Asymmetric Adhesion Separator for Battery Electrode Assembly
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Solution Overview
Problem
Secondary batteries face challenges in securing uniform quality of the electrode assembly due to deviations in adhesion between the positive and negative electrodes and the separator, with the positive electrode adhering more strongly than the negative electrode.
Innovation Solution
The electrode assembly features a first separator sheet with different adhesion surfaces, where the first electrode sheet adheres to a surface with high adhesion and the second electrode sheet to a surface with low adhesion, with optional plasma treatment and varying binder coating layer thickness to adjust adhesion uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the positive electrode and negative electrode are laminated on the separator under the same adhesion condition, then the manufacturing process is simple, but the adhesion uniformity deteriorates because the positive electrode has inherently greater adhesion than the negative electrode
Solution Approach 1:
The separator is designed with different adhesion properties on its two surfaces: the first surface (contacting the negative electrode) has lower adhesion, while the second surface (contacting the positive electrode) has higher adhesion. This local differentiation compensates for the inherent adhesion difference between electrode types, achieving uniform overall adhesion without complex manufacturing adjustments
Solution Approach 2:
The separator structure is made asymmetric by applying different adhesion treatments to each surface. The first surface undergoes treatment to reduce adhesion (e.g., lower plasma treatment intensity or thinner binder layer), while the second surface maintains or enhances adhesion (e.g., higher plasma treatment intensity or thicker binder layer), creating an asymmetric adhesion profile that balances the electrode adhesion differences
2Manufacturing precision
If the positive electrode adhesion is reduced to match the negative electrode adhesion, then adhesion uniformity improves, but the bond strength between the positive electrode and separator deteriorates
Solution Approach 1:
Rather than uniformly reducing adhesion across the separator, the invention applies local quality differentiation: the first surface is treated to have lower adhesion to match the negative electrode, while the second surface maintains higher adhesion to ensure strong bonding with the positive electrode. This resolves the contradiction by allowing each surface to be optimized for its specific electrode partner
Solution Approach 2:
The adhesion parameters of the separator surfaces are independently adjusted: the first surface uses parameters optimized for negative electrode bonding (lower adhesion), while the second surface uses parameters optimized for positive electrode bonding (higher adhesion). This parameter differentiation allows each electrode-separator interface to achieve optimal bond strength while maintaining overall uniformity
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 approach ensures uniform adhesion of the electrode sheets, improving the quality of the electrode assembly by differentially applying adhesion on the separator surfaces and enhancing the manufacturing process through selective plasma treatment and binder layer optimization.
Implementation Method 1
Both the surfaces of the first separator sheet may be activated in adhesion through plasma treatment, and the second surface may be relatively weakly plasma-treated compared to the first surface.
Data Source
AI summary
The present invention relates to an electrode assembly. The electrode assembly comprises: a first separator sheet; and first and second electrode sheets respectively adhering to both sides of the first separator sheet, wherein both the surfaces of the first separator sheet have adhesion different from each other, the first electrode sheet adheres to a first surface, which has relatively high adhesion, of both the surfaces, and the second electrode sheet adheres to a second surface, which has relatively low adhesion, of both the surfaces.