Aluminum paste for ibc battery and ibc battery

Abstract

The embodiment of the present application provides an IBC battery aluminum paste and an IBC battery, wherein the IBC battery aluminum paste provided by the embodiment of the present application comprises an organic additive, boron powder, aluminum powder, gallium powder, glass powder and an organic binder. By adding gallium powder in the aluminum paste, because the gallium element has etching effect and high density, it is faster than aluminum to drop to the silicon surface in the sintering process, so that the Ga-Si contact probability is increased, the contact resistance of the paste and the battery is reduced, and a high open circuit voltage can be maintained. At the same time, because part of the aluminum powder is replaced by gallium, the content of aluminum is reduced, which is beneficial to reducing the side effect of Al, so that the Al-Si reaction is weakened, the formed aluminum silicon corrosion pit is shallow, the recombination is reduced, so as to improve the open circuit voltage and the photoelectric conversion efficiency of the battery. Therefore, the problem that the existing IBC battery aluminum paste is easy to form metal recombination in the cooling process after being sintered into a positive electrode grid line, resulting in the decrease of the open circuit voltage and the photoelectric conversion efficiency of the battery piece is solved.

Description

Technical Field

[0001] This invention relates to the field of crystalline silicon solar cell manufacturing technology, and in particular to an IBC cell silver paste and an IBC cell. Background Technology

[0002] Interdigitated Back Contact (IBC) batteries are a new type of battery in which the P / N junction, substrate, and emitter region contact electrodes are formed in an interdigitated shape on the back of the battery. The core technology is to prepare high-quality p-regions and n-regions arranged in an interdigitated pattern on the back of the battery, and then print aluminum paste connected to the p-regions to form positive grid lines, and print silver paste connected to the n-regions to form negative grid lines.

[0003] Currently, in IBC batteries, aluminum paste is printed to form the positive grid lines in the P region. The aluminum element can form an alloy with silicon at high temperatures. However, during the cooling process of the cell, the aluminum element is prone to diffuse to the PN junction to form a metal composite, which leads to a decrease in the open circuit voltage and a decrease in the photoelectric conversion efficiency of the cell. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an IBC battery aluminum paste and an IBC battery, so as to solve the problem that the aluminum paste of the existing IBC battery is prone to forming metal composites during the cooling process after being sintered into positive electrode grid lines, which leads to a decrease in the open circuit voltage and photoelectric conversion efficiency of the battery cell.

[0005] To solve the above problems, the present invention is achieved through the following technical solution:

[0006] This invention proposes an aluminum paste for IBC batteries, wherein the components constituting the aluminum paste include organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binders.

[0007] Furthermore, in the IBC battery aluminum paste, the organic additive has a mass percentage of 0.2-0.6%; the boron powder has a mass percentage of 0.05-0.1%; the aluminum powder has a mass percentage of 78-82%; the gallium powder has a mass percentage of 0.5-1%; the glass powder has a mass percentage of 1.2-1.5%; and the organic binder has a mass percentage of 18.8-26.05%.

[0008] Furthermore, in the IBC battery aluminum paste, the gallium powder is elemental gallium and / or gallium-aluminum alloy powder.

[0009] Furthermore, in the IBC battery aluminum paste, the boron powder is micron-sized boron powder.

[0010] Furthermore, in the IBC battery aluminum paste, the organic additives include two or more of the following: fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl phosphate.

[0011] Furthermore, in the IBC battery aluminum paste, the aluminum powder comprises 85-95% by mass of micron-sized spherical aluminum powder and 5-15% by mass of nano-sized spherical aluminum powder.

[0012] Furthermore, in the IBC battery aluminum paste, the organic binder includes a polymer resin and an organic solvent;

[0013] The polymer in the organic binder has a mass fraction of 8-12%;

[0014] The organic solvent has a mass fraction of 88-92% in the organic binder.

[0015] Furthermore, in the IBC battery aluminum paste, the organic solvent is at least three of the following: benzyl alcohol, diethyl phthalate, terpineol, butyl carbiol, butyl carbiol acetate, tributyl citrate, Span 85, and 12-ol ester.

[0016] Furthermore, in the IBC battery aluminum paste, the glass powder comprises 20-25% Bi2O3, 6-8% Al2O3, 10-12% Pb2O5, 5-24% ZnO, 15-20% Sb2O5, 5-8% V2O5, 15-22% TiO2, and 5-20% BaO by mass.

