Ibc battery positive grid line aluminum paste and preparation method thereof and battery

Abstract

The embodiment of the present application provides an IBC battery positive electrode grid line aluminum paste, a preparation method thereof and a battery, wherein, in the IBC battery positive electrode grid line aluminum paste, lead, vanadium and titanium elements are added to glass powder, and silver powder is added, laser slotting is not needed, the aluminum paste is directly printed to the silicon nitride film on the surface of the P+ doped region, after high-temperature sintering, the aluminum paste can etch the silicon nitride film, and aluminum and silicon can form a good ohmic contact, the doping concentration of the P+ doped region is improved, the addition of silver powder can reduce the metal combination of aluminum in the aluminum paste, reduce the contact resistivity in the aluminum fine grid, and improve the efficiency of the IBC battery, thus solving the problems that the existing IBC battery aluminum paste needs to perform laser slotting on the silicon nitride film at the position of the P+ region before being printed into the positive electrode grid line, and the steps are complicated and the cost is high.

Description

Technical Field

[0001] The present invention relates to the technical field of crystalline silicon solar cell manufacturing, and in particular to an IBC battery positive grid line aluminum paste, a preparation method thereof, and a battery. Background Art

[0002] The interdigitated back contact (IBC) battery is a new type of battery in which the contact electrodes of the P / N junction, substrate and emitter region are made in an interdigitated shape on the back of the battery. Its core technology is to prepare high-quality p-regions and n-regions arranged in an interdigitated shape on the back of the battery.

[0003] Currently, the positive electrode grid lines (aluminum grid lines) of P-IBC batteries need to be printed in laser grooves, that is, the silicon nitride film of the IBC battery needs to be destroyed by laser to create grooves. The location of the grooves needs to be precise in the P+ layer of the IBC battery, so four-camera positioning of the laser is required, which not only increases the equipment cost, but also increases the material consumption and electricity costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an IBC battery positive electrode grid line aluminum paste, a preparation method thereof, and a battery, so as to solve the problem that the existing IBC battery aluminum paste requires laser grooving of the silicon nitride film at the P+ area before printing the positive electrode grid line, which is cumbersome and costly.

[0005] In order to solve the above problems, the present invention is achieved through the following technical solutions:

[0006] The present invention provides an aluminum paste for positive grid lines of IBC batteries, wherein the components constituting the aluminum paste include organic additives, boron powder, aluminum powder, silver powder, organic adhesive and glass powder, and the glass powder contains lead, vanadium and titanium elements.

[0007] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, silver powder, organic binder and glass powder are 0.15-0.4%, 0.04-0.08%, 68-75%, 2-6%, 17.94-24% and 0.8-1.2%, respectively.

[0008] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the aluminum powder includes micron-sized spherical aluminum powder and nano-sized spherical aluminum powder, and the silver powder includes micron-sized spherical silver powder and nano-sized spherical silver powder.

[0009] Furthermore, in the aluminum paste for the positive electrode grid line of the IBC battery, the glass powder includes Bi2O3 of 20-25%, Al2O3 of 6-8%, Pb2O5 of 10-12%, ZnO of 5-29%, Sb2O5 of 15-20%, V2O5 of 5-8%, T i O2.

[0010] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the organic additive includes one or more of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, lauryl phosphate, Digo 655, BYKl05, and Lubrizol 20000.

[0011] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the organic binder includes a high molecular polymer resin and an organic solvent;

[0012] The mass fraction of the high molecular weight polymer in the organic binder is 6 to 12%;

[0013] The mass fraction of the organic solvent in the organic binder is 88-94%.

[0014] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the high molecular polymer is one or more of ethyl cellulose-N20, ethyl cellulose N-50, and ethyl cellulose-N100;

[0015] 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 dodecahydrate.

[0016] Furthermore, in the IBC battery positive electrode grid line aluminum paste, the D50 of the glass powder is 1.2 to 2 μm.

