Aluminum paste for P region polished surface of P-type IBC battery, preparation method of aluminum paste and IBC battery

Abstract

The embodiment of the invention provides aluminum paste for a P-type IBC battery P-region polished surface, a preparation method of the aluminum paste and an IBC battery, the aluminum paste for the P-type IBC battery P-region polished surface provided by the embodiment of the invention comprises an organic auxiliary agent, boron powder, aluminum powder, glass powder and an organic binding agent, the organic binding agent comprises high-molecular polymer resin and an organic solvent, and the boron powder and the aluminum powder are added into the organic auxiliary agent. The high-molecular polymer resin comprises ethyl cellulose and hydrogenated castor oil. The hydrogenated castor oil is added into the aluminum paste, so that the thixotropy of the paste can be improved, the paste is not easy to collapse, the paste is stably printed in a P region, the pollution of the aluminum paste to an N region is avoided, the efficiency of a P-type IBC battery is improved, and the problems that the existing aluminum paste easily collapses during printing and overflows out of the P region, and the service life of the aluminum paste is prolonged are solved. The N region of the P-type IBC battery with the polished surface P region is polluted by the aluminum paste, and the photoelectric conversion efficiency of the battery is influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of crystalline silicon solar cell manufacturing, and particularly to an aluminum paste for the polished surface of the P region of a P-type IBC cell, a preparation method thereof, and an IBC cell. Background Art

[0002] The Interdigitated Back Contact (IBC) cell is a new type of cell in which the P / N junction, the contact electrodes of the substrate and the emitter region are made in an interdigitated shape on the back of the cell. The core technology is to prepare a p region and an n region with good quality and arranged in an interdigitated interval on the back of the cell, and then print an aluminum paste connected to the p region to form a positive grid line, and print a silver paste connected to the n region to form a negative grid line.

[0003] Currently, the morphology of the P region of a P-type IBC cell can be polished and textured respectively. For a P-type IBC cell with a polished surface P region, during the printing process of the aluminum paste, the aluminum paste is prone to collapse and overflow from the P region and enter the N region, resulting in contamination of the N region by the aluminum paste, thereby affecting the photoelectric conversion efficiency of the P-IBC cell. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an aluminum paste for the polished surface of the P region of a P-type IBC cell, a preparation method thereof, and an IBC cell, so as to solve the problem that the existing aluminum paste is prone to collapse and overflow during printing, resulting in contamination of the N region of the P-type IBC cell with a polished surface P region by the aluminum paste and affecting the photoelectric conversion efficiency of the cell.

[0005] To solve the above problems, the present invention is realized by the following technical solutions:

[0006] The present invention provides an aluminum paste for the polished surface of the P region of a P-type IBC cell. The components constituting the aluminum paste include an organic auxiliary agent, boron powder, aluminum powder, glass powder, and an organic binder. The organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil.

[0007] Further, in the aluminum paste, the mass fraction of the ethyl cellulose in the organic binder is 8-12%;

[0008] The mass fraction of the hydrogenated castor oil in the organic binder is 1-1.5%;

[0009] The mass fraction of the organic solvent in the organic binder is 86.5-91%.

[0010] Further, in the aluminum paste, the organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, span 85, and alcohol ester 12.

[0011] Further, in the aluminum paste, the mass percentage of the organic auxiliary agent is 0.3 - 0.6%; the mass percentage of the boron powder is 0.05 - 0.15%; the mass percentage of the aluminum powder is 73 - 79%; the mass percentage of the glass powder is 1 - 1.2%; the mass percentage of the organic binder is 19.05 - 25.65%.

[0012] Further, in the aluminum paste, the boron powder is micron-sized boron powder.

[0013] Further, in the aluminum paste, the organic auxiliary agent includes at least one of fatty alcohol ether phosphate ester, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl alcohol phosphate ester.

[0014] Further, in the aluminum paste, the aluminum powder includes 90 - 95% by mass of micron spherical aluminum powder and 5 - 10% by mass of nano spherical aluminum powder.

[0015] Further, in the aluminum paste, the glass powder includes 15 - 25% by mass of Bi2O3, 6 - 10% by mass of Al2O3, 8 - 12% by mass of Pb2O5, 15 - 25% by mass of ZnO, 15 - 22% by mass of Sb2O5, 6 - 10% by mass of V2O5, 15 - 22% by mass of TiO2, and 12 - 20% by mass of BaO.