[0017] The present invention also proposes an IBC battery, wherein multiple positive grid lines are attached to the back of the IBC battery, and the positive grid lines are prepared from the aforementioned aluminum paste.

[0018] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0019] In this embodiment of the invention, the provided IBC battery aluminum paste comprises organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binder. By adding gallium powder to the aluminum paste, gallium, due to its etching properties and high density, descends to the silicon surface more rapidly than aluminum during sintering, increasing the Ga-Si contact probability, reducing the contact resistance between the paste and the battery, and maintaining a high open-circuit voltage. Simultaneously, by replacing some aluminum powder with gallium, the aluminum content is reduced, which helps to minimize the side effects of Al, weakening the Al-Si reaction, resulting in shallower aluminum-silicon corrosion pits and reduced recombination. This improves the battery's open-circuit voltage and photoelectric conversion efficiency, thus solving the problem that existing IBC battery aluminum pastes easily form metal recombination during cooling after sintering into positive electrode grids, leading to a decrease in the open-circuit voltage and photoelectric conversion efficiency of the battery cell.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0021] Figure 1 This is a flowchart of the preparation method of IBC battery aluminum paste provided in the embodiments of the present invention. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This invention provides an IBC battery aluminum paste, the components of which include organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binder.

[0024] The aluminum paste for IBC batteries provided in this embodiment of the invention is used to form the positive grid lines of an IBC battery.

[0025] Aluminum powder is the main component, mainly replacing the P+ emitter of the battery, while boron powder can diffuse into the silicon interior for heavy doping during high-temperature sintering, which is beneficial to improving the contact performance of the slurry, reducing the reaction contact surface between aluminum and silicon, reducing the contact resistivity between the positive electrode grid and the battery, thereby improving the battery filling and battery efficiency.

[0026] Among them, gallium in gallium powder has an etching effect and a high density. During the sintering process, it descends to the silicon surface faster than aluminum, which increases the probability of Ga-Si contact, reduces the contact resistance between the paste and the battery, and can maintain a high open-circuit voltage. At the same time, by using gallium to replace part of the aluminum powder, the aluminum content is reduced, which helps to reduce the side effects of Al. This weakens the Al-Si reaction, resulting in shallower aluminum-silicon corrosion pits and reduced recombination, thereby improving the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0027] Among them, glass powder is an inorganic binder that melts into a liquid state under high temperature conditions and solidifies when cooled, thus playing a bonding role; organic binders can ensure the overall bonding effect; and organic additives can reduce the overall viscosity of the silver paste.

[0028] Therefore, the aluminum paste provided in this embodiment of the invention can solve the problem that the aluminum paste of existing IBC batteries easily forms metal composites during the cooling process after sintering into positive electrode grid lines, which leads to a decrease in the open circuit voltage and photoelectric conversion efficiency of the battery cell.

[0029] Optionally, in one embodiment, the aluminum paste contains 0.2-0.6% by mass of organic additives, 0.05-0.1% by mass of boron powder, 72-78% by mass of aluminum powder, 0.5-1% by mass of gallium powder, 1.2-1.5% by mass of glass powder, and 18.8-26.05% by mass of organic binder.

[0030] For example, in the aluminum paste, the mass fractions of organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binder are 0.5%, 0.05%, 76%, 0.5%, 1.5%, and 21.45%, respectively.

[0031] For example, in the aluminum paste, the mass fractions of organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binder are 0.5%, 0.08%, 76%, 0.8%, 1.3%, and 21.32%, respectively.

[0032] For example, in the aluminum paste, the mass fractions of organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binder are 0.2%, 0.05%, 72%, 0.5%, 1.2%, and 26.05%, respectively.

[0033] For example, in the aluminum paste, the mass fractions of organic additives, boron powder, aluminum powder, gallium powder, glass powder and organic binder are 0.6%, 0.1%, 78%, 1%, 1.5% and 18.8%, respectively.

[0034] Optionally, in one embodiment, the boron powder comprises elemental boron.

[0035] Optionally, in one specific embodiment, the boron powder comprises micron-sized elemental boron. By adding this micron-sized elemental boron, the boron powder can rapidly diffuse into the silicon interior for heavy doping during high-temperature sintering, which is beneficial for improving the contact performance of the slurry.

[0036] Optionally, in one specific embodiment, the boron powder is micron-sized boron powder with a purity of 99.99%.

[0037] Optionally, in one embodiment, the gallium powder comprises elemental gallium.

