Secondary Battery Electrode Binder Layer for Rapid-Charge Adhesion
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Solution Overview
Problem
Current secondary battery electrodes face challenges in achieving rapid charging performance due to poor interfacial adhesive strength between the current collector and the electrode active material layer, leading to issues like detachment and increased battery resistance, which are not adequately addressed by existing binder distribution methods.
Innovation Solution
The electrode design incorporates a binder layer with a specific composition and thickness, applied using a wet-on-wet method, ensuring a CA/B ratio of 0.6 or less and a binder suspension with 5-40 wt% binder and 5 wt% or less conductive material, to enhance interfacial adhesive strength and prevent binder aggregation, thereby improving battery resistance and rapid charging capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If binder content is reduced to improve rapid charging performance, then battery resistance decreases and rapid charging performance improves, but interfacial adhesive strength between current collector and electrode active material layer deteriorates causing detachment
Solution Approach 1:
The patent applies different binder contents to different layers: the lower layer (near current collector) has high binder content (5-40 wt%) to ensure strong adhesion, while the upper layer has low binder content (0.1-3 wt%) to maintain rapid charging performance. This local differentiation resolves the contradiction between adhesion and charging speed.
Solution Approach 2:
The electrode active material layer is divided into multiple layers with different binder contents. The lower layer serves as an adhesive layer with high binder content, while upper layers serve as functional layers with low binder content for optimal electrochemical performance. This segmentation allows each layer to fulfill its specific function without compromise.
2Reliability
If conductive material is added to primer layer to maintain electrical contact, then electrical conductivity improves, but binder aggregates in conductive material increasing electrode density and battery resistance
Solution Approach 1:
The patent extracts the conductive material from the binder layer and places it in the electrode active material layer instead. This separation prevents binder aggregation around conductive material while maintaining both electrical conductivity and low electrode density, resolving the contradiction between electrical contact and battery resistance.
3Manufacturing precision
If binder particles move to surface during drying to distribute binder efficiently, then binder distribution improves, but interfacial adhesive strength between current collector and electrode active material layer decreases
Solution Approach 1:
The patent applies a primer layer with high binder content to the current collector before applying the electrode active material layer. This preliminary action ensures strong interfacial adhesion is established before subsequent layers are applied, preventing binder migration from compromising adhesion while still allowing efficient binder distribution in the overall electrode structure.
Data Source
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AI summary
The present disclosure relates to an electrode for a secondary battery with improved rapid charging performance, a method of manufacturing the same, and a secondary battery including the same, and provides an electrode for a secondary battery including a current collector, an electrode active material layer located on at least one surface of the current collector, and a binder layer located on at least one surface of the current collector and protruding from at least one end of the electrode active material layer, in which the binder layer satisfies the following Expression 1. CA/B≤0.6 (In Expression 1, CA is wt% of a conductive material in the binder layer, and B is wt% of a binder in the binder layer, based on a total weight of the binder layer).