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CN-122007716-A - Preparation method of photovoltaic solder strip alloy solder

CN122007716ACN 122007716 ACN122007716 ACN 122007716ACN-122007716-A

Abstract

The invention relates to the technical field of tin-based composite solder preparation, in particular to a preparation method of photovoltaic solder strip alloy solder, which comprises 2.8-3.2% of silver, 0.45-0.55% of copper, 0.03-0.1% of nickel-coated nano aluminum oxide, 0.005-0.02% of germanium and the balance of tin, wherein after tin blocks are melted, copper particles and silver particles are added, heating is carried out until the alloy is completely melted, after cooling, sn-Ge master alloy is added, nickel-coated nano aluminum oxide powder is slowly added into a melt in a nitrogen blowing and ultrasonic coupling stirring mode, heating and refining are carried out, cooling and standing are carried out, alloy solder melt is obtained, copper strips are prepared into photovoltaic solder strips in a hot dipping mode, and the initial shear strength of solder welding spots is improved through coordination of the nickel-coated nano aluminum oxide and germanium, and the welding spots can maintain a high strength retention rate under cold and hot circulation and long-term high-temperature environment service, so that the problem of rapid attenuation of the shear performance of welding spots under severe environment is solved.

Inventors

  • DING CHENGJIN
  • CAO XIAOLEI

Assignees

  • 江苏盐昇光电新材料有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The preparation method of the photovoltaic solder strip alloy solder is characterized in that the alloy solder comprises the following components in parts by weight of 2.8-3.2% of silver, 0.45-0.55% of copper, 0.03-0.1% of nickel-coated nano aluminum oxide, 0.005-0.02% of germanium and the balance of tin; The preparation process of the alloy solder comprises the following steps: preparing a suspension, namely dissolving nickel nitrate hexahydrate in a mixed solvent prepared from absolute ethyl alcohol and deionized water, adding a dispersing agent, uniformly stirring, adding dried and activated nano aluminum oxide, and performing ultrasonic dispersion for 20-40min to form a uniform suspension; Preparing nickel-coated nano alumina powder, namely adjusting the pH of a suspension to 8.5-9.5, stirring for 2 hours at 50-60 ℃, then transferring the suspension into a high-pressure reaction kettle, adding a reducing agent, preserving heat for 3-4 hours at 160-180 ℃ under the protection atmosphere of N 2 , cooling, centrifuging, washing, vacuum drying for 10-12 hours at 70-80 ℃, grinding and sieving to obtain the nickel-coated nano alumina powder; The method comprises the steps of adding high-purity tin blocks into a graphite crucible, heating to 260-280 ℃ under N 2 protective atmosphere until the tin blocks are completely melted, adding copper particles and silver particles, heating to 300-310 ℃, stirring for 10-15 min until the alloy is completely melted, cooling the melt to 280-290 ℃, adding Sn-Ge master alloy, stirring at 200rpm for 5-10 min, slowly adding nickel-coated nano alumina powder into the melt by adopting a nitrogen blowing and ultrasonic coupling stirring mode, heating the melt to 310-320 ℃ and refining for 5-10 min, cooling to 290-300 ℃, skimming surface scum and standing for 5-10 min to obtain alloy solder melt.
  2. 2. The method for preparing the photovoltaic solder strip alloy solder according to claim 1, wherein the mixed solvent is prepared from absolute ethyl alcohol and deionized water according to a volume ratio of (4-6): 1, the concentration of nickel nitrate hexahydrate is 20-40 g/L, and the mass ratio of the nickel nitrate hexahydrate to nano-alumina is 5 (4-6).
  3. 3. The method for preparing the photovoltaic solder strip alloy solder according to claim 1, wherein the dispersing agent is one of PVP-K30, sodium polyacrylate and PVA, and the adding concentration of the dispersing agent is 0.3-1.2 g/L.
  4. 4. The method for preparing photovoltaic solder strip alloy solder according to claim 1, wherein the reducing agent is one of glycol, glucose and ascorbic acid.
  5. 5. The method of manufacturing a photovoltaic solder strip alloy solder according to claim 4, wherein when the reducing agent is ethylene glycol, the reducing agent is added in an amount equal to the volume of the suspension.
  6. 6. The method for preparing photovoltaic solder strip alloy solder according to claim 4, wherein the concentration of the reducing agent is 10-40 g/L.
  7. 7. The method for preparing the photovoltaic solder strip alloy solder according to claim 1, wherein the preparation process of the Sn-Ge master alloy is as follows: And (3) putting the high-purity tin blocks and germanium particles into a graphite crucible, heating to 330-370 ℃ for melting, stirring at 300-400 rpm for 8-15min under the protection atmosphere of N 2 , fully dissolving Ge into the Sn melt, pouring, cooling, and crushing to obtain the Sn-Ge master alloy.
  8. 8. The method of manufacturing a photovoltaic solder strip alloy solder according to claim 7, wherein the Sn-Ge master alloy comprises 85-95 parts by weight of Sn and 5-15 parts by weight of Ge.
  9. 9. The method for preparing the photovoltaic solder strip alloy solder according to claim 1, wherein the drying and activating condition of the nano aluminum oxide is that the nano aluminum oxide is dried and activated for 1.5-3 hours at 100-120 ℃.
  10. 10. The preparation method of the photovoltaic solder strip alloy solder is characterized in that the flow rate of nitrogen blowing is 0.5-1 g/min, the ultrasonic frequency is 20-30 kHz, the ultrasonic power is 300-500W, and the stirring speed is 400-500 rpm.

