Conductive resin applicable to heterojunction battery and preparation method therefor

Abstract

The present application provides a conductive resin applicable to a heterojunction battery and a preparation method therefor. The preparation method comprises the following steps: (1) mixing hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide to prepare isocyanate-functionalized carbon nanotubes; (2) adding a vegetable oil polyol to a reaction container, continuing adding xylylene diisocyanate, the isocyanate-functionalized carbon nanotubes, and cyclohexanone, heating to 65-75ºC in a nitrogen atmosphere, maintaining the temperature for 30-40 min, adding di-n-butyltin oxide, heating and reacting to prepare a polyurethane prepolymer; and (3) mixing the polyurethane prepolymer, an epoxy resin, and diethylene glycol, and maintaining the temperature at 80-85ºC for reaction for 3-4 h; and cooling to 40ºC, adding triethylamine for neutralization, and reacting for 4-5 min to obtain the conductive resin. The conductive resin prepared by the present application can be applied to the preparation of a heterojunction battery, and the conductive effect is more excellent.

Description

Conductive resin for heterojunction battery and preparation method thereof Technical Field

[0001] The present application belongs to the technical field of conductive resins, and specifically relates to a conductive resin used in heterojunction batteries and a preparation method thereof. Background Art

[0002] With the rapid development of the photovoltaic industry, the demand for new products continues to increase. To adapt to the diversified development of the photovoltaic market, when the power and voltage requirements cannot be met at the same time, solar cells need to be cut into half cells. The heterojunction (HIT) is a special PN junction formed by amorphous silicon and crystalline silicon materials. It is a type of N-type cell that is deposited by depositing an amorphous silicon thin film on crystalline silicon. HIT cells were first successfully developed by Sanyo Corporation of Japan in 1990. Because HIT has been registered as a trademark by Sanyo, it is also known as HJT, HDT, or SHJ. When assembling heterojunction cells, glass is usually placed on one side of the cell and a backplane is placed on the other side of the cell. The cell and glass, and the cell and backplane are connected by adhesive film, and the transparent conductive film on both sides of the cell is in direct contact with the adhesive film. The heterojunction cell is a high-efficiency crystalline silicon solar cell structure. It is a hybrid solar cell made of a crystalline silicon substrate and an amorphous silicon thin film. That is, a layer of non-doped (intrinsic) hydrogenated amorphous silicon thin film is added between the P-type hydrogenated amorphous silicon and the N-type hydrogenated amorphous silicon and the N-type silicon substrate. The full name of the heterojunction cell is the intrinsic thin-film heterojunction cell. It is a new type of cell based on the photovoltaic effect. Due to its unique double-sided symmetrical structure and the excellent clocking effect of the amorphous silicon layer, it has the advantages of high conversion efficiency, high bifaciality, almost no photo-induced degradation, good temperature characteristics, the use of thin silicon wafers, and the use of calcium phosphate. At the same time, its manufacturing process is relatively short and it will be more popular in the future.

[0003] The specific advantages of heterojunction solar cells include: 1. No PID (Potentially Induced Degradation) phenomenon: Because the top surface of the cell is TCO, charge polarization does not occur on the TCO surface, resulting in no PID phenomenon, a fact confirmed by field measurements. 2. Low-temperature manufacturing process: The processing temperature of all HJT cell processes is below 250°C, avoiding the inefficient and costly high-temperature diffusion junction process. Furthermore, the low-temperature process allows for precise control of the optical bandgap, deposition rate, absorption coefficient, and hydrogen content of the a-Si thin film, thus avoiding adverse effects such as thermal stress caused by high temperatures. 3. High efficiency: HJT cells continue to set new world records for mass-produced cell conversion efficiency. Their efficiency is 1-2% higher than that of P-type monocrystalline silicon cells, and the difference is gradually increasing. 4. High light stability: HJT solar cells do not exhibit the Staebler-Wronski effect common in amorphous silicon solar cells. Furthermore, HJT cells utilize N-type silicon wafers doped with phosphorus, resulting in virtually no photodegradation. 5. It can be developed towards thinness: The process temperature of HJT batteries is low, the upper and lower surface structures are symmetrical, and no mechanical stress is generated, so thinning can be achieved smoothly; in addition, according to research, for N-type silicon substrates with a longer minority carrier lifetime, the thinner the wafer, the higher its open circuit voltage.

