Patterned Separator Adhesive Layer for Faster Electrolyte Wetting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges with slow electrolyte impregnation due to excessive adhesion between electrodes and separators, leading to prolonged aging times, and twisting issues in electrode assemblies.
Innovation Solution
A separator with a patterned electrode adhesive layer is introduced, featuring non-coated portions that separate adhesive units, allowing for improved electrolyte impregnation and preventing electrode assembly twisting, achieved through a method involving binder solution coating and phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an electrode adhesive layer is coated on the separator surface to improve adhesion with electrodes, then adhesion strength is improved, but electrolyte impregnation time is excessively prolonged
Solution Approach 1:
The electrode adhesive layer is segmented into a patterned structure with multiple discrete adhesive regions rather than a continuous layer. This segmentation allows electrolyte to penetrate through non-adhesive regions while maintaining adhesion at specific locations, thus reducing electrolyte impregnation time while preserving necessary adhesion strength.
Solution Approach 2:
Different regions of the separator surface are given different properties: adhesive regions provide strong bonding to electrodes, while non-adhesive regions allow rapid electrolyte penetration. This local differentiation of surface properties resolves the contradiction between needing adhesion and needing fast electrolyte impregnation.
2Strength
If a binder is coated on the porous polymer substrate to improve adhesion, then adhesion is improved, but ion channel function is damaged
Solution Approach 1:
The binder application is segmented into specific regions rather than uniform coverage. Adhesive binders are applied only in regions where electrode contact is needed, while pore regions remain open for ion transport. This selective segmentation preserves ion channel function while providing necessary adhesion.
Solution Approach 2:
The separator surface exhibits local quality variation with adhesive properties concentrated in specific regions and porous properties maintained in other regions. This spatial differentiation allows simultaneous achievement of adhesion and ion transport functionality.
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
This solution enhances electrolyte impregnation efficiency and reduces the aging time for lithium secondary batteries while maintaining low resistance and effective adhesion between electrodes and separators.
Implementation Method 1
a method involving binder solution coating and phase separation
Data Source
AI summary
A separator for an electrochemical device is provided. The separator includes a porous polymer substrate, and an electrode adhesive layer formed on at least one surface of the porous polymer substrate, wherein the electrode adhesive layer includes a binder polymer and has at least two electrode adhesive layer units including at least two lines extending from a long side to a short side of the separator, and the units do not cross each other. Herein, a unit merely formed by lines extending from one long side to the other long side of the separator, or a unit merely formed by lines extending from one short side to the other short side of the separator is not included. The separator is effective for reducing a time required for impregnation of an electrode with an electrolyte, while providing excellent electrode-separator adhesion.