阅读说明：本技术 一种晶硅太阳能正银浆料用玻璃粉及其制备方法和用途 (Glass powder for crystalline silicon solar front silver paste and preparation method and application thereof ) 是由 许亚文 卢美军 刘白强 廖维林 于 2019-11-11 设计创作，主要内容包括：本发明公开一种晶硅太阳能正银浆料用玻璃粉,原料包括TeO-2、PbO、Tl-2O-3、Bi-2O-3、Li-2O,还选择性地包括WO-3、ZnO、MgO、B-2O-3、CaO、TiO-2、Fe-2O-3、Al-2O-3、Ag-2O、ZrO-2、Na-2O、K-2O、和MoO中的一种或多种,选择性地包括附着力添加剂或者腐蚀助剂。本发明的一种晶体硅太阳能正银浆料用玻璃粉,由于添加了Tl-2O-3,以及与其它原材料的特殊的配方配比,玻璃粉的软化温度降低、电导率增加、介电损耗较小。可以在较低温度蚀穿晶体硅片的钝化层,包括氮化硅膜以及PERC晶体硅片的氧化铝膜。由此玻璃制作的浆料能在720～800℃烧结,在一定程度上降低了晶硅电池,尤其是PERC晶硅电池片在高温烧结下的衰减问题,从而提高电池效率。(The invention discloses glass powder for crystalline silicon solar front silver paste, which comprises TeO as a raw material 2 、PbO、Tl 2 O 3 、Bi 2 O 3 、Li 2 O, optionally also including WO 3 、ZnO、MgO、B 2 O 3 、CaO、TiO 2 、Fe 2 O 3 、Al 2 O 3 、Ag 2 O、ZrO 2 、Na 2 O、K 2 One or more of O, and MoO, optionally including an adhesion additive or a corrosion aid. The invention relates to glass powder for crystalline silicon solar front silver paste, which is added with Tl 2 O 3 And the glass powder is matched with other raw materials in a special formula, so that the softening temperature of the glass powder is reduced, the conductivity is increased, and the dielectric loss is smaller. Can be used forAnd etching through the passivation layer of the crystalline silicon wafer at a lower temperature, wherein the passivation layer comprises a silicon nitride film and an aluminum oxide film of the PERC crystalline silicon wafer. The slurry made of the glass can be sintered at 720-800 ℃, so that the attenuation problem of a crystalline silicon battery, especially a PERC crystalline silicon battery piece, under high-temperature sintering is reduced to a certain extent, and the battery efficiency is improved.)

1. The glass powder for the crystalline silicon solar front silver paste is characterized in that: the glass powder comprises the following raw materials:

TeO₂5 to 70 parts by weight, preferably 10 to 60 parts by weight, more preferably 15 to 55 parts by weight;

PbO 3-60 parts by weight, preferably 5-50 parts by weight, more preferably 10-40 parts by weight;

Tl₂O₃0.3 to 40 parts by weight, preferably 1 to 30 parts by weight, more preferablyPreferably 5 to 20 parts by weight;

Bi₂O₃1 to 50 parts by weight, preferably 3 to 40 parts by weight, more preferably 5 to 30 parts by weight;

Li₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

Na₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

K₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

B₂O₃0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight;

CaO 0-20 parts by weight, preferably 0.1-15 parts by weight, more preferably 0.2-10 parts by weight;

SiO₂0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight.

2. The glass powder for the crystalline silicon solar front silver paste according to claim 1, characterized in that: the glass powder also comprises:

1-60 parts of adhesion additive, preferably 3-50 parts, more preferably 5-40 parts; and/or

The corrosion assistant is 1 to 60 parts by weight, preferably 3 to 50 parts by weight, and more preferably 5 to 40 parts by weight.

3. The glass powder for the crystalline silicon solar front silver paste according to claim 2, characterized in that: the adhesion additive is selected from ZnO and WO₃、SiO₂、P₂O₅、B₂O₃、Ge₂O₃One or more of NiO and a mixture of NiO mixed in any proportion; and/or

The corrosion assistant is selected from Al₂O₃、Cr₂O₃、TiO₂、Al₂O₃、MnO₂、LiF、PbF₂、AlF₃、TiF₄、Ge₂O₃、Fe₂O₃One or more of CuO and MoO in any proportion.

4. The glass frit for crystalline silicon solar front silver paste according to any one of claims 1 to 3, wherein: the Tg temperature of the glass powder is 150-420 ℃; the Ts temperature of the glass powder is 450-820 ℃; and/or

The average grain diameter D50 of the glass powder is 0.1-5 μm, preferably 0.2-4 μm; the maximum particle size of particles in the glass powder is not more than 20 mu m, and preferably not more than 10 mu m; the minimum particle size of the particles in the glass powder is not less than 0.1 mu m.

5. A method for preparing the glass powder for the crystalline silicon solar front silver paste of any one of claims 1 to 4, which comprises the following steps:

(1) weighing the raw materials of the glass powder according to the mass ratio, mixing (preferably, grinding and mixing or mixing by a stirrer), and drying;

(2) putting the dried glass powder raw material into a crucible, putting the crucible into a high-temperature furnace for firing, heating to 800-1400 ℃ (preferably 900-;

(3) quenching the glass solution by using deionized water, cooling, taking out broken glass slag, and drying;

(4) grinding the glass broken slag by using a ball mill until the average particle size is 0.1-5 mu m;

(5) sieving and drying to obtain the glass powder.

