An IBC battery positive electrode grid aluminum paste and IBC battery

Abstract

The embodiment of the present application provides an IBC battery positive electrode grid line aluminum paste and an IBC battery, wherein the aluminum paste provided by the embodiment of the present application comprises an organic additive, boron nitride powder, aluminum powder, gallium powder, an organic binder and glass powder. Because boron carbide has the boron element containing property, gallium and aluminum are both the third main group elements, have the similar chemical properties with aluminum, and the gallium element has the superconductivity and permeability, the addition of the boron nitride and the gallium powder in the aluminum paste can not only form the good aluminum-silicon alloy layer and the P+ layer doping with silicon, but also can permeate between the aluminum grains, improve the material structure, improve the conductivity of the battery, thereby improving the efficiency of the battery, thereby solving the problem that the existing IBC battery positive electrode grid line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crystalline silicon solar cell manufacturing, in particular to an IBC cell positive electrode grid line aluminum paste and an IBC cell. BACKGROUND

[0002] The interdigitated back contact (IBC) cell is a new type of cell in which the P / N junction, the base and the contact electrode of the emitter region are arranged in an interdigitated shape on the back surface of the cell. The core technology is to prepare p and n regions with good quality and in an interdigitated spaced arrangement on the back surface of the cell.

[0003] At present, in order to improve the doping concentration of the P region to improve the photoelectric conversion efficiency of the cell, the existing P-type IBC cell needs to laser groove the P+ region and print a positive electrode grid line aluminum paste doped with elemental boron to form a positive electrode grid line.

[0004] However, the above-mentioned positive electrode grid line aluminum paste doped with elemental boron has a relatively thin aluminum-silicon alloy layer after sintering, and the doping concentration on the silicon surface is improved little, so the photoelectric conversion efficiency of the cell cannot be effectively improved. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an IBC cell positive electrode grid line aluminum paste and an IBC cell to solve the problem that the existing IBC cell positive electrode grid line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the cell.

[0006] In order to solve the above-mentioned problem, the present application is realized by the following technical scheme:

[0007] The present application provides an IBC cell positive electrode grid line aluminum paste, wherein the components of the aluminum paste include organic additives, boron nitride powder, aluminum powder, gallium powder, organic binders and glass powder.

[0008] Further, in the aluminum paste, the mass fractions of the organic additives, boron nitride powder, aluminum powder, gallium powder, organic binders and glass powder are 0.2-0.4%, 0.1-0.4%, 72-78%, 0.2-0.5%, 19.4-26.3% and 1.2-1.4%, respectively.

[0009] Further, in the aluminum paste, the organic additives include one or more of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent and lauryl phosphate.

[0010] Further, in the aluminum paste, the gallium powder is micron-sized elemental gallium.

[0011] Further, in the aluminum paste, the aluminum powder comprises micron-sized spherical aluminum powder and nanometer-sized spherical aluminum powder.

[0012] Further, in the aluminum paste, the aluminum powder comprises 88-95 parts by mass of micron-sized spherical aluminum powder and 5-12 parts by mass of nanometer-sized spherical aluminum powder.

[0013] Further, in the aluminum paste, the organic binder comprises a high-molecular polymer resin and an organic solvent.

[0014] The mass fraction of the high-molecular polymer in the organic binder is 6-8%.

[0015] The mass fraction of the organic solvent in the organic binder is 92-94%.

[0016] Further, in the aluminum paste, the high-molecular polymer is ethyl cellulose-N100.

[0017] The organic solvent comprises at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbityl alcohol, butyl carbityl alcohol acetate, tributyl citrate, Span 85 and alcohol ester twelve.

[0018] Further, in the aluminum paste, the glass powder comprises Bi2O3 with a mass fraction of 15-25%, SiO2 with a mass fraction of 6-10%, Pb2O5 with a mass fraction of 10-15%, ZnO with a mass fraction of 5-15%, Sb2O5 with a mass fraction of 15-25%, V2O5 with a mass fraction of 15-25%, TiO2 with a mass fraction of 15-22%, and BaO with a mass fraction of 5-15%.

[0019] The application further provides an IBC battery, wherein the back surface of the IBC is attached with a positive grid line prepared from the aluminum paste.

[0020] Compared with the prior art, the embodiments of the application have the following advantages:

[0021] In the embodiments of the application, the IBC battery positive grid line aluminum paste comprises an organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, an organic binder and glass powder. Because boron carbide has the property of containing boron elements, gallium and aluminum are both elements of the third main group, have similar chemical properties to aluminum, and gallium elements have superconductivity and permeability, the addition of boron nitride and gallium powder in the aluminum paste can not only form a good aluminum-silicon alloy layer and P+ layer doping with silicon, but also permeate between aluminum grains, improve the material structure and improve the conductivity of the battery, thereby improving the efficiency of the battery, thereby solving the problem that the existing IBC battery positive grid line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery.