[0016] The present invention also provides a method for preparing an aluminum paste for the polished surface of the P region of a P-type IBC cell, which includes:

[0017] Mix aluminum powder, boron powder, organic binder, and glass powder to obtain a mixture; wherein, the organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil;

[0018] After grinding the mixture, add an organic additive to obtain the aluminum paste for forming the positive grid lines on the polished surface of the P region of the P-type IBC cell.

[0019] The present invention also provides a P-type IBC cell, wherein a P-type doping region is provided on the back of the IBC cell, the P-type doping region has a polished surface, and multiple positive grid lines are attached to the polished surface, and the positive grid lines are prepared from the above-mentioned aluminum paste.

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

[0021] In the embodiments of the present invention, the aluminum paste for the polished surface of the P region of the P-type IBC battery provided has components including an organic auxiliary agent, boron powder, aluminum powder, glass powder, and an organic binder. The organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil. By adding hydrogenated castor oil to the aluminum paste, the thixotropy of the paste can be improved, making the paste not easily collapse, ensuring that the paste is stably printed on the P region, avoiding the contamination of the N region by the aluminum paste, thereby improving the efficiency of the P-type IBC battery, and thus solving the problem that the existing aluminum paste is easily collapsed and overflows the P region during printing, resulting in the contamination of the N region of the P-type IBC battery with a polished surface P region by the aluminum paste, affecting the photoelectric conversion efficiency of the battery.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flowchart of a method for preparing an aluminum paste for the polished surface of the P region of a P-type IBC battery provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0025] The embodiments of the present invention provide an aluminum paste for the polished surface of the P region of a P-type IBC battery. The components constituting the aluminum paste include an organic auxiliary agent, boron powder, aluminum powder, glass powder, and an organic binder. The organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil.

[0026] The aluminum paste provided by the embodiments of the present invention is used to form the positive grid lines of a P-type IBC battery with a polished surface P region.

[0027] Among them, the aluminum powder is the main component. The aluminum powder mainly replaces the P+ emitter of the battery, while the boron powder can diffuse into the silicon during high-temperature sintering for heavy doping, which is beneficial to improving the contact performance of the paste, reducing the reaction contact surface between aluminum and silicon, reducing the contact resistivity between the positive grid and the battery, and thus improving the filling and efficiency of the battery;

[0028] Among them, the glass powder is an inorganic binder, which will melt into a liquid state under high-temperature conditions and solidify when cooled, playing a bonding role; the organic binder can ensure the overall bonding effect; the organic auxiliary agent can reduce the overall viscosity of the aluminum paste.

[0029] Among them, the hydrogenated castor oil in the organic binder can improve the thixotropy of the slurry. An object with high thixotropy has a reduced consistency when subjected to shear and an increased consistency when shear stops. By adding hydrogenated castor oil to the slurry, the slurry is not easily collapsed, ensuring that the slurry is stably printed in the P region, avoiding the contamination of the N region by the aluminum paste, and thus improving the efficiency of the P-type IBC cell.

[0030] Therefore, the aluminum paste provided by the embodiments of the present invention can solve the problem that the existing aluminum paste is prone to collapse and overflow the P region during printing, resulting in the contamination of the N region of the P-type IBC cell with a polished P region by the aluminum paste and affecting the photoelectric conversion efficiency of the cell.

[0031] Optionally, in one embodiment, the mass fraction of the ethyl cellulose in the organic binder is 8-12%; the mass fraction of the hydrogenated castor oil in the organic binder is 1-1.5%; the mass fraction of the organic solvent in the organic binder is 86.5-91%.

[0032] Among them, the ethyl cellulose is dissolved in the organic solvent, so that the organic solvent can be used as an organic binder, that is, the organic solvent plays a role in bonding the powder after the slurry is dried. Optionally, the above-mentioned ethyl cellulose can be one or several of ethyl cellulose-N20, ethyl cellulose N-50, and ethyl cellulose-N100.

[0033] Among them, the above-mentioned organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, span 85, and alcohol ester twelve.

[0034] Optionally, in one embodiment, in the above-mentioned aluminum paste, the mass percentage of the organic auxiliary agent is 0.3-0.6%, the mass percentage of the boron powder is 0.05-0.15%, the mass percentage of the aluminum powder is 73-78%, the mass percentage of the glass powder is 1-1.2%, and the mass percentage of the organic binder is 19.05-25.65%.