6. A solar cell silver paste prepared by adopting the glass powder for the crystalline silicon solar front silver paste as defined in any one of claims 1 to 4 or the glass powder for the crystalline silicon solar front silver paste as defined in claim 5, wherein the silver paste comprises or consists of the following components:

55 to 150 parts by weight of silver powder, preferably 65 to 120 parts by weight, more preferably 75 to 100 parts by weight;

1-25 parts by weight of binder, preferably 3-20 parts by weight, more preferably 5-15 parts by weight;

the glass powder for the crystalline silicon solar front silver paste is 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight.

7. The solar cell silver paste of claim 6, wherein: the silver paste also comprises:

0.1 to 10 parts by weight of organic gallium, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight; and/or

(ii) an organoaluminum compound in an amount of 0.1 to 25 parts by weight, preferably 0.2 to 20 parts by weight, more preferably 0.3 to 15 parts by weight; and/or

0.1 to 10 parts by weight of an auxiliary, preferably 0.2 to 8 parts by weight, and more preferably 0.3 to 5 parts by weight.

8. The solar cell silver paste of claim 7, wherein: the organic gallium is one or more of tricyclopentyl gallium, trimethyl gallium, triethyl gallium and triisobutyl gallium; and/or

The organic aluminum compound is dihydroxy amino aluminum acetate and/or aluminum acetate; and/or

The auxiliary agent is methyl silicone oil and/or lecithin.

9. The solar cell silver paste of any one of claims 6-8, wherein: the binder is an organic binder; preferably, the binder consists of 0.1 to 30 weight percent of high molecular polymer and 70 to 99 weight percent of organic solvent;

wherein: the high molecular polymer is selected from one or more of polymethacrylate, ethyl cellulose and ethyl hydroxyethyl cellulose; the organic solvent is selected from one or more of butyl carbitol, terpineol, tributyl citrate, propylene glycol butyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, butyl carbitol acetate, dibasic ester and alcohol ester.

10. The solar cell silver paste of any one of claims 6-9, wherein: the silver powder is micron spherical silver powder and/or nano silver powder; preferably, the silver powder is a mixture of micron-spherical silver powder and nano-silver powder; more preferably, the silver powder is a mixture of 70-99% by weight of micrometer spherical silver powder and 1-30% by weight of nanometer silver powder.

Technical Field

The invention relates to glass powder and a preparation method and application thereof, in particular to glass powder for crystalline silicon solar front silver paste and a preparation method and application thereof, and belongs to the technical field of solar photovoltaic cells.

Background

In the whole industry chain of solar cells, front-side silver paste is one of the most central materials and technologies in the solar cell process. With the progress of solar cell technology, especially for advanced high-efficiency new structure cells, such as high-efficiency PERC cells, including ultra-high sheet resistance PERC cells, PERC-SE cells, double-sided alumina PERC cells and the like. These new structure cells further improved the cell efficiency to 22%. Increasingly improved battery fabrication processes and new designs play an important role. For each new process and new design of the battery, the slurry must have corresponding innovation to realize the improvement of the efficiency.

The front silver package of the solar cell mainly comprises three parts, namely silver powder, glass powder and an organic carrier. The proportion of the binder phase glass powder in the raw materials is small, but the influence on the adhesion between the electrode and the substrate and the photoelectric conversion efficiency of the battery is very large. In order to greatly improve the photoelectric conversion efficiency and reduce the cost, the solar cell is developing towards the directions of high sheet resistance, shallow junction and fine grid, and the solar cell puts higher performance requirements on glass powder used by front silver paste. The glass powder plays a role in high-temperature bonding, and also serves as a fluxing agent for silver powder sintering and a medium substance for silver-silicon ohmic contact, the front silver paste of the solar cell is printed into a front electrode pattern through screen printing, and in the subsequent sintering film-forming process, the glass powder softening corrosion candle penetrates through the antireflection film and is mutually fused and bridged with silver particles to form a compact electrode conductive network. The glass powder for front silver paste is required to have the performances of lower softening temperature, high penetration of an antireflection film during high-temperature sintering and high vitrification degree. The performance of the glass frit directly affects the electrical performance, tensile force, cell efficiency, etc. of the solar cell. At present, the influence of the glass powder characteristics on the electrical performance of the solar cell has become a focus of the current crystalline silicon solar cell. Therefore, the improvement of front silver paste glass powder is urgent.

For various types of high efficiency PERC cells, compared with conventional solar cells, aluminum oxide (Al) is used₂O₃) Or a passivation layer is formed on the back surface of the battery by silicon nitride (SiNx), and local metal contact is adopted, so that the electron recombination speed of the back surface is effectively reduced, and meanwhile, the light reflection of the back surface is improved, and the efficiency and the generating capacity of the battery are improved. PERC cells are compatible with existing production lines and are relatively low cost compared to other high efficiency cells (e.g., N-cells, HIT cells, etc.), and therefore have developed rapidly over the past two years, which is a trend in the solar cell industry. Due to the passivation layer on the back of the PERC battery, the sintering process needs to be optimized in the production process of the battery, and the sintering temperature needs to be reduced. Meanwhile, the back side alumina deposition process can generate the winding plating on the front side of the silicon wafer, and alumina can wind to the front side of the silicon wafer. Some manufacturers even use double-sided alumina directly, with a layer of alumina plated on the front side. The sintering temperature of the glass used by the traditional slurry is higher or the glass cannot penetrate through alumina, so that new glass needs to be developed, and particularly, high requirements on low-temperature sintering and better etching performance are provided.

Disclosure of Invention

Aiming at the problems existing in the center of the prior art, the invention aims to solve the technical problem of overcoming the defects of the prior art and provide the improved front-side silver paste glass powder for the crystalline silicon solar cell, and particularly for the PERC cell and the high-efficiency PERC cell, the sintering temperature of the PERC cell and the high-efficiency PERC cell is reduced, the contact is improved, and the filling factor and the cell efficiency are improved. The maximization of the electrical property of the solar cell is realized while the high welding adhesion between the front silver electrode and the welding strip is realized, and the service life of the cell module is long. The invention also provides a preparation method of the front silver paste glass powder for the crystalline silicon solar cell.