[0004] Polyurethane resin is generally added to the conductive silver paste of the silver grid line of the existing heterojunction battery. However, the conductivity of the polyurethane resin is not ideal, which affects the conductivity of the conductive silver paste. Summary of the Invention

[0005] The present application provides a conductive resin for use in heterojunction batteries and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing a conductive resin for use in heterojunction batteries, comprising the following steps:

[0007] (1) mixing hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide in a mass ratio of 1:1:7-9, heating to 80-100°C for reaction for 25-30 hours, cooling, centrifuging, washing, and drying to obtain isocyanated carbon nanotubes;

[0008] (2) Adding vegetable oil polyol to a reaction vessel, heating to 60-70°C, stirring and vacuum degassing for 30-40 minutes under a vacuum degree of 0.07-0.08 MPa, cooling to 45°C, stopping stirring and vacuuming; continuing to add xylene diisocyanate, isocyanate-treated carbon nanotubes and cyclohexanone, heating to 65-75°C under a nitrogen atmosphere, keeping the temperature for 30-40 minutes, adding di-n-butyltin oxide, heating to 100-110°C, and reacting for 4-5 hours to obtain a polyurethane prepolymer;

[0009] (3) Cooling the polyurethane prepolymer to 80-85°C, mixing the polyurethane prepolymer, epoxy resin and diethylene glycol in a mass ratio of 12-14:1:0.2-0.5, and reacting at 80-85°C for 3-4 hours; cooling to 40°C, adding triethylamine for neutralization, and reacting for 4-5 minutes to obtain a conductive resin.

[0010] Furthermore, the mass ratio of the vegetable oil polyol, xylylene diisocyanate, and isocyanate-treated carbon nanotubes is 2-3:1:0.05-0.07.

[0011] Furthermore, the mass of the di-n-butyltin oxide accounts for 0.3-0.7% of the mass of the vegetable oil polyol.

[0012] Furthermore, the hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g.

[0013] Furthermore, the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.; the vegetable oil polyol is soybean oil polyol.

[0014] Furthermore, the hydroxylated carbon nanotubes are carbon nanotubes numbered XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0015] Furthermore, the epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin or alicyclic epoxy resin.

[0016] Furthermore, the epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin.

[0017] Furthermore, the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.4-1.6.

[0018] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0019] In the present application, the amount of triethylamine used is sufficient to neutralize the conductive resin until it becomes neutral.

[0020] In a second aspect, the present application also provides a conductive resin for use in heterojunction batteries, which is prepared by the above-mentioned preparation method.

[0021] Compared with the prior art, the advantages and beneficial effects of the present application are as follows: The present application provides a conductive resin for heterojunction batteries and a preparation method thereof. The conductivity of the resin is increased by adding conductive filler carbon nanotubes. Carbon nanotubes have excellent conductive properties. When they are evenly dispersed in the polyurethane resin, they can form a conductive network, thereby improving the overall conductivity. The prepared polyurethane prepolymer is epoxy-modified using soybean oil polyols, and epoxy groups are introduced into the conductive resin. The epoxy resin can make the conductive carbon nanotubes more evenly dispersed in the polyurethane resin system, forming a conductive network, thereby further improving the conductivity of the polyurethane resin. At the same time, the introduction of epoxy groups in the present application enhances the mechanical strength of the polyurethane resin. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0023] Example 1

[0024] This embodiment provides a conductive resin for use in heterojunction batteries, and a preparation method thereof includes the following steps:

[0025] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8, heated to 90°C for 27 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0026] (2) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, react for 4.5 hours to obtain a polyurethane prepolymer;

[0027] (3) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0028] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanated carbon nanotubes is 2.5:1:0.06.

[0029] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0030] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0031] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0032] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.5.

[0033] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0034] Example 2

[0035] This embodiment provides a conductive resin for use in heterojunction batteries, and a preparation method thereof includes the following steps:

[0036] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:7, heated to 80°C for 25 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0037] (2) Add the vegetable oil polyol to the reaction vessel, heat to 60°C, stir and vacuum degas for 30 minutes under a vacuum degree of 0.07 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 65°C under a nitrogen atmosphere, keep warm for 30 minutes, add di-n-butyltin oxide, heat to 100°C, and react for 4 hours to obtain a polyurethane prepolymer;

[0038] (3) The polyurethane prepolymer was cooled to 80°C, and the polyurethane prepolymer, epoxy resin and diethylene glycol were mixed in a mass ratio of 12:1:0.2, and the mixture was kept at 80°C for reaction for 3 hours; the mixture was cooled to 40°C, and triethylamine was added for neutralization, and the mixture was reacted for 4 minutes to obtain a conductive resin.

[0039] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanate-treated carbon nanotubes is 2:1:0.05.

[0040] The mass of the di-n-butyltin oxide accounts for 0.3% of the mass of the vegetable oil polyol.

[0041] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0042] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0043] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.4.

