Aluminum paste for textured surface of P region 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 textured surface, a preparation method of the aluminum paste and an IBC battery, and the aluminum paste for the P-type IBC battery P-region textured surface provided by the embodiment of the invention comprises an organic auxiliary agent, boron powder, aluminum powder, elemental gallium, glass powder and an organic adhesive. Elementary substance gallium is added into aluminum paste, gallium and aluminum are third main group elements and have similar chemical properties, and gallium has high density, can become liquid at 30 DEG C and is filled between suede surfaces of a silicon wafer and in laser holes, so that the quality of the silicon wafer is improved, and the quality of the silicon wafer is improved. Therefore, the problem that the filling factor of the P-type IBC battery is reduced and the battery efficiency is influenced because the aluminum powder in the existing aluminum paste cannot completely fill the textured surface and the laser hole between the silicon wafers due to the large particle size is solved.

Description

Technical Field

[0001] The invention relates to the technical field of crystalline silicon solar cell manufacturing, and in particular to an aluminum paste used for a velvet surface of a P-type IBC cell P region and a preparation method thereof, and an IBC cell. 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-region and n-region arranged in an interdigitated shape on the back of the battery, and then print aluminum paste connected to the p-region to form the positive electrode grid line, and print silver paste connected to the n-region to form the negative electrode grid line.

[0003] At present, the morphology of the P zone of a P-type IBC battery can be polished and velvet respectively. For a P-type IBC battery with a velvet P zone, during the process of printing aluminum paste, it is easy for the aluminum powder in the aluminum paste to be unable to penetrate into the velvet area due to the large particle size of the aluminum powder, making it impossible for the aluminum metal to completely bond with the silicon wafer and the laser holes to be filled densely, resulting in a decrease in the filling factor of the P-type IBC battery and affecting the battery efficiency. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an aluminum paste for the velvet surface of the P region of a P-type IBC battery and a preparation method thereof, and an IBC battery, so as to solve the problem that the existing aluminum paste easily leads to a decrease in the filling factor of the P-type IBC battery with a velvet surface P region, thereby affecting the photoelectric conversion efficiency of the battery.

[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 the velvet surface of the P region of a P-type IBC battery, wherein the components constituting the aluminum paste include organic additives, boron powder, aluminum powder, single-element gallium, glass powder and an organic adhesive.

[0007] Furthermore, in the aluminum paste, the mass percentage of the organic additive is 0.3-0.6%; the mass percentage of the boron powder is 0.03-0.1%; the mass percentage of the aluminum powder is 72-78%; the mass percentage of the elemental gallium is 0.15-0.3%; the mass percentage of the glass powder is 1-1.5%; and the mass percentage of the organic binder is 19.65-25.52%.

[0008] Furthermore, in the aluminum paste, the boron powder is micron-grade boron powder.

[0009] Furthermore, in the aluminum paste, the organic additive includes at least one of fatty alcohol ether phosphate, aluminate coupling agent, silane coupling agent, zirconium aluminate coupling agent, and lauryl alcohol phosphate.

[0010] Furthermore, 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.

[0011] Furthermore, in the 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 8%;

[0013] The mass fraction of the organic solvent in the organic binder is 92-94%.

[0014] Furthermore, 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 twelve.

[0015] Furthermore, in the aluminum paste, the glass powder includes 15-25% by mass of Bi 2 O 3 , Al with a mass fraction of 8 to 10% 2 O 3 , Pb with a mass fraction of 10-12% 2 O 5 , Sb with a mass fraction of 15 to 22% 2 O 5 , V with a mass fraction of 8 to 10% 2 O 5 , TiO with a mass fraction of 12-22% 2 , BaO with a mass fraction of 12 to 18%.

[0016] The present invention also proposes a method for preparing aluminum paste for the velvet surface of the P-type IBC battery P region, which comprises:

[0017] mixing aluminum powder, boron powder, elemental gallium, an organic binder and glass powder to obtain a mixture;

[0018] After grinding the mixture, an organic additive is added to obtain an aluminum paste for forming a positive electrode grid line on the textured surface of the P region of a P-type IBC battery.