The invention discloses a novel glass, which is prepared by Tl₂O₃Addition of raw materials and optimization of corresponding formulationsThe sintering temperature of the corresponding front silver paste can be obviously reduced, the etching performance of the front silver paste is improved, and the contact resistance is reduced, so that the conversion efficiency of the battery is improved.

According to a first embodiment provided by the invention, the glass powder for the crystalline silicon solar front silver paste is provided.

The glass powder for the crystalline silicon solar front silver paste comprises the following raw materials:

TeO₂5 to 70 parts by weight, preferably 10 to 60 parts by weight, more preferably 15 to 55 parts by weight;

PbO 3-60 parts by weight, preferably 5-50 parts by weight, more preferably 10-40 parts by weight;

Tl₂O₃0.3 to 40 parts by weight, preferably 1 to 30 parts by weight, more preferably 5 to 20 parts by weight;

Bi₂O₃1 to 50 parts by weight, preferably 3 to 40 parts by weight, more preferably 5 to 30 parts by weight;

Li₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

Na₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

K₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

B₂O₃0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight;

CaO 0-20 parts by weight, preferably 0.1-15 parts by weight, more preferably 0.2-10 parts by weight;

SiO₂0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight.

Preferably, the glass powder further comprises: the adhesion additive is 1 to 60 parts by weight, preferably 3 to 50 parts by weight, more preferably 5 to 40 parts by weight.

Preferably, the glass powder further comprises: the corrosion assistant is 1 to 60 parts by weight, preferably 3 to 50 parts by weight, and more preferably 5 to 40 parts by weight.

In the present invention, the adhesion additives are selected fromFrom ZnO, WO₃、SiO₂、P₂O₅、B₂O₃、Ge₂O₃And NiO, or a mixture of a plurality of these components in an arbitrary ratio.

In the present invention, the corrosion aid is selected from Al₂O₃、Cr₂O₃、TiO₂、Al₂O₃、MnO₂、LiF、PbF₂、AlF₃、TiF₄、Ge₂O₃、Fe₂O₃One or more of CuO and MoO in any proportion.

In the invention, the Tg temperature of the glass powder is 150-420 ℃; the Ts temperature of the glass powder is 450-820 ℃.

In the present invention, the average particle diameter D50 of the glass frit is 0.1 to 5 μm, preferably 0.2 to 4 μm.

In the present invention, the maximum particle diameter of the particles in the glass frit is not more than 20 μm, preferably not more than 10 μm.

In the present invention, the minimum particle diameter of the particles in the glass frit is not less than 0.1 μm.

According to a second embodiment provided by the invention, a preparation method of glass powder for crystalline silicon solar front silver paste is provided.

The method for preparing the glass powder for the crystalline silicon solar front silver paste in the first embodiment comprises the following steps:

(1) weighing the raw materials of the glass powder according to the mass ratio, mixing (preferably, grinding and mixing or mixing by a stirrer), and drying;

(2) putting the dried glass powder raw material into a crucible, putting the crucible into a high-temperature furnace for firing, heating to 800-1400 ℃ (preferably 900-;

(3) quenching the glass solution by using deionized water, cooling, taking out broken glass slag, and drying;

(4) grinding the glass broken slag by using a ball mill until the average particle size is 0.1-5 mu m;

(5) sieving and drying to obtain the glass powder.

According to a third embodiment provided by the invention, the application of the glass powder for the crystalline silicon solar front silver paste is provided.

A solar cell silver paste prepared by using the glass powder for the crystalline silicon solar front silver paste prepared by the method in the first embodiment or the glass powder for the crystalline silicon solar front silver paste prepared by the method in the second embodiment, wherein the silver paste comprises or consists of the following components:

55 to 150 parts by weight of silver powder, preferably 65 to 120 parts by weight, more preferably 75 to 100 parts by weight;

1-25 parts by weight of binder, preferably 3-20 parts by weight, more preferably 5-15 parts by weight;

the glass powder for the crystalline silicon solar front silver paste is 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight.

Preferably, the silver paste further comprises: 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight of an organic gallium.

Preferably, the silver paste further comprises: the organoaluminum compound is 0.1 to 25 parts by weight, preferably 0.2 to 20 parts by weight, more preferably 0.3 to 15 parts by weight.

Preferably, the silver paste further comprises: 0.1 to 10 parts by weight of an auxiliary, preferably 0.2 to 8 parts by weight, and more preferably 0.3 to 5 parts by weight.

In the invention, the organic gallium is one or more of tricyclopentyl gallium, trimethyl gallium, triethyl gallium and triisobutyl gallium.

In the present invention, the organoaluminum compound is dihydroxyaminoacetic acid aluminum and/or aluminum acetate.

In the invention, the auxiliary agent is methyl silicone oil and/or lecithin.

In the present invention, the binder is an organic binder.

Preferably, the binder is composed of 0.1-30% by weight of high molecular polymer and 70-99% by weight of organic solvent.

Wherein: the high molecular polymer is selected from one or more of polymethacrylate, ethyl cellulose and ethyl hydroxyethyl cellulose. The organic solvent is selected from one or more of butyl carbitol, terpineol, tributyl citrate, propylene glycol butyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, butyl carbitol acetate, dibasic ester and alcohol ester.

In the invention, the silver powder is micron-spherical silver powder and/or nano silver powder.

Preferably, the silver powder is a mixture of micro-sphere type silver powder and nano silver powder.

