Positive Electrode CNT Composition for Output and Fusing Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of carbon nanotubes (CNTs) as conductive materials in positive electrodes of batteries improves output and high-rate properties but reduces electrode fusing/disconnection properties due to decreased composite material layer resistance, necessitating a balance between conductivity and fusing/disconnection performance.
Innovation Solution
A positive electrode composite material layer with a CNT content of 0.45 wt % or less and a composite material layer area resistivity of 0.10 Ω·cm2 or more, combined with a high packing density and specific particle size ratios of active material particles, along with surface-modified CNTs and additive agents, to enhance charging/discharging efficiency and fusing/disconnection properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If CNT content is increased in the positive electrode composite material layer, then conductivity and output property are improved, but fusing/disconnection property is decreased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the CNT content within 0.01-0.45 wt% and the composite material layer area resistivity within 0.03-0.10 Ω·cm2. This optimization balances the conductivity improvement from CNT addition with the fusing/disconnection property degradation, achieving both high output property and reliable electrode integrity during battery operation.
Solution Approach 2:
The patent uses composite materials by combining CNT with positive electrode active material particles to form a composite material layer. This composite structure leverages the high conductivity of CNT while maintaining the electrochemical activity of the active material, resolving the contradiction between conductivity enhancement and structural stability.
2Reliability
If CNT content is reduced in the positive electrode composite material layer, then fusing/disconnection property is improved, but conductivity and output property are decreased
Solution Approach 1:
The patent resolves this contradiction by establishing a lower bound for CNT content (0.01 wt%) and resistivity (0.10 Ω·cm2), ensuring sufficient conductivity and output performance while preventing excessive CNT addition that would compromise fusing/disconnection properties. This parameter optimization achieves the balance between reliability and power.
3Quantity of substance
If content of positive electrode active material is increased, then energy density is improved, but conductivity is decreased
Solution Approach 1:
The patent uses CNT as an intermediary conductive material that forms a conductive network within the composite material layer. This CNT network mediates between the active material particles, providing continuous electron transport pathways that maintain high conductivity even when active material content is increased to improve energy density.
Solution Approach 2:
The patent creates a composite material layer where CNT and active material particles are combined in optimized proportions. This composite structure allows simultaneous achievement of high energy density (through sufficient active material content) and high conductivity (through the conductive CNT network), resolving the trade-off between these two critical parameters.
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
The solution achieves excellent charging/discharging efficiency, high initial capacity, and improved fusing/disconnection properties by optimizing CNT content and resistivity within the positive electrode composite material layer, while maintaining high energy density.
Implementation Method 1
an output property and a high-rate property can be improved due to high conductivity of the CNT
Data Source
AI summary
The present disclosure provides a positive electrode including a positive electrode composite material layer, wherein the positive electrode composite material layer includes an active material particle and a carbon nanotube, a content of the carbon nanotube is 0.45 wt % or less based on 100 wt % of a total solid content of the positive electrode composite material layer as a reference, and a composite material layer area resistivity of the positive electrode composite material layer is 0.10 Ω·cm2 or more. According to the present disclosure, there are provided: the positive electrode that is excellent in charging/discharging efficiency and that can exhibit a high capacity and a high fusing/disconnection property; and a battery including the positive electrode.