Positive Electrode Composition Mixing for Rate and Cycle Stability
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Solution Overview
Problem
There is a need for further performance improvements in lithium ion secondary batteries, specifically in discharge rate characteristics and cycle characteristics.
Innovation Solution
A method for producing a positive electrode composition that involves mixing a binding material, carbon black, and carbon nanotubes with an active material in a specific order to achieve excellent discharge rate and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional positive electrode paste containing carbon black is used, then electrical conductivity is improved, but discharge rate characteristics and cycle characteristics remain insufficient
Solution Approach 1:
The patent uses a composite conductive system combining carbon black particles and carbon nanotubes. The carbon nanotubes form a three-dimensional conductive network that complements the carbon black particles, creating a synergistic effect that improves both discharge rate characteristics and cycle characteristics while maintaining electrical conductivity.
Solution Approach 2:
The patent optimizes the ratio of carbon black to carbon nanotubes and controls the average particle size of carbon black within specific ranges (10-100 nm). These parameter changes enable the conductive material to achieve optimal performance for high-rate discharge and long-cycle stability without excessive complexity in paste preparation.
2Reliability
If more carbon black is added to improve electrical conductivity, then conductivity increases, but discharge rate characteristics do not sufficiently improve
Solution Approach 1:
Instead of increasing carbon black content alone, the patent introduces carbon nanotubes to form a composite conductive system. The carbon nanotubes provide efficient electron transport pathways that enhance discharge rate characteristics without requiring excessive carbon black, thus avoiding the limitations of single-material approaches.
Solution Approach 2:
The patent creates localized conductive networks where carbon nanotubes and carbon black particles work together in specific regions of the electrode. This local optimization allows efficient electron transport at critical interfaces between active material particles, improving discharge rate characteristics without uniformly increasing overall carbon content.
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 method results in a positive electrode composition that enhances the discharge rate characteristics and cycle characteristics of lithium ion secondary batteries, ensuring stable performance and extended battery life.
Implementation Method 1
an electrical conducting material such as carbon black has been added to the positive electrode paste for the purpose of imparting electrical conductivity
Implementation Method 2
a second step of applying the positive electrode composition onto a current collector to form a mixed material layer containing the carbon black, the carbon nanotubes, the binding material, and the active material on the current collector
Data Source
AI summary
A method for producing a positive electrode composition, the method including: a first step of mixing a first agent containing a binding material and a first liquid medium, a second agent containing carbon black and a second liquid medium, and a third agent containing carbon nanotubes and a third liquid medium to obtain a mixed solution; and a second step of mixing the mixed solution and an active material to obtain a positive electrode composition.