[0017] The present invention also provides a method for preparing aluminum paste for positive grid lines of IBC batteries, which comprises:

[0018] mixing an organic binder, nano-aluminum powder and nano-silver powder to obtain a first mixture;

[0019] adding micron aluminum powder, micron silver powder and glass powder to the first mixture, mixing and grinding to obtain a second mixture; the glass powder contains lead, vanadium and titanium elements;

[0020] An organic auxiliary agent is added to the second mixture to disperse and obtain an IBC battery positive electrode grid line aluminum paste.

[0021] The present invention also provides a method for preparing an IBC battery, which comprises:

[0022] After forming a silicon nitride layer covering the p+ doped region and the n+ doped region on the back side of the silicon wafer, aluminum paste is printed on a first region of the silicon nitride layer, and silver paste is printed on a second region of the silicon nitride layer; wherein the projection of the first region is on the p+ doped region, and the projection of the second region is on the n+ doped region, and the components of the aluminum paste include organic additives, boron powder, aluminum powder, organic binder, and glass powder, and the glass powder contains lead, vanadium, and titanium elements;

[0023] The silicon wafer with the aluminum paste printed on the first area and the silver paste printed on the second area is sintered at high temperature to produce an IBC battery.

[0024] The present invention also provides an IBC battery, which is prepared by the above method.

[0025] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0026] In an embodiment of the present invention, an aluminum paste for the positive grid lines of an IBC battery is provided, comprising an organic additive, boron powder, aluminum powder, silver powder, an organic binder, and glass powder, wherein the glass powder contains lead, vanadium, and titanium. By adding lead, vanadium, and titanium to the glass powder in the IBC battery aluminum paste, along with silver powder, the paste can be directly printed onto the silicon nitride film on the surface of the P+ doped region without laser grooving. After high-temperature sintering, the aluminum paste can corrode the silicon nitride film, and aluminum and silicon can form a good ohmic contact, increasing the doping concentration in the P+ doped region. The addition of silver powder can reduce the metal recombination of aluminum in the paste, lowering the contact resistivity in the aluminum fine grid and improving the efficiency of the IBC battery. This solves the cumbersome and costly problem of laser grooving the silicon nitride film in the P+ region before printing the positive grid lines in existing IBC battery aluminum pastes. It also avoids the reduced passivation and damage to the P+ region caused by laser grooving.

[0027] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for preparing aluminum paste for positive grid lines of IBC batteries provided by one embodiment of the present invention;

[0029] Figure 2 This is a flow chart of a method for preparing aluminum paste for positive grid lines of IBC batteries provided by another embodiment of the present invention;

[0030] Figure 3 This is a flow chart of the method for preparing an IBC battery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The applicants of this invention discovered that both N-type and P-type IBC cells require laser grooving before printing aluminum paste. This allows the laser to destroy the silicon nitride membrane of the IBC cell. Aluminum paste is then printed within the laser grooves to form the positive electrode grid lines. This process is not only cumbersome, but also requires four-camera positioning of the laser, as the grooves must be aligned with the P+ layer of the IBC cell. This increases equipment, material, and electricity costs.

[0033] In order to solve the above problems, an embodiment of the present invention provides an IBC battery positive electrode grid line aluminum paste, the components of which include organic additives, boron powder, aluminum powder, silver powder, organic adhesive and glass powder, and the glass powder contains lead, vanadium and titanium elements.

[0034] Among them, aluminum powder is the main component; glass powder is an inorganic adhesive, which will melt into liquid under high temperature conditions and condense when cooled to play a bonding role; organic adhesive can ensure the overall bonding effect, and organic additives can reduce the overall viscosity of the aluminum paste; at the same time, because the glass powder contains lead, vanadium and titanium elements, after high-temperature sintering, the oxidized lead can react with silicon nitride with the assistance of vanadium and titanium to produce lead, nitrogen and silicon dioxide, so that the aluminum paste can corrode the silicon nitride film, and use boron powder to increase the doping concentration of the P+ doped area, and aluminum and silicon can form a good ohmic contact, so when using the above-mentioned aluminum paste to print and form the positive grid line, there is no need to Laser grooving is performed and the silicon nitride film directly printed on the surface of the P+ doped area, and then high-temperature sintering can form the positive electrode grid line in contact with the P+ doped area, and the doping concentration of the P+ doped area can be increased, thereby improving the efficiency of the IBC battery; in addition, silver powder is added to the aluminum paste provided by the present invention, which can reduce the metal composite of aluminum in the aluminum paste and reduce the contact resistivity in the aluminum fine grid, which can further improve the efficiency of the IBC battery; therefore, the aluminum paste provided by the embodiment of the present invention can solve the problem that the existing IBC battery aluminum paste performs laser grooving on the silicon nitride film at the P+ area position before printing into the positive electrode grid line, which is a cumbersome and costly step.

