Microporous Battery Separator Coating for High-Voltage Oxidation Resistance
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Solution Overview
Problem
Existing coating techniques for microporous battery separator membranes struggle to achieve uniform, ultra-thin layers with thicknesses less than 1 micron, leading to non-uniformity and reduced oxidation resistance, especially at high voltages, which limits the safety and performance of lithium ion batteries.
Innovation Solution
Application of a binder-free and solvent-free deposition method, such as physical vapor deposition, to create ultra-thin layers of metal or metal oxide on polymeric microporous membranes, providing excellent oxidation resistance up to 5.2 volts or higher, with thicknesses ranging from 1 Å to 1 μm, enhancing the energy density and safety of lithium ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing coating techniques are used to coat microporous battery separator membranes, then coating can be applied, but uniform ultra-thin layers with thicknesses less than 1 micron cannot be achieved, leading to non-uniformity and reduced oxidation resistance
Solution Approach 1:
The patent replaces conventional mechanical coating techniques (such as dip coating, spray coating, or brush coating) with physical vapor deposition (PVD). This substitution enables atomic-level control over coating thickness and composition, achieving uniform ultra-thin layers (less than 1 micron) that conventional mechanical methods cannot produce. The PVD process deposits material in a vacuum environment, ensuring consistent coverage and precise thickness control across the entire separator surface.
Solution Approach 2:
The patent changes the fundamental parameters of the coating process by transitioning from liquid-based coating methods to vapor-phase deposition. This parameter change allows for precise control of coating thickness at the nanometer scale, achieving uniform ultra-thin layers that maintain excellent oxidation resistance. The vapor deposition process enables independent control of coating thickness, composition, and uniformity, resolving the contradiction between thinness and performance.
2Reliability
If thicker coating layers are used to improve oxidation resistance, then oxidation protection is enhanced, but energy density is reduced due to increased thickness
Solution Approach 1:
The patent changes the thickness parameter of the coating layer from micrometer scale (conventional) to nanometer scale (ultra-thin). This parameter change reduces the coating thickness to less than 1 micron while maintaining excellent oxidation resistance through the high-quality uniform deposition achieved by PVD. The ultra-thin coating minimizes the space occupied by non-active material, thereby maximizing energy density without compromising safety.
Solution Approach 2:
The patent employs composite material structures where an ultra-thin deposition layer (metal, metal oxide, or ceramic) is applied to the microporous separator membrane. This composite structure combines the mechanical integrity and porosity of the polymer separator with the oxidation resistance of the inorganic coating. The synergistic combination allows for minimal coating thickness while achieving superior oxidation protection, thus maintaining high energy density.
3Ease of manufacture
If conventional coating methods are used, then coating can be applied, but thickness control below 1 micron is not achieved, resulting in reduced energy density
Solution Approach 1:
The patent replaces conventional mechanical coating methods with physical vapor deposition (PVD) to achieve precise thickness control below 1 micron. This substitution maintains ease of manufacture through automated vacuum deposition processes while enabling ultra-thin coating layers that maximize energy density. The PVD process can be continuously operated and scaled for industrial production, ensuring both manufacturability and 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 ultra-thin deposition layers provide equivalent oxidation resistance and safety as thicker coatings while maintaining minimal thickness, improving the energy density and preventing thermal runaway in lithium ion batteries.
Implementation Method 1
a binder-free and solvent-free deposition method, such as physical vapor deposition
Data Source
AI summary
In accordance with at least selected embodiments, novel or improved porous membranes or substrates, separator membranes, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators, and/or batteries, and/or methods of using such membranes or substrates, separators and/or batteries are disclosed. In accordance with at least certain embodiments, novel or improved microporous membranes, battery separator membranes, separators, energy storage devices, batteries including such separators, methods of making such membranes, separators, and/or batteries, and/or methods of using such membranes, separators and/or batteries are disclosed. In accordance with at least certain selected embodiments, a separator for a battery which has an oxidation protective and binder-free deposition layer which is stable up to 5.2 volts or more, for example, up to 7 volts, in a battery is disclosed. The deposition layer is preferably a thin, very thin or ultra-thin deposition on a polymeric microporous membrane applied via a binder-free and solvent-free deposition method. By employing such an ultra-thin deposition layer, the energy density of a battery may be increased. In accordance with at least particular embodiments, the battery separator membrane described herein is directed to a multi-layer or composite microporous membrane battery separator which may have excellent oxidation resistance and may be stable in a high voltage battery system up to 5.2 volts or more. In accordance with at least other certain selected embodiments, the present invention is directed to a separator for a battery which has a conductive deposition layer which is stable up to at least 5.2 volts or higher in a battery.