[0038] Optionally, in one specific embodiment, the gallium powder comprises micron-sized elemental gallium. By adding this micron-sized elemental gallium, the gallium powder can rapidly diffuse into the silicon interior during high-temperature sintering, reducing the contact resistance between the paste and the battery.

[0039] Optionally, in one specific embodiment, the gallium powder is a micron-sized gallium powder with a purity of 2 nines.

[0040] Alternatively, in another embodiment, the gallium powder comprises a gallium-aluminum alloy. By adding this micron-sized gallium-aluminum alloy powder, the aluminum paste can quickly form a good gallium-silicon alloy with silicon at a relatively low sintering temperature.

[0041] Optionally, in one embodiment, the aluminum powder comprises 85-95% by mass of micron-sized spherical aluminum powder and 5-15% by mass of nano-sized spherical aluminum powder. The nano-sized spherical aluminum powder fills and penetrates into these gaps between the micron-sized aluminum powder particles, as there are gaps between them.

[0042] Optionally, in one specific embodiment, the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 85-95%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 5-15%.

[0043] Optionally, in one embodiment, the organic additives include two or more of the following: fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, lauryl phosphate, silicone oil, diester, lauryl phosphate, DIG655, BYK110, and BYK105.

[0044] In the aluminum paste provided in the embodiments of the present invention, the above-mentioned organic binder includes a polymer resin and an organic solvent; wherein, the polymer resin is dissolved in the organic solvent, so that the organic solvent can act as an organic binder, that is, the paste can act as a binder for powder after drying.

[0045] Optionally, in one embodiment, the polymer in the organic adhesive has a mass fraction of 8-12%; and the organic solvent in the organic adhesive has a mass fraction of 88-92%.

[0046] Optionally, in one embodiment, the above-mentioned polymer is one or more of ethyl cellulose-N20, ethyl cellulose N-50, and ethyl cellulose-N100;

[0047] The aforementioned organic solvents include at least three of the following: benzyl alcohol, diethyl phthalate, terpineol, butyl carbiol, butyl carbiol acetate, tributyl citrate, Span 85, and 12-ol ester.

[0048] Optionally, in one embodiment, the glass powder comprises, by mass fraction, 20-25% Bi2O3, 6-8% Al2O3, 10-12% Pb2O5, 5-24% ZnO, 15-20% Sb2O5, 5-8% V2O5, 15-22% TiO2, and 5-20% BaO. The D50 of the glass powder is 1.2-1.8 μm. If the D50 is less than 1.2 μm, the glass activity is too high, while if the D50 is greater than 1.8 μm, the glass activity is too low.

[0049] Among them, Bi2O3 forms the main network structure, ZnO can break the network structure and promote glass crystallization, Sb2O5 is used to clarify and homogenize the glass melt, Al2O3 can adjust the stability of the glass and increase its viscosity, Pb2O5 reacts with silicon nitride to produce lead, nitrogen and silicon dioxide, V2O5 and TiO2 can assist Pb2O5 and silicon nitride in their reaction, and BaO is used for local crystallization.

[0050] For example, by mass fraction, the glass powder comprises 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2, and 10% BaO.

[0051] For example, by mass fraction, the glass powder comprises 20% Bi2O3, 8% Al2O3, 10% Pb2O5, 5% ZnO, 20% Sb2O5, 5% V2O5, 22% TiO2, and 10% BaO.

[0052] For example, by mass fraction, the glass powder comprises 20% Bi2O3, 6% Al2O3, 10% Pb2O5, 24% ZnO, 15% Sb2O5, 5% V2O5, 15% TiO2, and 5% BaO.

[0053] This invention also provides a method for preparing aluminum paste for IBC batteries, wherein, as shown in the embodiments of the present invention... Figure 1 As shown, steps 101 to 102 are included:

[0054] Step 101: Mix aluminum powder, boron powder, gallium powder, organic binder and glass powder to obtain a mixture;

[0055] Step 102: After grinding the mixture, add organic additives to obtain aluminum paste for forming the positive grid line of the IBC battery.

[0056] In step 101 above, 72-78% of aluminum powder, 0.05-0.1% of boron powder, 0.5-1% of gallium powder, 18.8-26.05% of organic binder, and 1.2-1.5% of glass powder, accounting for the total mass of raw materials, are weighed and mixed, and dispersed using a disperser to obtain the above mixture.

[0057] Optionally, in one embodiment, in step 101 above, the organic binder and boron powder are first mixed and dispersed using a disperser, then aluminum powder and glass powder are added and dispersed again using a disperser, and then ground to obtain the above mixture.