More preferably, the silver powder is a mixture of 70-99% by weight of micrometer spherical silver powder and 1-30% by weight of nanometer silver powder.

The invention relates to glass powder for crystalline silicon solar front silver paste, which is added with Tl₂O₃And the glass powder is matched with other raw materials in a special formula, so that the softening temperature of the glass powder is reduced, the conductivity is increased, and the dielectric loss is smaller. The passivation layer of the crystalline silicon wafer, including the silicon nitride film and the aluminum oxide film of the PERC crystalline silicon wafer, can be etched through at a lower temperature. The slurry made of the glass can be sintered at the temperature of 720-800 ℃, so that the attenuation problem of a crystalline silicon battery, especially a PERC crystalline silicon battery piece, under high-temperature sintering is reduced to a certain extent, and the battery efficiency is improved.

The improved front silver paste glass powder for the crystalline silicon solar cell provided by the invention is especially used for a PERC cell and a high-efficiency PERC cell, the sintering temperature of the PERC cell and the high-efficiency PERC cell is reduced, the contact is improved, and the filling factor and the cell efficiency are improved. The maximization of the electrical property of the solar cell is realized while the high welding adhesion between the front silver electrode and the welding strip is realized, and the service life of the cell module is long.

In the invention, the glass powder is prepared by using the glass powder with the particle size of 0.1-5 μm (preferably 0.2-4 μm) and using specific raw materials, and has the following functions and effects:

the softening temperature of the glass is reduced by controlling the components and the particle size of the glass, and the silver is fully dissolved and the passivation layer is corroded; the proportion of components with strong corrosivity, such as lead or bismuth, is optimized, and passivation layers, such as silicon nitride, silicon oxide or aluminum oxide, on the surface of the silicon battery are well corroded, so that the silver and the silicon are in good ohmic contact, an electron transfer channel is formed, and the conductive effect is achieved; meanwhile, other oxides (such as ZnO/V2O5/SiO2) are introduced to control the structure and the expansion coefficient of the glass, so that the adhesive force between the slurry and silicon is improved, and the reliability of the battery is improved.

According to the invention, the gallium compound is added into the N-type solar cell silver paste, so that the influence on VOC caused by introducing aluminum powder, aluminum-silicon alloy and other aluminum alloy substances into the N-type solar cell silver paste in the prior art is avoided. The integrity of PN-junction can not be damaged by adding gallium compound, and the structure of silicon on the surface of the battery can not be influenced; meanwhile, the gallium has better conductivity, the line resistance of the grid line on the solar cell is weakened, and the contradiction between ohmic contact and open voltage is perfectly solved.

Experimental research shows that the organic gallium is added into the silver paste of the solar cell, and compared with an inorganic compound added with gallium, the organic gallium-containing silver paste has the following effects and effects:

1. gallium is used as a trivalent dopant, has a doping effect on P-type materials, reduces contact potential energy, and is beneficial to contact of silver paste and silicon; 2. the organic gallium is an organic matter, and compared with an inorganic compound of gallium, the organic gallium can be well dispersed into an organic solvent or an organic carrier due to the principle of similar compatibility, so that the organic gallium is more uniformly contacted with the surface of a silicon wafer printed with the organic gallium; meanwhile, gallium or gallium compounds with high surface activity are generated in the sintering process, and can be diffused to the silicon surface more quickly in the short sintering process, so that the doping solubility of the silicon surface is improved.

Experiments prove that the problem of contradiction between ohmic contact and open voltage can be well solved by adding the tricyclopentyl gallium, the trimethyl gallium, the triethyl gallium or the triisobutyl gallium into the silver paste of the N-type solar cell doped with the organic gallium, the contact and compounding problem between slurry and a silicon wafer in the process of preparing the solar cell is improved, the contact resistance between silver and silicon is reduced, the open voltage of the solar cell is improved, and the photoelectric conversion efficiency is improved.

In the invention, the silver powder is a mixture of micron-spherical silver powder and nano silver powder. By adopting the mixture of silver powders with different particle sizes, the following effects and effects are achieved:

1. the nano silver powder has high surface activation energy and a lower melting point, and can be compacted and dissolved in glass at a lower temperature, so that the conductivity of the micron spherical silver powder can be reached at a lower sintering temperature; 2. meanwhile, as the nano silver powder particles are small, the nano silver powder particles can be well filled into gaps of the micron spherical silver powder, the compactness of the grid line is improved, and the resistance of the grid line is reduced.

According to the invention, the organic aluminum compound is added into the N-type solar cell silver paste, so that the influence on VOC caused by introducing aluminum powder, aluminum-silicon alloy and other aluminum alloy substances into the N-type solar cell silver paste in the prior art is avoided. The addition of the organic aluminum compound does not damage the integrity of PN-junctions and does not influence the structure of silicon on the surface of the battery; meanwhile, the activity of an aluminum source, the activity of the silver powder and the silver nitrate are improved, the activity of conductive metal and the energy of reaction with silicon in the reaction process are enhanced, the contact resistance between a metal grid line of the solar cell and the cell can be reduced, higher open voltage is kept, and the contradiction between ohmic contact and open voltage is perfectly solved.

