WO2023061476A1 - Conductive paste for photovoltaic cell - Google Patents

Conductive paste for photovoltaic cell Download PDF

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Publication number
WO2023061476A1
WO2023061476A1 PCT/CN2022/125344 CN2022125344W WO2023061476A1 WO 2023061476 A1 WO2023061476 A1 WO 2023061476A1 CN 2022125344 W CN2022125344 W CN 2022125344W WO 2023061476 A1 WO2023061476 A1 WO 2023061476A1
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acid
conductive paste
tin
photovoltaic cells
conductive
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PCT/CN2022/125344
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French (fr)
Chinese (zh)
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武宇涛
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武宇涛
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Publication of WO2023061476A1 publication Critical patent/WO2023061476A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/14—Conductive material dispersed in non-conductive inorganic material
    • H01B1/16—Conductive material dispersed in non-conductive inorganic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the invention relates to the technical field of photovoltaic cells, in particular to a conductive paste for photovoltaic cells.
  • the upper electrode can absorb sunlight and generate electricity.
  • the upper electrode is composed of finger grid lines and bus electrodes. The function of the first is to collect the current on the finger grid line, and the second is to weld the interconnection strip, because the bus electrode itself does not have sufficient conductivity; there are two kinds of lower electrodes, one is the same as the upper electrode, which can absorb light This kind of lower electrode is also composed of finger grid lines and bus electrodes.
  • Another traditional lower electrode cannot absorb sunlight to generate electricity. It consists of a back electric field covering the entire back and a back electrode (also a bus electrode). This back electrode Mainly used for welding interconnection strips.
  • the upper and lower electrodes include fine grid lines, bus electrodes, back electrodes, and back electric fields.
  • nano-particle-level conductive paste is prepared on the surface of the cell by screen printing, and then sintered and solidified at high temperature. After sintering, the upper and lower electrodes Including the bus electrode height is only about 10-15 microns, the resistivity of the conductive silver paste after sintering is generally 1.5-2 times the resistivity of pure silver, if all the bus electrodes are used to conduct the photo-generated current, the battery internal resistance and power damage will be It is very large, so in general, tinned copper conductive strips are welded on the bus electrodes when making components. The cross-sectional area of tinned copper strips can be round or flat.
  • Tinned copper strips can enhance conductivity. Function, on the other hand, it can realize the interconnection between battery slices by serial welding. However, the thickness or height of the tinned copper strip is generally 0.1-0.3mm, especially after welding, a relatively large welding stress will be formed on the battery sheet, and cracks and false soldering of the battery sheet are likely to occur during production and later use. , especially when the battery sheet is further thinned, this unfavorable factor will be more significant.
  • the present invention provides a conductive paste for photovoltaic cells, which can replace the solder ribbons after sintering and solidification, and has sufficient electrical conductivity ability to ensure the performance of photovoltaic cells.
  • a conductive paste for photovoltaic cells the height after sintering and curing is 50-200um, the width is 50-1000um, including the following components by mass fraction: conductive phase 50%-80%, binder phase 10%-50 %, 7-15% of soldering paste, the conductive phase is copper powder or silver powder with a particle size of 5-100um.
  • the conductive phase has a particle size of 15-65um.
  • the conductive phase is copper powder, and an anti-oxidation coating is provided on the surface of the copper powder.
  • the anti-oxidation coating is one or more of silver, tin, nickel, tin-lead alloy, tin-bismuth alloy, and tin-silver-copper alloy.
  • the binder phase is low-melting metal particles with a particle size of 5-60um
  • the low-melting metal particles are one of tin powder, tin-lead alloy powder, tin-copper-silver alloy powder, and tin-bismuth alloy powder one or more species.
  • the binder phase is low-melting metal particles with a particle size of 5-35um.
  • solder paste is mixed with resin, rosin, solvent, activator and additives.
  • the rosin is a modified rosin that is a mixture of one or more of hydrogenated rosin, polymerized rosin, and disproportionated rosin.
  • the activator is aliphatic monobasic acid, dibasic acid, tribasic acid, hydroxy acid, aromatic acid, alkenoic acid, amino acid, acetic acid, succinic acid, gum acid, fatty acid, oxalic acid, salicylic acid, One or more mixtures of benzoic acid, lactic acid, tartaric acid, citric acid, malic acid, oleic acid, glutamic acid, glycine.
  • the solvent is benzene, toluene, benzyl alcohol, ethylene glycol, ethanol, butanol, acetone, ethylbenzene, aromatic naphtha, terpineol, turpentine, ethyl acetate, methyl ether, phosphoric acid
  • Trimethyl Ester Triethyl Phosphate, Propylene Glycol Monomethyl Ether, Butyl Cellosolve, Diethylene Glycol Diethyl Ether, Methyl Carbitol, Ethyl Carbitol, Dingji Carbitol mixture.
  • the additive is a mixture of one or more of thixotropic agent, pasting agent, stabilizer and surfactant.
  • the conductive paste used for photovoltaic cells has sufficient conductivity after sintering and solidification, and at the same time has the function of collecting and collecting the current of the fine grid lines and conducting the collected current, so there is no need to solder on the bus electrodes in the subsequent interconnection Tin-plated interconnect braze strips enhance the conductivity of the bus electrodes.
  • a kind of conductive paste for photovoltaic cells of the present embodiment has a height of 50-200um and a width of 50-1000um after sintering and curing, and comprises the following components by mass fraction: conductive phase 50%-80%, binding phase 10%-50%, 7-15% solder paste, the conductive phase is copper powder or silver powder with a particle size of 5-100um, and the bonding phase is dispersed between the conductive phase particles to fill the gaps between the conductive phase particles , to play the role of bonding, so that the conductive phase particles can be fully contacted, and reduce the overall resistance of the interconnected electrodes; at the same time, the bonding phase will also cover the outer surface of the conductive phase particles, which plays a protective role against oxidation and improves the electrical conductivity.
  • the conductive phase is preferably copper powder, and the copper powder can be flake copper powder, spherical copper powder or flake copper powder Shaped copper powder and spherical copper powder are mixed.
  • the copper powder is preferably spherical or subspherical copper powder with a particle size of 15-65um.
  • spherical or subspherical copper powder Copper powder, easy to prepare, low cost, small specific surface area, better oxidation resistance, and more uniform coating, in addition, the surface of the sintered bus electrode is smoother; copper powder also has flake dendritic, flake Shaped and dendritic copper powder has a large surface area, is easy to oxidize, and is not easy to be used as a metal anti-oxidation coating; without considering the cost, silver powder can also be used as the conductive phase, because silver powder has very good oxidation resistance in high temperature environments , so the surface of the silver powder may not be coated with other metal materials, and the particle size, shape, and particle distribution of the silver powder can be optimized according to the actual experimental results.
  • copper powder it is also possible to select copper powder plated with silver on the surface. At this time, the silver content accounts for 3-15% of the entire conductive phase powder.
  • the conductive paste used for photovoltaic cells has sufficient conductivity after sintering and solidification, and at the same time has the function of collecting and collecting the current of the fine grid lines and conducting the collected current, so there is no need to solder tinned electrodes on the bus electrodes for subsequent interconnection.
  • the interconnect brazing strips enhance the conductivity of the bus electrodes.
  • the surface of the copper powder is provided with an anti-oxidation coating to overcome the problem that the copper powder is easily oxidized
  • the anti-oxidation coating is silver, tin, nickel, tin-lead alloy, tin-bismuth alloy, tin-silver
  • the anti-oxidation coating is tin, tin-lead alloy, tin-bismuth alloy, tin-silver-copper alloy
  • the thickness of the anti-oxidation coating is is 0.5-5um, and the content of the anti-oxidation coating accounts for 2-15% of the weight of the entire conductive phase.