[0022] It is to be understood that the foregoing general description and the following detailed description are only exemplary and explanatory and are not restrictive of the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a preparation method flow chart of the IBC battery positive grid aluminum paste provided by the embodiment of the application.

[0024] Figure 2 is a preparation method flow chart of the IBC battery provided by the embodiment of the application. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the application more apparent, understandable and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0026] The applicant of the application finds that, in order to improve the doping concentration of the P region to improve the photoelectric conversion efficiency of the battery piece, the existing P-type IBC battery needs to be laser grooved in the P+ region and print the positive grid aluminum paste doped with elemental boron to form the positive grid.

[0027] However, the above-mentioned method of using the positive grid aluminum paste doped with elemental boron has a relatively thin aluminum-silicon alloy layer formed after sintering, and the doping concentration on the silicon surface is improved little, so the photoelectric conversion efficiency of the battery cannot be effectively improved.

[0028] The embodiment of the application provides an IBC battery positive grid aluminum paste to solve the above-mentioned problems.

[0029] The aluminum powder is the main component; the glass powder is an inorganic binder that will melt into a liquid state under high temperature conditions and will condense when cooled, playing a role of adhesion; the organic binder can ensure the overall adhesion effect, and the organic adjuvant can reduce the overall viscosity of the aluminum paste while making the components in the aluminum paste uniform and stable; the boron nitride has the characteristics of containing boron elements and is low in cost; and the gallium powder belongs to the third main group like aluminum and has similar chemical characteristics, so by adding the gallium powder in the paste, the above-mentioned doping substances can penetrate between the aluminum grains without affecting the formation of the aluminum-silicon alloy layer and the P+ layer doping, the material structure can be improved, the conductivity of the battery can be improved, and thus the photoelectric conversion efficiency of the battery can be improved.

[0030] In the embodiment of the application, by adding the boron nitride and the gallium powder in the aluminum paste, not only the paste cost can be reduced by using the boron nitride to replace the elemental boron, but also the thickness of the aluminum-silicon alloy formed by the paste and the silicon substrate and the doping concentration on the silicon surface can be improved, so the photoelectric conversion efficiency of the battery can be improved, and thus the problem that the existing IBC battery positive grid aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery is solved.

[0031] The IBC battery positive electrode grid aluminum paste provided by the embodiment of the present application is an IBC battery positive electrode grid aluminum paste doped with boron nitride instead of elemental boron and incorporating gallium powder, which is suitable for printing on the surface of a silicon wafer on the back of an IBC battery by a silk screen printing method to form a positive electrode fine grid.

[0032] Optionally, in an embodiment, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.2-0.4%, 0.1-0.3%, 72-78%, 0.2-0.5%, 19.4-26.3% and 1.2-1.4% respectively, that is, the aluminum paste is made by mixing 0.2-0.4 parts of the organic auxiliary agent, 0.1-0.3 parts of the boron nitride powder, 72-78 parts of the aluminum powder, 0.2-0.5 parts of the gallium powder, 19.4-26.3 parts of the organic binder and 1.2-1.4 parts of the glass powder, so that the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.2-0.4%, 0.1-0.4%, 72-78%, 0.2-0.5%, 19.4-26.3% and 1.2-1.4% respectively.

[0033] Optionally, in some embodiments, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder are 0.25-0.35%, 0.15-0.25%, 73-75%, 0.3-0.4%, 23-25% and 1.25-1.35% respectively.

[0034] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.2%, 0.3%, 72%, 0.5%, 25.6% and 1.4% respectively.

[0035] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.4%, 0.1%, 78%, 0.2%, 20.1% and 1.2% respectively.

[0036] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.2%, 0.1%, 72%, 0.2%, 26.3% and 1.2% respectively.

[0037] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.4%, 0.3%, 78%, 0.5%, 19.4% and 1.4% respectively.

[0038] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.3%, 0.3%, 75%, 0.3%, 23.2% and 1.2%, respectively.

[0039] For example, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder in the aluminum paste are 0.4%, 0.4%, 77%, 0.4%, 20.6% and 1.2%, respectively.

[0040] Optionally, the organic auxiliary agent can be one or more of aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, phosphoric acid ester, lauryl alcohol phosphoric acid ester, Digo 655 and BYK109.