[0035] The glass powder contains lead, vanadium and titanium elements, that is, the glass powder can be doped with lead, vanadium and titanium so that the above substances adhere to the glass powder to obtain the above glass powder containing lead, vanadium and titanium elements.

[0036] Optionally, in the IBC battery aluminum paste provided in an embodiment of the present invention, the mass fractions of organic additives, boron powder, aluminum powder, silver powder, organic adhesive and glass powder are 0.15-0.4%, 0.04-0.08%, 68-75%, 2-6%, 17.94-22.77% and 0.8-1.2%, respectively.

[0037] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, silver powder, organic binder and glass powder are 0.15%, 0.08%, 68%, 6%, 22.77% and 0.8%, respectively.

[0038] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, silver powder, organic binder and glass powder are 0.4%, 0.04%, 75%, 2%, 21.36% and 1.2% respectively.

[0039] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, silver powder, organic binder and glass powder are 0.3%, 0.06%, 74.9%, 5.7%, 17.94% and 1.1%, respectively.

[0040] Optionally, in an embodiment of the present invention, the glass powder includes Bi2O3 of 20-25% by mass, Al2O3 of 6-8% by mass, Pb2O5 of 10-12% by mass, ZnO of 5-29% by mass, Sb2O5 of 15-20% by mass, V2O5 of 5-8% by mass, T i Among them, Bi2O3 is the main network structure, Al2O3 can adjust the stability of glass and increase viscosity, ZnO can break the network structure and promote glass crystallization; Pb2O5 reacts with silicon nitride to produce lead, nitrogen and silicon dioxide, V2O5 reacts with T i O2 can assist the reaction between Pb2O5 and silicon nitride; the D50 of the glass powder is 1.5-2μm. If D50 is less than 1.5μm, the glass activity is too high, and if D50 is greater than 2μm, the glass activity is too low.

[0041] Optionally, in one embodiment, the aluminum powder includes micron-sized spherical aluminum powder and nano-sized spherical aluminum powder, and the silver powder includes micron-sized spherical silver powder and nano-sized spherical silver powder. Specifically, the aluminum powder includes micron-sized spherical aluminum powder with a purity of 3 nines and nano-sized spherical aluminum powder with a purity of 3 nines, and the silver powder includes micron-sized spherical silver powder with a purity of 3 nines and nano-sized spherical silver powder with a purity of 3 nines. In an embodiment of the present invention, the silver powder is micron-sized spherical silver powder with a purity of 3 nines. Since there are gaps between the micron-sized silver powders and the silver powders, and there are gaps between the micron-sized aluminum powders and the aluminum powders, the nano-sized spherical silver powder and the nano-sized spherical aluminum powder can just fill and penetrate into the gaps between the micron-sized powders.

[0042] Optionally, the organic additive includes one or more of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, lauryl alcohol phosphate, Digo 655, BYK105, and Lubrizol 20000.

[0043] In the IBC battery aluminum paste provided in the embodiment of the present invention, the above-mentioned organic binder includes a high molecular polymer resin and an organic solvent; wherein the high molecular polymer resin is dissolved in the organic solvent, so that the organic solvent can serve as an organic binder, that is, the paste plays the role of bonding powder after drying.

[0044] Optionally, in one embodiment, the mass fraction of the high molecular weight polymer in the organic binder is 6 to 12%; the mass fraction of the organic solvent in the organic binder is 88 to 94%.