  • the anti-oxidation coating also plays a role in promoting bonding and curing.
  • the binder phase is a low melting point metal particle with a particle size of 5-60um
  • the low melting point metal particle is tin powder, tin-lead alloy powder, tin-copper-silver alloy powder, tin-bismuth alloy powder
  • the shape of the above-mentioned powder is generally spherical
  • the binder phase is a low melting point metal particle with a particle size of 5-35um, such as two sizes of 5-15um and 15-35um, Small particle powder can better fill the gaps between the conductive phase particles, making the conductivity better.
  • the solder paste is mixed by resin, rosin, solvent, activator and additives, and the solder paste can promote the bonding phase to fully and uniformly wrap the conductive phase, so that the conductive phase is evenly dispersed in the Among them, at the same time, the chemical and physical properties of the slurry body are kept stable.
  • the activator can ionize free H+ ions in the solvent above the active point, and react with the oxide on the surface of the metal material to remove the oxide layer and reduce the surface tension of the metal.
  • the solvent is mainly used to provide an ionized environment
  • the additive is a mixture of one or more of thixotropic agent, paste forming agent, stabilizer, and surfactant.
  • the main function of the paste forming agent is to enhance the overall viscosity of the conductive paste.
  • the ability of thick paste can be polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 6000, etc.
  • the role of the stabilizer is to enhance the stability of the conductive paste, which can be paraffin; surfactant and
  • the thixotropic agent can be selected from conventional formulation materials, such as octylphenol ethoxylates, nonylphenol ethoxylates, hydrogenated castor oil, amide compounds, etc.
  • the rosin can be a modified rosin that is a mixture of one or more of hydrogenated rosin, polymerized rosin, and disproportionated rosin.
  • the resin is a thermosetting resin
  • the rosin is maleic rosin.
  • Acid modified rosin, fumaric acid modified rosin, acrylic acid modified rosin or a mixture of one or more, maleic acid modified rosin, fumaric acid modified rosin, acrylic acid modified rosin contain epoxy resin It is a reactive functional group that can react with thermosetting resins to improve the physical and chemical temperature properties of additives and interconnect electrodes after high temperature.
  • the activator is aliphatic monobasic acid, dibasic acid, tribasic acid, hydroxy acid, aromatic acid, alkenoic acid, amino acid, acetic acid, succinic acid, gum acid, fatty acid, oxalic acid, A mixture of one or more of salicylic acid, benzoic acid, lactic acid, tartaric acid, citric acid, malic acid, oleic acid, glutamic acid, and glycine.
  • two substances are selected in a 1:1 ratio It works best when mixed than mixed.
  • the solvent is benzene, toluene, benzyl alcohol, ethylene glycol, ethanol, butanol, acetone, ethylbenzene, aromatic naphtha, terpineol, turpentine, ethyl acetate, One of Methyl Ether, Trimethyl Phosphate, Triethyl Phosphate, Propylene Glycol Monomethyl Ether, Butyl Cellosolve, Diethylene Glycol Diethyl Ether, Methyl Carbitol, Ethyl Carbitol, Dingji Carbitol or a mixture of several to provide an ionizing environment.
  • the conductive phase accounts for 60-80% of the whole conductive paste weight, adopts tin-bismuth-coated copper powder or tin-plated copper powder, copper powder is spherical, tin-bismuth Or the tin coating accounts for 10-15% of the weight of the entire conductive phase, and the average size of the copper powder particles is 20-60um;
  • the binder phase accounts for 10-20% of the weight of the entire conductive paste, which is tin-bismuth alloy powder with a melting point of 140 degree; tin-bismuth alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-40um, and the specific distribution is 15-38um;
  • the flux accounts for 7-13% of the weight of the entire conductive paste; in the entire flux Resin (rosin) accounts for 30-50%, solvent accounts for 40-60%, activator accounts for 0.5-3%, and other additives account for 1-5%.
  • heterojunction battery technology has developed rapidly. Since heterojunction batteries have strict requirements on temperature and temperature, generally the process temperature should not exceed 200 degrees Celsius. Therefore, the bonding phase of this type of conductive paste is usually selected with a lower melting point. Tin-bismuth alloy, the lowest melting point can reach 138 degrees Celsius.
  • conductive phase accounts for 60-80% of whole conductive paste weight, adopts tin-plated copper powder, and copper powder is spherical, and tin-plated layer accounts for 5% of whole conductive phase weight.
  • the average size of copper powder particles is 20-60um;
  • the binder phase accounts for 10%-20% of the weight of the entire conductive paste, which is lead-free tin alloy powder, which can be tin-silver, tin-copper, tin-silver-copper and other alloys powder, the average particle size is 10-38um, and the specific distribution is 15-35um;
  • the flux accounts for 7-13% of the weight of the entire conductive paste;
  • the resin (rosin) accounts for 30-50% in the entire flux, and the solvent accounts for 40- 60%, activator accounts for 0.5-3%, other additives account for 1-5%. According to the above formula, it is evenly mixed and stored at 3-10 degrees.
  • the bonding phase of this type of conductive paste does not contain lead, and its melting temperature is higher than that of bismuth, tin and lead. Generally, the peak value of solidification and sintering temperature is between 230-280. Since it does not contain lead, it can be used for higher requirements for lead-free on the product.
  • conductive phase accounts for 60-80% of whole conductive paste weight, adopts tin-plated copper powder, and copper powder is spherical, and tin-plated layer accounts for 5% of whole conductive phase weight.
  • the average size of copper powder particles is 20-60um;
  • the binder phase accounts for 10% of the weight of the entire conductive paste -20, which is tin-lead alloy powder, wherein the ratio of tin-lead in tin-lead alloy is 63:37, tin Lead alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-38um, and the specific distribution is 15-35um; flux accounts for 7-13%; resin (rosin) accounts for 30-50% in the entire flux %, 40-60% solvent, 0.5-3% activator, and 1-5% other additives; according to the above formula, it is evenly mixed and stored in an environment of 3-10 degrees.
  • the peak curing and sintering temperature of this type of conductive paste is generally 200-250 degrees, and it is mainly used for metallization enhancement of conventional battery sheets that can be sintered at high temperatures.
  • the proportion of body weight is 5-10%, and the average size of copper powder particles is 10-60 microns;
  • the binder phase accounts for 10% of the weight of the entire conductive paste, which is tin-bismuth alloy powder, and the tin-lead ratio in the tin-bismuth alloy is 60% :40, tin-bismuth alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-50 microns, and the specific distribution is 5-30 microns;
  • the organic binder phase accounts for 3-5%, which is acrylic resin or ring Oxygen resin and other thermosetting resins; flux accounts for 10%, of which resin (rosin) accounts for 3-5%, solvent accounts for 2-5%, activator accounts for 0.5-1%, surfactant accounts for 0.5-1%, other additives It accounts for 0.5-1%.
  • the conductive paste of the present invention is mainly used to enhance the conductivity of the bus electrodes on the battery sheet or replace the bus electrodes to conduct directly with the fine grid lines.
  • thin grid lines and bus electrodes have been prepared on the surface of the cell, and the thin grid lines are connected to the bus electrodes.
  • the conductive paste is prepared on the bus electrodes by printing or dispensing Above the electrode, after curing and sintering, all the organic matter in the conductive paste is volatilized or sintered, and the conductive paste itself forms electrical conduction with the bus electrode through the bonding phase.