[0041] Optionally, the boron nitride powder has a purity of more than 99% in the micron level. In the embodiment of the present application, the boron nitride powder used for doping the P region only needs to have a purity of 99% to achieve effective doping, thereby effectively reducing the cost of the paste.

[0042] Optionally, in an embodiment, the gallium powder is micron-level elemental gallium, and specifically, the micron-level elemental gallium has a purity of 99%.

[0043] Optionally, in an embodiment, the aluminum powder includes micron-level spherical aluminum powder and nanometer-level spherical aluminum powder. The micron-level aluminum powder has gaps between the aluminum powder, and the nanometer-level aluminum powder is graded with the micron-level aluminum powder, so that the nanometer-level aluminum powder can fill the gaps between the micron-level aluminum powder.

[0044] Optionally, in a specific embodiment, the aluminum powder includes 88-95 parts of micron-level spherical aluminum powder and 5-12 parts of nanometer-level spherical aluminum powder by mass, i.e., the aluminum powder includes 88-95% of micron-level spherical aluminum powder and 5-12% of nanometer-level spherical aluminum powder by mass.

[0045] For example, the aluminum powder includes 88 parts of micron-level spherical aluminum powder and 12 parts of nanometer-level spherical aluminum powder by mass.

[0046] For example, the aluminum powder includes 90 parts of micron-level spherical aluminum powder and 10 parts of nanometer-level spherical aluminum powder by mass.

[0047] For example, the aluminum powder includes 92 parts of micron-level spherical aluminum powder and 8 parts of nanometer-level spherical aluminum powder by mass.

[0048] For example, the aluminum powder includes 95 parts of micron-level spherical aluminum powder and 5 parts of nanometer-level spherical aluminum powder by mass.

[0049] Optionally, in an embodiment, the organic binder includes 6-8 parts by mass of the high molecular polymer resin and 92-94 parts by mass of the organic solvent, i.e., the mass fraction of the high molecular polymer in the organic binder is 6-8%, and the mass fraction of the organic solvent in the organic binder is 92-94%. The high molecular polymer is dissolved in the organic solvent, so that the organic solvent can be used as the organic binder, i.e., the slurry after drying can play a role of binding the powder.

[0050] The high molecular polymer resin can be one or more of ethyl cellulose, acrylic resin, nitrocellulose, phenolic resin, rosin resin, cellulose acetate butyrate, epoxy resin, and polymethyl acrylate; and the organic solvent can be at least three of benzyl alcohol, terpineol, diethyl phthalate, terpineol, butyl carbate, butyl carbate acetate, tributyl citrate, and Span 85.

[0051] In the embodiment, the glass powder includes Bi2O3, SiO2, Pb2O5, ZnO, Sb2O5, V2O5, TiO2, and BaO, i.e., the glass powder is obtained by sintering and crushing Bi2O3, SiO2, Pb2O5, ZnO, Sb2O5, V2O5, TiO2, and BaO. Bi2O3 is the main network structure, ZnO can break the network structure and promote glass crystallization, and Sb2O5 is used for clarifying and uniforming the glass liquid; SiO2 is used as a glass network former to promote glass stability and increase the glass melting point; Pb2O5 reacts with silicon nitride to generate lead, nitrogen, and silicon dioxide; V2O5 and TiO2 can assist Pb2O5 and silicon nitride to react; and BaO is used for local crystallization.

[0052] Optionally, in an embodiment, the glass powder includes 15-25% by mass of Bi2O3, 6-10% by mass of SiO2, 10-15% by mass of Pb2O5, 5-15% by mass of ZnO, 15-25% by mass of Sb2O5, 5-15% by mass of V2O5, 15-22% by mass of TiO2, and 5-15% by mass of BaO, and the D50 of the glass powder is 1-1.6 μm.

[0053] For example, the glass powder includes 15% by mass of Bi2O3, 10% by mass of SiO2, 10% by mass of Pb2O5, 15% by mass of ZnO, 15% by mass of Sb2O5, 15% by mass of V2O5, 15% by mass of TiO2, and 5% by mass of BaO.

[0054] For example, the glass powder includes Bi2O3 with a mass fraction of 25%, SiO2 with a mass fraction of 6%, Pb2O5 with a mass fraction of 10%, ZnO with a mass fraction of 5%, Sb2O5 with a mass fraction of 15%, V2O5 with a mass fraction of 15%, TiO2 with a mass fraction of 15%, and BaO with a mass fraction of 9% by mass parts.