[0058] In step 102 above, the mixture is ground and then an organic additive accounting for 0.2 to 0.6% of the total mass of the raw materials is added. After high-speed dispersion, an aluminum paste for forming the positive grid line of the IBC battery is obtained.

[0059] In this embodiment of the invention, gallium powder is added to the aluminum paste. Because gallium has an etching effect and a high density, it descends to the silicon surface faster than aluminum during sintering, increasing the probability of Ga-Si contact, reducing the contact resistance between the paste and the battery, and maintaining a high open-circuit voltage. At the same time, by using gallium to replace part of the aluminum powder, the aluminum content is reduced, which helps to reduce the side effects of Al, weakening the Al-Si reaction, resulting in shallower aluminum-silicon corrosion pits and reduced recombination. This improves the open-circuit voltage and photoelectric conversion efficiency of the battery, thus solving the problem that existing IBC battery aluminum paste easily forms metal recombination during the cooling process after sintering into positive electrode grid lines, leading to a decrease in the open-circuit voltage and photoelectric conversion efficiency of the battery cell.

[0060] Optionally, in the preparation method provided in the embodiments of the present invention, the gallium powder is elemental gallium and / or gallium-aluminum alloy powder.

[0061] Optionally, in the preparation method provided in the embodiments of the present invention, the boron powder is micron-sized boron powder.

[0062] Optionally, in the preparation method provided in the embodiments of the present invention, the organic auxiliaries include two or more of fatty alcohol ether phosphates, aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, and lauryl phosphates.

[0063] Optionally, in the preparation method provided in the embodiments of the present invention, the aluminum powder includes 85-95% by mass micron-sized spherical aluminum powder and 5-15% by mass nano-sized spherical aluminum powder; in step 101 above, the organic binder, nano-aluminum powder, boron powder and gallium powder are first mixed and dispersed using a disperser, then micron-sized aluminum powder and glass powder are added, dispersed again using a disperser, and then ground to obtain the above mixture.

[0064] Optionally, in the preparation method provided in the embodiments of the present invention, the organic binder includes a polymer resin and an organic solvent;

[0065] The polymer in the organic binder has a mass fraction of 8-12%;

[0066] The organic solvent has a mass fraction of 88-92% in the organic binder.

[0067] Optionally, in the preparation method provided in the embodiments of the present invention, the organic solvent is at least three of the following: benzyl alcohol, diethyl phthalate, terpineol, butylcarbiol, butylcarbiol acetate, tributyl citrate, Span 85, and 12-ol ester.

[0068] Optionally, in the preparation method provided in the embodiments of the present invention, the glass powder includes 20-25% Bi2O3, 6-8% Al2O3, 10-12% Pb2O5, 5-24% ZnO, 15-20% Sb2O5, 5-8% V2O5, 15-22% TiO2, and 5-20% BaO by mass.

[0069] The present invention also proposes an IBC battery, wherein multiple positive grid lines are attached to the back of the IBC battery, and the positive grid lines are prepared from the aforementioned aluminum paste.

[0070] Among them, the aforementioned IBC battery can be a P-type IBC battery.

[0071] The steps for fabricating a P-type IBC battery using the aluminum paste provided in this embodiment of the invention are as follows:

[0072] (1) After forming a silicon oxide layer and a phosphorus-doped polycrystalline silicon layer sequentially on the back side of a P-type silicon wafer, a passivation film layer and an anti-reflection film layer are formed on both sides of the silicon wafer.

[0073] (2) Laser grooving is performed on the back of the silicon wafer to form p-type doped regions and n-type primary silicon regions arranged in an interdigitated pattern;

[0074] (3) 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 obtaining a P-type IBC cell.

[0075] The present invention will be described in detail below through embodiments.

[0076] Example 1

[0077] (1) Provide aluminum paste a1: by weight, aluminum paste a1 is composed of 0.5 parts organic additives, 0.05 parts boron powder, 76 parts aluminum powder, 0.5 parts gallium powder, 21.45 parts organic binder and 1.5 parts glass powder;

[0078] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 90%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 10%; the gallium powder is micron-sized elemental gallium with a purity of two nines; the organic binder includes 10% ethyl cellulose-N100 by mass and 90% organic solvent by mass, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO by mass percentage, and its D50 is 1.2~1.8μm.

[0079] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm through a 360-mesh screen to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 768℃. After sintering, a P-type IBC cell is obtained.

