Lead-Free Soldering Alloys for Solar Cell Interconnection

A low-temperature photovoltaic solder alloy for series welding of PERC, TOPcon, and HJT solar cells. The solder alloy combines a low melting point with high strength, enabling reliable welding of solar cells with thinned silicon wafers. The alloy composition includes Sb, Ni, Ge, In, and Co elements that enhance tensile strength and peeling force through solid solution strengthening and dispersion strengthening. The solder alloy is produced through a hot-dip coating process on copper substrates, providing a simple and cost-effective solution for series welding applications.

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Low-temperature lead-free solder for photovoltaic cells that eliminates thermal expansion issues while maintaining environmental sustainability. The solder has a low melting point and coefficient of thermal expansion, enabling precise assembly of ultra-thin photovoltaic cells. The solder is prepared through a novel coating process that enhances its performance characteristics while maintaining environmental compliance.

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A lead-free solder ribbon for photovoltaic cells with reduced melting point and improved thermal expansion properties. The ribbon comprises a base layer with a lead-free solder layer, where the solder layer is applied to the base layer surface. This composition enables lower melting point soldering at elevated temperatures (up to 200°C) while maintaining excellent thermal expansion properties compared to traditional lead-based soldering. The lead-free solder layer ensures reliable bonding in ultra-thin photovoltaic cell applications, while the base layer provides a stable substrate surface for cell assembly.

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Sn-Ag-Cu-Bi lead-free solder alloy for electronic packaging applications, comprising a composition of 0.5-1.0 wt.% Bi, with the remainder being Sn-3.0Ag-0.5Cu. The alloy is prepared through a two-step process: smelting and casting of the bulk alloy, followed by solidification molding into a solder alloy. This composition provides improved electromigration resistance compared to traditional Sn-3.0Ag-0.5Cu solder while maintaining the original low melting point.

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Lead-free and antimony-free solder alloys, solder balls, and solder joints with improved mechanical strength and thermal cycle resistance, achieved through a novel composition that balances the constituent elements. The solder alloy composition of Ag: 3.5% by mass, Cu: 0.8% by mass, Bi: 2.0% by mass, Ni: 0.05% by mass, Ge: 0.003% by mass, and a balance of Sn was prepared. This composition achieves a melting point near 230°C and a tensile strength of 50 MPa or more, enabling reliable die bonding and solder joints in high-temperature applications.

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A lead-free solder alloy that provides superior thermal and creep resistance properties for electronic applications, particularly in extreme operating environments. The alloy achieves lower undercooling temperatures compared to traditional tin-lead alloys, resulting in improved microstructural refinement and strengthening mechanisms. This leads to enhanced creep resistance and improved performance under high-temperature conditions. The alloy composition balances the key elements of tin-silver-copper (SAC) with additional elements like bismuth, cobalt, and antimony, while maintaining the necessary tin content for soldering and joining applications.

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Lead-free solder containing 93-98% indium, 1-4% tin, and an addition metal with 0.05-6% total mass, which comprises at least one of silver, antimony, copper, or nickel. The addition metal is added in amounts between 0.05-6% of the total solder composition. This composition enables the production of lead-free solder with excellent electrical conductivity, mechanical properties, and thermal stability, particularly suitable for high-temperature applications.

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Lead-free solder alloy for solar cell substrates and liquid crystal substrates that combines the strength and durability of traditional lead-free solders with improved adhesion properties. The alloy comprises a base of Sn-Zn alloy with trace amounts of P, In, Bi, and Sb, with additional alloying of Al, Si, Cu, Ag, Ni, and glass. The alloy maintains its melting point at lower temperatures compared to conventional lead-free solders, while maintaining excellent solderability and adhesion characteristics. The alloy can be formed into a paste or rod for welding applications, with the paste decomposing to improve adhesion during soldering.

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Lead-free solder alloy that combines superior thermal cycle reliability and drop impact resistance. The alloy contains a balance of tin, copper, and other elements, with specific concentrations of germanium, phosphorus, and gallium. This composition enables reliable bonding in thermal and mechanical stress environments, while maintaining high wetting properties and preventing oxidation. The alloy can be used in semiconductor devices where lead-free soldering is required, particularly in applications where environmental concerns and cost savings are critical.

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A lead-free low-temperature solder alloy for photovoltaic ribbon coatings that combines high mechanical properties with improved wettability and reliability. The alloy contains 35-37% Bi, 1% Ag, 0.5% Ni, and the balance of Sn by weight percentage. The alloy achieves a melting point of 138°C, which is significantly lower than traditional Sn-Pb-based solder alloys. The alloy also exhibits excellent wetting characteristics and mechanical properties, making it suitable for high-temperature photovoltaic applications.

