Novel organic carrier for photovoltaic silver paste and preparation method thereof

Abstract

The invention discloses a novel organic carrier for photovoltaic silver paste, the novel organic carrier comprises a solid substance and a solvent, the solid substance accounts for 10-40% of the total mass of the organic carrier, the solvent accounts for 60-90% of the organic carrier, the solid substance comprises polymethyl ethylene carbonate and ethyl cellulose, and the solvent accounts for 10-30% of the total mass of the organic carrier. The solvent comprises one or more of terpilenol, butyl carbitol and ethylene glycol butyl ether acetate. Compared with the prior art, the organic carrier can achieve high fine line resolution and good printing screen passing performance, after high-temperature rapid sintering, the residual carbon content is extremely low and is in the ppm level, and great benefits are brought to the performance of the photovoltaic silver paste.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic silver paste, in particular to a novel organic carrier for photovoltaic silver paste and a preparation method thereof. BACKGROUND

[0002] The photovoltaic silver paste mentioned in the present application is a high-temperature sintering type photovoltaic silver paste. The photovoltaic silver paste is generally mixed by silver powder, glass powder, organic carrier and additives in a certain proportion. The silver powder is the conductive phase in the silver paste, generally accounting for more than 85% of the proportion of the silver paste; the glass powder is the functional phase and the bonding phase, and the proportion used accounts for 2.5-3.5% of the silver paste, although the amount is small, but it is very critical; the organic carrier is the medium for dispersing the silver powder and the glass powder, which affects the printing performance, fine line resolution and carbon residue after sintering of the silver paste, and to some extent, it has an impact on the comprehensive performance of the solar cell; the additives are mainly added to adjust the thixotropy, viscosity and dispersibility of the silver paste, and the amount added is generally small, which is mainly adjusted according to the test data. The main components of the organic carrier used in the photovoltaic silver paste on the market at present are ethyl cellulose, acrylic resin and other high molecular resin systems. The high molecular resin system has a relatively high carbon residue (about 0.4%) after high-temperature sintering, which will reduce the conductivity of the silver paste. SUMMARY

[0003] The present application aims to provide a novel organic carrier for photovoltaic silver paste.

[0004] The present application also provides a preparation method of the novel organic carrier for photovoltaic silver paste.

[0005] The innovation of the present application lies in that the organic carrier in the present application can achieve high fine line resolution, good printing screenability, and very little carbon residue (ppm level) after high-temperature rapid sintering, which is of great benefit to the performance of the photovoltaic silver paste.

[0006] To achieve the above-mentioned application purposes, the technical solution of the present application is as follows: a novel organic carrier for photovoltaic silver paste, comprising solid substances and solvents, the solid substances accounting for 10-40% of the total mass of the organic carrier, the solvents accounting for 60-90% of the organic carrier, the solid substances comprising polymethyl ethylene carbonate and ethyl cellulose, and the solvents comprising one or more of terpineol, butyl carbitol and ethylene glycol butyl ether acetate.

[0007] Further, the polymethyl ethylene carbonate accounts for 50-100% of the total mass of the solid substances, and the ethyl cellulose accounts for 0-50% of the total mass of the solid substances.

[0008] The preparation method of a novel organic carrier for photovoltaic silver paste comprises the following steps: sequentially weighing polymethyl ethylene carbonate and ethyl cellulose according to a formula, adding a solvent, and fully dissolving by heating and stirring to obtain a finished product.

[0009] Further, the heating is performed under a water bath at 60 DEG C.

[0010] The present application has the following advantages:

[0011] 1. The organic carrier in the present application can realize high fine line resolution, good printing through net property, and after high-temperature rapid sintering, the residual carbon content is ppm level, which is greatly beneficial to the performance of the photovoltaic silver paste. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present application will be clearly and completely described below.

[0013] Embodiment 1: A novel organic carrier for photovoltaic silver paste comprises solid substances and a solvent, the solid substances account for 10% of the total mass of the organic carrier, the solvent accounts for 90% of the organic carrier, the solid substances comprise polymethyl ethylene carbonate, and the solvent comprises terpineol; ethyl cellulose accounts for 50% of the total mass of the solid substances.

[0014] Embodiment 2: A novel organic carrier for photovoltaic silver paste comprises solid substances and a solvent, the solid substances account for 40% of the total mass of the organic carrier, the solvent accounts for 60% of the organic carrier, the solid substances comprise polymethyl ethylene carbonate and ethyl cellulose, and the solvent comprises butyl carbitol; polymethyl ethylene carbonate accounts for 50% of the total mass of the solid substances, and ethyl cellulose accounts for 50% of the total mass of the solid substances.

