Ceramic-Coated Battery Separator Binder for Low Shrinkage and Wettability
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Solution Overview
Problem
Current ceramic binder compositions for lithium ion battery separators lack desirable mechanical properties, such as low shrinkage at elevated temperatures and electrolyte resistance, while maintaining electrochemical performance.
Innovation Solution
A ceramic binder composition comprising ceramic particles, a crosslinked polymer produced from monomers like vinylpyrrolidone and amine or epoxide functional groups, and optionally a surfactant, which forms a ceramic coated separator with improved permeability, wettability, and reduced shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer coatings are applied to separators, then electrochemical performance is improved, but mechanical stability and shrinkage resistance at elevated temperatures deteriorate
Solution Approach 1:
The patent applies composite materials by combining ceramic particles (such as alumina, silica, or boehmite) with polymer binders to form a ceramic-polymer composite coating on the separator. This composite structure provides both the electrochemical benefits of polymer coatings and the thermal-mechanical stability of ceramic materials, resolving the contradiction between improved electrochemical performance and maintained mechanical stability at elevated temperatures.
2Temperature
If ceramic coatings are applied to improve thermal stability, then shrinkage resistance improves, but electrolyte wettability and permeability deteriorate
Solution Approach 1:
The patent applies local quality by creating a coating with spatially varying properties: the ceramic particles provide thermal stability and shrinkage resistance in the bulk coating structure, while the polymer binder and its functional groups (carboxyl, hydroxyl, amine) provide electrolyte wettability at the coating-electrolyte interface. This local differentiation of functions resolves the contradiction between thermal stability and electrolyte wettability.
Solution Approach 2:
The patent applies parameter changes by controlling the chemical composition parameters of the coating, specifically incorporating polymers with functional groups (carboxyl, hydroxyl, amine) that enhance electrolyte affinity. By adjusting these chemical parameters while maintaining ceramic content for thermal stability, the patent achieves both thermal stability and improved electrolyte wettability.
3Strength
If binder composition is optimized for mechanical properties, then shrinkage resistance improves, but electrochemical performance deteriorates
Solution Approach 1:
The patent uses composite materials where ceramic particles (5-50 wt%) provide shrinkage resistance and mechanical strength, while the polymer binder matrix maintains porosity and electrolyte uptake for electrochemical performance. This composite approach allows simultaneous optimization of both shrinkage resistance and electrochemical performance.
Solution Approach 2:
The patent applies porous materials by designing the coating with controlled porosity (30-70%) through the ceramic-polymer composite structure. The porous network allows electrolyte penetration and ion transport necessary for electrochemical performance while the ceramic framework provides shrinkage resistance, resolving the contradiction between mechanical strength and electrochemical performance.
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 ceramic coated separator exhibits enhanced mechanical stability, electrolyte resistance, and electrochemical performance, making it suitable for lithium ion batteries without compromising their safety and efficiency.
Implementation Method 1
a binder comprising a crosslinking agent at least partially crosslinked with a copolymer
Implementation Method 2
a ceramic coated separator comprising a separator and a ceramic binder composition coated on the separator
Implementation Method 3
and (c) a surfactant, provides a ceramic coated separator having desirable properties... desirable permeability and electrolyte wettability properties
Data Source
AI summary
A ceramic binder composition is disclosed as well as a method of making and using the same. Additionally, a ceramic coated separator used in, for example but without limitation, lithium ion batteries is disclosed.