[0055] For example, the glass powder includes Bi2O3 with a mass fraction of 22%, SiO2 with a mass fraction of 6%, Pb2O5 with a mass fraction of 12%, ZnO with a mass fraction of 10%, Sb2O5 with a mass fraction of 18%, V2O5 with a mass fraction of 7%, TiO2 with a mass fraction of 15%, and BaO with a mass fraction of 10% by mass parts.

[0056] The embodiment of the present application further provides a preparation method of the IBC battery positive electrode grid line aluminum paste, as shown in the figure, comprising steps 101-103: Figure 1

[0057] Step 101, mixing boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder to obtain a mixture;

[0058] Step 102, after grinding the mixture, adding an organic auxiliary agent to obtain the IBC battery positive electrode grid line aluminum paste.

[0059] In step 101, 0.1-0.3% of boron nitride powder, 72-78% of aluminum powder, 0.2-0.5% of gallium powder, 19.4-26.3% of organic binder, and 1.2-1.4% of glass powder are weighed and mixed, and a disperser is used for dispersion to obtain the mixture.

[0060] Optionally, in an embodiment, in step 101, the organic binder, nanoscale aluminum powder, boron nitride powder and gallium powder are first mixed, a disperser is used for dispersion, then micron-scale aluminum powder is added, a disperser is used for dispersion again, and then grinding is performed to obtain the mixture.

[0061] In step 102, after the mixture is ground, 0.2-0.4% of the organic auxiliary agent is added to the total mass of the raw materials, and high-speed dispersion is performed to obtain the IBC battery positive electrode grid line aluminum paste which can effectively improve the photoelectric conversion efficiency of the battery without laser slotting.

[0062] ​In the embodiment of the present application, because boron carbide has the property of containing boron element, gallium and aluminum are both elements of the third main group, have similar chemical properties with aluminum, and gallium element has superconductivity and permeability, adding boron nitride and gallium powder in the aluminum paste can not only form a good aluminum-silicon alloy layer and P+ layer doping with silicon, but also penetrate between aluminum grains, improve the material structure, improve the conductivity of the battery, thereby improving the efficiency of the battery, thereby solving the problem that the existing IBC battery positive gate line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery.

[0063] Optionally, in the preparation method provided by the embodiment of the present application, the organic adjuvant includes one or more of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl phosphate.

[0064] Optionally, in the preparation method provided by the embodiment of the present application, the gallium powder is micron-level elemental gallium.

[0065] Optionally, in the preparation method provided by the embodiment of the present application, the aluminum powder includes micron-level spherical aluminum powder and nanometer-level spherical aluminum powder.

[0066] Optionally, in the preparation method provided by the embodiment of the present application, the aluminum powder includes 88-95 parts by mass of micron-level spherical aluminum powder and 5-12 parts by mass of nanometer-level spherical aluminum powder.

[0067] Optionally, in the preparation method provided by the embodiment of the present application, the organic binder includes a high-molecular polymer resin and an organic solvent.

[0068] The mass fraction of the high-molecular polymer in the organic binder is 6-8%.

[0069] The mass fraction of the organic solvent in the organic binder is 92-94%.

[0070] Optionally, in the preparation method provided by the embodiment of the present application, the high-molecular polymer is ethyl cellulose-N100.

[0071] The organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbityl alcohol, butyl carbityl alcohol acetate, tributyl citrate, Span 85, and alcohol ester twelve.

[0072] Optionally, in the preparation method provided by the embodiment of the present application, the glass powder includes Bi2O3 with a mass fraction of 15-25%, SiO2 with a mass fraction of 6-10%, Pb2O5 with a mass fraction of 10-15%, ZnO with a mass fraction of 5-15%, Sb2O5 with a mass fraction of 15-25%, V2O5 with a mass fraction of 15-25%, TiO2 with a mass fraction of 15-22%, and BaO with a mass fraction of 5-15%.

[0073] The application further provides a preparation method of the IBC battery. Figure 2 As shown in the figure, the method comprises steps 201-203:

[0074] Step 201: after forming the interdigitated and spaced n+ doped regions and p+ doped regions on the back of the silicon wafer, a passivation layer is formed on the surface of the n+ doped regions and p+ doped regions;

[0075] Step 202: after laser slotting the first region of the passivation layer, printing aluminum paste, and printing silver paste on the second region of the passivation layer; the projection of the first region is within the range of the p+ doped region, and the projection of the second region is within the range of the n+ doped region; wherein the components of the aluminum paste include organic additives, boron nitride powder, aluminum powder, gallium powder, organic binder and glass powder;

[0076] Step 203: high-temperature sintering the P-type silicon wafer on which the aluminum paste is printed in the first region and the silver paste is printed in the second region to obtain the IBC battery.