[0035] Optionally, in one embodiment, the above-mentioned boron powder includes elemental boron.

[0036] Optionally, in a specific embodiment, the above-mentioned boron powder includes micron-sized elemental boron. By adding the micron-sized elemental boron, the boron powder can quickly diffuse into the silicon during high-temperature sintering for heavy doping, which is beneficial to improving the contact performance of the slurry.

[0037] Optionally, in a specific embodiment, the above-mentioned boron powder is micron-sized boron powder with a purity of three 9s.

[0038] Optionally, in one embodiment, the aluminum powder comprises spherical micron-sized aluminum powder with a mass percentage of 90-95% and spherical nano-sized aluminum powder with a mass percentage of 5-10%. Among them, there are gaps between the micron-sized aluminum powder particles, and the above-mentioned nano-sized spherical aluminum powder can just fill and penetrate into the gaps between the micron-sized particles.

[0039] Optionally, in a specific embodiment, the aluminum powder comprises spherical micron-sized aluminum powder with a purity of 99.9% and a mass fraction of 90-95%, and spherical nano-sized aluminum powder with a purity of 99.9% and a mass fraction of 5-10%.

[0040] Optionally, in one embodiment, the above-mentioned organic auxiliary agents include at least one of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, lauryl phosphate, silicone oil, dibasic acid ester, lauryl alcohol phosphate, Disperbyk 655, BYK 110, BYK 105, BYK 109.

[0041] Optionally, in one embodiment, by mass, the above-mentioned glass comprises 15-25% of Bi2O3, 6-10% of Al2O3, 8-12% of Pb2O5, 15-25% of ZnO, 15-22% of Sb2O5, 6-10% of V2O5, 15-22% of TiO2, 10-20% of BaO. The D50 of the glass powder is 1.2-1.5 μm. If D50 is less than 1.2 μm, the glass activity is too high, and if D50 is greater than 1.5 μm, the glass activity is too low.

[0042] Among them, Bi2O3 forms the main network structure, and Sb2O5 is used for clarifying and homogenizing the glass melt; Al2O3 can adjust the glass stability and increase the viscosity; Pb2O5 reacts with silicon nitride to form lead, nitrogen and silicon dioxide; ZnO can lower the melting point of the glass; V2O5 and TiO2 can assist Pb2O5 in reacting with silicon nitride; BaO is used for local crystallization.

[0043] Exemplarily, by mass, the above-mentioned glass powder comprises 20% of Bi2O3, 7% of Al2O3, 13% of Pb2O5, 10% of ZnO, 16% of Sb2O5, 8% of V2O5, 16% of TiO2, 10% of BaO.

[0044] Exemplarily, by mass parts, the above glass powder includes Bi2O3 with a mass fraction of 22%, Al2O3 with a mass fraction of 8%, Pb2O5 with a mass fraction of 10%, ZnO with a mass fraction of 10%, Sb2O5 with a mass fraction of 19%, V2O5 with a mass fraction of 6%, TiO2 with a mass fraction of 17%, and BaO with a mass fraction of 8%.

[0045] Exemplarily, by mass parts, the above glass powder includes Bi2O3 with a mass fraction of 15%, Al2O3 with a mass fraction of 10%, Pb2O5 with a mass fraction of 8%, ZnO with a mass fraction of 15%, Sb2O5 with a mass fraction of 21%, V2O5 with a mass fraction of 6%, TiO2 with a mass fraction of 15%, and BaO with a mass fraction of 10%.

[0046] Exemplarily, by mass parts, the above glass powder includes Bi2O3 with a mass fraction of 25%, Al2O3 with a mass fraction of 6%, Pb2O5 with a mass fraction of 8%, ZnO with a mass fraction of 15%, Sb2O5 with a mass fraction of 15%, V2O5 with a mass fraction of 6%, TiO2 with a mass fraction of 15%, and BaO with a mass fraction of 10%.

[0047] Exemplarily, by mass parts, the above glass powder includes Bi2O3 with a mass fraction of 15%, Al2O3 with a mass fraction of 6%, Pb2O5 with a mass fraction of 8%, ZnO with a mass fraction of 25%, Sb2O5 with a mass fraction of 15%, V2O5 with a mass fraction of 6%, TiO2 with a mass fraction of 15%, and BaO with a mass fraction of 10%.