[0045] Optionally, in one embodiment, the high molecular weight polymer is hexyl cellulose N-50;

[0046] 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.

[0047] The present invention also provides a method for preparing IBC battery aluminum paste, such as Figure 1 As shown, it includes steps 101 to 103:

[0048] Step 101: Mixing an organic binder, nano-aluminum powder, and nano-silver powder to obtain a first mixture;

[0049] Step 102: adding micron aluminum powder, micron silver powder and glass powder to the first mixture, mixing and grinding to obtain a second mixture; the glass powder contains lead, vanadium and titanium elements;

[0050] Step 103: Add an organic additive to the second mixture to disperse and obtain an IBC battery positive electrode grid line aluminum paste.

[0051] In step 101, an organic binder is mixed with nano-aluminum powder and nano-silver powder, and then dispersed using a disperser to obtain the first mixture. The nano-aluminum powder is nano-spherical aluminum powder with a purity of 3.9, and the nano-silver powder is nano-spherical silver powder with a purity of 3.9. The organic binder comprises a polymer resin and an organic solvent. The polymer resin is dissolved in the organic solvent, allowing the organic solvent to act as an organic binder, i.e., the slurry acts as a binder for the powders after drying.

[0052] In step 102, micron aluminum powder, micron silver powder, and glass powder containing one or more of lead, vanadium, and titanium are added to the first mixture, which is then dispersed again using a disperser and ground to obtain a powder, which is the second mixture. The micron aluminum powder is micron-grade spherical aluminum powder with a purity of 3.9, and the micron silver powder is micron-grade spherical silver powder with a purity of 3.9.

[0053] In step 103, an organic additive is added to the second mixture, and after high-speed dispersion, a high-efficiency aluminum paste for positive electrode grid lines of an IBC battery is obtained. The organic additive has a dispersing effect and specifically includes one or more of a fatty alcohol ether phosphate, an aluminate coupling agent, a silane coupling agent, a zirconium aluminate coupling agent, lauryl phosphate, Digo 655, and a BYK105 mixture.

[0054] Optionally, in the above steps, the mass ratio of the organic additive, boron powder, aluminum powder, silver powder, organic adhesive and glass powder is 0.15-0.4: 0.04-0.08: 68-75: 2-6: 17.94-22.77: 0.8-1.2.

[0055] Alternatively, in one embodiment, the glass powder comprises Bi2O3 of 20-25%, Al2O3 of 6-8%, Pb2O5 of 10-12%, ZnO of 5-29%, Sb2O5 of 15-20%, V2O5 of 5-8%, T i O2.

[0056] Optionally, the organic binder includes a high molecular polymer resin and an organic solvent;

[0057] The mass fraction of the high molecular weight polymer in the organic binder is 6 to 12%;

[0058] The mass fraction of the organic solvent in the organic binder is 88-94%.

[0059] Optionally, in the above-mentioned IBC battery aluminum paste, the high molecular weight polymer is one or more of ethyl cellulose-N20, ethyl cellulose N-50, and ethyl cellulose-N100;

[0060] The organic solvent includes at least three of benzyl alcohol, diethyl phthalate, terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, Span 85 and alcohol ester dodecahydrate.

[0061] The present invention also provides another method for preparing IBC battery aluminum paste, wherein: Figure 2 As shown, it includes steps 201 to 202:

[0062] Step 201: Mixing an organic binder, boron powder, nano-aluminum powder, nano-silver powder, glass powder, and an organic additive to obtain a third mixture; wherein the glass powder contains lead, vanadium, and titanium elements;

[0063] Step 202: Add micron aluminum powder and micron silver powder to the third mixture, mix well, and grind to obtain aluminum paste for positive electrode grid lines of IBC batteries.

[0064] In this embodiment, an organic binder, boron powder, nano-aluminum powder, nano-silver powder, glass powder, and an organic additive are mixed, dispersed using a disperser, and then micron aluminum powder and micron silver powder are added. The mixture is dispersed again using a disperser and ground to obtain the above-mentioned IBC battery positive electrode grid line aluminum paste that does not require laser grooving.