[0019] The present invention also proposes a P-type IBC battery, wherein a P-type doping region is provided on the back of the IBC battery, the P-type doping region has a velvet surface, a plurality of positive electrode grid lines are attached to the velvet surface, and the positive electrode 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 an embodiment of the present invention, the aluminum paste provided for the velvet of the P region of a P-type IBC battery comprises an organic additive, boron powder, aluminum powder, elemental gallium, glass powder and an organic adhesive. By adding elemental gallium to the aluminum paste, since gallium and aluminum are both third-group elements, the chemical properties of the two are similar. At the same time, gallium has a high density and will become liquid at 30 degrees Celsius and fill in the velvet between the silicon wafers and the laser holes, thereby solving the problem that the aluminum powder in the existing aluminum paste cannot completely fill the velvet between the silicon wafers and the laser holes due to its large particle size, resulting in a reduced filling factor of the P-type IBC battery and affecting the battery efficiency.

[0022] 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

[0023] Figure 1 It is a flow chart of a method for preparing aluminum paste for the velvet surface of the P region of a P-type IBC battery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] 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.

[0025] An embodiment of the present invention provides an aluminum paste for a P-type IBC battery P-region textured surface, wherein the components constituting the aluminum paste include an organic additive, boron powder, aluminum powder, single-element gallium, glass powder and an organic adhesive.

[0026] The aluminum paste provided in the embodiment of the present invention is used to form the positive electrode grid line of a P-type IBC battery with a velvet P region.

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

[0028] Gallium and aluminum are both group III elements with similar chemical properties. Gallium has a higher density and becomes liquid at 30 degrees Celsius. Therefore, during the sintering process, it falls to the silicon surface faster than aluminum and fills into the velvet surfaces and laser holes of the silicon wafer, increasing the contact probability between Ga and Si and reducing the contact resistance between the slurry and the battery.

[0029] Among them, 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; organic additives can reduce the overall viscosity of silver paste.

[0030] Therefore, the aluminum paste provided in the embodiment of the present invention can solve the problem that the aluminum powder in the existing aluminum paste cannot completely fill the velvet surface and laser holes between silicon wafers due to its large particle size, resulting in a reduced filling factor of the P-type IBC battery and affecting the battery efficiency.

[0031] Optionally, in one embodiment, in the above-mentioned aluminum paste, the mass percentage of organic additives is 0.3-0.6%, the mass percentage of boron powder is 0.03-0.1%, the mass percentage of aluminum powder is 72-78%, the mass percentage of elemental gallium is 0.15-0.3%, the mass percentage of glass powder is 1-1.5%, and the mass percentage of organic binder is 19.65-25.62%.

[0032] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, elemental gallium, glass powder and organic binder are 0.3%, 0.05%, 74.5%, 0.2%, 1.2% and 23.75% respectively.

[0033] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, elemental gallium, glass powder and organic binder are 0.6%, 0.1%, 76.2%, 0.25%, 1.2% and 21.65% respectively.

[0034] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, elemental gallium, glass powder and organic binder are 0.5%, 0.08%, 78%, 0.15%, 1% and 20.27% respectively.

[0035] For example, in the aluminum paste, the mass fractions of the organic additive, boron powder, aluminum powder, elemental gallium, glass powder and organic binder are 0.6%, 0.08%, 72%, 0.3%, 1.5% and 25.52% respectively.

[0036] Optionally, in one embodiment, the boron powder comprises elemental boron.

[0037] Optionally, in a specific embodiment, the boron powder includes micron-sized elemental boron. By adding the micron-sized elemental boron, the boron powder can quickly diffuse into the silicon for heavy doping during high-temperature sintering, which is beneficial to improving the contact performance of the slurry.

[0038] Optionally, in a specific embodiment, the boron powder is micron-grade boron powder with a purity of 3 9s.

[0039] Optionally, in a specific embodiment, the gallium powder includes micron-sized single-element gallium. By adding the micron-sized single-element gallium, the gallium powder can quickly diffuse into the silicon during high-temperature sintering, thereby reducing the contact resistance between the slurry and the battery.

[0040] Optionally, in a specific embodiment, the gallium powder is micron-grade gallium powder with a purity of 1 9.

[0041] Optionally, in one embodiment, the aluminum powder includes 90-95% by mass of micron-sized spherical aluminum powder and 5-10% by mass of nano-sized spherical aluminum powder. Since there are gaps between the micron-sized aluminum powders, the nano-sized spherical aluminum powder can just fill and penetrate into the gaps between the micron-sized aluminum powders.

