Multilayer Composite Separator for Battery Lamination
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Solution Overview
Problem
Current battery cell technologies face challenges in achieving balanced lamination strength, porosity, and conductivity in separator layers, with polymer-rich layers being easy to laminate but compromising on conductivity and inorganic filler-rich layers being difficult to laminate while offering better conductivity.
Innovation Solution
A bilayer composite separator is introduced, comprising an inorganic particulate material-rich layer and a polymer-rich layer with different weight ratios, where the polymer-rich layer is the outermost to facilitate easy lamination and maintain high conductivity and porosity, and the inorganic filler-rich layer provides mechanical strength and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer-rich separator layers are used, then lamination ease is improved, but conductivity and porosity deteriorate
Solution Approach 1:
The separator is divided into multiple layers with different compositions: a polymer-rich outer layer for easy lamination and an inorganic filler-rich inner layer for high conductivity and porosity. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
Different regions of the separator have different material compositions tailored to their specific functions. The outer layer uses polymer-rich composition for lamination ease, while the inner layer uses inorganic filler-rich composition for conductivity, creating local optimization of properties.
2Reliability
If inorganic filler-rich separator layers are used, then conductivity and porosity are improved, but lamination strength deteriorates
Solution Approach 1:
The separator structure segments the inorganic filler-rich layer from the polymer-rich layer, placing the inorganic layer internally where it provides conductivity without bearing the lamination load, while the polymer layer externally provides lamination strength.
Solution Approach 2:
The separator uses a composite structure combining polymer and inorganic filler materials in distinct layers, allowing the composite system to exhibit both the lamination properties of polymers and the conductivity properties of inorganic materials.
3Stability of the object's composition
If mechanically applied pressure is used to keep interfaces intact, then interface integrity is improved, but cell weight and volume increase
Solution Approach 1:
The separator structure itself provides the interface integrity function through its multilayer design, where the polymer-rich layer acts as a self-contained bonding interface between electrodes, eliminating the need for additional mechanical pressure components or structures.
Data Source
AI summary
Electrodes with a multilayer or monolayer composite separator are described. The multilayer composite separator comprises multiple individual composite separator layers. Each individual composite separator layer comprises inorganic particulate material(s) and organic polymer(s) with different inorganic particulate material/polymer weight ratios. The multilayer composite separator layer is constructed in a way such that the composite separator layer adjacent to the electrode active material contains a higher weight percentage of the inorganic particulate material and lower weight percentage of the organic polymer than the composite separator layer outermost from the electrode current collector. Laminated cells comprising a positive electrode, a negative electrode, a laminated multilayer or monolayer composite separator layer are described, wherein at least one of the electrodes has a multilayer or monolayer composite separator disposed onto the surface of the electrode. Methods of making such laminated cells are also described.