[0065] The present invention also provides a method for preparing an IBC battery, wherein: Figure 3 As shown, it includes steps 301 to 302:

[0066] Step 301: After forming a silicon nitride layer covering the p+ doped region and the n+ doped region on the back side of the silicon wafer, aluminum paste is printed on a first region of the silicon nitride layer, and silver paste is printed on a second region of the silicon nitride layer; wherein the projection of the first region is on the p+ doped region, and the projection of the second region is on the n+ doped region; the aluminum paste comprises an organic additive, boron powder, aluminum powder, an organic binder, and glass powder, wherein the glass powder contains lead, vanadium, and titanium elements;

[0067] Step 302: sintering the silicon wafer with the aluminum paste printed on the first area and the silver paste printed on the second area at high temperature to produce an IBC battery.

[0068] In the embodiment of the present invention, because the glass powder contains lead, vanadium and titanium elements, after high-temperature sintering, the aluminum paste can corrode the silicon nitride film and use boron powder to increase the doping concentration of the P+ doped area, and aluminum and silicon can form a good ohmic contact. Therefore, when the above-mentioned aluminum paste is used to print to form the positive electrode grid line, there is no need to perform laser grooving, and it can be directly printed on the silicon nitride film on the surface of the P+ doped area. Then, through high-temperature sintering, the positive electrode grid line in contact with the P+ doped area can be formed, and the doping concentration of the P+ doped area can be increased. The addition of silver powder can reduce the metal composite of aluminum in the aluminum paste and reduce the contact resistivity in the aluminum fine grid, thereby improving the efficiency of the IBC battery. Therefore, the problem that the existing IBC battery aluminum paste performs laser grooving on the silicon nitride film at the P+ area before printing the positive electrode grid line is solved, which is cumbersome and costly.

[0069] In addition, in the embodiment of the present invention, since there is no need to laser groove the silicon nitride film on the surface of the P+ doped region, the situation in which the passivation of the P+ region is reduced and the P+ region is damaged due to the laser groove is avoided.

[0070] Optionally, the high temperature sintering temperature is 785-790°C, for example, 786°C or 788°C.

[0071] The silver paste mentioned above can be the silver paste conventionally printed on the contact electrode of the n+ doped region.

[0072] The present invention also provides an IBC battery, wherein the battery is prepared by the above-mentioned IBC battery preparation method.

[0073] The present invention is described in detail below by way of examples.

[0074] Example 1

[0075] IBC battery positive electrode grid line aluminum paste A1 is composed of organic additives, boron powder, aluminum powder, silver powder, organic binder and glass powder. In terms of mass percentage, the organic additives account for 0.3%, aluminum powder accounts for 74%, silver powder accounts for 3%, boron powder accounts for 0.03%, organic binder accounts for 23.47%, and glass powder accounts for 1.2%. The glass powder contains three elements: lead, vanadium and titanium.

[0076] Among them, the organic additives include aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, lauryl phosphate, and silicone oil;

[0077] The aluminum powder includes micron-sized spherical aluminum powder with a mass percentage of 92% and a purity of 3 9s, and nano-sized spherical aluminum powder with a mass percentage of 8% and a purity of 3 9s;

[0078] The silver powder includes micron-sized spherical silver powder with a mass percentage of 94% and a purity of 3 9s, and nano-sized spherical silver powder with a mass percentage of 6% and a purity of 3 9s;

[0079] The organic binder comprises 6% by mass of a high molecular weight polymer and 94% by mass of an organic solvent, wherein the high molecular weight polymer is ethyl cellulose N50 having a low sintering residual viscoelastic modulus;

[0080] The organic solvent is composed of benzyl alcohol, diethyl phthalate, terpineol, tributyl citrate, Span 85 and alcohol ester twelve;

[0081] The glass powder is obtained by sintering and crushing 22% Bi2O3, 7% Al2O3, 12% Pb2O5, 15% ZnO, 18% Sb2O5, 7% V2O5 and 19% TiO2 by mass, and its D50 is 1.5-2μm.