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Lead-free solder alloy for semiconductor devices with enhanced thermal stability, mechanical strength, and surface resistance. The alloy comprises silver (Ag), copper (Cu), bismuth (Bi), nickel (Ni), and tin (Sn) with controlled silver content between 2.8% and 3.5%. The alloy maintains excellent thermal cycling reliability, mechanical properties, and surface resistance even when soldering to complex pads and interfaces.

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A method for joining solar cells through a novel soldering process that addresses common issues associated with traditional soldering techniques. The method employs a modified solder alloy that incorporates metal powders during the molten state, which are then incorporated into the solder upon solidification. This approach eliminates the need for additional powder additions after soldering, eliminating the potential for partial chromatic aberration and improving weld quality.

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A lead-free solder strip for solar photovoltaic cells that enhances soldering performance and reliability through its unique composition. The solder strip comprises Sn-Bi alloy with an added layer of I2, which significantly improves solder wetting properties and reduces brittleness compared to traditional Sn-Pb solder. The I2 layer also enhances the solder's ability to form strong, full-flow joints in solar cells. The composition is achieved by combining Sn-Bi with I2 in a calculated weight ratio, with the added layer applied from the inside of the strip to the surface. This composition provides superior soldering performance, reliability, and durability for solar photovoltaic applications.

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Lead-free eutectic solder alloy containing zinc (Zn) as a main component and aluminum (Al) as an alloy metal. The alloy has a solidus temperature of 320-390°C, achieved through a single melting point. This characteristic enables high-temperature applications like die-attach electronics, where soldering temperatures typically range from 280°C to 400°C. The alloy's unique composition allows for improved thermal stability and reduced thermal expansion compared to traditional lead-containing eutectic solders.

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Pb-free solder alloy with improved wetting performance and environmental sustainability. The alloy contains 4-12% zinc, 0.5-4% bismuth, 0.5-5% indium, 0.005-0.5% phosphorus, 0.001-0.5% zirconium, and 0.001-0.5% silver, with the balance of tin. The composition provides excellent wetting characteristics, high melting point, and environmentally friendly properties.

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A lead-free solder alloy comprising Sn-Cu-Ni-In with improved performance characteristics compared to conventional Sn-Ag-Cu alloys. The alloy comprises 60 wt. % Sn, 20 wt. % Cu, 15 wt. % Ni, and 5 wt. % In, with the addition of Ce, Pr, Nd, Eu, Bi, Ge, and Ag in controlled proportions. The alloy achieves superior oxidation resistance, wettability, and corrosion resistance at elevated temperatures, making it suitable for high-performance electronic packaging applications.

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A lead-free solder alloy composition and manufacturing process that enables reliable performance in high-temperature and vibration environments. The composition comprises Sn-Bi-Cu, Sn-Ag-Bi, or Sn-Ag-Cu alloys with nano-sized ceramic additives. The ceramic additives, such as B, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Mo, Y, La, Sn, Si, Ag, Bi, Cu, Au, Mg, Pd, Pt, or Zn, are dispersed in the molten solder alloy. The nano-dispersed ceramic particles enhance mechanical properties, particularly strength and toughness, while maintaining excellent wetting characteristics. This composition and process enable reliable soldering in demanding environments without compromising the solder's performance.

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Lead-free solder alloy composition with enhanced mechanical properties and improved wettability, comprising a lead-free solder alloy containing Sn and a high entropy alloy nanopowder. The composition includes an alloy solder containing Sn and a high entropy alloy nanopowder, with the high entropy alloy nanopowder having an average particle diameter of 10-500 nm.

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Lead-free solder alloy composition and manufacturing process that addresses environmental concerns associated with traditional lead-based solders. The composition comprises a Sn-Sb alloy solder with tungsten nanopowder surface coatings. The surface coatings, which are formed through plasma etching or sputtering, enhance solder wetting and intermetallic compound formation. The coatings are precisely controlled to achieve optimal performance while minimizing processing steps and material waste. The composition is manufactured through a single-step process that combines the solder alloy with the tungsten nanopowder coatings, resulting in a lead-free solder with improved wettability and mechanical properties.

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Lead-free solder alloy composition and manufacturing process that addresses environmental concerns by replacing lead with non-toxic elements while maintaining excellent solderability and mechanical properties. The composition comprises a lead-free solder alloy with a lead-free solder alloy composition and an intermetallic compound additive, which is added to the solder. The intermetallic compound additive, comprising metal nanoparticles, forms irregular microgrooves on the surface of the additive, enhancing bonding strength through increased wetting. The additive is prepared through a controlled process of metal nanoparticle formation using a rotating impeller and a rotating vessel. The resulting solder alloy composition is manufactured through a powder process, where the additive is mixed with the solder powder before forming the solder ball.

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