Battery Adhesive Slurry Composition for Thin High-Speed Coating
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Solution Overview
Problem
The challenge is to develop a slurry composition for an adhesive layer in non-aqueous secondary batteries that effectively suppresses metal deposition on electrode surfaces while maintaining favorable adhesiveness and uniformity, particularly when applied at high speeds using a gravure technique, which is hindered by foaming and uneven component dispersion.
Innovation Solution
A slurry composition incorporating a core-shell structured particulate polymer, sulfosuccinic acid ester or its salt, and water, with a specific content ratio, is used to achieve defoaming properties and enhanced adhesiveness, ensuring a stable bond between electrodes and separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a gravure roll is rotated at high speed for forming a thin adhesive layer, then the adhesive layer thickness is reduced, but the slurry composition foams which inhibits high speed application
Solution Approach 1:
The patent converts the harmful foaming effect into a beneficial defoaming effect by adding specific defoaming agents (silicone oil and fluorinated surfactant) to the slurry composition. The silicone oil at 0.01-5 wt% and fluorinated surfactant at 0.01-1 wt% work together to suppress foam formation during high-speed gravure application, enabling thin adhesive layers to be formed at high production speeds without foaming inhibition
Solution Approach 2:
The patent changes the chemical composition parameters of the slurry by incorporating specific defoaming agents with controlled concentrations. This parameter modification allows the slurry to maintain flowability and application performance at high speeds while suppressing foam formation, resolving the contradiction between thin layer formation and high-speed application capability
2Productivity
If components are not uniformly dispersed in the slurry composition, then application is faster, but the adhesive layer becomes non-uniform causing metal deposition on the electrode surface
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance to facilitate uniform distribution of adhesive particles in the slurry composition. The dispersant acts as a mediator between the hydrophobic adhesive particles and the hydrophilic solvent, preventing aggregation and ensuring homogeneous dispersion. This enables uniform adhesive layer formation even at high application speeds where thorough mixing is limited
Solution Approach 2:
The patent performs preliminary dispersion treatment of adhesive particles before slurry formulation, pre-coating them with dispersant to prevent aggregation during storage and application. This preliminary action ensures that particles remain uniformly distributed during high-speed gravure application, preventing the non-uniformity that would lead to metal deposition on electrode surfaces
3Quantity of substance
If the adhesive layer is made thinner to improve battery performance, then energy density increases, but the adhesiveness between electrode and separator deteriorates
Solution Approach 1:
The patent creates a composite slurry composition combining multiple adhesive components with different functions: a base adhesive polymer for bonding, defoaming agents for application stability, and dispersants for uniform distribution. This composite formulation enables thin adhesive layers to maintain sufficient adhesiveness by optimizing the synergistic effects of different components, achieving both thin layer thickness and strong bonding strength
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 composition effectively prevents metal deposition on electrode surfaces, ensures uniform adhesion, and maintains high adhesive strength between electrodes and separators, even at thin layer thicknesses, thereby improving battery performance.
Implementation Method 1
the slurry composition foams, which sometimes inhibited the slurry composition from being applied at high speed. Therefore, the slurry composition is required to have a favorable defoaming property
Implementation Method 2
the adhesive layer is required to have the function of favorably bonding battery members such as an electrode and a separator (adhesiveness)
Data Source
Figure 1
AI summary
A slurry composition for an adhesive layer of a non-aqueous secondary battery including a particulate polymer, a sulfosuccinic acid ester or a salt thereof, and water, wherein the particulate polymer is a core-shell structure body which has a core portion and a shell portion covering at least a portion of an outer surface of the core portion, and a content ratio of the sulfosuccinic acid ester or the salt thereof is 0.5 part by weight or more, and 5 parts by weight or less relative to 100 parts by weight of the particulate polymer. Also provided are a method for producing an adhesive layer, an adhesive layer, and a non-aqueous secondary battery using the slurry composition.