Al-Li-Ca Alloy Solar Cell Interconnector for Space
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Solution Overview
Problem
Current solar cell interconnectors face challenges with thermo-mechanical stability, atomic oxygen resistance, and Xe ion erosion resistance, leading to power degradation and potential breakage in space applications.
Innovation Solution
A high electrical conductive, high temperature stable foil material comprising an aluminium alloy with scandium, magnesium, zirconium, ytterbium, and manganese, specifically with ytterbium in the range of 0.075 to 0.5 wt.%, is developed, which is processed through melting, cooling, rolling, and annealing to achieve improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ag or Au foil materials are used for solar cell interconnectors, then good electrical conductivity and weldability are achieved, but susceptibility to atomic oxygen erosion and Xe ion erosion increases
Solution Approach 1:
The patent applies composite material principle by creating an Al-Li-Ca alloy that combines the benefits of aluminum (low density, good conductivity) with lithium and calcium additions that provide both enhanced mechanical properties and resistance to atomic oxygen and Xe ion erosion. This composite alloy structure allows the interconnector to maintain electrical conductivity while resisting space environment degradation.
Solution Approach 2:
The patent applies parameter changes by specifically optimizing the alloy composition parameters (Al-Li-Ca with defined weight percentages) and processing parameters (rolling reduction ratio of 80-95%, annealing temperature of 300-500°C) to achieve a material that simultaneously provides good electrical conductivity and resistance to atomic oxygen and ion erosion, transforming the material properties to resolve the contradiction.
2Stability of the object's composition
If Mo or Invar materials are used to reduce CTE mismatch, then thermo-mechanical stability is improved, but electrical conductivity and weldability deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the Al-Li-Ca alloy composition and processing parameters to achieve a material with intermediate properties - the CTE is reduced compared to pure Ag/Au through aluminum base and alloying, while electrical conductivity is maintained through the aluminum matrix and optimized heat treatment parameters (300-500°C annealing), resolving the contradiction between thermo-mechanical stability and electrical conductivity.
3Reliability
If Ag or Au foils are plated with additional Ag or Au to improve corrosion resistance, then manufacturing complexity and cost increase
Solution Approach 1:
The patent applies the extraction principle by removing the need for additional plating processes. The Al-Li-Ca alloy inherently provides the required corrosion and erosion resistance through its composition and microstructure, eliminating the separate plating step that would add complexity and cost, while maintaining the protective function.
Solution Approach 2:
The patent applies self-service principle where the Al-Li-Ca alloy material itself provides the corrosion and erosion resistance that would otherwise require additional plating layers. The alloy's inherent properties (through Li and Ca additions) enable it to resist atomic oxygen and ion erosion without needing external protective coatings, making the material self-protecting.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The foil material exhibits enhanced thermo-mechanical stability, atomic oxygen resistance, and Xe ion erosion resistance, maintaining electrical conductivity and mechanical properties even after exposure to elevated temperatures, thus extending the lifespan of solar cell interconnectors.
Implementation Method 1
a melting of a pre-material comprising aluminium and at least two elements selected from the group consisting of scandium (Sc), magnesium (Mg), zirconium (Zr), ytterbium (Yb) and manganese (Mn) for forming a molten aluminium alloy
Implementation Method 2
cooling the molten aluminium alloy to room temperature for forming a solidified aluminium alloy
Implementation Method 3
annealing the rolled aluminium alloy at a temperature of at least 250 °C
Data Source
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AI summary
The present invention relates to a high electrical conductive, high temperature stable foil material, a process for the preparation of such a high electrical conductive, high temperature stable foil material, a solar cell interconnector comprising the high electrical conductive, high temperature stable foil material as well as the use of the high electrical conductive, high temperature stable foil material and/or the solar cell interconnector in solar power, aircraft or space applications.