Experimental research shows that the organic aluminum compound is added into the silver paste of the solar cell, and compared with an inorganic compound added with aluminum, the organic aluminum compound has the following effects and effects:

the preparation method has the main advantages that the preparation method is more beneficial to dispersion in an organic carrier and is uniformly dispersed in a slurry system, so that the phenomenon that the compounding of the silicon solar cell is increased and the open-circuit voltage of the cell is influenced due to excessive diffusion of silver into a silicon substrate in the sintering process is more effectively reduced; compared with the conventional aluminum or aluminum compound, the surface of the silicon wafer has higher energy and a certain catalytic action, is beneficial to corroding passivation layers such as silicon nitride/silicon oxide and the like on the surface of the silicon wafer by glass, increases the contact area between the silicon wafer and silver and reduces the series resistance;

experiments prove that the problem of contradiction between ohmic contact and open voltage can be well solved by adding dihydroxy aluminum aminoacetate and/or aluminum acetate into the silver paste of the N-type solar cell doped with the organic aluminum compound, the contact and compounding problems between slurry and a silicon wafer in the process of preparing the solar cell are improved, the contact resistance between silver and silicon is reduced, the open voltage of the solar cell is improved, and the photoelectric conversion efficiency is improved.

The method mainly aims at the contradiction between ohmic contact and open voltage of the current N-type solar cell silicon wafer, well solves the contact and compounding problem between the slurry and the silicon wafer by doping organic gallium, combining glass component adjustment, nano silver powder and the like, reduces the contact resistance between silver and silicon, improves the open voltage of the solar cell, and achieves the aim of improving the photoelectric conversion efficiency.

Compared with the prior art, the technical scheme of the invention has the following beneficial technical effects:

1. the invention relates to glass powder for crystalline silicon solar front silver paste, which is added with Tl₂O₃And the glass powder is matched with other raw materials in a special formula, so that the softening temperature of the glass powder is reduced, the conductivity is increased, and the dielectric loss is smaller.

2. According to the invention, the organic gallium compound is added into the silver paste of the N-type solar cell doped with the organic gallium, so that the P-type material is doped, the contact potential energy is reduced, the silver paste is favorably contacted with silicon to generate gallium or gallium compound with high surface activity in the sintering process, the gallium or gallium compound can be more quickly diffused to the silicon surface in the transient sintering process, and the doping solubility of the silicon surface is improved.

3. The silver powder adopted in the silver paste of the N-type solar cell doped with the organic gallium is a mixture of the micron spherical silver powder and the nanometer silver powder, and can be compacted and dissolved in glass at a lower temperature, so that the micron spherical silver powder has high conductivity and can be well filled in gaps of the micron spherical silver powder at a lower sintering temperature, the compactness of grid lines is improved, and the resistance of the grid lines is reduced.

4. The organic aluminum compound is added into the high-activity low-series-resistance N-type solar cell silver paste, so that the high-activity low-series-resistance N-type solar cell silver paste is more beneficial to being dispersed in an organic carrier and uniformly dispersed in a paste system, and the phenomenon that the compounding of a silicon solar cell is increased and the open-circuit voltage of the cell is influenced due to the fact that silver excessively diffuses into a silicon substrate in the sintering process is effectively reduced.

Detailed Description

The technical solution of the present invention is illustrated below, and the claimed scope of the present invention includes, but is not limited to, the following examples.

According to a first embodiment provided by the invention, the glass powder for the crystalline silicon solar front silver paste is provided.

The glass powder for the crystalline silicon solar front silver paste comprises the following raw materials:

TeO₂5 to 70 parts by weight, preferably 10 to 60 parts by weight, more preferably 15 to 55 parts by weight;

PbO 3-60 parts by weight, preferably 5-50 parts by weight, more preferably 10-40 parts by weight;

Tl₂O₃0.3 to 40 parts by weight, preferably 1 to 30 parts by weight, more preferably 5 to 20 parts by weight;

Bi₂O₃1 to 50 parts by weight, preferably 3 to 40 parts by weight, more preferably 5 to 30 parts by weight;

Li₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

Na₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

K₂0.1 to 20 parts by weight of O, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight;

B₂O₃0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight;

CaO 0-20 parts by weight, preferably 0.1-15 parts by weight, more preferably 0.2-10 parts by weight;

SiO₂0 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight.

Preferably, the glass powder further comprises: the adhesion additive is 1 to 60 parts by weight, preferably 3 to 50 parts by weight, more preferably 5 to 40 parts by weight.

Preferably, the glass powder further comprises: the corrosion assistant is 1 to 60 parts by weight, preferably 3 to 50 parts by weight, and more preferably 5 to 40 parts by weight.

In the present invention, the adhesion force is addedThe agent is selected from ZnO and WO₃、SiO₂、P₂O₅、B₂O₃、Ge₂O₃And NiO, or a mixture of a plurality of these components in an arbitrary ratio.

In the present invention, the corrosion aid is selected from Al₂O₃、Cr₂O₃、TiO₂、Al₂O₃、MnO₂、LiF、PbF₂、AlF₃、TiF₄、Ge₂O₃、Fe₂O₃One or more of CuO and MoO in any proportion.

In the invention, the Tg temperature of the glass powder is 150-420 ℃; the Ts temperature of the glass powder is 450-820 ℃.

In the present invention, the average particle diameter D50 of the glass frit is 0.1 to 5 μm, preferably 0.2 to 4 μm.

In the present invention, the maximum particle diameter of the particles in the glass frit is not more than 20 μm, preferably not more than 10 μm.

In the present invention, the minimum particle diameter of the particles in the glass frit is not less than 0.1 μm.

According to a second embodiment provided by the invention, the application of the glass powder for the crystalline silicon solar front silver paste is provided.

A solar cell silver paste prepared by using the glass powder for the crystalline silicon solar front silver paste prepared by the method in the first embodiment or the glass powder for the crystalline silicon solar front silver paste prepared by the method in the second embodiment, wherein the silver paste comprises or consists of the following components:

55 to 150 parts by weight of silver powder, preferably 65 to 120 parts by weight, more preferably 75 to 100 parts by weight;

1-25 parts by weight of binder, preferably 3-20 parts by weight, more preferably 5-15 parts by weight;

the glass powder for the crystalline silicon solar front silver paste is 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight.