[0080] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7241V, the short-circuit current was 13.915mA, the fill factor was 83.4%, and the photoelectric conversion efficiency was 25.45%.

[0081] Example 2

[0082] (1) Provide aluminum paste a2: by weight, aluminum paste a1 is composed of 0.5 parts organic additives, 0.08 parts boron powder, 76 parts aluminum powder, 0.8 parts gallium powder, 21.32 parts organic binder and 1.3 parts glass powder;

[0083] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 92%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 8%; the gallium powder is micron-sized elemental gallium with a purity of two nines; the organic binder includes 10% ethyl cellulose-N100 by mass and 90% organic solvent by mass, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO by mass percentage, and its D50 is 1.2~1.8μm.

[0084] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm through a 360-mesh screen to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 768℃. After sintering, a P-type IBC cell is obtained.

[0085] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7251V, the short-circuit current was 13.935mA, the fill factor was 83.35%, and the photoelectric conversion efficiency was 25.51%.

[0086] Example 3

[0087] (1) Provide aluminum paste a3: by weight, aluminum paste a1 is composed of 0.2 parts organic additives, 0.05 parts boron powder, 72 parts aluminum powder, 0.5 parts gallium powder, 26.05 parts organic binder and 1.2 parts glass powder;

[0088] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 90%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 10%; the gallium powder is micron-sized elemental gallium with a purity of two nines; the organic binder includes 10% ethyl cellulose-N100 by mass and 90% organic solvent by mass, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO by mass percentage, and its D50 is 1.2~1.8μm.

[0089] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm through a 360-mesh screen to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 768℃. After sintering, a P-type IBC cell is obtained.

[0090] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7235V, the short-circuit current was 13.918mA, the fill factor was 83.21%, and the photoelectric conversion efficiency was 25.379%.

[0091] Example 4

[0092] (1) Provide aluminum paste a4: by weight, aluminum paste a1 is composed of 0.6 parts organic additives, 0.1 parts boron powder, 78 parts aluminum powder, 1 part gallium powder, 18.8 parts organic binder and 1.5 parts glass powder;

[0093] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 90%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 10%; the gallium powder is micron-sized gallium-aluminum alloy with a purity of two nines; the organic binder includes 10% ethyl cellulose-N100 and 90% organic solvent, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO, with a D50 of 1.2 to 1.8 μm.

[0094] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm through a 360-mesh screen to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 768℃. After sintering, a P-type IBC cell is obtained.

[0095] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7255V, the short-circuit current was 13.941mA, the fill factor was 83.382%, and the photoelectric conversion efficiency was 25.544%.

[0096] Example 5

[0097] (1) Provide aluminum paste a5: by weight, aluminum paste a1 is composed of 0.5 parts organic additives, 0.08 parts boron powder, 76 parts aluminum powder, 0.8 parts gallium powder, 21.32 parts organic binder and 1.3 parts glass powder;

[0098] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 90%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 10%; the gallium powder is micron-sized elemental gallium with a purity of two nines; the organic binder includes 10% ethyl cellulose-N100 by mass and 90% organic solvent by mass, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO by mass percentage, and its D50 is 1.2~1.8μm.

[0099] (2) The above aluminum paste is screen-printed on a single crystal N-type silicon wafer with a specification of 182mm×182mm to form an aluminum grid, and then sintered in a sintering furnace at a peak temperature of 774℃. After sintering, an N-type IBC cell is obtained.

[0100] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7261V, the short-circuit current was 13.954mA, the fill factor was 83.345%, and the photoelectric conversion efficiency was 25.577%.

[0101] Comparative Example 1

[0102] (1) Provide aluminum paste b1: by weight, aluminum paste a1 is composed of 0.5 parts organic additives, 0.05 parts boron powder, 76.5 parts aluminum powder, 21.45 parts organic binder and 1.5 parts glass powder;

[0103] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 90%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 10%; the organic binder includes 10% ethyl cellulose-N100 and 90% organic solvent, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 22% Bi2O3, 6% Al2O3, 12% Pb2O5, 10% ZnO, 18% Sb2O5, 7% V2O5, 15% TiO2 and 10% BaO, with a D50 of 1.2 to 1.8 μm.

[0104] (2) The aluminum paste is screen-printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm after laser grooving to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 768℃. After sintering, a P-type IBC cell is obtained.

[0105] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7217V, the short-circuit current was 13.945mA, the fill factor was 83.185%, and the photoelectric conversion efficiency was 25.357%.