[0048] An embodiment of the present invention further provides a method for preparing an aluminum paste for the polished surface of the P region of a P-type IBC battery. As Figure 1 shown, it includes step 101 to step 102:

[0049] Step 101: Mix aluminum powder, boron powder, an organic binder, and glass powder to obtain a mixture; wherein, the organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil;

[0050] Step 102: After grinding the mixture, add an organic additive to obtain the aluminum paste for forming the positive grid line on the polished surface of the P region of the P-type IBC battery.

[0051] In the above step 101, weigh 73 - 79% of the total mass of the raw materials of aluminum powder, 0.05 - 0.15 of boron powder, 19.05 - 25.65 of the organic binder, and 1 - 1.2 of glass powder and mix them, and disperse them with a disperser to obtain the above mixture.

[0052] In the above step 101, ethyl cellulose and hydrogenated castor oil are first added to an organic solvent to prepare the above-mentioned organic binder. Optionally, ethyl cellulose, hydrogenated castor oil and the organic solvent are mixed in a mass ratio of (8-12):(1-1.5):(86.5-91) to obtain the above-mentioned organic binder.

[0053] Optionally, in one embodiment, in the above step 101, the organic binder and boron powder are first mixed and dispersed by a disperser, then aluminum powder and glass powder are added, and the mixture is dispersed again by the disperser, and then ground to obtain the above-mentioned mixture.

[0054] In the above step 102, after the above-mentioned mixture is ground, an organic auxiliary agent accounting for 0.3-0.6% of the total mass of the raw materials is added, and after high-speed dispersion, an aluminum paste for forming the positive grid line of the IBC battery is obtained.

[0055] In the embodiment of the present invention, by adding hydrogenated castor oil to the slurry, the slurry is not easily collapsed, ensuring that the slurry is stably printed in the P region, avoiding the pollution of the N region by the aluminum paste, thereby improving the efficiency of the P-type IBC battery.

[0056] Optionally, in the preparation method provided by the embodiment of the present invention, the boron powder is micron-sized boron powder.

[0057] Optionally, in the preparation method provided by the embodiment of the present invention, the organic auxiliary agent includes at least one of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl alcohol phosphate.

[0058] Optionally, in the preparation method provided by the embodiment of the present invention, the aluminum powder includes micron spherical aluminum powder with a mass percentage of 90-95% and nano spherical aluminum powder with a mass percentage of 5-10%; in the above step 101, the organic binder, nano aluminum powder, boron powder and gallium powder are first mixed and dispersed by a disperser, then micron aluminum powder and glass powder are added, and the mixture is dispersed again by the disperser, and then ground to obtain the above-mentioned mixture.

[0059] Optionally, in the preparation method provided by the embodiment of the present invention, the organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, span 85 and alcohol ester 12.

[0060] Optionally, in the preparation method provided by the embodiments of the present invention, the above glass includes Bi2O3 with a mass fraction of 15-25%, Al2O3 with a mass fraction of 6-10%, Pb2O5 with a mass fraction of 8-12%, ZnO with a mass fraction of 15-25%, Sb2O5 with a mass fraction of 15-22%, V2O5 with a mass fraction of 6-10%, TiO2 with a mass fraction of 15-22%, and BaO with a mass fraction of 10-20%.

[0061] The present invention also provides a P-type IBC cell, in which a P-type doping region is provided on the back surface of the IBC cell, the P-type doping region has a polished surface, and a plurality of positive grid lines are attached to the polished surface, and the positive grid lines are prepared from the above-mentioned aluminum paste.

[0062] Among them, the steps of manufacturing a P-type IBC cell using the aluminum paste provided by the embodiments of the present invention are as follows:

[0063] (1) After sequentially forming a silicon oxide layer and a phosphorus-doped polysilicon layer on the back surface of the P-type silicon wafer, laser grooving is performed on the back surface of the silicon wafer to form finger-like spaced-apart n-type doped regions and p-type original silicon regions;

[0064] (2) The surface of the silicon wafer after laser grooving is subjected to texturing treatment;

[0065] (3) After the texturing treatment, a passivation film layer and an antireflection film layer are formed on both sides of the silicon wafer;

[0066] (4) Laser grooving is performed on the back surface of the silicon wafer to expose the p-type original silicon region;

[0067] (5) The laser grooved area is subjected to alkaline polishing treatment;

[0068] (5) Aluminum paste is printed in the laser grooved area to form positive grid lines, and silver paste is printed in the n-type doped area to form negative grid lines, thus manufacturing a P-type IBC cell.