Description

Preparation method of photovoltaic solder strip alloy solder Technical Field The invention relates to the technical field of tin-based composite solder preparation, in particular to a preparation method of photovoltaic solder strip alloy solder. Background The photovoltaic solder strip, also called tin-plated copper strip or tin-plated copper strip, is a core solder material for connecting the battery pieces of the photovoltaic module, and is mainly used for current transmission and collection. The device is divided into an interconnection welding strip and a confluence welding strip according to purposes, and the material consists of a copper base material and a tin alloy coating. At present, two main ways of copper strip tinning are hot dip tinning, namely, continuously feeding a copper strip into molten tin alloy liquid, forming a plating layer through physical infiltration and interface metallurgical bonding, and electroplating, namely, utilizing an electrolytic deposition mode to plate tin on the surface of the copper strip. The traditional SAC (tin-silver-copper) solder is a mainstream solder system of a photovoltaic solder strip, but the photovoltaic module paved in desert areas and northeast areas is easy to rapidly increase in IMC at a welding spot interface due to long-term high-temperature aging service environment and high-low-temperature circulating environment, so that interface embrittlement is caused, mechanical properties are accelerated and attenuated, and high stability and long service life of the photovoltaic module under severe environments are difficult to meet. In the prior art, an attempt is made to improve the solder structure and inhibit the IMC growth by independently adding nano alumina particles, specifically, sn3.0Ag0.5Cu (SAC) is taken as a matrix, al 2O3 nano particles are taken as a reinforcing phase, and SAC-XAl 2O3 composite solder is prepared by a powder metallurgy method, and research shows that after ball milling, the Al 2O3 particles are embedded into the surface of SAC welding powder to form tight combination with the welding powder, and the addition of the Al 2O3 nano particles into the composite solder can refine the solder structure and inhibit the IMC growth of a welding spot interface, and the refining effect and the inhibiting effect are more remarkable along with the increase of the Al 2O3 nano particles. However, the Al 2O3 nano particles have high surface energy, are easy to agglomerate at high temperature to cause uneven dispersion, and the Al 2O3 nano particles are typical ceramic materials, have weak interfacial reaction activity with tin alloy melt to cause poor wettability, and further cause lower shearing strength and insufficient reliability of welding spots. The nano-alumina alone cannot stabilize the interface structure from the metallurgical layer, and the improvement of the shear strength retention rate after high-temperature aging and cold-hot circulation is limited. The nickel element or the germanium element is added independently, so that the initial shear strength and the long-term service shear strength retention rate of the welding spot are difficult to synchronously improve, and the technical problem that the welding spot has rapid attenuation of the shear performance and poor thermal fatigue resistance under a severe environment can not be solved. Disclosure of Invention The invention provides a preparation method of photovoltaic solder strip alloy solder, which comprises the following components, by weight, 2.8-3.2% of silver, 0.45-0.55% of copper, 0.03-0.1% of nickel-coated nano aluminum oxide, 0.005-0.02% of germanium and the balance of tin, wherein the preparation process of the alloy solder comprises the steps of preparing suspension, dissolving nickel nitrate hexahydrate in a mixed solvent prepared by absolute ethyl alcohol and deionized water, adding a dispersing agent, stirring uniformly, adding dried and activated nano aluminum oxide, and performing ultrasonic dispersion for 20-40min to form uniform suspension. The preparation method of the nickel-coated nano alumina powder comprises the steps of adjusting pH of a suspension to 8.5-9.5, stirring for 2 hours at 50-60 ℃ to enable nickel ions to be uniformly deposited and coated on the surfaces of alumina particles in a nickel hydroxide mode, then transferring the suspension into a high-pressure reaction kettle, adding a reducing agent, preserving heat for 3-4 hours at 160-180 ℃ under the protection atmosphere of N2, reducing nickel hydroxide into metallic nickel, cooling, centrifuging at 6000-10000 rpm for 8-15 minutes, alternately washing for 3 times by using absolute ethyl alcohol and deionized water, drying in vacuum for 10-12 hours at 70-80 ℃, and grinding through a 150-300 mesh sieve to obtain the nickel-coated nano alumina powder. The method comprises the steps of adding high-purity tin blocks into a graphite crucible, heating to 260-280 ℃ under the protection of N2 until the