Preferably, the silver paste further comprises: 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight of an organic gallium.

Preferably, the silver paste further comprises: the organoaluminum compound is 0.1 to 25 parts by weight, preferably 0.2 to 20 parts by weight, more preferably 0.3 to 15 parts by weight.

Preferably, the silver paste further comprises: 0.1 to 10 parts by weight of an auxiliary, preferably 0.2 to 8 parts by weight, and more preferably 0.3 to 5 parts by weight.

In the invention, the organic gallium is one or more of tricyclopentyl gallium, trimethyl gallium, triethyl gallium and triisobutyl gallium.

In the present invention, the organoaluminum compound is dihydroxyaminoacetic acid aluminum and/or aluminum acetate.

In the invention, the auxiliary agent is methyl silicone oil and/or lecithin.

In the present invention, the binder is an organic binder.

Preferably, the binder is composed of 0.1-30% by weight of high molecular polymer and 70-99% by weight of organic solvent.

Wherein: the high molecular polymer is selected from one or more of polymethacrylate, ethyl cellulose and ethyl hydroxyethyl cellulose. The organic solvent is selected from one or more of butyl carbitol, terpineol, tributyl citrate, propylene glycol butyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, butyl carbitol acetate, dibasic ester and alcohol ester.

In the invention, the silver powder is micron-spherical silver powder and/or nano silver powder.

Preferably, the silver powder is a mixture of micro-sphere type silver powder and nano silver powder.

More preferably, the silver powder is a mixture of 70-99% by weight of micrometer spherical silver powder and 1-30% by weight of nanometer silver powder.

Example 1

1. Glass powder formula

The embodiment provides a front silver paste glass powder for a crystalline silicon solar cell, which comprises the following raw material components in percentage by weight: 35% TeO₂、25％PbO、10％Tl₂O₃、13％Bi₂O₃4% of Li₂O、1％CaO、5％SiO₂、7％ZnO。

2. Preparation of glass powder

(1) The oxide raw materials are weighed by the mass parts of 60 g and fully ground and mixed.

(2) After being mixed evenly, the mixture is put into a constant temperature drier for 20 minutes at 100 ℃.

(3) And putting the dried glass powder raw material into a crucible, putting the crucible into a high-temperature furnace for firing, heating to 1000 ℃, and keeping the temperature for 1 hour at the constant temperature to obtain the glass melt.

(4) And putting the glass melt into deionized water for quenching, cooling, taking out broken glass, putting into a constant temperature dryer at 120 ℃, and drying.

(5) Pouring the dried glass slag into an agate pot, adding 60ml of ethanol, and adding an agate ball phi 6: 150 g, φ 10: 30 particles are put into an all-directional ball mill to be ball-milled for 2 hours.

(6) The average grain diameter of the glass measured by a laser particle sizer is D50 ═ 1.5 micrometers

(7) Sieving to separate the agate balls. And drying and crushing the product, and sieving the product with a 500-mesh sieve to obtain the required glass powder.

3. Preparation of organic Binders

Weighing 12 parts of polymethacrylate and 76 parts of butyl carbitol according to the mass parts, mixing, heating to 60 degrees on a dispersion machine for dispersion for 60min, and dispersing and dissolving to obtain the transparent and uniform organic adhesive.

4. Preparation of Mixed silver powder

Weighing 85 wt% of micron silver powder and 15 wt% of nano silver powder, and mixing to obtain the mixed silver powder.

5. Preparation of front silver paste

89.5 parts of mixed silver powder, 2 parts of glass powder, 8 parts of organic binder, 3 parts of tricyclopentyl gallium and 0.5 part of methyl silicone oil are weighed according to the mass parts, uniformly mixed by a dispersion machine, and ground by a three-roll grinder to obtain silver paste with the fineness of below 8 microns.

Reference slurry: Pb-Te system glass powder purchased from the market is selected and does not contain Tl raw material. Similarly, 89.5 parts of mixed silver powder, 2 parts of Pb-Te system glass powder, 8 parts of organic binder and 0.5 part of methyl silicone oil are weighed according to the parts by mass, uniformly mixed by a dispersion machine and ground by a three-roll grinder to silver paste with the fineness of below 8 microns.

Solar cell fabrication and measurement

Using the sample prepared above, electrode films were formed on 156mm by 156mm PERC silicon wafers by 430 mesh screen printing, the width of the main gate was 0.7 μm, and the wafer was sintered in a Despatch sintering furnace at a peak actual temperature of 700-.

The electrical data after sintering are tested as follows:

electrode films prepared using example 1: the short-circuit current is 9.843A, the open-circuit voltage is 678mv, the filling factor is 78.89%, the photoelectric conversion efficiency is 21.613%, and the welding tension is tested to be 2.0 newtons.

Electrode film prepared with reference paste: the short-circuit current is 9.839A, the open-circuit voltage is 677mv, the filling factor is 78.54 percent, the photoelectric conversion efficiency is 21.511 percent, and the welding tension is 1.8N.

It can be seen that the short-circuit current of the glass given in the example is 0.004A higher than that of the glass of the Pb-Te system, the efficiency is 0.1 percent higher, and the tensile force is 0.2N higher.

Example 2

1. Glass powder formula

The embodiment provides a front silver paste glass powder for a crystalline silicon solar cell, which comprises the following raw material components in percentage by weight: 53% TeO2, 11% PbO, 12% Tl2O3, 6% Bi2O3, 4.5% Li2O, 0.5% Cr2O3, 3% SiO2, 2% Al2O3, and 8% MgO.