[0069] The present invention will be described in detail below through embodiments.

[0070] Example 1

[0071] (1) Provide aluminum paste a1: By mass, aluminum paste a1 is composed of 0.4 parts of organic additives, 0.08 parts of boron powder, 74 parts of aluminum powder, 24.42 parts of organic binder, and 1.1 parts of glass powder;

[0072] Among them, the above-mentioned organic auxiliary is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-scale elemental boron with 99.9% purity; the aluminum powder includes micron-scale spherical aluminum powder with 99.9% purity and a mass fraction of 95%, and nano-spherical aluminum powder with 99.9% purity and a mass fraction of 5%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 8%, hydrogenated castor oil with a mass fraction of 1%, and an organic solvent with a mass fraction of 91%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 20% Bi2O3, 7% Al2O3, 13% Pb2O5, 10% ZnO, 16% Sb2O5, 8% V2O5, 16% TiO2, and 10% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0073] (2) The above-mentioned aluminum paste is screen-printed on a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a P-region polished surface through a 480-mesh screen to form aluminum fine grids, and then sintered in a sintering furnace. The peak temperature of sintering is 762 °C, and a P-type IBC battery is obtained after sintering.

[0074] Test the electrical performance data of the above battery. The results show that the open-circuit voltage is 0.722 V, the short-circuit current is 13.905 mA, the fill factor is 82.8%, and the photoelectric conversion efficiency is 25.17%;

[0075] Observe the above battery under a display, and no phenomenon of the aluminum paste overflowing the P region is found.

[0076] Example 2

[0077] (1) Provide aluminum paste a2: By mass, aluminum paste a2 is composed of 0.6 parts of organic auxiliary, 0.1 part of boron powder, 77.4 parts of aluminum powder, 20.8 parts of organic binder, and 1.1 parts of glass powder;

[0078] Among them, the above-mentioned organic auxiliary agent is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-level elemental boron with a purity of 99.9%; the aluminum powder includes micron-level spherical aluminum powder with a purity of 99.9% and a mass fraction of 92%, and nano-spherical aluminum powder with a purity of 99.9% and a mass fraction of 8%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 9%, hydrogenated castor oil with a mass fraction of 1%, and an organic solvent with a mass fraction of 90%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 8% Al2O3, 10% Pb2O5, 10% ZnO, 19% Sb2O5, 6% V2O5, 17% TiO2, and 8% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0079] (2) Screen-print the above aluminum paste onto a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a polished P-region surface through a 480-mesh screen to form aluminum fine grids, and then sinter them in a sintering furnace. The peak sintering temperature is 768 °C, and a P-type IBC battery is obtained after sintering.

[0080] Test the electrical performance data of the above battery. The results show that the open-circuit voltage is 0.722 V, the short-circuit current is 13.935 mA, the fill factor is 82.2%, and the photoelectric conversion efficiency is 25.049%;

[0081] Observe the above battery under a display, and no phenomenon of the aluminum paste overflowing the P-region is found.

[0082] Example 3

[0083] (1) Provide aluminum paste a3: By mass, aluminum paste a3 is composed of 0.4 parts of organic auxiliary agent, 0.08 parts of boron powder, 74 parts of aluminum powder, 24.42 parts of organic binder, and 1.1 parts of glass powder;

[0084] Among them, the above-mentioned organic auxiliary agent is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-scale elemental boron with 99.9% purity; the aluminum powder includes micron-scale spherical aluminum powder with 99.9% purity and a mass fraction of 95%, and nano-spherical aluminum powder with 99.9% purity and a mass fraction of 5%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 12%, hydrogenated castor oil with a mass fraction of 1.5%, and an organic solvent with a mass fraction of 86.5%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 20% Bi2O3, 7% Al2O3, 13% Pb2O5, 10% ZnO, 16% Sb2O5, 8% V2O5, 16% TiO2, and 10% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0085] (2) Screen-print the above aluminum paste onto a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a polished P-region surface through a 480-mesh screen to form aluminum fine grids, and then sinter in a sintering furnace. The peak temperature of sintering is 762 °C, and a P-type IBC battery is obtained after sintering.