[0044] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0045] Example 3

[0046] This embodiment provides a conductive resin for use in heterojunction batteries, and a preparation method thereof includes the following steps:

[0047] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:9, heated to 100°C for reaction for 30 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0048] (2) Add vegetable oil polyol to a reaction vessel, heat to 70°C, stir and vacuum degas for 40 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 75°C under a nitrogen atmosphere, keep warm for 40 minutes, add di-n-butyltin oxide, heat to 110°C, react for 5 hours, and prepare a polyurethane prepolymer;

[0049] (3) The polyurethane prepolymer was cooled to 85°C, and the polyurethane prepolymer, epoxy resin and diethylene glycol were mixed in a mass ratio of 14:1:0.5, and the mixture was kept at 85°C for 4 hours; the mixture was cooled to 40°C, triethylamine was added for neutralization, and the mixture was reacted for 5 minutes to obtain a conductive resin.

[0050] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanate-treated carbon nanotubes is 3:1:0.07.

[0051] The mass of the di-n-butyltin oxide accounts for 0.7% of the mass of the vegetable oil polyol.

[0052] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g.

[0053] The vegetable oil polyol is the FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0054] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0055] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.6.

[0056] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that carbon nanotubes are directly added.

[0059] Specifically: A conductive resin for heterojunction batteries, the preparation method comprising the following steps:

[0060] (1) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, hydroxylated carbon nanotubes and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, and react for 4.5 hours to obtain a polyurethane prepolymer;

[0061] (3) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0062] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and hydroxylated carbon nanotubes is 2.5:1:0.06.

[0063] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0064] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0065] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0066] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.5.

[0067] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0068] Comparative Example 2

[0069] This comparative example provides a method for preparing a carbon nanotube. The difference between this comparative example and Example 1 is that the isocyanate-treated carbon nanotubes are replaced with diphenylmethane 4,4'-diisocyanate.

[0070] Specifically: A conductive resin for heterojunction batteries, the preparation method comprising the following steps:

[0071] (1) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, diphenylmethane 4,4'-diisocyanate and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, react for 4.5 hours to prepare a polyurethane prepolymer;

[0072] (2) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0073] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and diphenylmethane 4,4'-diisocyanate is 2.5:1:0.06.

[0074] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0075] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0076] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0077] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.5.

[0078] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0079] Comparative Example 3

[0080] The difference between this comparative example and Example 1 is that the epoxy resin is bisphenol A epoxy resin.

[0081] Specifically: A conductive resin for heterojunction batteries, the preparation method comprising the following steps:

[0082] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8, heated to 90°C for 27 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0083] (2) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, react for 4.5 hours to obtain a polyurethane prepolymer;

[0084] (3) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0085] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanate-treated carbon nanotubes is 2.5:1:0.06.

[0086] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0087] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0088] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0089] The epoxy resin is bisphenol A epoxy resin.

[0090] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent weight of 180-190 g / eq.

[0091] Comparative Example 4

[0092] The difference between this comparative example and Example 1 is that the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:0.6.

[0093] Specifically: A conductive resin for heterojunction batteries, the preparation method comprising the following steps:

[0094] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8, heated to 90°C for 27 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0095] (2) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, react for 4.5 hours to obtain a polyurethane prepolymer;

[0096] (3) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0097] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanate-treated carbon nanotubes is 2.5:1:0.06.

[0098] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0099] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0100] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0101] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:0.6.

[0102] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0103] Comparative Example 5

[0104] The difference between this comparative example and Example 1 is that the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:3.

[0105] Specifically: A conductive resin for heterojunction batteries, the preparation method comprising the following steps:

[0106] (1) hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8, heated to 90°C for 27 hours, cooled, centrifuged, washed, and dried to prepare isocyanated carbon nanotubes;

[0107] (2) Add vegetable oil polyol to a reaction vessel, heat to 65°C, stir and vacuum degas for 35 minutes under a vacuum degree of 0.08 MPa, cool to 45°C, stop stirring and vacuuming; continue to add xylene diisocyanate, isocyanate carbon nanotubes and cyclohexanone, heat to 70°C under a nitrogen atmosphere, keep warm for 35 minutes, add di-n-butyltin oxide, heat to 105°C, react for 4.5 hours to obtain a polyurethane prepolymer;

[0108] (3) Cooling the polyurethane prepolymer to 82° C., mixing the polyurethane prepolymer, epoxy resin, and diethylene glycol in a mass ratio of 13:1:0.4, and reacting at 82° C. for 3.5 hours; cooling to 40° C., adding triethylamine for neutralization, and reacting for 4.5 minutes to obtain a conductive resin.

[0109] The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanate-treated carbon nanotubes is 2.5:1:0.06.

[0110] The mass of the di-n-butyltin oxide accounts for 0.5% of the mass of the vegetable oil polyol.

[0111] The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g; the vegetable oil polyol is FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

[0112] The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0113] The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin, and the mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:3.

