Conductive Composition Underlayer for Battery Electrode Adhesion
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Solution Overview
Problem
Existing electrode compositions for electrical storage devices face challenges in achieving good conductivity, adhesion, and durability, particularly in high-temperature environments, due to inadequate dispersion of conductive carbon materials and insufficient adhesion between electrode components, leading to reduced charge-discharge cycle performance and increased risk of delamination.
Innovation Solution
A conductive composition comprising conductive carbon material, a water-soluble resin binder, and a water-dispersed resin fine particle binder in specific ratios, applied as an underlayer on a current collector, enhances adhesion and maintains dispersibility, thereby improving the electrical storage device's charge-discharge cycle characteristics and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly conductive carbon materials are used to improve conductivity, then electrical conductivity is improved, but uniform dispersion becomes difficult due to strong cohesion and large structure
Solution Approach 1:
A dispersant is introduced as an intermediary substance between the conductive carbon material and the solvent. The dispersant contains specific functional groups that interact with the carbon material surface, reducing aggregation and improving uniform dispersion while maintaining electrical conductivity.
Solution Approach 2:
The invention creates a composite system consisting of conductive carbon material, dispersant, and solvent. This composite approach allows the dispersant to mediate the interaction between carbon particles and solvent, resolving the contradiction between conductivity and dispersibility.
2Strength
If adhesion between electrode components is strengthened to prevent delamination, then adhesion is improved, but the composition becomes less fluid and harder to apply
Solution Approach 1:
The invention changes the chemical parameters of the binder by selecting specific polymers with appropriate molecular weights and functional groups. This allows achieving strong adhesion while maintaining suitable fluidity for application, as the binder's chemical structure can be optimized independently of its physical state during application.
3Manufacturing precision
If the electrode composition is made more viscous to form a flat surface with uniform thickness, then surface quality is improved, but fluidity decreases making application difficult
Solution Approach 1:
The solvent type and concentration are carefully selected and optimized to achieve the precise viscosity range needed. This allows the composition to remain fluid enough for application while forming a flat, uniform surface during the coating process.
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 proposed composition effectively forms a stable underlayer that enhances the electrical storage device's performance by maintaining conductivity and adhesion, even in harsh environments, leading to improved durability and extended lifespan.
Implementation Method 1
the state of dispersion of an active material or a conductive carbon material in the electrode mixture ink or the state of dispersion of a conductive carbon material in the underlayer-forming composition
Implementation Method 2
adhesion between components of the electrode formed after the drying of the electrode mixture ink or the underlayer-forming composition
Data Source
AI summary
This conductive composition contains a conductive carbon material (A), a water-soluble resin binder (B), a water-dispersible resin particle binder (C) and an aqueous liquid medium (D), and is characterized in that, of the total 100wt% of solid content of the conductive carbon material (A), the water-soluble resin binder (B) and the water-dispersible resin particle binder (C), the content of the conductive carbon material (A) is 20-70wt%, and of the total 100 wt% of solid content of the water-soluble resin binder (B) and the water-dispersible resin particle binder (C), the content of the water-soluble resin binder (B) is greater than or equal to 3 wt% and less than 40 wt%. Hereby, it is possible to provide a conductive composition for forming a power storage device with excellent conductivity and adhesion, excellent dispersibility of the conductive carbon material and electrode adhesion, and excellent charge-discharge cycle characteristics.