the silicon wafer, and after sintering, an aluminum back electric field electrode is formed on the back of the silicon wafer of the solar cell, which can reduce the contact resistance and improve the photoelectric conversion efficiency of the cell. [0003] The aluminum paste is composed of aluminum powder, an organic binder, glass powder as an inorganic binder, additives and the like. Amon...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J101/28C09J101/14H01L31/18H01L31/0224
CPCY02P70/50
Inventor 毛毅强蔡纪法夏国锐丁冰冰
Owner WUXI RUXING TECH DEV
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