Multilayer Battery Electrode Structure for Uniform CNT Distribution
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Solution Overview
Problem
The existing manufacturing methods for secondary battery electrodes using carbon nanotubes as conductive materials result in uneven distribution of binders and conductive materials, leading to reduced adhesive force and deteriorated input/output characteristics due to the migration of binders during the drying process.
Innovation Solution
A multilayer electrode structure is introduced, where a first mixture layer with single-walled carbon nanotubes is formed on a current collector, followed by a second mixture layer with multi-walled carbon nanotubes, and optionally additional layers, with the concentration of multi-walled carbon nanotubes decreasing as distance from the second layer increases, to improve the uniformity of conductive material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer electrode structure is used with carbon nanotubes as conductive material, then the manufacturing process is simple, but the distribution of binder and conductive material becomes uneven during drying
Solution Approach 1:
The electrode is divided into multiple layers (first mixture layer and second mixture layer) with different conductive material compositions. This segmentation allows each layer to have optimized properties, preventing the binder and conductive material from migrating uniformly during drying, thus solving the distribution uniformity problem while maintaining manufacturing feasibility.
Solution Approach 2:
Different mixture compositions are applied to different layers of the electrode. The first mixture layer contains a specific ratio of binder to conductive material, while the second mixture layer has a different ratio. This local quality variation ensures that each layer contributes differently to the overall electrode performance, preventing uniform migration issues during drying.
2Reliability
If carbon nanotubes are used as conductive material to reduce electrode resistance, then electrical conductivity improves, but binder distribution becomes uneven during drying process
Solution Approach 1:
The electrode structure is segmented into multiple layers with different conductive material compositions. This segmentation prevents the binder and conductive material from migrating uniformly during drying, thus solving the distribution uniformity problem while maintaining electrical conductivity through the optimized multi-layer configuration.
Solution Approach 2:
The electrode uses a composite structure with multiple mixture layers, each having different ratios of binder to conductive material. This composite approach allows the electrode to maintain excellent electrical conductivity while preventing uneven binder distribution during the drying process.
3Quantity of substance
If high-pressure pressing is applied to form high-density electrode to reduce space between particles, then energy density improves, but electrolyte permeability is reduced
Solution Approach 1:
Different regions of the electrode (different layers) have different mixture compositions optimized for their specific functions. This local quality variation allows the electrode to achieve high energy density in certain layers while maintaining electrolyte permeability in other layers, resolving the contradiction between these two properties.
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 enhances the uniformity of conductive material distribution, reducing electrode resistance and improving the output characteristics of secondary batteries by maintaining excellent conductivity and mechanical properties.
Implementation Method 1
carbon nanotubes, which are fibrous carbon-based conductive materials capable of further reducing electrode resistance by forming an electrically conductive path within an electrode
Implementation Method 2
a first mixture layer including an active material, a binder, and a single-walled carbon nanotube... and a second mixture layer including an active material, a binder, and a multi-walled carbon nanotube
Data Source
AI summary
The present disclosure relates to a multilayer electrode for a secondary battery. The multilayer electrode for a secondary battery includes: an electrode current collector; a first mixture layer including an active material, a binder, and a single-walled carbon nanotube, the first mixture layer being formed on at least one surface of the electrode current collector; and a second mixture layer including an active material, a binder, and a multi-walled carbon nanotube, the second mixture layer being formed on the first mixture layer. According to the present disclosure, by improving the uniformity of the distribution of the conductive material in the electrode mixture layer, it is possible to prevent the resistance from increasing, and as a result, it is possible to improve the output characteristics of the secondary battery.