[0077] In step 201, the silicon wafer is first alkali textured, then the interdigitated and spaced n+ doped regions and p+ doped regions are formed on the back of the silicon wafer, and then a silicon oxide layer or a silicon nitride layer covering the entire back of the silicon wafer is deposited as the passivation layer.

[0078] In step 202, the silicon wafer after forming the passivation layer is laser slotted and then screen printed to prepare the electrode grid lines. Specifically, the aluminum paste is printed after laser slotting the first region of the passivation layer on the back of the silicon wafer, and the projection of the first region is within the range of the p+ doped region to form a positive electrode grid line in conduction with the p+ doped region; at the same time, the silver paste is also printed in the second region of the back passivation layer, and the projection of the second region is within the range of the n+ doped region to form a negative electrode grid line spaced from the positive electrode grid line, wherein the silver paste can be a traditional silver paste.

[0079] In step 203, the aluminum paste is added with boron nitride and gallium powder, which not only realizes the reduction of paste cost by using boron nitride instead of elemental boron, but also improves the thickness of the aluminum-silicon alloy formed by the paste and the silicon substrate and the doping concentration of the silicon surface, thereby improving the photoelectric conversion efficiency of the battery; gallium powder, like aluminum, belongs to the third main group and has similar chemical characteristics, and by adding gallium powder in the paste, the above-mentioned doping substances can penetrate between aluminum grains without affecting the formation of the aluminum-silicon alloy layer and the P+ layer doping, thereby improving the material structure and the conductivity of the battery, and further improving the photoelectric conversion efficiency of the battery.

[0080] Therefore, the embodiment of the application solves the problem that the existing IBC battery positive electrode grid line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery.

[0081] The silicon wafer can be an N-type silicon wafer or a P-type silicon wafer.

[0082] For example, when the silicon wafer is a P-type silicon wafer, the step 101 specifically includes:

[0083] (1) A P-type original silicon wafer is taken, a layer of ultra-thin silicon oxide is formed on the back surface of the P-type silicon wafer by using low pressure chemical vapor deposition (LPCVD) as an ultra-thin tunnel oxide layer, and then a polysilicon layer with a thickness capable of meeting the passivation effect is prepared on both surfaces; because the polysilicon layer is prepared on both surfaces, it is beneficial to subsequent removal of the polysilicon layer on the front surface, and it is not easy to appear two extreme cases of excessive removal or insufficient removal, and the yield is better controlled;

[0084] (2) After the polysilicon layer is prepared, the silicon wafer is sent into a furnace tube to perform phosphorus doping on the polysilicon layer to form an n+ doped region;

[0085] (3) Laser grooving is performed on the back surface of the silicon wafer to expose the p+ doped region, to form the n+ doped region and the p+ doped region arranged in an interdigital and spaced manner, and then the polysilicon layer on the front surface is removed by using a wet method;

[0086] (4) An atomic layer deposition (ALD) process is used to plate a passivation layer on the entire front surface and the entire back surface of the product to form field passivation; after the aluminum oxide film layer is formed, a reflection-reducing film layer is plated on the front surface of the cell first, and then a reflection-reducing film layer is plated on the back surface, to further improve the passivation effect of the cell wafer.

[0087] The application further provides an IBC cell, wherein the back surface of the IBC is attached with a positive electrode grid line, and the positive electrode grid line is prepared from the aluminum paste.

[0088] The application will be described in detail below through examples.

[0089] Example 1

[0090] (1) Preparation of glass powder: 22 parts of Bi2O3, 6 parts of SiO2, 12 parts of Pb2O5, 10 parts of ZnO, 18 parts of Sb2O5, 7 parts of V2O5, 15 parts of TiO2 and 10 parts of BaO are weighed according to the mass fraction, uniformly mixed by using a mixer, loaded into a porcelain crucible, placed in a muffle furnace, and kept at 950 DEG C for 120 minutes, and then the glass powder particles after melting are quenched by using ion water, ball milled for 4 hours, and then taken through a 300-mesh screen to obtain glass powder with a particle size D50 of 1-1.6 μm;

[0091] (2) Preparation of organic binder: 6 parts of ethyl cellulose-N100 and 94 parts of organic solvent are weighed by mass fraction, and after mixing, they are dispersed on a large disperser for 40-50 min to obtain a transparent and uniform organic binder; wherein, the organic solvent includes 0.5 parts of benzyl alcohol, 62 parts of butyl carbol, 32.7 parts of butyl carbol acetate, 0.3 parts of tributyl citrate, 0.5 parts of Span 85, and 4 parts of alcohol ester twelve by mass fraction;

