Dry Electrode Powder Fiberization Control for High Energy Density
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Solution Overview
Problem
The existing methods for manufacturing electrodes for secondary batteries through dry processes face challenges in quantifying and standardizing the degree of fiberization, which affects the physical and electrochemical properties, leading to inconsistent results and reduced reproducibility.
Innovation Solution
A powder for electrodes comprising an active material, solid electrolyte, conductive material, and fibrous binder, with a controlled degree of fiberization between 2.7 and 3.6, achieved through a specific kneading and pulverizing process, is used to design high energy density electrodes, ensuring consistent ion conductivity, composite density, and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image analysis is used to measure fiber thickness and length, then the degree of fiberization can be confirmed, but the analysis lacks reproducibility and representativeness due to limited analysis amount
Solution Approach 1:
The patent replaces the conventional image analysis method with a standardized mechanical measurement method. A blade is inserted into the electrode at a predetermined depth, and the force required to insert the blade is measured. This mechanical measurement provides quantitative and standardized data for the degree of fiberization, eliminating the limitations of image analysis while ensuring reproducibility and representativeness.
2Strength
If a fibrous binder is used in the dry process, then the degree of fiberization affects physical properties such as tensile strength and density, but electron/ion conductivity paths are blocked affecting electrochemical properties
Solution Approach 1:
The patent optimizes the degree of fiberization to a specific range (0.3 to 0.7) to balance the conflicting requirements. By controlling the fiberization parameter within this optimal range, the electrode achieves sufficient tensile strength while maintaining adequate electron and ion conductivity paths, thus resolving the trade-off between mechanical strength and electrochemical performance.
3Manufacturing precision
If the degree of fiberization is increased to improve physical properties, then tensile strength and density are enhanced, but electrochemical properties deteriorate due to blocked conductivity paths
Solution Approach 1:
The patent establishes an optimal range for the degree of fiberization (0.3 to 0.7) that simultaneously satisfies both physical property requirements and electrochemical performance. By controlling this parameter within the specified range, the electrode achieves consistent tensile strength and density while maintaining sufficient conductivity paths for electrons and ions.
4Ease of manufacture
If conventional dry mixing is used to manufacture the powder, then the process is simple, but the degree of fiberization cannot be controlled precisely
Solution Approach 1:
The patent introduces a preliminary kneading step before the final mixing process. The binder is kneaded separately to achieve the desired degree of fiberization, and then this pre-fiberized binder is mixed with the active material and other components. This preliminary action ensures precise control over the degree of fiberization while maintaining relative process simplicity.
Data Source
AI summary
The present disclosure can implement a high energy density electrode by quantifying and standardizing a degree of fiberization of powder for an electrode used in a dry electrode. The powder includes an active material; a solid electrolyte; a conductive material; and a fibrous binder.