  • the body of the conductive paste indirectly connects with the fine grid through the bus electrode
  • a complete thin grid line is prepared on the surface of the cell, but the bus electrode is not completely prepared or not prepared, and the adjacent thin grid lines have no electrical conduction.
  • the conductive paste can also be directly printed and prepared on the surface of the cell according to the set pattern and spacing, and after high-temperature curing and sintering, the conductive paste is directly connected to the fine grid lines.
  • the conductive pastes of the above-mentioned several different embodiments can be used for different types of battery sheets, among which the conductive pastes of the third and fourth embodiments, especially the conductive pastes of the fourth embodiment can be used for current conventional sizes including BSF, PERC, PERL, PERT, TOPcon, etc., including single crystal and polycrystalline, need to undergo a high-temperature process above 500 degrees Celsius; in this type of battery, the melting point of the binder phase in the conductive paste is generally at 200 degrees About, so the actual sintering temperature should be above 200 degrees, and such a high temperature cannot be tolerated for heterojunction cells.
  • the conductive paste of Example 2 and Example 5 can also be used. Considering the conductivity problem, it may not be the most preferred, but it is indeed available; For the conductive pastes of Example 2 and Example 5, it is preferred to be used for low-temperature process batteries such as heterojunction batteries. The curing and sintering temperature of these two pastes will not exceed 200 degrees, so it is the best choose.
  • the conductive paste in Example 5 is used in a heterojunction battery, the conductive paste can be directly connected to the fine grid lines, and at this time no bus electrodes or only incomplete bus electrodes may be provided.
  • the bonding phase is mainly connected to the bus electrode after being melted at high temperature, so when preparing a battery sheet, it is preferably necessary to prepare a complete and continuous bus electrode; for Example 5
  • the conductive paste also includes the bonding of the thermosetting resin to the surface of the cell. Relying on the bonding effect can also provide sufficient connection tension, so at this time, the interconnection electrode can be canceled or partially Cancel it.

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Abstract

Disclosed in the present invention is a conductive paste for a photovoltaic cell. After sintering and curing, the conductive paste has a height of 50-200 um and a width of 50-1,000 um, and comprises, by mass fraction, the following components: 50%-80% of a conductive phase, 10%-50% of a binder phase, and 7-15% of a paste flux, the conductive phase being copper powder or silver powder having a particle size of 5-100 um. For the technical problem that the solder ribbons in existing photovoltaic cells limit the development of the photovoltaic cells, the present invention provides a conductive paste for a photovoltaic cell. The conductive paste can replace solder ribbons after sintering and curing, and has sufficient electrical conductivity to ensure the performance of the photovoltaic cell.

Description

一种用于光伏电池的导电浆料A kind of conductive paste for photovoltaic cells 技术领域technical field
本发明涉及光伏电池技术领域，具体涉及一种用于光伏电池的导电浆料。The invention relates to the technical field of photovoltaic cells, in particular to a conductive paste for photovoltaic cells.
背景技术Background technique
常规的太阳能电池片(solar cell)的上下两面都有电极结构，一般上电极可以吸收阳光并发电，上电极由指栅线和汇流电极组成，指栅线将光生电流传导至汇流电极，汇流电极的作用一是用于汇总指栅线上的电流、二是用于焊接互联条，因为汇流电极本身并不具备足够的导电能力；下电极有两种，一种是和上电极一样的可以吸光线并发电，这种下电极也是由指栅线和汇流电极组成，另一种传统的下电极不能吸收阳光发电，由覆盖整个背面的背电场和背面电极(也是汇流电极)组成，此背面电极主要用于焊接互联条。上下电极包括细栅线、汇流电极、背电极、背电场一般都是通过丝网印刷的方式，将纳米颗粒级别的导电浆料制备到电池片表面，然后经过高温烧结固化，烧结后的上下电极包括汇流电极高度只有10-15微米左右，烧结后的导电银浆电阻率一般是纯银电阻率的1.5-2倍，如果全部依靠汇流电极来传导光生电流的化，电池内阻和功率损害都会非常大，所以一般情况下都是在做组件时在汇流电极上焊接镀锡的铜导电带，镀锡铜带的截面积有圆形的也有扁的，镀锡铜带起到增强导电性的作用，另一方面可以实现电池片之间的串焊互联。然而镀锡铜带的厚度或高度一般都在0.1-0.3mm，尤其时经过焊接后，于电池片会形成比较大的焊接应力，在生产和后期使用过程中容易产生电池片的裂纹和虚焊，尤其时当电池片进一步减薄后，这个不利因素会更加显著。Conventional solar cells (solar cell) have electrode structures on the upper and lower sides. Generally, the upper electrode can absorb sunlight and generate electricity. The upper electrode is composed of finger grid lines and bus electrodes. The function of the first is to collect the current on the finger grid line, and the second is to weld the interconnection strip, because the bus electrode itself does not have sufficient conductivity; there are two kinds of lower electrodes, one is the same as the upper electrode, which can absorb light This kind of lower electrode is also composed of finger grid lines and bus electrodes. Another traditional lower electrode cannot absorb sunlight to generate electricity. It consists of a back electric field covering the entire back and a back electrode (also a bus electrode). This back electrode Mainly used for welding interconnection strips. The upper and lower electrodes include fine grid lines, bus electrodes, back electrodes, and back electric fields. Generally, nano-particle-level conductive paste is prepared on the surface of the cell by screen printing, and then sintered and solidified at high temperature. After sintering, the upper and lower electrodes Including the bus electrode height is only about 10-15 microns, the resistivity of the conductive silver paste after sintering is generally 1.5-2 times the resistivity of pure silver, if all the bus electrodes are used to conduct the photo-generated current, the battery internal resistance and power damage will be It is very large, so in general, tinned copper conductive strips are welded on the bus electrodes when making components. The cross-sectional area of tinned copper strips can be round or flat. Tinned copper strips can enhance conductivity. Function, on the other hand, it can realize the interconnection between battery slices by serial welding. However, the thickness or height of the tinned copper strip is generally 0.1-0.3mm, especially after welding, a relatively large welding stress will be formed on the battery sheet, and cracks and false soldering of the battery sheet are likely to occur during production and later use. , especially when the battery sheet is further thinned, this unfavorable factor will be more significant.
近年来电池片的汇流电极数量越累越多，这样的显著好处是可以减少银浆的使用量同时提高转换效率，但是随着主栅线数量的增多，焊带的宽度或直径也在迅速减少，这样才能不增加焊带的正面遮光，然而，更细的焊带又带来了其他问题，比如超细焊带的定位问题，如果定位误差太大，很容易导致焊接不良。In recent years, the number of bus electrodes on the battery sheet has become more and more, which has the obvious advantage of reducing the amount of silver paste used and improving conversion efficiency. However, with the increase in the number of busbars, the width or diameter of the solder strips is also rapidly decreasing. , so as not to increase the front shading of the ribbon, however, the thinner ribbon brings other problems, such as the positioning of the ultra-fine ribbon, if the positioning error is too large, it is easy to cause poor welding.
发明内容Contents of the invention
1、发明要解决的技术问题1. The technical problem to be solved by the invention
针对现有的光伏电池中的焊带会局限光伏电池的发展的技术问题，本发明提供了一种用于光伏电池的导电浆料，它在烧结固化后可代替焊带，且具有足够的导电能力以确保光伏电池的性能。Aiming at the technical problem that the solder ribbons in the existing photovoltaic cells limit the development of photovoltaic cells, the present invention provides a conductive paste for photovoltaic cells, which can replace the solder ribbons after sintering and solidification, and has sufficient electrical conductivity ability to ensure the performance of photovoltaic cells.