[0114] The bisphenol A epoxy resin was purchased from Wanqing Chemical Technology Co., Ltd., with an epoxy equivalent of 180-190 g / eq; the alicyclic epoxy resin was purchased from Jiangsu Pules Biotechnology Co., Ltd., with a viscosity of 400-750 mPa·s.

[0115] Performance Testing

[0116] Conductive silver paste for heterojunction battery silver grid lines was prepared using the conductive resin prepared in the examples and comparative examples. The paste consisted of the following raw materials: 4.5 g of conductive resin, 0.045 g of coupling agent KH560, 0.01 g of BYK203, 0.40 g of 4,4-diaminodiphenyl sulfone, 0.008 g of benzyldimethylamine, 0.5 g of a 1:1 (weight ratio) mixed solvent of ethanol and acetone, 0.10 g of carboxyl-terminated liquid nitrile rubber, 0.05 g of salicylic acid, 8.0 g of a 1:0.5 (weight ratio) mixed diluent of cyclohexanone and ethylene glycol monomethyl ether, 0.01 g of tributyl phosphate, 90 g of flaky silver powder, and 5 g of nano-silver powder. The control group was a commercially available polyurethane resin purchased from Shanghai Shouxing Industrial Co., Ltd., model CR606. The conductive silver paste was cured at 180°C for 10 min, and its bond strength and volume resistivity were then measured.

[0117] Table 1 Performance test results

[0118] The examples show that the conductive silver paste prepared using the conductive resins prepared in Examples 1-3 of this application has different volume resistivities, with lower volume resistivities indicating higher conductivity. Comparative Examples 1-5 show that the conductive resins prepared in this application outperform commercially available polyurethane resins, but that varying the raw materials and conditions for preparation can lead to varying degrees of performance degradation.

[0119] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles described in the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for preparing a conductive resin for use in heterojunction batteries, comprising the following steps: (1) mixing hydroxylated carbon nanotubes, diphenylmethane 4,4'-diisocyanate, and N,N-dimethylformamide in a mass ratio of 1:1:7-9, heating to 80-100°C for reaction for 25-30 hours, cooling, centrifuging, washing, and drying to obtain isocyanated carbon nanotubes; (2) Adding vegetable oil polyol to a reaction vessel, heating to 60-70°C, stirring and vacuum degassing for 30-40 minutes under a vacuum degree of 0.07-0.08 MPa, cooling to 45°C, stopping stirring and vacuuming; continuing to add xylene diisocyanate, isocyanate-treated carbon nanotubes and cyclohexanone, heating to 65-75°C under a nitrogen atmosphere, keeping the temperature for 30-40 minutes, adding di-n-butyltin oxide, heating to 100-110°C, and reacting for 4-5 hours to obtain a polyurethane prepolymer; (3) Cooling the polyurethane prepolymer to 80-85°C, mixing the polyurethane prepolymer, epoxy resin and diethylene glycol in a mass ratio of 12-14:1:0.2-0.5, and reacting at 80-85°C for 3-4 hours; cooling to 40°C, adding triethylamine for neutralization, and reacting for 4-5 minutes to obtain a conductive resin.

2. The method for preparing a conductive resin for heterojunction batteries according to claim 1, wherein: The mass ratio of the vegetable oil polyol, xylylene diisocyanate and isocyanated carbon nanotubes is 2-3:1:0.05-0.

07.

3. The method for preparing a conductive resin for heterojunction batteries according to claim 1, wherein: The mass of the di-n-butyltin oxide accounts for 0.3-0.7% of the mass of the vegetable oil polyol.

4. The method for preparing a conductive resin for heterojunction batteries according to claim 1, wherein: The hydroxyl value of the vegetable oil polyol is 170±10 mgKOH / g.

5. The method for preparing a conductive resin for heterojunction batteries according to claim 4, wherein: The vegetable oil polyol is the FH3170 model polyol produced by Zhangjiagang Feihang Technology Co., Ltd.

6. The method for preparing a conductive resin for heterojunction batteries according to claim 1, wherein: The hydroxylated carbon nanotubes are carbon nanotubes with the number XFD02 produced by Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

7. The method for preparing a conductive resin for heterojunction batteries according to claim 1, wherein: The epoxy resin is selected from one or more of bisphenol A epoxy resin, alicyclic epoxy resin, bisphenol F epoxy resin or bisphenol S epoxy resin.

8. The method for preparing a conductive resin for heterojunction batteries according to claim 7, wherein: The epoxy resin is a compound of bisphenol A epoxy resin and alicyclic epoxy resin.

9. The method for preparing a conductive resin for heterojunction batteries according to claim 8, wherein: The mass ratio of the bisphenol A epoxy resin to the alicyclic epoxy resin is 1:1.4-1.

6.

10. A conductive resin for use in heterojunction batteries, prepared according to the preparation method according to any one of claims 1 to 9.

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