Multilayer Battery Electrode Coating to Suppress Binder Migration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in fabricating multilayer electrodes for secondary batteries is the interlayer mixing of binders during the drying process, which leads to decreased adhesion between the current collector and the electrode active material layer, resulting in non-uniform thickness and reduced performance.
Innovation Solution
A method involving the preparation of high-viscosity electrode slurries with varying binder content, where one slurry is heated to a temperature below its boiling point, coated on a current collector, and then cooled to restore viscosity, followed by controlled drying to minimize binder migration and maintain layer integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrode slurries are coated and dried to form multilayer electrodes, then electrode structure is formed, but binder migration occurs causing interlayer mixing and loss of multilayer structure
Solution Approach 1:
The patent changes the physical state parameters of the electrode slurry by controlling temperature and viscosity. Specifically, the slurry is heated to reduce viscosity for uniform coating, then cooled to increase viscosity and prevent binder migration during drying. This parameter control maintains the multilayer structure while enabling proper coating.
Solution Approach 2:
The patent applies preliminary cooling action after coating to restore the slurry's viscosity before the drying process begins. This preliminary restoration of high viscosity state prevents binder migration and interlayer mixing during the subsequent drying step, thereby preserving the multilayer structure.
2Strength
If binder content in slurry is increased to improve adhesion, then adhesion between current collector and electrode layer improves, but interlayer mixing increases during drying
Solution Approach 1:
The patent uses temperature and viscosity parameter changes to decouple the relationship between binder content and adhesion. By controlling viscosity through temperature, the patent enables proper coating of slurries with optimal binder content without requiring excessive binder that would cause migration, thus maintaining both adhesion and composition stability.
Solution Approach 2:
The patent dynamically adjusts the slurry viscosity during the coating and drying process through temperature control. The slurry transitions from a low-viscosity state during coating (enabling uniform application) to a high-viscosity state during drying (preventing binder migration), thereby maintaining both adhesion and layer integrity.
3Productivity
If drying temperature is increased to speed up drying process, then productivity improves, but binder migration accelerates reducing adhesion
Solution Approach 1:
The patent optimizes the drying temperature parameter to balance productivity and adhesion. By controlling the drying temperature to be below the boiling point of the solvent and managing the viscosity transition, the patent achieves sufficient drying speed while preventing excessive binder migration that would compromise adhesion.
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 approach enhances adhesion between the current collector and electrode active material layers, ensuring uniform thickness and improved battery performance by suppressing binder migration and maintaining the multilayer structure.
Implementation Method 1
heating at least one electrode slurry selected from the prepared two or more electrode slurries to a temperature lower than a boiling point (Tb) of the solvent contained in the selected electrode slurry
Implementation Method 2
cooling the coated two or more electrode slurries
Implementation Method 3
drying the cooled two or more electrode slurries
Data Source
AI summary
The present invention provides a fabrication method of a multilayer electrode for a secondary battery including: (a) preparing two or more electrode slurries each containing an electrode active material, a binder, and a solvent and heating at least one electrode slurry selected from the prepared two or more electrode slurries to a temperature lower than a boiling point (Tb) of the solvent contained in the selected electrode slurry; (b) coating the two or more electrode slurries on a current collector; and (c) cooling the coated two or more electrode slurries.