Ceramic-Polymer Composite Membrane for Li-Ion Battery Safety
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Solution Overview
Problem
Existing electrochemical separation membranes for lithium ion batteries face challenges with low ion conductivity, poor thermal stability, and non-uniform distribution of ceramic particles, leading to safety concerns and performance issues.
Innovation Solution
A manufacturing method involving the uniform dispersion of ceramic precursors within a polymer solution, followed by hydrolysis to form a ceramic-polymer composite membrane with ceramic particles distributed uniformly, enhancing ion conductivity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyolefin polymers are used as separation membrane material, then manufacturing cost is reduced and mechanical strength is improved, but ion conductivity decreases due to low polarity and poor electrolyte wetting
Solution Approach 1:
The patent applies composite materials by combining polyolefin polymer with ceramic particles to create a composite separation membrane. The ceramic particles are dispersed within the polymer matrix, allowing the membrane to maintain the low cost and mechanical strength of polyolefin while gaining the high ion conductivity and thermal stability of ceramic materials, thus resolving the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent applies local quality by creating regions with different properties within the separation membrane. Ceramic particles are distributed throughout the polymer matrix, creating local zones of high ion conductivity within the overall polymer structure. This allows the membrane to maintain bulk polymer properties (low cost, mechanical strength) while having localized ceramic regions that enhance ion conductivity
2Temperature
If ceramic particles are added to improve thermal stability, then thermal stability is enhanced, but uniform distribution of ceramic particles is difficult to achieve
Solution Approach 1:
The patent applies intermediary by using a solgel process as a mediating mechanism to achieve uniform ceramic particle distribution. The solgel method allows ceramic precursors to be dissolved and dispersed uniformly in the polymer solution before gelation, ensuring homogeneous distribution of ceramic particles throughout the membrane without aggregation, thus resolving the manufacturing precision challenge while maintaining thermal stability
3Ease of manufacture
If traditional stretching process is used to form micro holes, then manufacturing cost is low, but micro hole shapes are straight leading to potential short circuits
Solution Approach 1:
The patent applies parameter changes by modifying the formation process of micro holes from mechanical stretching to phase separation during solgel. This changes the fundamental mechanism of pore formation, allowing control over pore shape and distribution parameters to create more favorable curved or irregular micro hole structures that prevent straight-line penetration by lithium crystals, thereby improving short circuit prevention while maintaining cost-effectiveness
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 improves the ion conductivity and thermal stability of the separation membrane, leading to better battery performance and safety by ensuring uniform ceramic distribution and increased adhesive strength.
Implementation Method 1
the ceramic precursors are hydrolyzed into ceramic particles
Implementation Method 2
The solvent and water are evaporated from the porous base material upon hydrolyzing
Data Source
AI summary
An electrochemical separation membrane and the manufacturing method thereof are disclosed. The method includes: a polymer solution preparing step to mix a polymer material, solvent and ceramic precursors thoroughly to form a polymer solution, wherein the polymer material and the ceramic precursors are dissolved uniformly in the solvent; a coating step to coat the polymer solution on a porous base material; a hydrolysis step to cause the porous base material coated with the polymer solution to contact an aqueous solution to hydrolyze the ceramic precursor into ceramic particles; and a drying step to remove the water and the solvent from the porous base material and in order to form the electrochemical separation membrane. The electrochemical separation membrane made of this method have better ion conductivity, interface stability and thermal stability based on the ceramic particles.