[0015] Embodiment 3: A novel organic carrier for photovoltaic silver paste comprises solid substances and a solvent, the solid substances account for 30% of the total mass of the organic carrier, the solvent accounts for 70% of the organic carrier, the solid substances comprise polymethyl ethylene carbonate and ethyl cellulose, and the solvent comprises ethylene glycol butyl ether acetate; polymethyl ethylene carbonate accounts for 75% of the total mass of the solid substances, and ethyl cellulose accounts for 25% of the total mass of the solid substances.

[0016] Embodiment 4: According to Embodiment 1, the solvent comprises one or more of terpineol, butyl carbitol and ethylene glycol butyl ether acetate.

[0017] Embodiment 5: A preparation method of a novel organic carrier for photovoltaic silver paste comprises the following steps: sequentially weighing polymethyl ethylene carbonate and ethyl cellulose according to the formula in Embodiment 1, adding a solvent, fully dissolving by heating and stirring, heating under a water bath at 60 DEG C, and cooling to obtain a finished product.

[0018] Example 6: A method for preparing a new type of organic carrier for photovoltaic silver paste, comprising the following steps: taking polymethyl ethylene carbonate, ethyl cellulose according to the formulation of Example 2, then adding solvent, heating and stirring to fully dissolve, heating is under a water bath at 60°C, and cooling to obtain the finished product.

[0019] Example 7: A method for preparing a new type of organic carrier for photovoltaic silver paste, comprising the following steps: taking polymethyl ethylene carbonate, ethyl cellulose according to the formulation of Example 3, then adding solvent, heating and stirring to fully dissolve, heating is under a water bath at 60°C, and cooling to obtain the finished product.

[0020] Test: According to the following silver paste formulation: take silver powder 85g, glass powder 2.5g, organic carrier 11.5g, additive (BYK-333) 1g, respectively take the organic carrier of Example 1, 2, 3 for testing, numbered 1-3 respectively, first mix the organic carrier and the additive evenly with a homogenizing mixer, then add the silver powder into the above mixture in three times, mix well after each addition with a homogenizing mixer or planetary mixer before adding, when all the materials are mixed, use a three-roll mill to roll repeatedly for several times, stop rolling when the silver paste fineness reaches below 10 microns, the silver paste preparation is completed, and it is stored at 4°C in a sealed cold storage.

[0021] Silver paste performance test: After the silver paste is prepared, test its viscosity (test conditions: Brookfield HBT utility cup and spindle (SC4-14 / 6R), 10 rpm, 25±1°C) and print the above silver paste with screen printing screen with opening of 10 microns, 15 microns, 20 microns, 25 microns and 30 microns to evaluate its fine line resolution. Residual carbon content test: take 1 gram of silver paste in a crucible, sinter in a muffle furnace at 850°C in air atmosphere for 30 minutes, then test the residual carbon content with a carbon, nitrogen, oxygen and sulfur element analyzer.

[0022] Table 11: Performance test of three batches of silver paste

[0023] Example Viscosity (Pa.s.) Fine line resolution (microns) Residual carbon content (%) Example 1 125 15 0.5 Example 2 120 12 0.07 Example 3 117 10 0.005

[0024] The data results in the table show that the more polymethyl ethylene carbonate is contained, the better the fine line resolution of the silver paste is. In addition, the organic carrier prepared with polymethyl ethylene carbonate keeps a lower residual carbon content after sintering of the silver paste, which is beneficial to the improvement of the conductivity of the silver paste.

[0025] The described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

Claims

1. A novel organic carrier for photovoltaic silver paste, characterized in that, It includes a solid substance and a solvent, wherein the solid substance accounts for 10-40% of the total mass of the organic carrier, and the solvent accounts for 60-90% of the organic carrier. The solid substance includes polymethyl ethylene carbonate and ethyl cellulose, and the solvent includes one or more of terpineol, butyl carbitol, and ethylene glycol butyl ether acetate.

2. The novel organic carrier for photovoltaic silver paste according to claim 1, characterized in that, The polymethyl ethylene carbonate accounts for 50-100% of the total mass of the solid matter, and the ethyl cellulose accounts for 0-50% of the total mass of the solid matter.

3. A method for preparing a novel organic carrier for photovoltaic silver paste as described in claim 1 or 2, characterized in that, Includes the following steps: Weigh out polymethyl ethylene carbonate and ethyl cellulose according to the formula, add solvent, heat and stir to dissolve completely, and cool to obtain the finished product.

4. The method for preparing a novel organic carrier for photovoltaic silver paste according to claim 3, characterized in that, The heating is performed in a water bath at 60°C.