[0042] Optionally, in a specific embodiment, the aluminum powder includes micron-sized spherical aluminum powder with a purity of 3 9s and a mass fraction of 90-95%, and nano-sized spherical aluminum powder with a purity of 3 9s and a mass fraction of 5-10%.

[0043] Optionally, in one embodiment, the organic auxiliary agent includes 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, Digo 655, BYK110, and BYK105.

[0044] In the 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 be used as an organic binder, that is, the paste plays a role of bonding powder after drying.

[0045] Optionally, in one embodiment, the mass fraction of the high molecular weight polymer in the organic binder is 6-8%; the mass fraction of the organic solvent in the organic binder is 92-94%.

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

[0047] 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 twelve.

[0048] Optionally, in one embodiment, the glass powder comprises 15-25% by mass of Bi 2 O 3 , Al with a mass fraction of 8 to 10% 2 O 3 , Pb with a mass fraction of 10-12% 2 O 5 , Sb with a mass fraction of 15 to 22% 2 O 5 , V with a mass fraction of 8 to 10% 2 O 5 , TiO with a mass fraction of 12-22% 2 , the mass fraction of BaO is 12-18%, and the D50 of the glass powder is 1.2-1.8μm. If D50 is less than 1.2μm, the glass activity is too high, and if D50 is greater than 1.8μm, the glass activity is too low.

[0049] Among them, Bi 2 O 3 As the main network structure, Sb 2 O 5 Used to clarify and even the glass liquid; Al 2 O 3 Can adjust glass stability and increase viscosity; Pb 2 O 5 Reacts with silicon nitride to generate lead, nitrogen and silicon dioxide; V 2 O 5 With TiO 2 It can assist Pb 2 O 5 Reacts with silicon nitride; BaO is used for local crystallization.

[0050] For example, the glass powder includes 20% by mass of Bi 2 O 3 , mass fraction of 8% Al 2 O 3 , Pb with a mass fraction of 12% 2 O 5 , Sb with a mass fraction of 15% 2 O 5 , V with a mass fraction of 8% 2 O 5 , TiO with a mass fraction of 22% 2 , BaO with a mass fraction of 15%.

[0051] For example, the glass powder includes 20% by mass of Bi 2 O 3 , mass fraction of 8% Al 2 O 3 , Pb with a mass fraction of 12% 2 O 5 , Sb with a mass fraction of 15% 2 O 5 , mass fraction of 10% V 2 O 5 , TiO with a mass fraction of 22% 2 , BaO with a mass fraction of 13%.

[0052] For example, the glass powder includes 15% by mass of Bi 2 O 3 , mass fraction of 10% Al 2 O 3 , Pb with a mass fraction of 10% 2 O 5 , Sb with a mass fraction of 22% 2 O 5 , mass fraction of 10% V 2 O 5 , TiO with a mass fraction of 15% 2 , BaO with a mass fraction of 18%.

[0053] For example, the glass powder includes 25% by mass of Bi 2 O 3 , mass fraction of 9.5% Al 2 O 3 , Pb with a mass fraction of 11.5% 2 O 5 , Sb with a mass fraction of 21% 2 O 5 , V with a mass fraction of 9% 2 O 5 , TiO with a mass fraction of 12% 2 , BaO with a mass fraction of 12%.

[0054] The embodiment of the present invention also provides a method for preparing aluminum paste for the velvet surface of the P-type IBC battery P region, wherein Figure 1 As shown, it includes steps 101 to 102:

[0055] Step 101, mixing aluminum powder, boron powder, elemental gallium, an organic binder and glass powder to obtain a mixture;

[0056] Step 102: grind the mixture, add an organic additive, and obtain an aluminum paste for forming a positive electrode grid line on the textured surface of the P region of a P-type IBC battery.

[0057] In the above step 101, 72-78% of aluminum powder, 0.03-0.1% of boron powder, 0.15-0.3% of elemental gallium, 19.65-25.52% of organic binder, and 1-1.5% of glass powder accounting for the total mass of the raw materials are weighed and mixed, and dispersed by a disperser to obtain the above mixture.

[0058] Optionally, in one embodiment, in the above step 101, the organic adhesive, boron powder and elemental gallium are first mixed and dispersed using a disperser, and then aluminum powder and glass powder are added, dispersed again using a disperser, and then ground to obtain the above mixture.

[0059] In the above step 102, the above mixture is ground and then an organic additive 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 an IBC battery is obtained.

