Polycarbonate Polyurethane Separator for Non-aqueous Flow Cells
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Solution Overview
Problem
Current separators for non-aqueous flow cells, particularly those using organic solvents, face challenges with mechanical stability, excessive swelling, and poor conductivity, limiting their performance and energy density.
Innovation Solution
A non-aqueous flow cell utilizing a polycarbonate-based polyurethane separator that maintains dimensional stability and enhances ion conductivity, swelled by organic solvents without excessive expansion, and embedded with metal salts for improved mechanical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional separators are used in non-aqueous flow cells with organic solvents, then the cell structure is simple, but the separator exhibits excessive swelling and poor mechanical stability
Solution Approach 1:
The patent employs composite materials by combining polycarbonate-based polyurethane with metal salts (such as lithium perchlorate, lithium tetrafluoroborate, or lithium hexafluorophosphate) to create a separator that exhibits both mechanical stability and enhanced ion conductivity. This composite approach allows the separator to maintain structural integrity while providing the necessary ionic pathways for non-aqueous flow cell operation.
Solution Approach 2:
The patent utilizes parameter changes by controlling the swelling behavior of the polycarbonate-based polyurethane through selective absorption of organic solvents. The separator is designed to swell to a controlled extent (maintaining porosity between 30-70%) to enhance ion conductivity while preserving mechanical stability, achieving optimal performance through precise parameter control.
2Reliability
If the separator swells to enhance ion conductivity, then ion conductivity improves, but mechanical stability deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the degree of swelling through selective solvent absorption. The polycarbonate-based polyurethane is designed to absorb specific organic solvents (such as acetonitrile, dimethyl carbonate, ethyl methyl carbonate, or propylene carbonate) to achieve optimal porosity (30-70%) that balances ion conductivity enhancement with mechanical stability preservation.
Solution Approach 2:
The patent implements local quality by creating regions of controlled porosity within the separator structure. The metal salt components are distributed throughout the polyurethane matrix to provide localized ion conduction pathways, while the overall structure maintains mechanical integrity through the polymer framework.
3Reliability
If metal salts are embedded in the separator to improve conductivity, then ion conductivity increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-mixing the metal salts with the polycarbonate-based polyurethane components before the final separator formation process. This allows the metal salts to be uniformly distributed throughout the polymer matrix during the initial manufacturing stage, simplifying subsequent processing while ensuring consistent ion conductivity throughout the separator.
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 polycarbonate-based polyurethane separator provides improved ion selectivity, conductivity, and mechanical stability, enhancing the energy storage capacity and efficiency of non-aqueous flow cells while maintaining low water content.
Implementation Method 1
a non-aqueous flow cell utilizing a polycarbonate-based polyurethane separator that maintains dimensional stability and enhances ion conductivity, swelled by organic solvents without excessive expansion
Implementation Method 2
the separator comprises a polycarbonate based polyurethane... provides improved ion selectivity, conductivity
Data Source
AI summary
A non-aqueous flow cell energy storage device comprises a ionically conductive separator, which separator comprises a polyurethane prepared by curing an isocyanate capped prepolymer, which prepolymer was prepared from a polyol having polycarbonate backbone, wherein the separator may be impregnated with electrolyte salts and/or swelled by an organic solvent.