[0092] (3) Preparation of aluminum powder: 90 parts of micron-sized aluminum powder and 10 parts of nano-sized aluminum powder are weighed by mass fraction, and mixed to obtain mixed aluminum powder;

[0093] (4) Preparation of aluminum paste: 0.3 parts of boron nitride powder, 75 parts of aluminum powder, 0.3 parts of elemental gallium powder, 23.2 parts of organic binder, 1.2 parts of glass powder are weighed by mass fraction, mixed uniformly using a disperser, and then ground to below 20 microns using a three-roll grinder. Then, 0.1 parts of zirconium aluminate coupling and 0.2 parts of lauryl alcohol phosphate are added, and thoroughly stirred to obtain the aluminum paste.

[0094] The sample aluminum paste prepared above is used to form a positive electrode fine grid on the back of a P-type single crystal silicon wafer with a size of 182 mm x 182 mm by 380 mesh screen printing, and then sintered in a sintering furnace with a peak temperature of 766°C.

[0095] After sintering, the electrical data is tested as follows: open circuit voltage is 0.719V, short circuit current is 13.845A, fill factor is 83.45, and photoelectric conversion efficiency is 25.16%.

[0096] Example 2

[0097] (1) Preparation of glass powder: 22 parts of Bi2O3, 6 parts of SiO2, 12 parts of Pb2O5, 10 parts of ZnO, 18 parts of Sb2O5, 7 parts of V2O5, 15 parts of TiO2, and 10 parts of BaO are weighed by mass fraction, mixed uniformly using a mixer, loaded into a porcelain crucible, placed in a muffle furnace, and kept at 950°C for 120 minutes. After the molten glass powder particles are quenched with ionized water, they are ball milled for 4 hours, and then sieved through a 300 mesh screen to obtain glass powder with a particle size D50 of 1-1.6 μm;

[0098] (2) Preparation of organic binder: 6 parts of ethyl cellulose-N100 and 94 parts of organic solvent are weighed by mass fraction, and after mixing, they are dispersed on a large disperser for 40-50 min to obtain a transparent and uniform organic binder; wherein, the organic solvent includes 0.5 parts of benzyl alcohol, 62 parts of butyl carbol, 32.7 parts of butyl carbol acetate, 0.3 parts of tributyl citrate, 0.5 parts of Span 85, and 4 parts of alcohol ester twelve by mass fraction;

[0099] (3) Preparation of aluminum powder: 92 parts of micron-sized aluminum powder and 8 parts of nano-sized aluminum powder are weighed by mass fraction, and mixed to obtain mixed aluminum powder;

[0100] (4) Preparation of aluminum paste: 0.4 parts of boron nitride powder, 77 parts of aluminum powder, 0.4 parts of elemental gallium powder, 20.6 parts of organic binder, 1.2 parts of glass powder are weighed by mass fraction, mixed uniformly using a dispersing machine, and then ground to below 20 microns using a three-roll grinding machine. Then, 0.2 parts of zirconium aluminate coupling and 0.2 parts of lauryl alcohol phosphatide are added, and stirred thoroughly to obtain the aluminum paste.

[0101] The sample aluminum paste prepared above is used to form a positive electrode fine grid on the back of a P-type monocrystalline silicon wafer with a size of 182 mm x 182 mm by 380 mesh screen printing, and then sintered in a sintering furnace with a peak temperature of 768°C.

[0102] After sintering, the electrical data is tested to be: open-circuit voltage of 0.722 V, short-circuit current of 13.885 A, fill factor of 83.2, and photoelectric conversion efficiency of 25.17%.

[0103] Example 3

[0104] Example 3 differs from Example 2 in that, in step (1), 15 parts of Bi2O3, 10 parts of SiO2, 10 parts of Pb2O5, 15 parts of ZnO, 15 parts of Sb2O5, 15 parts of V2O5, 15 parts of TiO2, and 5 parts of BaO are weighed by mass fraction, mixed uniformly using a mixer, loaded into a porcelain crucible, placed in a muffle furnace, and heated at 950°C for 120 minutes. After quenching the molten glass powder particles with ionized water, they are ball-milled for 4 hours, and then sieved through a 300 mesh screen to obtain glass powder with a particle size D50 of 1-1.6 μm.