[0060] In the embodiment of the present invention, by adding single element gallium to the aluminum paste, because gallium and aluminum are both elements of the third main group, the chemical properties of the two are similar. At the same time, gallium has a high density and will become liquid at 30 degrees Celsius and fill into the velvet surfaces and laser holes of the silicon wafer, thereby solving the problem that the aluminum powder in the existing aluminum paste cannot completely fill the velvet surfaces and laser holes between the silicon wafers due to its large particle size, resulting in a reduced filling factor of the P-type IBC battery and affecting the battery efficiency.

[0061] Optionally, in the preparation method provided in an embodiment of the present invention, the boron powder is micron-grade boron powder.

[0062] Optionally, in the preparation method provided in 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.

[0063] Optionally, in the preparation method provided in an embodiment of the present invention, the aluminum powder includes 90-95% by mass of micron spherical aluminum powder and 5-10% by mass of nano spherical aluminum powder; in the above step 101, the organic adhesive, nano aluminum powder, boron powder and gallium powder are first mixed and dispersed using a disperser, and then the micron 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 embodiment of the present invention, the organic binder comprises a high molecular polymer resin and an organic solvent;

[0065] The mass fraction of the high molecular weight polymer in the organic binder is 6 to 8%;

[0066] The mass fraction of the organic solvent in the organic binder is 92-94%.

[0067] Optionally, in the preparation method provided in an 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 twelve.

[0068] Optionally, in the preparation method provided in the embodiment of the present invention, the glass powder comprises Bi with a mass fraction of 15 to 25%. 2 O 3 , Al with a mass fraction of 8 to 10% 2 O 3 , Pb with a mass fraction of 10-12% 2 O 5 , Sb with a mass fraction of 15 to 22% 2 O 5 , V with a mass fraction of 8 to 10% 2 O 5 , TiO with a mass fraction of 12-22% 2 , BaO with a mass fraction of 12 to 18%.

[0069] The present invention also proposes a P-type IBC battery, wherein a P-type doping region is provided on the back of the IBC battery, the P-type doping region has a velvet surface, a plurality of positive electrode grid lines are attached to the velvet surface, and the positive electrode grid lines are prepared from the above-mentioned aluminum paste.

[0070] The steps of using the aluminum paste provided in the embodiment of the present invention to make a P-type IBC battery are as follows:

[0071] (1) After sequentially forming a silicon oxide layer and a phosphorus-doped polysilicon layer on the back of a P-type silicon wafer, laser grooving is performed on the back of the silicon wafer to form an n-type doped region and a p-type original silicon region arranged in an interdigitated manner;

[0072] (2) Texturing the surface of the silicon wafer after laser grooving;

[0073] (3) After the texturing process, a passivation film layer and an anti-reflection film layer are formed on both sides of the silicon wafer;

[0074] (4) laser grooving the back of the silicon wafer to expose the p-type original silicon area;

[0075] (5) Aluminum paste is printed in the laser grooved area to form positive electrode grid lines, and silver paste is printed in the n-type doped area to form negative electrode grid lines, thereby producing a P-type IBC battery.

[0076] The present invention is described in detail below by way of examples.

[0077] Example 1

[0078] (1) providing aluminum paste a1: the aluminum paste a1 is composed of 0.3 parts of an organic additive, 0.05 parts of boron powder, 74.5 parts of aluminum powder, 0.2 parts of elemental gallium, 23.75 parts of an organic binder and 1.2 parts of glass powder, by weight;

[0079] The organic additive is composed of lauryl phosphate, Digo 655 and BYK110 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 95%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 5%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 6% and an organic solvent with a mass fraction of 94%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 20% by mass of Bi 2 O 3 , 8% Al 2 O 3 , 12% Pb 2 O 5 , 15% Sb 2 O 5 , 8% V 2 O 5 , 22% TiO 2 , 15% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0080] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 754°C to obtain a P-type IBC battery.

[0081] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7252V, the short circuit current was 13.885mA, the fill factor was 83.8%, and the photoelectric conversion efficiency was 25.33%.