[0082] The above-mentioned IBC battery positive electrode grid line aluminum paste a1 is screen-printed on a P-IBC silicon wafer with a size of 182mm×182mm through a 360-mesh screen to form an aluminum fine grid, which is then sintered in a sintering furnace with a peak sintering temperature of 788°C.

[0083] After sintering, the electrical properties tested were: open circuit voltage 0.723V, short circuit current 13.845, filling 83.1%, and photoelectric conversion efficiency 25.19%.

[0084] Example 2

[0085] IBC battery aluminum paste a2 is composed of organic additives, boron powder, aluminum powder, silver powder, organic binder and glass powder; wherein, by mass percentage, the organic additive accounts for 0.6%, aluminum powder accounts for 70.2%, silver powder accounts for 5%, boron powder accounts for 0.08%, organic binder accounts for 22.92%, and glass powder accounts for 1.2%;

[0086] Among them, the organic additives include aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, lauryl phosphate, and silicone oil;

[0087] The aluminum powder includes micron-sized spherical aluminum powder with a mass percentage of 93% and a purity of 3 9s, and nano-sized spherical aluminum powder with a mass percentage of 7% and a purity of 3 9s;

[0088] The silver powder includes micron-sized spherical silver powder with a mass percentage of 95% and a purity of 3 9s, and nano-sized spherical silver powder with a mass percentage of 5% and a purity of 3 9s;

[0089] The organic binder comprises 7% by weight of a high molecular weight polymer and 93% by weight of an organic solvent, wherein the high molecular weight polymer is ethyl cellulose N50 having a low sintering residual viscoelastic modulus;

[0090] The organic solvents are benzyl alcohol, diethyl phthalate, terpineol, tributyl citrate and Span 85;

[0091] The glass powder is obtained by sintering and crushing 20% ​​Bi2O3, 8% Al2O3, 12% Pb2O5, 12% ZnO, 20% Sb2O5, 6% V2O5 and 22% TiO2 by mass, and its D50 is 1.5-2μm.

[0092] The above-mentioned IBC battery aluminum paste a2 is screen-printed on a single crystal P-IBC silicon wafer with a size of 182mm×182mm through a 360-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering, with a peak sintering temperature of 788°C.

[0093] After sintering, the electrical properties tested were: open circuit voltage 0.724V, short circuit current 13.855, filling 83.15%, and photoelectric conversion efficiency 25.26%.

[0094] Comparative Example 1

[0095] IBC battery aluminum paste b1 is composed of organic additives, boron powder, aluminum powder, organic binder and glass powder; wherein, by mass percentage, the organic additives account for 0.5%, aluminum powder accounts for 78%, boron powder accounts for 0.06%, organic binder accounts for 19.94%, and glass powder accounts for 1.5%;

[0096] Among them, the organic additives include aluminate coupling agents, silane coupling agents, zirconium aluminate coupling agents, lauryl phosphate, and silicone oil;

[0097] The aluminum powder includes micron-sized spherical aluminum powder with a mass percentage of 93% and a purity of 3 9s, and nano-sized spherical aluminum powder with a mass percentage of 7% and a purity of 3 9s;

[0098] The organic binder comprises 8% by weight of a high molecular weight polymer and 92% by weight of an organic solvent, wherein the high molecular weight polymer is hexyl cellulose N-50 having a low sintering residual viscoelastic modulus;

[0099] The organic solvent consists of terpineol, butyl carbitol, butyl carbitol acetate, tributyl citrate, and Span 85;

[0100] The glass powder is obtained by sintering and crushing 20% ​​SiO, 8% Al2O3, 12% Pb2O5, 12% ZnO, 20% V2O5, 6% B2O3 and 22% TeO2 by mass, and its D50 is 1.5-2μm.

[0101] The above-mentioned IBC battery aluminum paste b1 is screen-printed with 360 mesh on a laser-grooved single crystal P-IBC silicon wafer with a size of 182mm×182mm to form an aluminum fine grid, and then sintered in a sintering furnace with a peak sintering temperature of 788°C.

