Secondary Battery Electrode Layer Mixing Prevention
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Solution Overview
Problem
Conventional methods for manufacturing secondary battery electrodes result in mixing of layers at the interface, leading to decreased charge/discharge capacity, increased battery resistance, and reduced insulation effects, compromising battery performance.
Innovation Solution
A method involving the application of a first layer slurry with a first binder on a current collector, followed by the application of a second layer slurry with a second binder before the first layer is dried, where the second layer slurry has a solid content ratio greater than 50% by mass and a binder composition ratio greater than 2% by mass, to prevent mixing and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the second layer slurry is applied before the first layer slurry is dried to improve adhesion, then the adhesion between layers is improved, but significant mixing occurs causing decreased charge/discharge capacity and increased battery resistance
Solution Approach 1:
The invention changes the physical parameters of the second layer slurry by setting its solid content ratio to more than 50% by mass and binder composition ratio to more than 2% by mass. These parameter changes allow the slurry to maintain high adhesion to the first layer while having reduced fluidity that prevents excessive mixing, thereby resolving the contradiction between adhesion improvement and capacity maintenance
Solution Approach 2:
The invention applies the second layer slurry before the first layer slurry is completely dried, creating a preliminary bonding state. This timing control allows the layers to adhere well while the subsequent drying process consolidates the structure without excessive mixing, achieving both good adhesion and preserved battery performance
2Strength
If the second layer slurry is applied before the first layer slurry is dried to improve adhesion, then the adhesion between layers is improved, but insulation effect decreases due to mixing at the interface
Solution Approach 1:
By setting the solid content ratio of the second layer slurry to more than 50% by mass and binder composition ratio to more than 2% by mass, the invention creates a slurry that bonds strongly to the first layer but has sufficient viscosity to minimize interfacial mixing. This parameter optimization maintains both adhesion and insulation properties
3Ease of manufacture
If conventional coating methods are used with lower solid content slurries, then the coating process is easier and more uniform, but significant mixing occurs between layers reducing battery performance
Solution Approach 1:
The invention uses a second layer slurry with solid content ratio more than 50% by mass and binder composition ratio more than 2% by mass. These elevated parameters create a thicker, more viscous slurry that is easier to apply uniformly while preventing excessive mixing with the first layer, thus improving both manufacturability and battery reliability
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 effectively suppresses layer mixing, maintaining battery characteristics and improving insulation and charge/discharge performance without compromising the electrode structure.
Implementation Method 1
applying a second layer slurry containing a second binder on the first layer slurry before the first layer slurry is dried
Implementation Method 2
drying the first layer slurry and the second layer slurry after applying the first layer slurry and the second layer slurry
Data Source
AI summary
A method for manufacturing an electrode for a secondary battery includes: applying a first layer slurry containing a first binder to a surface of a current collector, applying a second layer slurry containing a second binder on the first layer slurry before the first layer slurry is dried, and drying the first layer slurry and the second layer slurry after applying the first layer slurry and the second layer slurry to obtain a laminated structure in which a first layer and a second layer are laminated in this order on the current collector. The second layer slurry has a solid content ratio of more than 50% by mass and a composition ratio of the second binder of more than 2% by mass.