Surface-Oxygen VDF Copolymer Particles for Battery Adhesion
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Solution Overview
Problem
The existing vinylidene fluoride copolymer compositions for non-aqueous electrolyte secondary batteries face variability in adhesion between electrodes and separators, even when containing the same oxygen atom-containing functional groups, leading to inconsistent battery performance and lifespan.
Innovation Solution
The development of vinylidene fluoride copolymer particles with a higher oxygen atom ratio on the surface compared to the interior, utilizing specific oxygen atom-containing functional groups such as unsaturated dibasic acids and their esters, to enhance adhesion between electrodes and separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a vinylidene fluoride copolymer composition contains oxygen atom-containing functional groups (such as acrylpropyl succinate and monomethyl maleate) to improve adhesion between electrode and separator, then adhesion is improved, but adhesion consistency varies even at the same compound content
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the particle interior contains the base vinylidene fluoride copolymer with oxygen atom-containing functional groups, while the particle surface is modified with a different composition or treatment that provides consistent adhesion properties. This allows the surface region to have optimized adhesion characteristics independent of the interior composition, resolving the variability issue while maintaining overall adhesion improvement.
Solution Approach 2:
The patent changes physical or chemical parameters of the copolymer particles, specifically modifying surface properties through controlled oxidation, plasma treatment, or surface grafting to increase oxygen atom concentration at the surface. This parameter change at the surface level ensures consistent adhesion performance regardless of variations in bulk composition, thereby improving reliability while maintaining the adhesion benefits.
2Strength
If the copolymer composition uses oxygen atom-containing functional groups to enhance adhesion, then adhesion improves, but the mechanism of action is not controlled leading to variability
Solution Approach 1:
The patent applies preliminary action by pre-modifying the copolymer particles during the polymerization process or through subsequent surface treatment before the particles are used in battery assembly. This preliminary surface modification ensures that oxygen atoms are already positioned at the surface in a controlled manner, eliminating the need for complex in-situ control mechanisms during battery operation and simplifying the overall system while ensuring consistent adhesion.
Solution Approach 2:
The patent replaces complex mechanical or process control systems with a chemically predetermined surface structure. By incorporating oxygen atom-containing functional groups into the particle surface through controlled chemical synthesis or treatment, the adhesion mechanism becomes inherently self-regulating based on chemical affinity rather than requiring external control systems, thereby reducing device complexity while maintaining effective adhesion.
Data Source
AI summary
Provided is a vinylidene fluoride copolymer particle which is capable of efficiently exhibiting high adhesion between an electrode and a separator. The vinylidene fluoride copolymer particle of the present invention comprises vinylidene fluoride; anda compound having an oxygen atom-containing functional group; wherein a ratio of oxygen atom in a surface of the vinylidene fluoride copolymer particle is higher than a ratio of oxygen atom in the vinylidene fluoride copolymer particle other than the surface thereof.