Solid Electrolyte Multilayer Membrane Casting
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Solution Overview
Problem
Existing methods for producing solid electrolyte membranes face challenges such as impurities remaining in the membrane, complexity in production processes, non-uniformity, and limitations in materials used, particularly for large-scale manufacturing and achieving desired proton conductivity.
Innovation Solution
A method involving layered casting of dopes with different compositions of solid electrolytes and organic solvents, followed by drying with a poor solvent to form a solid electrolyte multilayer membrane, utilizing a hydrocarbon polymer with sulfonic acid groups and specific solvent ratios to achieve high proton conductivity and membrane quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a melt extrusion method is used to produce the membrane, then the production process is simplified and no solvent is required, but the polymer is denatured due to heating and impurities remain in the membrane
Solution Approach 1:
The patent changes the processing parameters from high-temperature melt extrusion to low-temperature solution casting followed by controlled drying, thereby avoiding polymer denaturation while maintaining production feasibility
Solution Approach 2:
The patent extracts and removes impurities from the polymer material through the solution casting process, achieving high-purity membranes without the denaturation problems associated with melt extrusion
2Manufacturing precision
If a solution casting method is used to produce the membrane, then low heating temperature is required and impurities can be removed, but a large sized facility including solvent recovery device is required
Solution Approach 1:
The patent uses a disposable support for casting the membrane, eliminating the need for complex solvent recovery devices and large-scale facilities while maintaining the benefits of solution casting
Solution Approach 2:
The patent employs a support that changes state from liquid slurry to solid membrane, simplifying the overall production system
3Ease of manufacture
If a polymer membrane is immersed in water to produce proton conductive membrane, then the membrane is formed, but micropores are formed on the membrane and uniform membrane is not obtained
Solution Approach 1:
The patent changes the immersion medium from water to an organic solvent system, and controls the drying process to prevent micropore formation, thereby achieving uniform membrane structure
Solution Approach 2:
The patent uses a composite dope composition containing polymer, inorganic compound, and organic solvent to achieve both ease of manufacture and membrane uniformity
4Ease of manufacture
If conventional methods are used to produce solid electrolyte membranes, then production is possible, but the methods are for small-scale production and not suitable for large scale manufacture
Solution Approach 1:
The patent implements a continuous production process where the membrane is cast on a moving support, enabling large-scale manufacture while maintaining production feasibility
Solution Approach 2:
The patent prepares the dope solution in advance and uses a moving support for casting, enabling continuous large-scale production
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 method produces a solid electrolyte multilayer membrane with excellent proton conductivity, uniformity, and stability, suitable for large-scale production, with controlled thickness and enhanced mechanical strength, while minimizing impurities and production complexity.
Implementation Method 1
The casting membrane is peeled from the support as a layered membrane containing the organic solvent. At least one of the casting membrane and the layered membrane is contacted with a liquid which is a poor solvent for the solid electrolyte and having a lower boiling point than that of the organic solvent. The membrane is dried to form a solid electrolyte multilayer membrane.
Implementation Method 2
At least one of the casting membrane and the layered membrane is contacted with a liquid which is a poor solvent for the solid electrolyte and having a lower boiling point than that of the organic solvent.
Data Source
Figure 1
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Figure 3
AI summary
First, second and third dopes 114, 115 and 116 each of which contains a solid electrolyte and an organic solvent are cast from a casting die 81 provided with a feed block 119 to a moving belt 82. A three-layer casting membrane 112 is peeled off from the belt 82 as a three-layer membrane 62 containing the organic solvent. After being dried in a tenter device 64, the membrane 62 still containing the organic solvent is contacted with a liquid which is a poor solvent of the solid electrolyte and having lower boiling point than the organic solvent. Thereafter, the membrane 62 is transported to a drying chamber 69 and dried while being supported by the plural rollers.