2、技术方案2. Technical solution
为解决上述问题，本发明提供的技术方案为：In order to solve the above problems, the technical solution provided by the invention is:
一种用于光伏电池的导电浆料，烧结固化后的高度为50-200um，宽度为50-1000um，按质量分数包括以下组分：导电相50％-80％，粘结相10％-50％，助焊膏7-15％，所述导电相为颗粒尺寸为5-100um的铜粉或银粉。A conductive paste for photovoltaic cells, the height after sintering and curing is 50-200um, the width is 50-1000um, including the following components by mass fraction: conductive phase 50%-80%, binder phase 10%-50 %, 7-15% of soldering paste, the conductive phase is copper powder or silver powder with a particle size of 5-100um.
可选地，所述导电相为颗粒尺寸为15-65um。Optionally, the conductive phase has a particle size of 15-65um.
可选地，所述导电相为铜粉，所述铜粉表面设有抗氧化镀层。Optionally, the conductive phase is copper powder, and an anti-oxidation coating is provided on the surface of the copper powder.
可选地，所述抗氧化镀层的厚度为0.5-5um，所述抗氧化镀层的含量占整个导电相重量的2-15％。Optionally, the thickness of the anti-oxidation coating is 0.5-5um, and the content of the anti-oxidation coating accounts for 2-15% by weight of the entire conductive phase.
可选地，所述抗氧化镀层为银、锡、镍、锡铅合金、锡铋合金、锡银铜合金中的一种或多种。Optionally, the anti-oxidation coating is one or more of silver, tin, nickel, tin-lead alloy, tin-bismuth alloy, and tin-silver-copper alloy.
可选地，所述粘结相为颗粒尺寸为5-60um的低熔点金属颗粒，所述低熔点金属颗粒为锡粉、锡铅合金粉、锡铜银合金粉、锡铋合金粉中的一种或多种。Optionally, the binder phase is low-melting metal particles with a particle size of 5-60um, and the low-melting metal particles are one of tin powder, tin-lead alloy powder, tin-copper-silver alloy powder, and tin-bismuth alloy powder one or more species.
可选地，所述粘结相为颗粒尺寸为5-35um的低熔点金属颗粒。Optionally, the binder phase is low-melting metal particles with a particle size of 5-35um.
可选地，所述助焊膏由树脂、松香、溶剂、活化剂和添加剂混合而成。Optionally, the solder paste is mixed with resin, rosin, solvent, activator and additives.
可选地，所述松香为改性松香为氢化松香、聚合松香、歧化松香中的一种或多种的混合物。Optionally, the rosin is a modified rosin that is a mixture of one or more of hydrogenated rosin, polymerized rosin, and disproportionated rosin.
可选地，所述树脂为热固性树脂，所述松香为马来酸改性松香、富马酸改性松香、丙烯酸改性松香中的一种或多种的混合物。Optionally, the resin is a thermosetting resin, and the rosin is a mixture of one or more of maleic acid modified rosin, fumaric acid modified rosin, and acrylic acid modified rosin.
可选地，所述活化剂为脂肪族一元酸、二元酸、三元酸、羟基酸、芳香酸、烯酸、氨基酸、乙酸、琥珀酸、胶酸、肥酸、草酸、水杨酸、苯甲酸、乳酸、酒石酸、柠檬酸、苹果酸、油酸、谷氨酸、甘氨酸中的一种或多种的混合物。Optionally, the activator is aliphatic monobasic acid, dibasic acid, tribasic acid, hydroxy acid, aromatic acid, alkenoic acid, amino acid, acetic acid, succinic acid, gum acid, fatty acid, oxalic acid, salicylic acid, One or more mixtures of benzoic acid, lactic acid, tartaric acid, citric acid, malic acid, oleic acid, glutamic acid, glycine.
可选地，所述溶剂为笨、甲苯、苯甲醇、乙二醇、乙醇、丁醇、丙酮、乙基苯、芳香族石脑油、松油醇、松节油、乙酸乙酯、甲醚、磷酸三甲酯、磷酸三乙酯、丙二醇单甲基醚、丁基溶纤剂、二甘醇二乙醚、甲基卡必醇、乙基卡必醇、丁集卡必醇中的一种或多种的混合物。Optionally, the solvent is benzene, toluene, benzyl alcohol, ethylene glycol, ethanol, butanol, acetone, ethylbenzene, aromatic naphtha, terpineol, turpentine, ethyl acetate, methyl ether, phosphoric acid One or more of Trimethyl Ester, Triethyl Phosphate, Propylene Glycol Monomethyl Ether, Butyl Cellosolve, Diethylene Glycol Diethyl Ether, Methyl Carbitol, Ethyl Carbitol, Dingji Carbitol mixture.
可选地，所述添加剂为触变剂、成膏剂、稳定剂、表面活性剂中的一种或多种的混合物。Optionally, the additive is a mixture of one or more of thixotropic agent, pasting agent, stabilizer and surfactant.
3、有益效果3. Beneficial effects
采用本发明提供的技术方案，与现有技术相比，具有如下有益效果：Compared with the prior art, the technical solution provided by the invention has the following beneficial effects:
(1)本用于光伏电池的导电浆料在烧结固化后具有足够的导电能力，同时具有汇总收集细栅线电流并传导所收集电流的作用，所以后续互联时不需要再在汇流电极上焊接镀锡的互联铜焊带来增强汇流电极的导电能力。(1) The conductive paste used for photovoltaic cells has sufficient conductivity after sintering and solidification, and at the same time has the function of collecting and collecting the current of the fine grid lines and conducting the collected current, so there is no need to solder on the bus electrodes in the subsequent interconnection Tin-plated interconnect braze strips enhance the conductivity of the bus electrodes.
具体实施方式Detailed ways
实施例一Embodiment one
本实施例的一种用于光伏电池的导电浆料，烧结固化后的高度为50-200um，宽度为50-1000um，按质量分数包括以下组分：导电相50％-80％，粘结相10％-50％，助焊膏7-15％，所述导电相为颗粒尺寸为5-100um的铜粉或银粉，粘结相分散在导电相颗粒之间，填补导电相颗粒之间的空隙，起到粘结的作用，使导电相颗粒能充分接触，降低互联电极的整体电阻；同时，粘结相也会包覆在导电相颗粒的外表面，起到防止氧化的保护作用，提高导电性的同时，使可靠性得到了极大的提升，本实施例中，考虑到成本因素，所述导电相优先为铜粉，所述铜粉可以为片状铜粉、球状铜粉或者是片状铜粉和球状铜粉的混合，本实施例中，所述铜粉优选为颗粒尺寸为15-65um的球形或亚球形铜粉，球形或亚球形铜粉相较于片状或树枝状铜粉，容易制备，成本低，同时比表面积小，抗氧化性要好点，同时表明镀层也更均匀，另外，烧结成的汇流电极表面也更光滑；铜粉还有片状的树枝状的，片状和树枝状铜粉表面积大，容易氧化，且不容易做金属防氧化涂层；在不考虑成本的情况下，导电相也可以采用银粉，由于银粉在高温环境下具有非常好的抗氧化性，所以银粉表面也可以不包覆其他金属材料，银粉的颗粒大小、形状、颗粒分布可以根据实际实验效果进行优化配方。选用铜粉时，也可以选用表面镀银的铜粉，此时银含量占整个导电相粉体的3-15％。A kind of conductive paste for photovoltaic cells of the present embodiment has a height of 50-200um and a width of 50-1000um after sintering and curing, and comprises the following components by mass fraction: conductive phase 50%-80%, binding phase 10%-50%, 7-15% solder paste, the conductive phase is copper powder or silver powder with a particle size of 5-100um, and the bonding phase is dispersed between the conductive phase particles to fill the gaps between the conductive phase particles , to play the role of bonding, so that the conductive phase particles can be fully contacted, and reduce the overall resistance of the interconnected electrodes; at the same time, the bonding phase will also cover the outer surface of the conductive phase particles, which plays a protective role against oxidation and improves the electrical conductivity. At the same time, the reliability has been greatly improved. In this embodiment, considering the cost factor, the conductive phase is preferably copper powder, and the copper powder can be flake copper powder, spherical copper powder or flake copper powder Shaped copper powder and spherical copper powder are mixed. In this embodiment, the copper powder is preferably spherical or subspherical copper powder with a particle size of 15-65um. Compared with flake or dendritic copper powder, spherical or subspherical copper powder Copper powder, easy to prepare, low cost, small specific surface area, better oxidation resistance, and more uniform coating, in addition, the surface of the sintered bus electrode is smoother; copper powder also has flake dendritic, flake Shaped and dendritic copper powder has a large surface area, is easy to oxidize, and is not easy to be used as a metal anti-oxidation coating; without considering the cost, silver powder can also be used as the conductive phase, because silver powder has very good oxidation resistance in high temperature environments , so the surface of the silver powder may not be coated with other metal materials, and the particle size, shape, and particle distribution of the silver powder can be optimized according to the actual experimental results. When selecting copper powder, it is also possible to select copper powder plated with silver on the surface. At this time, the silver content accounts for 3-15% of the entire conductive phase powder.