2. Preparation of glass powder

(1) The oxide raw materials are weighed by the mass parts of 60 g and fully ground and mixed.

(2) After being mixed evenly, the mixture is put into a constant temperature drier for 20 minutes at 100 ℃.

(3) And putting the dried glass powder raw material into a crucible, putting the crucible into a high-temperature furnace for firing, heating to 1000 ℃, and keeping the temperature for 1 hour at the constant temperature to obtain the glass melt.

(4) And putting the glass melt into deionized water for quenching, cooling, taking out broken glass, putting into a constant temperature dryer at 120 ℃, and drying.

(5) Pouring the dried glass slag into an agate pot, adding 60ml of ethanol, and adding an agate ball phi 6: 150 g, φ 10: 30 particles are put into an all-directional ball mill to be ball-milled for 2 hours.

(6) The average grain diameter of the glass measured by a laser particle sizer is D50-1.58 microns

(7) Sieving to separate the agate balls. And drying and crushing the product, and sieving the product with a 500-mesh sieve to obtain the required glass powder.

3. Preparation of organic Binders

Weighing 11 parts of ethyl cellulose and 89 parts of terpineol according to the mass parts, mixing, heating to 60 degrees on a dispersion machine for dispersion for 60min, and dispersing and dissolving to obtain a transparent and uniform organic adhesive;

4. preparation of Mixed silver powder

Weighing 90 wt% of micron silver powder and 10 wt% of nano silver powder, and mixing to obtain the mixed silver powder.

5. Preparation of front silver paste

Weighing 85 parts of mixed silver powder, 2 parts of glass powder, 8 parts of organic binder and 1 part of methyl silicone oil according to the mass parts, uniformly mixing by using a dispersion machine, and grinding to obtain silver paste with the fineness of below 8 microns by using a three-roll grinder.

Reference slurry: Pb-Te system glass powder purchased from the market is selected and does not contain Tl raw material. Similarly, 855 parts of mixed silver powder, 2 parts of glass powder, 8 parts of organic binder and 1 part of methyl silicone oil are weighed according to the parts by mass, uniformly mixed by a dispersion machine, and ground by a three-roll grinder to obtain silver paste with the fineness of less than 8 microns.

Solar cell fabrication and measurement

Using the sample prepared above, electrode films were formed on 156mm by 156mm PERC silicon wafers by 430 mesh screen printing, the width of the main gate was 0.7 μm, and the wafer was sintered in a Despatch sintering furnace at a peak actual temperature of 700-.

The electrical data after sintering are tested as follows:

electrode films prepared using example 2: the short-circuit current 9.845A, the open-circuit voltage 678mv, the fill factor 78.79% and the photoelectric conversion efficiency 21.624% are tested, and the welding tension is 3.1N.

Electrode film prepared with reference paste: the short-circuit current is 9.839A, the open-circuit voltage is 677mv, the filling factor is 78.54 percent, the photoelectric conversion efficiency is 21.511 percent, and the welding tension is 1.8N.

It can be seen that the glass given in example 2 has a 0.006A higher short-circuit current, 0.113% higher efficiency and 1.3N higher tensile force than the glass of the Pb-Te system.

The efficiency of the crystalline silicon solar cell front silver paste glass powder in the embodiments 1 and 2 is higher than that of the conventional glass powder in the market, and the welding tension can be far higher than that of the conventional Pb-Te glass powder according to different formulas. The glass powder has low welding reject ratio after being used for front silver paste, has good electrical property, and has excellent performance in the aspects of filling factor FF, contact resistance Rs, open-circuit voltage Voc and comprehensive electrical property EFF, which also indicates that the glass powder has proper glass softening temperature and corrosion rate, and has good wettability and fluidity on the surfaces of silver powder and batteries.

Example 3

A preparation method of an N-type solar cell silver paste doped with organic gallium comprises the following steps:

(1) the glass frit prepared in example 1 was used;

(2) preparation of organic binder: weighing 8 parts of polymethacrylate and 92 parts of butyl carbitol according to the mass parts, mixing, dispersing for 60min on a dispersion machine, and dispersing and dissolving to obtain a transparent and uniform organic binder;

(3) preparing battery silver paste: the weight percentage of the mixed silver powder is 85 percent of micron silver powder and 15 percent of nano silver powder; weighing 2 parts of glass powder prepared in the step (1), 11 parts of organic binder prepared in the step (2), 3 parts of tricyclopentyl gallium and 0.5 part of methyl silicone oil according to the mass parts, uniformly mixing by using a dispersion machine, adding 83.5 parts of the mixed silver powder, mixing, grinding by using a three-roll grinder until the fineness is below 8 micrometers, and adding 3% of butyl carbitol based on the total weight of the raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short-circuit current 9.93A, open-circuit voltage 686.9mv, series resistance (silver and silicon contact resistance) 3.0 milliohm m omega; the photoelectric conversion efficiency is 22.40%, and the welding tension is 2.1N.

Example 4

A preparation method of an N-type solar cell silver paste doped with organic gallium comprises the following steps:

(1) the glass frit prepared in example 2 was used;

(2) preparation of organic binder: weighing 11 parts of ethyl cellulose and 89 parts of terpineol according to the mass parts, mixing, and dispersing for 60min on a dispersion machine to obtain a transparent and uniform organic adhesive;

(3) preparing the battery front silver paste: the mixed silver powder is 90 percent of micron silver powder and 10 percent of nano silver powder in percentage by weight; weighing 1 part of the glass powder prepared in the step (1), 8.5 parts of the organic binder prepared in the step (2), 4.5 parts of trimethyl gallium and 1 part of methyl silicone oil according to parts by mass; and (3) uniformly mixing by using a dispersion machine, adding 85 parts of the mixed silver powder, mixing, grinding by using a three-roll grinder until the fineness is below 8 micrometers, and adding terpineol accounting for 3% of the total weight of the raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short circuit current 9.887A, open circuit voltage 687.6mv, series resistance (silver and silicon contact resistance) 3.03 milliohm m omega; the photoelectric conversion efficiency is 22.44%, and the welding tension is 2.3N.

