Battery Separator Resin Composition for Viscosity and Thickness Control
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Solution Overview
Problem
Conventional resin compositions for separators in batteries face challenges in controlling viscosity and thickness, leading to issues like reduced hydrogen ion conductivity and durability, and the remnants of additives affecting battery performance after drying.
Innovation Solution
A resin composition comprising a sulfonated polymer, an amide group-containing organic solvent, and water, with specific weight ratios and amounts, allowing for controlled viscosity and thickness of the separator without residual additives post-drying, using a method that involves mixing the sulfonated polymer with water and adding the amide solvent, followed by shaping and heat treatment to remove the solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of separator is increased to reduce vanadium ion permeation, then crossover phenomenon is suppressed, but hydrogen ion conductivity and durability are reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the separator by incorporating specific sulfonated polymers with controlled sulfonate content (5-20 mmol/g) and using specific solvent systems (N,N-dimethylacetamide with water). This allows optimization of the membrane's ion transport properties to achieve both low vanadium permeation and high hydrogen ion conductivity without increasing thickness
Solution Approach 2:
The patent creates a composite separator structure by combining sulfonated polymers (such as sulfonated polyether ether ketone or sulfonated polyarylene) with specific additives and solvents. This composite approach enables the separator to simultaneously exhibit low vanadium ion permeability and high hydrogen ion conductivity through synergistic material interactions
2Ease of manufacture
If conventional resin compositions are used for separator fabrication, then manufacturing is simplified, but additive residues remain after drying and affect battery performance
Solution Approach 1:
The patent removes harmful additive residues from the separator fabrication process by using a minimal-component resin composition consisting only of sulfonated polymer, N,N-dimethylacetamide, and water. The amide solvent and water completely evaporate during drying, leaving no residual additives that could contaminate the battery
Solution Approach 2:
The patent employs volatile solvents (N,N-dimethylacetamide and water) that serve their purpose during fabrication and then completely evaporate without residue. These short-living solvent molecules fulfill their function of enabling polymer processing and then disappear, leaving a clean separator without persistent harmful residues
3Manufacturing precision
If viscosity control agents are added to resin composition to control separator thickness, then thickness uniformity is improved, but conductivity and durability are reduced due to remaining additives
Solution Approach 1:
The patent employs the N,N-dimethylacetamide solvent itself to provide the necessary viscosity control for the resin composition without requiring additional thickening agents. The solvent's inherent properties and its interaction with the sulfonated polymer enable controlled film formation and uniform thickness, while the solvent completely evaporates afterward, leaving no residual additives to compromise conductivity or durability
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 composition effectively enhances and controls viscosity, ensuring a separator with optimal thickness and performance, preventing additive residues that could impair battery efficiency, thereby improving battery capacity and efficiency.
Implementation Method 1
a resin composition for fabricating a separator comprising: a sulfonated polymer, an amide group-containing organic solvent, and water
Implementation Method 2
heating to 70 to 220 °C to remove the amide group-containing organic solvent
Data Source
Figure 1
AI summary
The present invention relates to a resin composition for fabricating a separator which is easy to control viscosity, a method of preparing the same, and a battery comprising the same.