[0082] Example 2

[0083] (1) providing aluminum paste a2: the aluminum paste a2 is composed of 0.6 parts of an organic additive, 0.1 parts of boron powder, 76.2 parts of aluminum powder, 0.25 parts of elemental gallium, 21.65 parts of an organic binder and 1.2 parts of glass powder, by weight;

[0084] The organic additive is composed of lauryl phosphate, Digo 655 and BYK106 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 92%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 8%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 6% and an organic solvent with a mass fraction of 94%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 20% by mass of Bi 2 O 3 , 8% Al 2 O 3 , 12% Pb 2 O 5 , 15% Sb 2 O 5 , 10% V 2 O 5 , 22% TiO 2 , 13% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0085] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 762°C to obtain a P-type IBC battery.

[0086] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7262V, the short circuit current was 13.905mA, the fill factor was 83.6%, and the photoelectric conversion efficiency was 25.346%.

[0087] Example 3

[0088] (1) providing aluminum paste a3: in parts by mass, the aluminum paste a1 is composed of 0.5 parts of an organic additive, 0.08 parts of boron powder, 78 parts of aluminum powder, 0.15 parts of elemental gallium, 20.27 parts of an organic binder and 1 part of glass powder;

[0089] The organic additive is composed of lauryl phosphate, Digo 655 and BYK106 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 92%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 8%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 6% and an organic solvent with a mass fraction of 94%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 20% by mass of Bi 2 O 3 , 8% Al 2 O 3 , 12% Pb 2 O 5 , 15% Sb 2 O 5 , 10% V 2 O 5 , 22% TiO 2 , 13% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0090] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 762°C to obtain a P-type IBC battery.

[0091] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7264V, the short circuit current was 13.915mA, the fill factor was 83.55%, and the photoelectric conversion efficiency was 25.356%.

[0092] Example 4

[0093] (1) providing aluminum paste a4: the aluminum paste a4 is composed of 0.6 parts of an organic additive, 0.08 parts of boron powder, 72 parts of aluminum powder, 0.3 parts of elemental gallium, 25.52 parts of an organic binder and 1.5 parts of glass powder, by weight;

[0094] The organic additive is composed of lauryl phosphate, Digo 655 and BYK106 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 92%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 8%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 8% and an organic solvent with a mass fraction of 92%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 20% by mass of Bi 2 O 3 , 8% Al 2 O 3 , 12% Pb 2 O 5 , 15% Sb 2 O 5 , 10% V 2 O 5 , 22% TiO 2 , 13% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0095] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 762°C to obtain a P-type IBC battery.

[0096] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7272V, the short circuit current was 13.918mA, the fill factor was 83.45%, and the photoelectric conversion efficiency was 25.359%.

[0097] Example 5

[0098] (1) providing aluminum paste a5: the aluminum paste a5 is composed of 0.6 parts of an organic additive, 0.08 parts of boron powder, 72 parts of aluminum powder, 0.3 parts of elemental gallium, 25.52 parts of an organic binder and 1.5 parts of glass powder, by weight;

[0099] The organic additive is composed of lauryl phosphate, Digo 655 and BYK106 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 92%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 8%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 6% and an organic solvent with a mass fraction of 94%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 15% by mass of Bi 2 O 3 , 10% Al 2 O 3 , 10% Pb 2 O 5 , 22% Sb 2 O 5 , 10% V 2 O 5 , 15% TiO 2 , 18% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0100] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 762°C to obtain a P-type IBC battery.

[0101] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7276V, the short circuit current was 13.92mA, the fill factor was 83.4%, and the photoelectric conversion efficiency was 25.362%.

[0102] Comparative Example 1

[0103] (1) providing aluminum paste b1: the aluminum paste b1 is composed of 0.6 parts of an organic additive, 0.1 parts of boron powder, 76.2 parts of aluminum powder, 21.9 parts of an organic binder and 1.2 parts of glass powder, by weight;

[0104] The organic additive is composed of lauryl phosphate, Digo 655 and BYK106 in a mass ratio of 3:3:4; the boron powder is a micron-grade elemental boron with a purity of 3 9s; the aluminum powder includes a micron-grade spherical aluminum powder with a purity of 3 9s and a mass fraction of 95%, and a nano-spherical aluminum powder with a purity of 3 9s and a mass fraction of 5%; the elemental gallium is a micron-grade elemental gallium with a purity of 1 9; the organic binder includes ethyl cellulose-N50 with a mass fraction of 6% and an organic solvent with a mass fraction of 94%, and the organic solvent is composed of benzyl alcohol, diethyl phthalate, pineneol, butyl carbitol, and butyl carbitol acetate in a mass ratio of 1:3:2:2:2; the glass powder is 20% by mass of Bi 2 O 3 , 8% Al 2 O 3 , 12% Pb 2 O 5 , 15% Sb 2 O 5 , 10% V 2 O 5 , 22% TiO 2 , 13% BaO is obtained by sintering and crushing, and its D50 is 1.0~1.5μm.