[0106] Comparative Example 2

[0107] (1) Provide aluminum paste b2: by weight, aluminum paste a1 is composed of 0.8 parts organic additives, 0.1 parts boron powder, 76.5 parts aluminum powder, 21.1 parts organic binder and 1.5 parts glass powder;

[0108] Among them, the above-mentioned organic additives are lauryl phosphate and BYK110; the boron powder is micron-sized elemental boron with a purity of three nines; the aluminum powder includes micron-sized spherical aluminum powder with a purity of three nines and a mass fraction of 93%, and nano-spherical aluminum powder with a purity of three nines and a mass fraction of 7%; the organic binder includes 8% ethyl cellulose-N100 and 92% organic solvent, the organic solvent being composed of benzyl alcohol, terpineol, butylcarbiol, butylcarbiol acetate and Span 85; the glass powder is obtained by sintering and pulverizing 20% ​​SiO2, 8% Al2O3, 12% Pb2O5, 12% ZnO, 20% V2O5, 6% B2O3 and 22% TeO2, with a D50 of 1.5 to 1.8 μm.

[0109] (2) The aluminum paste is screen-printed on a single crystal P-type silicon wafer with a specification of 182mm×182mm after laser grooving to form an aluminum grid. The wafer is then sintered in a sintering furnace at a peak temperature of 788℃. After sintering, a P-type IBC cell is obtained.

[0110] The electrical properties of the battery were tested, and the results showed that the open-circuit voltage was 0.7208V, the short-circuit current was 13.931mA, the fill factor was 83.187%, and the photoelectric conversion efficiency was 25.301%.

[0111] Comparing Examples 1 to 5 with Comparative Examples 1 and 2, it can be seen that the embodiments of the present invention can effectively improve the open-circuit voltage and photoelectric conversion efficiency of the battery.

[0112] In summary, in this embodiment, by adding gallium powder to the aluminum paste, gallium, due to its etching properties and high density, descends to the silicon surface more rapidly than aluminum during sintering, increasing the Ga-Si contact probability, reducing the contact resistance between the paste and the battery, and maintaining a high open-circuit voltage. Simultaneously, by using gallium to replace some of the aluminum powder, the aluminum content is reduced, which helps to minimize the side effects of Al, weakening the Al-Si reaction, resulting in shallower aluminum-silicon corrosion pits and reduced recombination. This improves the open-circuit voltage and photoelectric conversion efficiency of the battery, thus solving the problem that existing IBC battery aluminum paste easily forms metal recombination during cooling after sintering into positive electrode grids, leading to a decrease in the open-circuit voltage and photoelectric conversion efficiency of the battery cell.

[0113] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0114] The above provides a detailed description of the IBC battery aluminum paste and IBC battery provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An aluminum paste for IBC batteries, characterized in that, The components constituting the aluminum paste include organic additives, boron powder, aluminum powder, gallium powder, glass powder, and organic binders; The organic additives comprise 0.2-0.6% by mass; the boron powder comprises 0.05-0.1% by mass; the aluminum powder comprises 72-78% by mass; the gallium powder comprises 0.5-1% by mass, wherein the gallium powder is elemental gallium and / or gallium-aluminum alloy powder; the glass powder comprises 1.2-1.5% by mass; and the organic binder comprises 18.8-26.05% by mass. The glass powder comprises 20-25% Bi2O3, 6-8% Al2O3, 10-12% Pb2O5, 5-24% ZnO, 15-20% Sb2O5, 5-8% V2O5, 15-22% TiO2, and 5-20% BaO by mass.

2. The aluminum paste according to claim 1, characterized in that, The boron powder is micron-sized boron powder.

3. The aluminum paste according to claim 1, characterized in that, The organic additives include two or more of the following: fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl phosphate.

4. The aluminum paste according to claim 1, characterized in that, The aluminum powder comprises 85-95% by mass micron-sized spherical aluminum powder and 5-15% by mass nano-sized spherical aluminum powder.

5. The aluminum paste according to claim 1, characterized in that, The organic adhesive comprises a polymer resin and an organic solvent; The polymer resin in the organic adhesive has a mass fraction of 8-12%; The organic solvent has a mass fraction of 88-92% in the organic adhesive.

6. The aluminum paste according to claim 5, characterized in that, The organic solvent includes at least five of the following: benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, Span 85, and 12-ol ester.

7. An IBC battery, characterized in that, The back of the IBC battery has multiple positive grid lines attached, which are prepared from aluminum paste as described in any one of claims 1 to 6.

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