[0086] Test the electrical performance data of the above battery. The results show that the open-circuit voltage is 0.7225 V, the short-circuit current is 13.915 A, the fill factor is 82.65%, and the photoelectric conversion efficiency is 25.168%;

[0087] Observe the above battery under a display, and no phenomenon of the aluminum paste overflowing the P-region is found.

[0088] Example 4

[0089] (1) Provide aluminum paste a4: By mass, aluminum paste a4 is composed of 0.4 parts of organic auxiliary agent, 0.08 parts of boron powder, 74 parts of aluminum powder, 24.42 parts of organic binder, and 1.1 parts of glass powder;

[0090] Among them, the above-mentioned organic auxiliary agent is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-scale elemental boron with 99.9% purity; the aluminum powder includes micron-scale spherical aluminum powder with 99.9% purity and a mass fraction of 95%, and nano-spherical aluminum powder with 99.9% purity and a mass fraction of 5%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 10%, hydrogenated castor oil with a mass fraction of 1.2%, and an organic solvent with a mass fraction of 88.8%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 20% Bi2O3, 7% Al2O3, 13% Pb2O5, 10% ZnO, 16% Sb2O5, 8% V2O5, 16% TiO2, and 10% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0091] (2) The above aluminum paste is screen-printed on a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a polished P-region surface through a 480-mesh screen to form aluminum fine grids, and then sintered in a sintering furnace. The peak temperature of sintering is 762 °C, and a P-type IBC battery is obtained after sintering.

[0092] The electrical performance data of the above battery are tested. The results show that the open-circuit voltage is 0.7238 V, the short-circuit current is 13.921 A, the fill factor is 82.78%, and the photoelectric conversion efficiency is 25.264%;

[0093] When observing the above battery under a display, no phenomenon of the aluminum paste overflowing the P-region is found.

[0094] Example 5

[0095] (1) Provide aluminum paste a4: By mass, aluminum paste a4 is composed of 0.6 parts of organic auxiliary agent, 0.15 parts of boron powder, 79 parts of aluminum powder, 19.05 parts of organic binder, and 1.2 parts of glass powder;

[0096] Among them, the above-mentioned organic auxiliary is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-scale elemental boron with a purity of 99.9%; the aluminum powder includes micron-scale spherical aluminum powder with a purity of 99.9% and a mass fraction of 95%, and nano-spherical aluminum powder with a purity of 99.9% and a mass fraction of 5%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 10%, hydrogenated castor oil with a mass fraction of 1.2%, and an organic solvent with a mass fraction of 88.8%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 20% Bi2O3, 7% Al2O3, 13% Pb2O5, 10% ZnO, 16% Sb2O5, 8% V2O5, 16% TiO2, and 10% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0097] (2) The above-mentioned aluminum paste is screen-printed on a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a polished P-region surface through a 480-mesh screen to form aluminum fine grids, and then sintered in a sintering furnace. The peak sintering temperature is 762 °C, and a P-type IBC battery is obtained after sintering.

[0098] The electrical performance data of the above battery are tested, and the results show that the open-circuit voltage is 0.7218 V, the short-circuit current is 13.908 A, the fill factor is 82.56%, and the photoelectric conversion efficiency is 25.104%;

[0099] When observing the above battery under a display, no phenomenon of the aluminum paste overflowing the P-region is found.

[0100] Comparative Example 1

[0101] (1) Provide aluminum paste b1: By mass, aluminum paste b1 is composed of 0.4 parts of organic auxiliary, 0.08 parts of boron powder, 74 parts of aluminum powder, 24.42 parts of organic binder, and 1.1 parts of glass powder;

[0102] Among them, the above-mentioned organic auxiliary is composed of silicone oil and lauryl alcohol phosphate mixed in a mass ratio of 1:1; the boron powder is micron-scale elemental boron with a purity of 99.9%; the aluminum powder includes micron-scale spherical aluminum powder with a purity of 99.9% and a mass fraction of 95%, and nano-spherical aluminum powder with a purity of 99.9% and a mass fraction of 5%; the organic binder includes ethyl cellulose-N50 with a mass fraction of 10% and an organic solvent with a mass fraction of 90%. The organic solvent is composed of benzyl alcohol, terpineol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 5:5:65:25; the glass powder is obtained by sintering and pulverizing 20% Bi2O3, 7% Al2O3, 13% Pb2O5, 10% ZnO, 16% Sb2O5, 8% V2O5, 16% TiO2, and 10% BaO by mass percentage, and its D50 is 1.2 - 1.5 μm.

