Secondary Battery Electrode Binder Gradient for Fast-Charge Adhesion
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Solution Overview
Problem
Existing secondary battery electrodes face issues with binder content limitations, leading to detachment of the electrode active material layer from the current collector during charging/discharging, and non-uniform binder distribution causing side rings and uneven coating, which hinder rapid charging performance and productivity.
Innovation Solution
The electrode design optimizes binder distribution by ensuring a higher interfacial binder content at the side portion relative to the center portion, with a specific binder content range and application method that includes applying a binder suspension followed by drying and then electrode slurry, maintaining uniformity and reducing total binder content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If binder content is reduced to improve rapid charging performance, then resistance is lowered and charging speed is improved, but adhesion between current collector and electrode active material layer deteriorates causing detachment
Solution Approach 1:
The patent applies different binder contents at different locations within the electrode active material layer. The interfacial region (near current collector) has higher binder content (0.5-5 wt%) to ensure adhesion, while the bulk region has lower binder content (0.1-2 wt%) to reduce resistance and improve charging speed. This spatial variation in binder quality resolves the contradiction between adhesion and charging performance.
Solution Approach 2:
The patent applies a binder suspension as a primer layer before applying the electrode slurry. This preliminary binder layer ensures strong adhesion between the current collector and the subsequent electrode active material layer, allowing the overall binder content to be reduced while maintaining reliable attachment. The primer layer is formed first to establish the adhesive foundation.
2Speed
If electrode slurry is applied on liquid binder suspension to reduce total binder content, then rapid charging performance is improved, but side ring phenomenon and non-uniform coating occur
Solution Approach 1:
The patent applies a binder suspension as a primer layer before applying the electrode slurry. This preliminary step creates a stable foundation that prevents the side ring phenomenon by ensuring proper adhesion and uniform distribution before the main electrode material is applied. The primer layer is formed first to establish the adhesive foundation.
Solution Approach 2:
The patent creates different binder concentrations at different locations by applying binder suspension first, then electrode slurry on top. This results in higher binder content at the interface (preventing detachment) and lower binder content in the bulk (improving charging speed), while maintaining uniform coating appearance by controlling the application sequence and conditions.
3Reliability
If dual layer electrode slurry is formed with high binder content in lower layer, then adhesion is improved and binder content in upper layer can be reduced, but process complexity increases and thickness control is limited
Solution Approach 1:
The patent extracts the binder-rich layer as a separate primer layer applied first, then applies the binder-thin electrode slurry on top. This separation allows the lower layer to provide adhesion while the upper layer provides active material functionality with minimal binder. The process complexity is managed by using sequential coating of two distinct layers with different functions.
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 enhances adhesion between the current collector and electrode active material layer, prevents detachment, and improves rapid charging performance while maintaining electrode integrity and productivity.
Implementation Method 1
drying a side portion of the current collector to which the binder suspension is applied
Implementation Method 2
drying a resultant of step c)
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Provided are an electrode for a secondary battery, a method of manufacturing the same, and a secondary battery comprising the same. According to an exemplary embodiment of the present invention, an electrode for a secondary battery includes a current collector, and an electrode active material layer located on at least one surface of the current collector, in which the following relational expression 1 is satisfied. 1.0≤Bei/Bci≤2.0 In Relational Expression 1, Bci is an interfacial binder content of a center portion of the electrode active material layer in a width direction, and Bei is an interfacial binder content of a side portion of the electrode active material in the width direction.