[0102] After sintering, the electrical properties tested were: open circuit voltage 0.719V, short circuit current 13.865, filling 83.11%, and photoelectric conversion efficiency 25.095%.

[0103] Comparing Example 1 and Example 2 with Comparative Example 1, it can be seen that aluminum fine grid lines can be formed using aluminum paste doped with lead, vanadium, and titanium without laser grooving, and the resulting IBC battery has an efficiency improvement of 0.1% over conventional IBC aluminum paste.

[0104] To summarize, in this embodiment, lead, vanadium and titanium elements are added to the glass powder in the IBC battery aluminum paste, and silver powder is added, without the need for laser grooving, and the silicon nitride film is directly printed on the surface of the P+ doped area. After high-temperature sintering, the aluminum paste can corrode the silicon nitride film, and aluminum and silicon can form a good ohmic contact, thereby increasing the doping concentration of the P+ doped area. The addition of silver powder can reduce the metal composite of aluminum in the aluminum paste, reduce the contact resistivity in the aluminum fine grid, and improve the efficiency of the IBC battery. This solves the problem of cumbersome and costly laser grooving of the silicon nitride film at the P+ area before printing the positive electrode grid line in the existing IBC battery aluminum paste.

[0105] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0106] The above is a detailed introduction to the IBC battery positive grid line aluminum paste, its preparation method and battery provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing an IBC battery, characterized in that: include: After forming a silicon nitride layer covering the p+ doped region and the n+ doped region on the back side of the silicon wafer, aluminum paste is printed on the first region of the silicon nitride layer, and silver paste is printed on the second region of the silicon nitride layer; wherein the projection of the first region is on the p+ doped region, and the projection of the second region is on the n+ doped region, the aluminum paste is composed of organic additives, boron powder, aluminum powder, silver powder, organic binder and glass powder, and the glass powder contains lead, vanadium and titanium elements; in the aluminum paste, the mass fractions of the organic additives, boron powder, aluminum powder, silver powder, organic binder and glass powder are 0.15-0.4%, 0.04-0.08%, 68-75%, 2-6%, 17.94-22.77% and 0.8-1.2% respectively, the aluminum powder includes micron-sized spherical aluminum powder and nano-sized spherical aluminum powder, the silver powder includes micron-sized spherical silver powder and nano-sized spherical silver powder, and the glass powder includes Bi2O3 with a mass fraction of 20-25%, 6-8% It is composed of 10~12% Al2O3, 5~29% Pb2O5, 15~20% Sb2O5, 5~8% V2O5, and 15~22% TiO2; The silicon wafer with the aluminum paste printed on the first area and the silver paste printed on the second area is sintered at high temperature to produce an IBC battery.

2. The preparation method according to claim 1, characterized in that The D50 of the glass powder is 1.2-2 μm.

3. The preparation method according to claim 1, characterized in that The organic binder is composed of a high molecular polymer resin and an organic solvent; The mass fraction of the high molecular polymer resin in the organic binder is 6-12%; The mass fraction of the organic solvent in the organic binder is 88-94%.

4. The preparation method according to claim 3, characterized in that The high molecular weight polymer is one or more of ethyl cellulose-N20, ethyl cellulose N-50, and ethyl cellulose-N100; 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 dodecahydrate.

5. The preparation method according to any one of claims 1 to 4, characterized in that The preparation method of the aluminum paste comprises: mixing an organic binder, nano-sized spherical aluminum powder, and nano-sized spherical silver powder to obtain a first mixture; adding micron-sized spherical aluminum powder, micron-sized spherical silver powder, and glass powder to the first mixture, mixing and then grinding to obtain a second mixture; the glass powder contains lead, vanadium, and titanium elements; An organic auxiliary agent is added to the second mixture to disperse and obtain an IBC battery positive electrode grid line aluminum paste.

6. An IBC battery, characterized in that: The method is prepared by any one of claims 1 to 4.

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