[0103] (2) The above aluminum paste is screen-printed on a single-crystalline P-type silicon wafer with a specification of 182 mm × 182 mm and a polished P region through a 480-mesh screen to form aluminum fine grids, and then sintered in a sintering furnace. The peak temperature of sintering is 762 °C, and a P-type IBC cell is obtained after sintering.

[0104] The electrical performance data of the above cell are tested. The results show that the open-circuit voltage is 0.719 V, the short-circuit current is 13.895 A, the fill factor is 82.52%, and the photoelectric conversion efficiency is 24.98%.

[0105] When observing the above cell under a display, it is found that there is a phenomenon that the aluminum paste overflows the P region.

[0106] Comparing Examples 1 to 5 and Comparative Example 1, it can be seen that the embodiments of the present invention can effectively improve the photoelectric conversion efficiency of the cell.

[0107] In summary, in this embodiment, by adding hydrogenated castor oil to the aluminum paste, the thixotropy of the paste can be improved, making the paste not easily collapse, ensuring that the paste is stably printed in the P region, avoiding the pollution of the N region by the aluminum paste, thereby improving the efficiency of the P-type IBC cell, and thus solving the problem that the existing aluminum paste is easily collapsed during printing and overflows the P region, resulting in the pollution of the N region of the P-type IBC cell with a polished P region by the aluminum paste, which affects the photoelectric conversion efficiency of the cell.

[0108] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the claims are intended to be interpreted to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

[0109] The above provides a detailed introduction to an aluminum paste for the polished surface of the P region of a P-type IBC cell, its preparation method, and the IBC cell. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An aluminum paste for the polished surface of the P region of a P-type IBC cell, characterized in that, The components constituting the aluminum paste include an organic auxiliary agent, boron powder, aluminum powder, glass powder, and an organic binder. The organic binder includes a high molecular polymer resin and an organic solvent. The high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil.

2. The aluminum paste according to claim 1, wherein, The mass fraction of the ethyl cellulose in the organic binder is 8-12%; The mass fraction of the hydrogenated castor oil in the organic binder is 1-1.5%; The mass fraction of the organic solvent in the organic binder is 86.5-91%.

3. The aluminum paste according to claim 1, wherein The organic solvent includes at least four of benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, span 85, and alcohol ester 12.

4. The aluminum paste according to claim 1, characterized in that, The mass percentage of the organic auxiliary agent is 0.3-0.6%; the mass percentage of the boron powder is 0.05-0.15%; the mass percentage of the aluminum powder is 73-79%; the mass percentage of the glass powder is 1-1.2%; the mass percentage of the organic binder is 19.05-25.65%.

5. The aluminum paste according to claim 1, wherein, The boron powder is micron-sized boron powder.

6. The aluminum paste according to claim 1, wherein The organic auxiliary agent includes at least one of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl alcohol phosphate.

7. The aluminum paste according to claim 1, wherein The aluminum powder includes micron-sized spherical aluminum powder with a mass percentage of 90-95% and nano-sized spherical aluminum powder with a mass percentage of 5-10%.

8. The aluminum paste according to claim 1, wherein The glass powder includes Bi2O3 with a mass fraction of 15-25%, Al2O3 with a mass fraction of 6-10%, Pb2O5 with a mass fraction of 8-12%, ZnO with a mass fraction of 15-25%, Sb2O5 with a mass fraction of 15-22%, V2O5 with a mass fraction of 6-10%, TiO2 with a mass fraction of 15-22%, and BaO with a mass fraction of 10-20%.

9. A preparation method of aluminum paste for the polished surface of the P region of a P-type IBC cell, characterized in that, Comprising: Mix aluminum powder, boron powder, an organic binder, and glass powder to obtain a mixture; wherein, the organic binder includes a high molecular polymer resin and an organic solvent, and the high molecular polymer resin includes ethyl cellulose and hydrogenated castor oil; After grinding the mixture, add an organic additive to obtain an aluminum paste for forming a positive grid line on the polished surface of the P region of a P-type IBC cell.

10. A P-type IBC battery, characterized in that, The back surface of the IBC cell is provided with a P-type doping region, the P-type doping region has a polished surface, and multiple positive grid lines are attached to the polished surface. The positive grid lines are prepared from the aluminum paste as described in any one of claims 1-8.

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