Coated Lithium Battery Separator With Low Resistance and Strong Adhesion
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high energy density, capacity, stability, and lifetime due to high membrane resistance and heat shrinkage.
Innovation Solution
A separator for rechargeable lithium batteries is developed, comprising a porous substrate with a coating layer containing a (meth)acryl-based binder and a filler with a particle diameter of 50-250 nm, along with a fluorine-based adhesive binder, which reduces membrane resistance and heat shrinkage, enhancing bonding strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional separators are used, then the battery can operate, but the membrane resistance is high which limits capacity
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the separator through coating it with a heat-resistant layer containing specific fillers (alumina, silica, boehmite) and binders. This coating process changes the surface characteristics, porosity, and thermal properties of the separator, resulting in reduced membrane resistance and improved ion conductivity, thereby increasing battery capacity
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure consisting of a base separator combined with a heat-resistant coating layer. The coating layer itself is a composite of filler particles (alumina, silica, or boehmite), binder polymers, and functional additives. This composite structure provides both low membrane resistance for high capacity and adequate mechanical strength
2Reliability
If conventional separators are used, then the battery can operate, but heat shrinkage is high which reduces stability and lifetime
Solution Approach 1:
The patent applies parameter changes by modifying the thermal properties of the separator through coating it with a heat-resistant layer containing specific fillers (alumina, silica, boehmite) and binders. This coating process changes the surface characteristics, porosity, and thermal properties of the separator, resulting in reduced membrane resistance and improved ion conductivity, thereby increasing battery capacity
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure consisting of a base separator combined with a heat-resistant coating layer. The coating layer itself is a composite of filler particles (alumina, silica, or boehmite), binder polymers, and functional additives. This composite structure provides both low membrane resistance for high capacity and adequate mechanical strength
3Ease of manufacture
If the separator structure is simplified, then manufacturing is easier, but bonding strength between layers is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the separator through coating it with a heat-resistant layer containing specific fillers (alumina, silica, boehmite) and binders. This coating process changes the surface characteristics, porosity, and thermal properties of the separator, resulting in reduced membrane resistance and improved ion conductivity, thereby increasing battery capacity
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure consisting of a base separator combined with a heat-resistant coating layer. The coating layer itself is a composite of filler particles (alumina, silica, or boehmite), binder polymers, and functional additives. This composite structure provides both low membrane resistance for high capacity and adequate mechanical strength
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 separator achieves low membrane resistance, low heat shrinkage, and high bonding strength, thereby increasing the capacity, stability, and lifetime of the lithium battery.
Implementation Method 1
a heat-resistant layer including a binder and a filler... The binder includes a (meth)acryl-based binder including a first structural unit derived from (meth)acrylic acid, (meth)acrylate, or a salt thereof
Implementation Method 2
an adhesive layer on the heat-resistant layer and including an adhesive binder... the adhesive binder includes a fluorine-based adhesive binder having a carbonyl (C═O) functional group
Implementation Method 3
The separator for a rechargeable lithium battery includes a porous substrate and a coating layer on at least one surface of the porous substrate
Data Source
AI summary
The present disclosure relates to a separator for a rechargeable lithium battery, and a rechargeable lithium battery including the separator. The separator includes a porous substrate and a coating layer on at least one surface of the porous substrate. The coating layer includes a heat-resistant layer including a binder and a filler, and an adhesive layer including an adhesive binder on the heat-resistant layer. The binder includes a (meth)acryl-based binder including a first structural unit derived from (meth)acrylic acid or a derivative of (meth)acrylic acid, a hydroxyl group-containing second structural unit, and a sulfonate group-containing third structural unit. The filler includes a cubic filler having a particle diameter D50 ranging from about 50 nm to about 250 nm. The adhesive binder includes a fluorine-based adhesive binder having a carbonyl (C═O) functional group.