Microporous Membrane Coating for High-Voltage Battery Separators
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Solution Overview
Problem
Existing battery separators in lithium ion batteries face challenges with inconsistent performance due to the need for thicker aluminum oxide layers, which affect mechanical strength, charge/discharge capacity, and electrochemical properties, while advanced deposition techniques struggle to achieve uniformity and thinness.
Innovation Solution
Application of an ultra-thin multi-phase metal or metal oxide deposition layer, preferably containing alpha-phase aluminum oxide and boehmite, on porous membranes using techniques like pulsed laser deposition, enhancing stability up to 7 volts, improving charge/discharge capacity, wettability, and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thicker aluminum oxide layer is applied to improve oxidation resistance and stability, then the mechanical strength and charge/discharge capacity deteriorate due to increased thickness
Solution Approach 1:
The patent changes the thickness parameter of the aluminum oxide layer from microns to nanometers (ultra-thin), and modifies the phase composition parameter by incorporating multiple crystalline phases (alpha, gamma, eta, delta, chi, theta) along with amorphous phases. This parameter transformation allows achieving adequate oxidation resistance at ultra-thin dimensions while maintaining mechanical strength and charge/discharge capacity that would be compromised by thicker layers.
2Reliability
If traditional coating techniques are used to apply ceramic coatings, then the coating thickness increases to 2-6 microns, but the uniformity and thinness required for high performance cannot be achieved
Solution Approach 1:
The patent replaces traditional mechanical coating techniques (dip coating, knife coating, gravure, curtain, and spray coating) with physical vapor deposition (PVD) methods. This substitution enables precise control over coating thickness at the nanometer scale and achieves superior uniformity across the membrane surface, which is critical for consistent electrochemical performance in high-voltage lithium batteries.
3Stability of the object's composition
If pure alpha-phase aluminum oxide is used to achieve thermodynamic stability and chemical inertness, then the layer thickness must be several microns, but this results in inconsistent performance and loss of mechanical properties
Solution Approach 1:
The patent creates a composite deposition layer containing multiple crystalline phases of aluminum oxide (alpha, gamma, eta, delta, chi, theta) combined with amorphous phases. This multi-phase composite structure provides the chemical stability and inertness needed for high-voltage applications while the distributed phase morphology maintains mechanical strength and enables the layer to be applied at ultra-thin nanometer dimensions rather than requiring several microns of pure alpha-phase material.
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 ultra-thin deposition layer increases energy density, enhances impedance/charge transfer, and provides improved safety and oxidation resistance, maintaining porosity and mechanical strength, suitable for high voltage lithium batteries.
Implementation Method 1
The multi-phase deposition is preferably an ultra-thin layer of metal or metal oxide applied to a porous membrane via a deposition technique that utilizes an external energy source, such as laser, pulsed laser, or ultra-short pulsed laser deposition
Data Source
AI summary
A microporous membrane or substrate for an electrochemical device having a layer of a metal and/or metal oxide on at least one side of a polymeric porous membrane, wherein said layer is applied using a deposition method or technique such as vapor deposition, and wherein said layer contains one or more phases of a reactive metal oxide.