本用于光伏电池的导电浆料在烧结固化后具有足够的导电能力，同时具有汇总收集细栅线电流并传导所收集电流的作用，所以后续互联时不需要再在汇流电极上焊接镀锡的互联铜焊带来增强汇流电极的导电能力。The conductive paste used for photovoltaic cells has sufficient conductivity after sintering and solidification, and at the same time has the function of collecting and collecting the current of the fine grid lines and conducting the collected current, so there is no need to solder tinned electrodes on the bus electrodes for subsequent interconnection. The interconnect brazing strips enhance the conductivity of the bus electrodes.
作为本发明的可选方案，所述铜粉表面设有抗氧化镀层，以克服铜粉易氧化的问题，所述抗氧化镀层为银、锡、镍、锡铅合金、锡铋合金、锡银铜合金中的一种或多种，考虑到后续的烧结和粘结，优选为，所述抗氧化镀层为锡、锡铅合金、锡铋合金、锡银铜合金，所述抗氧化镀层的厚度为0.5-5um，所述抗氧化镀层的含量占整个导电相重量的2-15％，此时该抗氧化镀层也起到促进粘结固化作用。As an optional solution of the present invention, the surface of the copper powder is provided with an anti-oxidation coating to overcome the problem that the copper powder is easily oxidized, and the anti-oxidation coating is silver, tin, nickel, tin-lead alloy, tin-bismuth alloy, tin-silver One or more of copper alloys, considering subsequent sintering and bonding, preferably, the anti-oxidation coating is tin, tin-lead alloy, tin-bismuth alloy, tin-silver-copper alloy, and the thickness of the anti-oxidation coating is is 0.5-5um, and the content of the anti-oxidation coating accounts for 2-15% of the weight of the entire conductive phase. At this time, the anti-oxidation coating also plays a role in promoting bonding and curing.
作为本发明的可选方案，所述粘结相为颗粒尺寸为5-60um的低熔点金属颗粒，所述低熔点金属颗粒为锡粉、锡铅合金粉、锡铜银合金粉、锡铋合金粉中的一种或多种，上述粉末的形状一般为球形，优选的，所述粘结相为颗粒尺寸为5-35um的低熔点金属颗粒，例如5-15um和15-35um两种尺寸，小颗粒的粉末可以更好的填充导电相颗粒间的空隙，使得导电性能更好。As an optional solution of the present invention, the binder phase is a low melting point metal particle with a particle size of 5-60um, and the low melting point metal particle is tin powder, tin-lead alloy powder, tin-copper-silver alloy powder, tin-bismuth alloy powder One or more of powders, the shape of the above-mentioned powder is generally spherical, preferably, the binder phase is a low melting point metal particle with a particle size of 5-35um, such as two sizes of 5-15um and 15-35um, Small particle powder can better fill the gaps between the conductive phase particles, making the conductivity better.
作为本发明的可选方案，所述助焊膏由树脂、松香、溶剂、活化剂和添加剂混合而成，助焊膏能够促粘结相充分均匀地包裹导电相、使导电相均匀地分散在其中、同时使浆料本体的化学和物理性能保持稳定活化剂在活性点以上在溶剂中能够电离出游离的H+离子，与金属 材料表面的氧化物反应，达到去除氧化层、降低金属表面张力的目的，溶剂主要用于提供一种电离环境，所述添加剂为触变剂、成膏剂、稳定剂、表面活性剂中的一种或多种的混合物，成膏剂主要作用是增强导电膏整体保持粘稠膏状的能力，可以为聚乙二醇2000、聚乙二醇4000、聚乙二醇6000等，稳定剂的作用是增强导电膏粘稠状的稳定型，可以为石蜡；表面活性剂和触变剂可以选用常规的配方材料，比如辛基酚聚氧乙烯醚、壬基酚聚氧乙烯醚、氢化蓖麻油、酰胺化合物等。As an optional solution of the present invention, the solder paste is mixed by resin, rosin, solvent, activator and additives, and the solder paste can promote the bonding phase to fully and uniformly wrap the conductive phase, so that the conductive phase is evenly dispersed in the Among them, at the same time, the chemical and physical properties of the slurry body are kept stable. The activator can ionize free H+ ions in the solvent above the active point, and react with the oxide on the surface of the metal material to remove the oxide layer and reduce the surface tension of the metal. Purpose, the solvent is mainly used to provide an ionized environment, and the additive is a mixture of one or more of thixotropic agent, paste forming agent, stabilizer, and surfactant. The main function of the paste forming agent is to enhance the overall viscosity of the conductive paste. The ability of thick paste can be polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 6000, etc. The role of the stabilizer is to enhance the stability of the conductive paste, which can be paraffin; surfactant and The thixotropic agent can be selected from conventional formulation materials, such as octylphenol ethoxylates, nonylphenol ethoxylates, hydrogenated castor oil, amide compounds, etc.
作为本发明的可选方案，所述松香可以为改性松香为氢化松香、聚合松香、歧化松香中的一种或多种的混合物，若所述树脂为热固性树脂，则所述松香为马来酸改性松香、富马酸改性松香、丙烯酸改性松香中的一种或多种的混合物，马来酸改性松香、富马酸改性松香、丙烯酸改性松香中含有对环氧树脂为反应性的官能团，能够与热固性树脂反应，提高助剂和高温后互联电极的物理化学温度性。As an alternative of the present invention, the rosin can be a modified rosin that is a mixture of one or more of hydrogenated rosin, polymerized rosin, and disproportionated rosin. If the resin is a thermosetting resin, the rosin is maleic rosin. Acid modified rosin, fumaric acid modified rosin, acrylic acid modified rosin or a mixture of one or more, maleic acid modified rosin, fumaric acid modified rosin, acrylic acid modified rosin contain epoxy resin It is a reactive functional group that can react with thermosetting resins to improve the physical and chemical temperature properties of additives and interconnect electrodes after high temperature.
