Secondary Battery Mixture Sheet With Controlled PTFE Fibrillation
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Solution Overview
Problem
Conventional secondary battery mixtures using polytetrafluoroethylene (PTFE) as a binder fail to achieve optimal performance due to insufficient fibrillation, leading to inadequate mechanical properties and flexibility in secondary battery sheets.
Innovation Solution
The use of a fibrillatable PTFE resin with a maximum fibril diameter of 90 nm or more, along with specific particle size and moisture content, to create a fibrous structure that effectively binds powder components and enhances the mechanical properties of secondary battery mixture sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polytetrafluoroethylene resin is used as a binder in secondary battery mixture, then the mixture can be formed into sheets, but the sheets exhibit insufficient mechanical properties and flexibility due to inadequate fibrillation
Solution Approach 1:
The patent applies parameter changes by controlling the fibril diameter of polytetrafluoroethylene resin within a specific range (0.03 μm to 0.09 μm) and optimizing the binder content (0.1 wt% to 10 wt%). These parameter adjustments transform the resin's structural characteristics to achieve both adequate mechanical strength and flexibility in the secondary battery sheets.
Solution Approach 2:
The patent creates a composite material system where polytetrafluoroethylene resin forms a fibrous network structure that binds powder components (electrode active material and conductive aid). This composite structure combines the binding capability of the resin with the functional properties of the powder components, achieving both mechanical integrity and flexibility.
2Ease of manufacture
If conventional PTFE binder is used without sufficient fibrillation, then the mixture can be processed, but the resulting sheets lack adequate mechanical strength and structural integrity
Solution Approach 1:
The patent applies preliminary action by pre-forming the polytetrafluoroethylene resin into a fibrillar structure with controlled diameter (0.03 μm to 0.09 μm) before mixing with powder components. This preliminary structural preparation ensures that the binder is ready to provide mechanical strength upon sheet formation, eliminating the need for extensive post-processing fibrillation steps.
3Reliability
If fibril diameter is reduced to enhance binding capability, then the binder effectiveness improves, but the fibril structure becomes too fine and weak
Solution Approach 1:
The patent optimizes the fibril diameter parameter within a narrow range (0.03 μm to 0.09 μm) that balances binding effectiveness and structural strength. This parameter optimization ensures that fibrils are fine enough to effectively bind powder components while maintaining sufficient individual fibril strength and overall network 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
The approach results in a secondary battery mixture sheet with improved flexibility, mechanical strength, and reduced deterioration of the solid-state electrolyte, enabling the production of high-strength, self-supporting sheets suitable for solid-state batteries.
Implementation Method 1
the binder is a fibrillatable resin, and the fibrillatable resin has a fibrous structure with a maximum fibril diameter of 90 nm or more
Data Source
AI summary
Provided is a secondary battery mixture that has good properties, a secondary battery mixture sheet containing the mixture, and a secondary battery using the secondary battery sheet. The secondary battery mixture contains a solid-state electrolyte and/or electrode active material, and a binder, wherein the binder is a fibrillatable resin having a fibrous structure with a maximum fibril diameter of 90 nm or more.