Positive Electrode Pore Distribution for Stable Battery Conductive Paths
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Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges in maintaining initial battery output characteristics and preventing increased battery resistance during repeated charge and discharge cycles due to deterioration of the conductive path from the current collector to the active material, which is exacerbated by the use of conductive materials with large specific surface areas or high aspect ratios, and the need for increased binder amounts to improve binding ability.
Innovation Solution
A positive electrode with a specific pore diameter distribution and CO2 generation profile is designed, featuring a first peak in the pore distribution curve between 0.1-0.3 μm and a second peak between 0.3-1 μm, with a binder content of 0.1-4 parts by weight per 100 parts of active material, to maintain the conductive path and prevent binder degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive material having a large specific surface area is added to maintain the conductive path, then the conductive path can be maintained, but the slurry becomes difficult to handle and side reactions on the electrode easily occur
Solution Approach 1:
The patent applies porous carbon material with controlled pore structure (average pore diameter 0.003-0.6 μm, total pore volume 0.03-0.20 mL/g) as the conductive material. The porous structure provides large surface area for conductive path maintenance while the controlled pore size and volume prevent excessive solvent absorption, resolving the contradiction between conductive path maintenance and slurry handleability.
2Reliability
If a conductive material having a large aspect ratio is added to maintain the conductive path, then the conductive path can be maintained, but the conductive material is expensive and easily aggregated, making it difficult to uniformly distribute
Solution Approach 1:
The patent uses porous carbon material with controlled pore dimensions instead of high aspect ratio materials. The porous structure provides sufficient surface area for conductive function while maintaining a particle morphology that resists aggregation and enables uniform distribution in the slurry, addressing both conductive path maintenance and distribution uniformity.
Solution Approach 2:
The patent controls specific parameters of the porous carbon material (average pore diameter 0.003-0.6 μm, total pore volume 0.03-0.20 mL/g) to optimize both conductive performance and dispersibility. By adjusting these parameters, the material maintains effective conductive paths while preventing aggregation and ensuring uniform distribution.
3Reliability
If the amount of binder is increased to improve binding ability and maintain conductive path, then the conductive path can be maintained, but the initial battery output characteristics deteriorate
Solution Approach 1:
The patent replaces excessive binder with controlled amounts of porous carbon material (0.01-5 parts by weight per 100 parts active material). The porous carbon provides both conductive pathways and binding functionality through its surface properties, eliminating the need for large binder amounts and preserving initial battery output characteristics while maintaining conductive path integrity.
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 initial battery output characteristics while controlling battery resistance and maintaining the electrode structure's integrity during charge and discharge cycles, ensuring favorable Li ion diffusibility and electron conductivity.
Implementation Method 1
ensuring favorable Li ion diffusibility
Implementation Method 2
maintaining the electrode structure's integrity during charge and discharge cycles, ensuring favorable electron conductivity
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A positive electrode for nonaqueous electrolyte battery includes specific peaks in pyrolysis GC/MS measurement, and includes specific pore diameters and pore volumes in a pore distribution curve attained by a mercury intrusion method.