[0105] The sample aluminum paste prepared in Example 3 is used to form a positive electrode fine grid on the back of a P-type monocrystalline silicon wafer with a size of 182 mm x 182 mm by 360 mesh screen printing, and then sintered in a sintering furnace with a peak temperature of 768°C.

[0106] After sintering, the electrical data is tested to be: open-circuit voltage of 0.720 V, short-circuit current of 13.835 A, fill factor of 83.25, and photoelectric conversion efficiency of 25.117%.

[0107] Example 4

[0108] Example 4 differs from Example 2 in that in step (1), 25 parts of Bi2O3, 6 parts of SiO2, 10 parts of Pb2O5, 5 parts of ZnO, 15 parts of Sb2O5, 15 parts of V2O5, 15 parts of TiO2, and 9 parts of BaO are weighed by mass parts, mixed uniformly by a mixer, loaded into a porcelain crucible, placed in a muffle furnace, and kept at 950°C for 120 minutes. After the glass powder particles are melted, they are quenched with ionized water, ball-milled for 4 hours, and sieved through a 300-mesh screen to obtain glass powder with a particle size D50 of 1-1.6 μm.

[0109] The sample aluminum paste prepared in Example 4 is screen-printed on the back of a P-type single crystal silicon wafer with a size of 182 mm x 182 mm through a 380-mesh screen to form a positive electrode fine grid, and is sintered in a sintering furnace with a peak temperature of 768°C.

[0110] After sintering, the electrical data is tested to be an open-circuit voltage of 0.7205 V, a short-circuit current of 13.832 A, a fill factor of 83.28, and a photoelectric conversion efficiency of 25.139%.

[0111] Example 5

[0112] Example 5 differs from Example 2 in that in step (4), 0.1 parts of boron nitride powder, 72 parts of aluminum powder, 0.2 parts of elemental gallium powder, 26.3 parts of an organic binder, and 1.2 parts of glass powder are mixed, uniformly mixed by a disperser, and ground to below 20 μm by a three-roll grinder. Then, 0.1 parts of zirconium aluminate coupling and 0.1 parts of lauryl alcohol phosphatide are added, and the mixture is thoroughly stirred to prepare an aluminum paste.

[0113] The sample aluminum paste prepared in Example 5 is screen-printed on the back of a P-type single crystal silicon wafer with a size of 182 mm x 182 mm through a 380-mesh screen to form a positive electrode fine grid, and is sintered in a sintering furnace with a peak temperature of 768°C.

[0114] After sintering, the electrical data is tested to be an open-circuit voltage of 0.7201 V, a short-circuit current of 13.828 A, a fill factor of 83.31, and a photoelectric conversion efficiency of 25.126%.

[0115] Example 6

[0116] Example 6 differs from Example 2 in that in step (4), 0.3 parts of boron nitride powder, 72 parts of aluminum powder, 0.5 parts of elemental gallium powder, 25.6 parts of an organic binder, and 1.4 parts of glass powder are mixed, uniformly mixed by a disperser, and ground to below 20 μm by a three-roll grinder. Then, 0.1 parts of zirconium aluminate coupling and 0.1 parts of lauryl alcohol phosphatide are added, and the mixture is thoroughly stirred to prepare an aluminum paste.

[0117] The sample aluminum paste prepared in Example 6 was screen printed on the back of a P-type single crystal silicon wafer with a size of 182 mm x 182 mm to form a positive electrode fine grid, and was sintered in a sintering furnace with a peak temperature of 768°C.

[0118] After sintering, the electrical data of the sample was tested as follows: open circuit voltage was 0.7205 V, short circuit current was 13.831 A, fill factor was 83.26, and photoelectric conversion efficiency was 25.131%.

[0119] Comparative Example 1

[0120] (1) Preparation of glass powder: 22 parts of Bi2O3, 6 parts of SiO2, 12 parts of Pb2O5, 10 parts of ZnO, 18 parts of Sb2O5, 7 parts of V2O5, 15 parts of TiO2, and 10 parts of BaO were weighed according to the mass fraction, mixed uniformly with a mixer, loaded into a porcelain crucible, and placed in a muffle furnace at 950°C for 120 minutes. After the glass powder particles were melted, they were quenched with ionized water, ball milled for 4 hours, and sieved through a 300 mesh screen to obtain glass powder with a particle size D50 of 1-1.6 μm;

[0121] (2) Preparation of organic binder: 9 parts of ethyl cellulose-N100 and 91 parts of organic solvent were weighed according to the mass fraction, mixed, and dispersed on a high-speed dispersion machine for 40-50 minutes to obtain a transparent and uniform organic binder. The organic solvent included 0.5 parts of benzyl alcohol, 62 parts of butyl carbitol, 32.7 parts of butyl carbitol acetate, 0.3 parts of tributyl citrate, 0.5 parts of Span 85, and 4 parts of alcohol ester twelve, according to the mass fraction.