Example 5

A preparation method of N-type solar cell silver paste with high activity and low series resistance comprises the following steps:

(1) the glass frit prepared in example 1 was used;

(2) preparation of organic binder: weighing 8 parts of polymethacrylate and 92 parts of butyl carbitol according to the mass parts, mixing, dispersing for 60min on a dispersion machine, and dispersing and dissolving to obtain a transparent and uniform organic binder;

(3) preparing battery silver paste: the silver-containing mixture comprises 85 percent of micron silver powder and 15 percent of silver nitrate in percentage by weight; weighing 2 parts of the glass powder prepared in the step (1), 11 parts of the organic binder prepared in the step (2), 3 parts of dihydroxyaluminum aminoacetate and 0.5 part of methyl silicone oil according to parts by mass, uniformly mixing by using a dispersion machine, adding 83.5 parts of the silver-containing mixture, mixing, grinding by using a three-roll grinder until the fineness is below 8 microns, and adding 3% of butyl carbitol based on the total weight of the raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short circuit current 9.815A, open circuit voltage 681.8mv, series resistance (silver and silicon contact resistance) 3.03 milliohm m omega; the photoelectric conversion efficiency is 22.19%, and the welding tension is 2.13N.

Example 6

A preparation method of N-type solar cell silver paste with high activity and low series resistance comprises the following steps:

(1) example 2 a glass frit was prepared;

(2) preparation of organic binder: weighing 11 parts of ethyl cellulose and 89 parts of terpineol according to the mass parts, mixing, and dispersing for 60min on a dispersion machine to obtain a transparent and uniform organic adhesive;

(3) preparing the battery front silver paste: the silver-containing mixture is 90 percent of micron silver powder and 10 percent of silver nitrate in percentage by weight; weighing 1 part of glass powder prepared in the step (1), 8.5 parts of organic binder prepared in the step (2), 4.5 parts of dihydroxyaluminum aminoacetate and 1 part of methyl silicone oil according to parts by mass; and (3) uniformly mixing by using a dispersion machine, adding 85 parts of the silver-containing mixture, mixing, grinding by using a three-roll grinder until the fineness is below 8 micrometers, and adding terpineol accounting for 3% of the total weight of the raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short circuit current 9.831A, open circuit voltage 684.1mv, series resistance (silver to silicon contact resistance) 3.11 milliohm m omega; the photoelectric conversion efficiency is 22.32%, and the welding tension is 2.19N.

Comparative example 1

A preparation method of an N-type solar cell silver paste doped with a gallium compound comprises the following steps:

(1) the glass frit prepared in example 1 was used;

(2) preparation of organic binder: weighing 8 parts of polymethacrylate and 92 parts of butyl carbitol according to the mass parts, mixing, dispersing for 60min on a dispersion machine, and dispersing and dissolving to obtain a transparent and uniform organic binder;

(3) preparing battery silver paste: the weight percentage of the mixed silver powder is 85 percent of micron silver powder and 15 percent of nano silver powder; weighing 2 parts of glass powder prepared in the step (1), 11 parts of organic binder prepared in the step (2), 3 parts of gallium nitride and 0.5 part of methyl silicone oil according to parts by mass, uniformly mixing by using a dispersion machine, adding 83.5 parts of the mixed silver powder, mixing, grinding by using a three-roll grinder until the fineness is below 8 micrometers, and adding 3% of butyl carbitol based on the total weight of raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short circuit current 9.821A, open circuit voltage 681.1mv, series resistance (silver to silicon contact resistance) 5.16 milliohm m omega; the photoelectric conversion efficiency is 22.08%, and the welding tension is 1.47N.

Comparative example 2

The method for preparing the aluminum oxide doped N-type solar cell silver paste comprises the following steps:

(1) the glass frit prepared in example 1 was used;

(2) preparation of organic binder: weighing 8 parts of polymethacrylate and 92 parts of butyl carbitol according to the mass parts, mixing, dispersing for 60min on a dispersion machine, and dispersing and dissolving to obtain a transparent and uniform organic binder;

(3) preparing battery silver paste: the silver-containing mixture comprises 85 percent of micron silver powder and 15 percent of silver nitrate in percentage by weight; weighing 2 parts of the glass powder prepared in the step (1), 11 parts of the organic binder prepared in the step (2), 3 parts of aluminum oxide and 0.5 part of methyl silicone oil according to parts by mass, uniformly mixing by using a dispersion machine, adding 83.5 parts of the silver-containing mixture, mixing, grinding by using a three-roll grinder until the fineness is below 8 micrometers, and adding 3% of butyl carbitol based on the total weight of the raw materials to obtain the N-type solar cell silver paste.

By using the prepared sample, electrode films are formed on an N-type silicon wafer with the specification of 156mm multiplied by 156mm by 430-mesh screen printing, the width of a main gate is 0.7 micron, and the electrode films are sintered in a Despatch sintering furnace, wherein the peak actual temperature is 700-.

The electrical data after sintering are tested as follows: short circuit current 9.809A, open circuit voltage 677.9mv, series resistance (silver to silicon contact resistance) 5.41 milliohm m omega; the photoelectric conversion efficiency is 21.76%, and the welding tension is 1.36N.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.