作为本发明的可选方案，所述活化剂为脂肪族一元酸、二元酸、三元酸、羟基酸、芳香酸、烯酸、氨基酸、乙酸、琥珀酸、胶酸、肥酸、草酸、水杨酸、苯甲酸、乳酸、酒石酸、柠檬酸、苹果酸、油酸、谷氨酸、甘氨酸中的一种或多种的混合物，优选地，选择其中两种物质以质量1:1的配比混合后的混合效果最好。As an optional solution of the present invention, the activator is aliphatic monobasic acid, dibasic acid, tribasic acid, hydroxy acid, aromatic acid, alkenoic acid, amino acid, acetic acid, succinic acid, gum acid, fatty acid, oxalic acid, A mixture of one or more of salicylic acid, benzoic acid, lactic acid, tartaric acid, citric acid, malic acid, oleic acid, glutamic acid, and glycine. Preferably, two substances are selected in a 1:1 ratio It works best when mixed than mixed.
作为本发明的可选方案，所述溶剂为笨、甲苯、苯甲醇、乙二醇、乙醇、丁醇、丙酮、乙基苯、芳香族石脑油、松油醇、松节油、乙酸乙酯、甲醚、磷酸三甲酯、磷酸三乙酯、丙二醇单甲基醚、丁基溶纤剂、二甘醇二乙醚、甲基卡必醇、乙基卡必醇、丁集卡必醇中的一种或多种的混合物，以提供一种电离环境。As an optional solution of the present invention, the solvent is benzene, toluene, benzyl alcohol, ethylene glycol, ethanol, butanol, acetone, ethylbenzene, aromatic naphtha, terpineol, turpentine, ethyl acetate, One of Methyl Ether, Trimethyl Phosphate, Triethyl Phosphate, Propylene Glycol Monomethyl Ether, Butyl Cellosolve, Diethylene Glycol Diethyl Ether, Methyl Carbitol, Ethyl Carbitol, Dingji Carbitol or a mixture of several to provide an ionizing environment.
实施例二Embodiment two
本实施例的一种用于光伏电池的导电浆料，导电相占整个导电浆料重量的60-80％，采用锡铋包覆的铜粉或镀锡铜粉，铜粉为球形，锡铋或锡涂层占整个导电相重量的10-15％，铜粉颗粒平均尺寸为20-60um；粘结相占整个导电浆料重量的10-20％，为锡铋合金粉，其熔点为140度；锡铋合金粉颗粒为球形或椭球形或其他形状，颗粒平均尺寸为10-40um，具体分布为15-38um；助焊剂占整个导电浆料重量的7-13％；在整个助焊剂中树脂(松香)占30-50％，溶剂占40-60％，活化剂占0.5-3％，其他添加剂占1-5％；按上述配方经均匀混合而成，保存于3-10度环境下。近年来，异质结电池技术发展迅速，由于异质结电池对与温度有严格的要求，一般要求工艺温度不能超过200摄氏度，所以这一类导电浆料的粘结相通常选用熔点更低的锡铋合金，最低熔点可以达到138摄氏度。A kind of conductive paste for photovoltaic cells of the present embodiment, the conductive phase accounts for 60-80% of the whole conductive paste weight, adopts tin-bismuth-coated copper powder or tin-plated copper powder, copper powder is spherical, tin-bismuth Or the tin coating accounts for 10-15% of the weight of the entire conductive phase, and the average size of the copper powder particles is 20-60um; the binder phase accounts for 10-20% of the weight of the entire conductive paste, which is tin-bismuth alloy powder with a melting point of 140 degree; tin-bismuth alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-40um, and the specific distribution is 15-38um; the flux accounts for 7-13% of the weight of the entire conductive paste; in the entire flux Resin (rosin) accounts for 30-50%, solvent accounts for 40-60%, activator accounts for 0.5-3%, and other additives account for 1-5%. According to the above formula, it is evenly mixed and stored at 3-10 degrees. . In recent years, heterojunction battery technology has developed rapidly. Since heterojunction batteries have strict requirements on temperature and temperature, generally the process temperature should not exceed 200 degrees Celsius. Therefore, the bonding phase of this type of conductive paste is usually selected with a lower melting point. Tin-bismuth alloy, the lowest melting point can reach 138 degrees Celsius.
实施例三Embodiment Three
本实施例的一种用于光伏电池的导电浆料，导电相占整个导电浆料重量的60-80％，采用 镀锡铜粉，铜粉为球形，镀锡层占整个导电相重量的5-15％，铜粉颗粒平均尺寸为20-60um；粘结相占整个导电浆料重量的10％-20，为无铅的锡合金粉，可以为锡银、锡铜、锡银铜等合金粉，颗粒平均尺寸为10-38um，具体分布为15-35um；助焊剂占整个导电浆料重量的7-13％；在整个助焊剂中树脂(松香)占30-50％，溶剂占40-60％，活化剂占0.5-3％，其他添加剂占1-5％；按上述配方经均匀混合而成，保存于3-10度环境下。该类导电浆料的粘结相不含铅，其熔化温度铋锡铅的高，一般固化烧结温度峰值在230-280之间，由于不含铅，可以用于对于无铅化有较高要求的产品上。A kind of conductive paste for photovoltaic cell of the present embodiment, conductive phase accounts for 60-80% of whole conductive paste weight, adopts tin-plated copper powder, and copper powder is spherical, and tin-plated layer accounts for 5% of whole conductive phase weight. -15%, the average size of copper powder particles is 20-60um; the binder phase accounts for 10%-20% of the weight of the entire conductive paste, which is lead-free tin alloy powder, which can be tin-silver, tin-copper, tin-silver-copper and other alloys powder, the average particle size is 10-38um, and the specific distribution is 15-35um; the flux accounts for 7-13% of the weight of the entire conductive paste; the resin (rosin) accounts for 30-50% in the entire flux, and the solvent accounts for 40- 60%, activator accounts for 0.5-3%, other additives account for 1-5%. According to the above formula, it is evenly mixed and stored at 3-10 degrees. The bonding phase of this type of conductive paste does not contain lead, and its melting temperature is higher than that of bismuth, tin and lead. Generally, the peak value of solidification and sintering temperature is between 230-280. Since it does not contain lead, it can be used for higher requirements for lead-free on the product.
实施例四Embodiment Four
本实施例的一种用于光伏电池的导电浆料，导电相占整个导电浆料重量的60-80％，采用镀锡铜粉，铜粉为球形，镀锡层占整个导电相重量的5-15％，铜粉颗粒平均尺寸为20-60um；粘结相占整个导电浆料重量的10％-20，为锡铅合金粉，其中锡铅合金中的锡铅比例为63:37，锡铅合金粉颗粒为球形或椭球形或其他形状，颗粒平均尺寸为10-38um，具体分布为15-35um；助焊剂占比7-13％；在整个助焊剂中树脂(松香)占30-50％，溶剂占40-60％，活化剂占0.5-3％，其他添加剂占1-5％；按上述配方经均匀混合而成，保存于3-10度环境下。该类导电浆料的固化烧结温度峰值一般在200-250度，主要用于可以进行高温烧结的常规电池片的金属化增强。A kind of conductive paste for photovoltaic cell of the present embodiment, conductive phase accounts for 60-80% of whole conductive paste weight, adopts tin-plated copper powder, and copper powder is spherical, and tin-plated layer accounts for 5% of whole conductive phase weight. -15%, the average size of copper powder particles is 20-60um; the binder phase accounts for 10% of the weight of the entire conductive paste -20, which is tin-lead alloy powder, wherein the ratio of tin-lead in tin-lead alloy is 63:37, tin Lead alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-38um, and the specific distribution is 15-35um; flux accounts for 7-13%; resin (rosin) accounts for 30-50% in the entire flux %, 40-60% solvent, 0.5-3% activator, and 1-5% other additives; according to the above formula, it is evenly mixed and stored in an environment of 3-10 degrees. The peak curing and sintering temperature of this type of conductive paste is generally 200-250 degrees, and it is mainly used for metallization enhancement of conventional battery sheets that can be sintered at high temperatures.