[0105] (2) The aluminum paste is printed on a single crystal P-type silicon wafer with a size of 182 mm × 182 mm and a P-region velvet surface through a 480-mesh screen to form an aluminum fine grid, which is then put into a sintering furnace for sintering at a peak temperature of 762°C to obtain a P-type IBC battery.

[0106] The electrical performance data of the above battery was tested, and the results showed that the open circuit voltage was 0.7248V, the short circuit current was 13.875mA, the fill factor was 83.15%, and the photoelectric conversion efficiency was 25.107%.

[0107] By comparing Examples 1 to 5 and Comparative Example 1, it can be seen that the embodiments of the present invention can effectively improve the fill factor and photoelectric conversion efficiency of the battery.

[0108] To summarize, in this embodiment, by adding elemental gallium to the aluminum paste, because gallium and aluminum are both elements of the third main group, the chemical properties of the two are similar. At the same time, gallium has a high density and will become liquid at 30 degrees Celsius and fill into the velvet surfaces and laser holes of the silicon wafer, thereby solving the problem that the aluminum powder in the existing aluminum paste cannot completely fill the velvet surfaces and laser holes between the silicon wafers due to its large particle size, resulting in a reduction in the filling factor of the P-type IBC battery and affecting the battery efficiency.

[0109] 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 concept. 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.

[0110] The above is a detailed introduction to an aluminum paste for the velvet surface of the P-zone of a P-type IBC battery and its preparation method, as well as an IBC 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 a limitation on the present invention.

Claims

1. Aluminum paste for the velvet surface of the P-type IBC battery P area, It is characterized in that The components constituting the aluminum paste include organic additives, boron powder, aluminum powder, single-element gallium, glass powder and organic adhesive.

2. The aluminum paste according to claim 1, It is characterized in that The mass percentage of the organic auxiliary agent is 0.3-0.6%; the mass percentage of the boron powder is 0.03-0.1%; the mass percentage of the aluminum powder is 72-78%; the mass percentage of the elemental gallium is 0.15-0.3%; the mass percentage of the glass powder is 1-1.5%; and the mass percentage of the organic binder is 19.65-25.52%.

3. The aluminum paste according to claim 1, It is characterized in that The boron powder is micron-grade boron powder.

4. The aluminum paste according to claim 1, It is characterized in that 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.

5. The aluminum paste according to claim 1, It is characterized in that The aluminum powder comprises 90-95% by mass of micron spherical aluminum powder and 5-10% by mass of nanometer spherical aluminum powder.

6. The aluminum paste according to claim 1, It is characterized in that The organic binder includes a high molecular polymer resin and an organic solvent; The mass fraction of the high molecular weight polymer in the organic binder is 6 to 8%; The mass fraction of the organic solvent in the organic binder is 92-94%.

7. The aluminum paste according to claim 6, It is characterized in that 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 twelve.

8. The aluminum paste according to claim 1, It is characterized in that The glass powder includes Bi with a mass fraction of 15 to 25%. 2 O 3 , Al with a mass fraction of 8 to 10% 2 O 3 , Pb with a mass fraction of 10-12% 2 O 5 , Sb with a mass fraction of 15 to 22% 2 O 5 , V with a mass fraction of 8 to 10% 2 O 5 , TiO with a mass fraction of 12-22% 2 , BaO with a mass fraction of 12 to 18%.

9. A method for preparing aluminum paste for the velvet surface of the P-type IBC battery P area, It is characterized in that include: mixing aluminum powder, boron powder, elemental gallium, an organic binder and glass powder to obtain a mixture; After grinding the mixture, an organic additive is added to obtain an aluminum paste for forming a positive electrode grid line on the textured surface of the P region of a P-type IBC battery.

10. A P-type IBC battery, It is characterized in that A P-type doping region is disposed on the back of the IBC battery. The P-type doping region has a velvet surface. A plurality of positive electrode grid lines are attached to the velvet surface. The positive electrode grid lines are prepared from the aluminum paste as described in any one of claims 1 to 8.

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