[0122] (3) Preparation of aluminum powder: 92 parts of micron-sized aluminum powder and 8 parts of nano-sized aluminum powder were weighed according to the mass fraction, mixed uniformly to obtain mixed aluminum powder.

[0123] (4) Preparation of aluminum paste: 0.15 parts of boron powder, 77 parts of aluminum powder, 0.4 parts of elemental gallium powder, 20.55 parts of organic binder, 1.2 parts of glass powder were weighed according to the mass fraction, mixed uniformly using a dispersion machine, and then ground to less than 20 microns using a three-roll grinder. Then, 0.2 parts of zirconium aluminate coupling and 0.2 parts of lauryl alcohol phosphate were added, and the mixture was stirred thoroughly to obtain the aluminum paste.

[0124] The sample aluminum paste prepared above was screen printed on the back of a P-type single crystal silicon wafer with a size of 182 mm x 182 mm to form a positive electrode fine grid, and was sintered in a sintering furnace with a peak temperature of 788°C.

[0125] After sintering, the electrical data of the sample was tested as follows: open circuit voltage was 0.715 V, short circuit current was 13.855 A, fill factor was 83.52, and photoelectric conversion efficiency was 25.061%.

[0126] Experiments show that the aluminum paste provided by the embodiment of the present application can improve the battery conversion efficiency by more than 0.08% under the premise of reducing the cost.

[0127] In summary, in the embodiment of the present application, the IBC battery positive grid line aluminum paste provided comprises an organic additive, boron nitride powder, aluminum powder, gallium powder, an organic binder and glass powder. Because boron carbide has the property of containing boron elements, gallium and aluminum are both elements of the third main group, have similar chemical properties to aluminum, and gallium elements have superconductivity and permeability. Adding boron nitride and gallium powder to the aluminum paste can not only form a good aluminum-silicon alloy layer and P+ layer doping with silicon, but also penetrate between aluminum grains, improve the material structure, and improve the conductivity of the battery, thereby improving the efficiency of the battery, thereby solving the problem that the existing IBC battery positive grid line aluminum paste cannot effectively improve the photoelectric conversion efficiency of the battery.

[0128] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic creative concept. Therefore, the claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0129] The IBC battery positive grid line aluminum paste and IBC battery provided by the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation mode and application range. In summary, the content of the present description should not be understood as a limitation of the present application.

Claims

1. An IBC battery positive grid line aluminum paste, characterized by, The components of the aluminum paste include an organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, an organic binder, and glass powder; The glass powder includes Bi2O3 with a mass fraction of 15-25%, SiO2 with a mass fraction of 6-10%, Pb2O5 with a mass fraction of 10-15%, ZnO with a mass fraction of 5-15%, Sb2O5 with a mass fraction of 15-25%, V2O5 with a mass fraction of 5-15%, TiO2 with a mass fraction of 15-22%, and BaO with a mass fraction of 5-15%; In the aluminum paste, the mass fractions of the organic auxiliary agent, boron nitride powder, aluminum powder, gallium powder, organic binder, and glass powder are 0.2-0.4%, 0.1-0.4%, 72-78%, 0.2-0.5%, 19.4-26.3%, and 1.2-1.4%, respectively. The gallium powder is micron-level elemental gallium.

2. The aluminum paste of claim 1, wherein The organic auxiliary agent includes one or more of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl phosphate.

3. The aluminum paste of claim 1, wherein The aluminum powder includes micron-level spherical aluminum powder and nanometer-level spherical aluminum powder.

4. The aluminum paste of claim 1, wherein The aluminum powder includes 88-95 parts of micron-level spherical aluminum powder and 5-12 parts of nanometer-level spherical aluminum powder by mass fraction.

5. The aluminum paste of claim 1, wherein The organic binder includes a high-molecular polymer resin and an organic solvent. The mass fraction of the high-molecular polymer in the organic binder is 6-8%. The mass fraction of the organic solvent in the organic binder is 92-94%.

6. The aluminum paste of claim 5, wherein The high-molecular polymer is ethyl cellulose-N100. The organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbityl alcohol, butyl carbityl alcohol acetate, tributyl citrate, Span 85, and alcohol ester twelve.

7. An IBC cell characterized in that, The back of the IBC battery is attached with a positive grid line, which is prepared from the aluminum paste according to any one of claims 1-6.

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