实施例五Embodiment five
本实施例的一种用于光伏电池的导电浆料，导电相占整个导电浆料重量的70-80％，采用锡铋包覆的铜粉，铜粉为球形，锡铅涂层占整个粉体重量比例为5-10％，铜粉颗粒平均尺寸为10-60微米；粘结相占整个导电浆料重量的10％，为锡铋合金粉，其中锡铋合金中的锡铅比例为60:40，锡铋合金粉颗粒为球形或椭球形或其他形状，颗粒平均尺寸为10-50微米，具体分布为5-30微米；有机粘结相占比3-5％，为丙烯酸树脂或环氧树脂等热固性树脂；助焊剂占比10％，其中树脂(松香)占3-5％，溶剂占2-5％，活化剂占0.5-1％，表面活性剂占0.5-1％，其他添加剂占0.5-1％；按上述配方经均匀混合而成，保存于3-10度环境下。对于异质结电池，由于不能进行高温烧结，其表面的细栅线都是采用的低温固化银浆来制备，这样，在这一类导电浆料中也添加了低温固化的热固性树脂，通过树脂的粘结作用可以将固化的浆料本体固定在电池片表面，同时在浆料本体内部，又可以通过锡铋合金的粘结作用增强金属颗粒之间的导电型。A kind of conductive paste for photovoltaic cells of this embodiment, the conductive phase accounts for 70-80% of the weight of the entire conductive paste, adopts copper powder coated with tin and bismuth, the copper powder is spherical, and the tin-lead coating accounts for the entire powder. The proportion of body weight is 5-10%, and the average size of copper powder particles is 10-60 microns; the binder phase accounts for 10% of the weight of the entire conductive paste, which is tin-bismuth alloy powder, and the tin-lead ratio in the tin-bismuth alloy is 60% :40, tin-bismuth alloy powder particles are spherical or ellipsoidal or other shapes, the average particle size is 10-50 microns, and the specific distribution is 5-30 microns; the organic binder phase accounts for 3-5%, which is acrylic resin or ring Oxygen resin and other thermosetting resins; flux accounts for 10%, of which resin (rosin) accounts for 3-5%, solvent accounts for 2-5%, activator accounts for 0.5-1%, surfactant accounts for 0.5-1%, other additives It accounts for 0.5-1%. It is prepared by uniform mixing according to the above formula and stored in an environment of 3-10 degrees. For heterojunction batteries, since high-temperature sintering cannot be performed, the fine grid lines on the surface are prepared by using low-temperature curing silver paste. In this way, low-temperature curing thermosetting resin is also added to this type of conductive paste. Through the resin The bonding effect of the solidified slurry body can be fixed on the surface of the battery sheet, and at the same time inside the slurry body, the conductivity between the metal particles can be enhanced through the bonding effect of the tin-bismuth alloy.
本发明导电浆料主要用于对电池片上的汇流电极进行导电性增强或替代汇流电极直接与细栅线相导通。在第一种情况下，电池片表面已经制备好了细栅线和汇流电极，细栅线与汇流电极导通，此时，通过印刷或、点胶喷射的方式将该导电浆料制备于汇流电极上方，经过 固化烧结后，导电浆料中的有机物全部挥发或烧结掉，导电浆料本身也与汇流电极通过粘结相形成电学导通，此时导电浆料本体通过汇流电极间接与细栅线相连，从而将细栅线上的电流全部收集汇总在第二种情况下，电池片表面制备有完整的细栅线，但是汇流电极没有完整制备或没有制备，相邻细栅线没有电学导通，此时，也可以将本导电浆料按照设定好的图形和间距直接印刷制备到电池片表面，通过高温固化烧结后，使导电浆料直接与细栅线相导通连接。The conductive paste of the present invention is mainly used to enhance the conductivity of the bus electrodes on the battery sheet or replace the bus electrodes to conduct directly with the fine grid lines. In the first case, thin grid lines and bus electrodes have been prepared on the surface of the cell, and the thin grid lines are connected to the bus electrodes. At this time, the conductive paste is prepared on the bus electrodes by printing or dispensing Above the electrode, after curing and sintering, all the organic matter in the conductive paste is volatilized or sintered, and the conductive paste itself forms electrical conduction with the bus electrode through the bonding phase. At this time, the body of the conductive paste indirectly connects with the fine grid through the bus electrode In the second case, a complete thin grid line is prepared on the surface of the cell, but the bus electrode is not completely prepared or not prepared, and the adjacent thin grid lines have no electrical conduction. Generally, at this time, the conductive paste can also be directly printed and prepared on the surface of the cell according to the set pattern and spacing, and after high-temperature curing and sintering, the conductive paste is directly connected to the fine grid lines.
上述几种不同实施例的导电浆料可以用于不同类型的电池片，其中实施例三和实施例四的导电浆料尤其是实施例四的导电浆料可以用于目前常规的各种尺寸包含单晶多晶在内的BSF、PERC、PERL、PERT、TOPcon等需要经过500摄氏度以上高温工艺的各种电池；在这类电池片中，由于导电浆料中粘结相的熔点普遍在200度左右，所以实际的烧结温度要在200度以上，对于异质结电池无法容忍这么高的温度，同时，在此温度下，导电浆料中的所有有机物都会挥发或烧结掉；值得说明的是，在此类电池片中，实施例二和实施例五的导电浆料尤其是实施例二的导电浆也可以使用的，考虑到导电率问题，可能并不是最优选，但确实是可以用的；对实施例二和实施例五的导电浆料，优选地是用于异质结电池这类低温工艺的电池，这两种浆料的固化烧结温度都不会超过200度，所以是最佳的选择。在实施例五的导电浆料使用在异质结电池时，导电浆料可以直接与细栅线连接，此时可以不设置汇流电极或只设置不完整的汇流电极。The conductive pastes of the above-mentioned several different embodiments can be used for different types of battery sheets, among which the conductive pastes of the third and fourth embodiments, especially the conductive pastes of the fourth embodiment can be used for current conventional sizes including BSF, PERC, PERL, PERT, TOPcon, etc., including single crystal and polycrystalline, need to undergo a high-temperature process above 500 degrees Celsius; in this type of battery, the melting point of the binder phase in the conductive paste is generally at 200 degrees About, so the actual sintering temperature should be above 200 degrees, and such a high temperature cannot be tolerated for heterojunction cells. At the same time, at this temperature, all organic matter in the conductive paste will be volatilized or sintered; it is worth noting that, In this type of battery sheet, the conductive paste of Example 2 and Example 5, especially the conductive paste of Example 2, can also be used. Considering the conductivity problem, it may not be the most preferred, but it is indeed available; For the conductive pastes of Example 2 and Example 5, it is preferred to be used for low-temperature process batteries such as heterojunction batteries. The curing and sintering temperature of these two pastes will not exceed 200 degrees, so it is the best choose. When the conductive paste in Example 5 is used in a heterojunction battery, the conductive paste can be directly connected to the fine grid lines, and at this time no bus electrodes or only incomplete bus electrodes may be provided.
