CIGS Solar Cell Recycling via Thermal Strain Separation
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Solution Overview
Problem
Current methods for recycling CIGS thin-film solar cells are inefficient, producing waste gases and solvents, and result in impure recycled metals due to heating treatments or solvent use, posing environmental risks and inefficiencies.
Innovation Solution
A method involving a cooling treatment to separate components, followed by annealing to remove selenide and extract copper, indium, and gallium ions using inorganic acids and di(2-ethylhexyl)phosphoric acid for effective separation and purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heating treatment or solvent is used to remove encapsulated materials, then the solar cell components can be separated, but large amounts of waste gases and waste solvents are produced
Solution Approach 1:
The patent uses phase transition of the encapsulated material from solid to gas through controlled thermal decomposition at 200-400°C, transforming the material directly into vapor that can be condensed and recovered, thereby avoiding the generation of harmful waste gases and solvents
Solution Approach 2:
The patent changes the temperature parameter to a specific range (200-400°C) that enables selective decomposition of the encapsulated material without damaging the underlying solar cell components, achieving clean separation without harmful byproducts
2Ease of manufacture
If heating treatment is used to recover metals, then the encapsulated materials can be removed, but the recycled metals contain relatively high amounts of impurities
Solution Approach 1:
The patent segments the solar cell structure by selectively removing only the encapsulated material layer through controlled thermal decomposition, leaving the metal components intact and separately recoverable, which enables high-purity metal extraction without contamination from organic residues
Solution Approach 2:
The patent replaces conventional mechanical fragmentation and sorting methods with controlled thermal decomposition followed by condensation, achieving cleaner separation and higher metal purity by avoiding physical mixing of materials
3Productivity
If the solar cell is fragmented into small pieces for sorting, then the metals can be recovered, but large amounts of waste materials are produced and the process is inefficient
Solution Approach 1:
The patent extracts and removes only the encapsulated material layer through selective thermal decomposition, leaving the valuable metal components intact for direct recovery, thereby eliminating the need for fragmentation and reducing waste material generation
Solution Approach 2:
The patent performs preliminary removal of the encapsulated material before metal recovery, creating a clean separation that simplifies subsequent metal extraction processes and reduces waste generation throughout the entire recycling workflow
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
This method reduces waste production, maintains metal purity, and effectively recycles valuable metals from CIGS thin-film solar cells without generating waste gases, improving environmental sustainability.
Implementation Method 1
subjecting the CIGS thin-film solar cell to a cooling treatment at a predetermined temperature lower than a brittleness temperature of the second adhesive layer such that the light absorbing unit is separated from the electrical contact layer as a result of a thermal strain produced between the electrical contact layer and the rear substrate unit
Implementation Method 2
subjecting the recovered light absorbing unit to an annealing treatment at a temperature ranging from 800° C. to 950° C. in an oxygen ambient to remove the selenide in the light absorbing unit, and to collect selenium oxide
Implementation Method 3
dissolving copper, indium, and gallium ions from the intermediate using an inorganic acid aqueous solution as a solvent so as to obtain a first acid solution including the copper, indium, and gallium ions
Implementation Method 4
subjecting the first acid solution to extraction using di(2-ethylhexyl)phosphoric acid as an eluent whilst keeping aqueous phase pH value to be not greater than 1 so as to obtain a first organic phase solution including the indium ions
Data Source
AI summary
A method for recovering a resource from a CIGS thin-film solar cell to be recycled includes a) providing the CIGS thin-film solar cell, and b) subjecting the CIGS thin-film solar cell to a cooling treatment at a predetermined temperature, such that a light absorbing unit of the CIGS thin-film solar cell can be recovered due to thermal strain difference of materials of the CIGS thin-film solar cell.