Dry Electrode Mixed Powder for Conductive Material Dispersibility
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Solution Overview
Problem
Existing methods for manufacturing dry electrodes face challenges in improving the dispersibility of conductive materials, leading to increased resistance and degradation of battery performance, and there is a need for an evaluation tool to determine dispersibility.
Innovation Solution
A dry electrode with a high conductive material dispersibility index, achieved through a method involving mixing electrode materials, fibrillizing a binder polymer, and forming a sheet-like electrode active material layer with a predetermined thickness, using thermocompression binding and lamination with a current collector, and evaluating dispersibility through specific indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of conductive material is increased to improve energy density, then the energy density is improved, but the resistance increases and output characteristics degrade
Solution Approach 1:
The patent changes the physical state parameter of the conductive material from linear to spherical form. This parameter change allows the conductive material to achieve better dispersibility and form more effective conduction paths at lower concentrations, resolving the contradiction between conductive material content and output characteristics
Solution Approach 2:
The patent creates a composite structure where spherical conductive materials are embedded within the electrode active material matrix. This composite approach optimizes the distribution and effectiveness of conductive material, improving both energy density and output characteristics
2Ease of manufacture
If a linear conductive material is used in a dry process, then the manufacturing process is simplified, but the conductive material is broken by shear force and cannot retain its original length, preventing sufficient conduction path formation
Solution Approach 1:
The patent inverts the conventional approach by using spherical conductive material instead of linear conductive material. This inversion eliminates the weakness of linear materials against shear force while maintaining ease of manufacture in dry processes, as spherical particles are inherently more resistant to breakage
Solution Approach 2:
The patent changes the geometric parameter of the conductive material from linear to spherical shape. This parameter change fundamentally alters the material's response to shear force during mixing, preventing breakage and enabling effective conduction path formation through particle-to-particle contact
3Manufacturing precision
If dispersant is introduced to improve conductive material dispersibility, then the dispersibility is improved, but the dry process cannot effectively improve dispersibility without solvent
Solution Approach 1:
The patent changes the physical form parameter of the conductive material to spherical shape, which inherently provides better dispersibility in dry mixing processes. The spherical geometry reduces inter-particle entanglement and promotes uniform distribution without requiring dispersants or solvent
Solution Approach 2:
The patent uses the spherical conductive material itself as an intermediary that facilitates uniform distribution throughout the electrode mixture. The spherical shape acts as a mediator that prevents aggregation and promotes homogeneous dispersion during the dry mixing and calendering processes
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 method enhances conductive material dispersibility, reducing internal and interfacial resistance, improving battery efficiency and life characteristics, and provides a quantitative evaluation of dispersibility.
Implementation Method 1
fibrilizing a binder through a high-shear mixing process, such as jet-milling
Implementation Method 2
carrying out compression molding of the mixture into a film shape
Data Source
AI summary
A dry electrode having high dispersibility of the conductive material in the electrode active material layer, a method of making the dry electrode, and an evaluation tool capable of determining the dispersibility of a conductive material in an electrode as a quantitative value. As the dispersibility of the conductive material in the disclosed dry electrode is increased, the internal resistance of the electrode active material layer and the interfacial resistance with a current collector are reduced, under the same content of the conductive material in the electrode. When this electrode is included in a battery, ohmic resistance is reduced during the operation of the battery to improve a drop in voltage and to enhance high-output efficiency.