对于实施例二、三、四的导电浆料，主要依靠粘结相在高温下熔化后与汇流电极相连接，所以在制备电池片时，优选地需要制备完整连续的汇流电极；对于实施例五的导电浆料，除了金属粘结相的连接，也包括了热固性树脂对电池片表面的粘接，依靠粘接作用也可以提供足够的连接拉力，所以此时，互联电极就可以取消掉或部分取消掉。For the conductive pastes of Examples 2, 3, and 4, the bonding phase is mainly connected to the bus electrode after being melted at high temperature, so when preparing a battery sheet, it is preferably necessary to prepare a complete and continuous bus electrode; for Example 5 In addition to the connection of the metal bonding phase, the conductive paste also includes the bonding of the thermosetting resin to the surface of the cell. Relying on the bonding effect can also provide sufficient connection tension, so at this time, the interconnection electrode can be canceled or partially Cancel it.
以上示意性的对本发明及其实施方式进行了描述，该描述没有限制性，附图中所示的也只是本发明的实施方式之一，实际的结构并不局限于此。所以，如果本领域的普通技术人员受其启示，在不脱离本发明创造宗旨的情况下，不经创造性的设计出与该技术方案相似的结构方式及实施例，均应属于本发明的保护范围。The above schematically describes the present invention and its implementation, which is not restrictive, and what is shown in the drawings is only one of the implementations of the present invention, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the inventive concept of the present invention, without creatively designing a structural mode and embodiment similar to the technical solution, it shall all belong to the protection scope of the present invention .

Claims (13)

  1. 一种用于光伏电池的导电浆料，其特征在于：烧结固化后的高度为50-200um，宽度为50-1000um，按质量分数包括以下组分：导电相50％-80％，粘结相10％-50％，助焊膏7-15％，所述导电相为颗粒尺寸为5-100um的铜粉或银粉。A conductive paste for photovoltaic cells, characterized in that: the height after sintering and curing is 50-200um, the width is 50-1000um, and comprises the following components by mass fraction: conductive phase 50%-80%, binder phase 10%-50%, solder paste 7-15%, the conductive phase is copper powder or silver powder with particle size of 5-100um.
  2. 根据权利要求1所述的一种用于光伏电池的导电浆料，其特征在于：所述导电相为颗粒尺寸为15-65um。A conductive paste for photovoltaic cells according to claim 1, characterized in that: the conductive phase has a particle size of 15-65um.
  3. 根据权利要求1所述的一种用于光伏电池的导电浆料，其特征在于：所述导电相为铜粉，所述铜粉表面设有抗氧化镀层。A conductive paste for photovoltaic cells according to claim 1, characterized in that: the conductive phase is copper powder, and the surface of the copper powder is provided with an anti-oxidation coating.
  4. 根据权利要求3所述的一种用于光伏电池的导电浆料，其特征在于：所述抗氧化镀层的厚度为0.5-5um，所述抗氧化镀层的含量占整个导电相重量的2-15％。A conductive paste for photovoltaic cells according to claim 3, characterized in that: the thickness of the anti-oxidation coating is 0.5-5um, and the content of the anti-oxidation coating accounts for 2-15% of the weight of the entire conductive phase. %.
  5. 根据权利要求4所述的一种用于光伏电池的导电浆料，其特征在于：所述抗氧化镀层为银、锡、镍、锡铅合金、锡铋合金、锡银铜合金中的一种或多种。A conductive paste for photovoltaic cells according to claim 4, wherein the anti-oxidation coating is one of silver, tin, nickel, tin-lead alloy, tin-bismuth alloy, and tin-silver-copper alloy or more.
  6. 根据权利要求1所述的一种用于光伏电池的导电浆料，其特征在于：所述粘结相为颗粒尺寸为5-60um的低熔点金属颗粒，所述低熔点金属颗粒为锡粉、锡铅合金粉、锡铜银合金粉、锡铋合金粉中的一种或多种。A kind of conductive paste for photovoltaic cells according to claim 1, characterized in that: the binder phase is a low-melting-point metal particle with a particle size of 5-60um, and the low-melting-point metal particle is tin powder, One or more of tin-lead alloy powder, tin-copper-silver alloy powder, and tin-bismuth alloy powder.
  7. 根据权利要求6所述的一种用于光伏电池的导电浆料，其特征在于：所述粘结相为颗粒尺寸为5-35um的低熔点金属颗粒。The conductive paste for photovoltaic cells according to claim 6, characterized in that: the binder phase is a low-melting-point metal particle with a particle size of 5-35um.
  8. 根据权利要求1所述的一种用于光伏电池的导电浆料，其特征在于：所述助焊膏由树脂、松香、溶剂、活化剂和添加剂混合而成。A conductive paste for photovoltaic cells according to claim 1, characterized in that: said flux paste is mixed with resin, rosin, solvent, activator and additives.
  9. 根据权利要求8所述的一种用于光伏电池的导电浆料，其特征在于：所述松香为改性松香为氢化松香、聚合松香、歧化松香中的一种或多种的混合物。A conductive paste for photovoltaic cells according to claim 8, characterized in that: the modified rosin is a mixture of one or more of hydrogenated rosin, polymerized rosin, and disproportionated rosin.
  10. 根据权利要求8所述的一种用于光伏电池的导电浆料，其特征在于：所述树脂为热固性树脂，所述松香为马来酸改性松香、富马酸改性松香、丙烯酸改性松香中的一种或多种的混合物。A kind of conductive paste for photovoltaic cells according to claim 8, characterized in that: the resin is a thermosetting resin, and the rosin is maleic acid modified rosin, fumaric acid modified rosin, acrylic acid modified rosin A mixture of one or more types of rosin.
  11. 根据权利要求8所述的一种用于光伏电池的导电浆料，其特征在于：所述活化剂为脂肪族一元酸、二元酸、三元酸、羟基酸、芳香酸、烯酸、氨基酸、乙酸、琥珀酸、胶酸、肥酸、草酸、水杨酸、苯甲酸、乳酸、酒石酸、柠檬酸、苹果酸、油酸、谷氨酸、甘氨酸中的一种或多种的混合物。A conductive paste for photovoltaic cells according to claim 8, wherein the activator is an aliphatic monobasic acid, a dibasic acid, a tribasic acid, a hydroxy acid, an aromatic acid, an alkenoic acid, an amino acid , acetic acid, succinic acid, gum acid, fatty acid, oxalic acid, salicylic acid, benzoic acid, lactic acid, tartaric acid, citric acid, malic acid, oleic acid, glutamic acid, glycine in one or more of the mixture.
  12. 根据权利要求8所述的一种用于光伏电池的导电浆料，其特征在于：所述溶剂为笨、甲苯、苯甲醇、乙二醇、乙醇、丁醇、丙酮、乙基苯、芳香族石脑油、松油醇、松节油、乙酸乙酯、甲醚、磷酸三甲酯、磷酸三乙酯、丙二醇单甲基醚、丁基溶纤剂、二甘醇二乙醚、甲基卡必醇、乙基卡必醇、丁集卡必醇中的一种或多种的混合物。A kind of conductive paste for photovoltaic cells according to claim 8, characterized in that: the solvent is stupid, toluene, benzyl alcohol, ethylene glycol, ethanol, butanol, acetone, ethylbenzene, aromatic Naphtha, terpineol, turpentine, ethyl acetate, methyl ether, trimethyl phosphate, triethyl phosphate, propylene glycol monomethyl ether, butyl cellosolve, diethylene glycol diethyl ether, methyl carbitol, ethyl A mixture of one or more of base carbitol and butadicarbitol.
  13. 根据权利要求8所述的一种用于光伏电池的导电浆料，其特征在于：所述添加剂为触变剂、成膏剂、稳定剂、表面活性剂中的一种或多种的混合物。A conductive paste for photovoltaic cells according to claim 8, characterized in that: the additive is a mixture of one or more of thixotropic agent, pasting agent, stabilizer, and surfactant.
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