Battery Electrode Intermediate Layer for Low Interface Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electrodes for secondary batteries, particularly those using a dry method, face challenges with high interface resistance between the core and the mixture layer, which can be improved by optimizing the structure of the electrically conductive intermediate layer.
Innovation Solution
The electrode comprises a core, a mixture layer with an active material and a first binder, and an electrically conductive intermediate layer with a specific particle size distribution and a thermoplastic resin binder, where the intermediate layer includes conductive agents with distinct particle sizes and aspect ratios, and a thickness that optimizes conductivity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically conductive intermediate layer is provided between the core and the mixture layer, then the interface resistance is reduced, but the interface resistance significantly varies depending on the structure of the intermediate layer
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of conductive agents (bimodal distribution with peaks at 0.005-0.07 μm and 0.3-20 μm), the aspect ratio of particles (1-9), and the thickness of the intermediate layer (0.1-5 μm). These parameter optimizations ensure consistent low interface resistance while maintaining reliable electrical conductivity across different production batches.
Solution Approach 2:
The patent uses composite materials by combining conductive agents with different particle sizes and shapes in a bimodal distribution within the intermediate layer. This composite structure of spherical and flake-shaped particles creates a more consistent and reliable conductive network compared to single-size particles, reducing variability in interface resistance.
2Ease of manufacture
If a dry method is used to produce the electrode, then the interface resistance tends to increase, but the production process needs to be simplified
Solution Approach 1:
The patent introduces an electrically conductive intermediate layer as a mediator between the core and the mixture layer. This intermediate layer specifically addresses the high interface resistance problem inherent in dry method production, enabling the use of simplified dry processing while maintaining low interface resistance through the conductive bridge it provides.
Solution Approach 2:
The patent optimizes specific parameters of the intermediate layer including conductive agent content (1-40 mass%), particle size distribution, and layer thickness (0.1-5 μm) to achieve low interface resistance in dry method production, balancing manufacturing simplicity with electrical performance.
3Strength
If the intermediate layer thickness is increased, then the adhesion force is improved, but the interface resistance may increase
Solution Approach 1:
The patent identifies and controls the optimal thickness range of the intermediate layer (0.1-5 μm) as a critical parameter. Within this range, the layer provides sufficient adhesion strength while maintaining adequate electrical conductivity. The bimodal particle size distribution and aspect ratio control (1-9) further optimize this balance between mechanical adhesion and electrical performance.
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 configuration significantly reduces the interface resistance and enhances the adhesion force between the core and the mixture layer, leading to improved power characteristics and rapid charging/discharging capabilities.
Implementation Method 1
the second binder has, as a primary component, a thermoplastic resin having a melting point of greater than or equal to 100° C. and less than or equal to 200° C.
Data Source
AI summary
An electrode with a core material, a mixture layer, and an electrically conductive intermediate layer. A conductive agent contained in the intermediate layer has a particle size distribution which has a first peak that is within the particle diameter range of greater than or equal to 0.005 μm and less than or equal to 0.07 μm and a second peak that is within the particle diameter range of greater than or equal to 0.3 μm and less than or equal to 20 μm.