Dry Electrode Mixture Film With Carbon-Coated Active Material
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrode manufacturing processes face challenges such as defects in the electrode active material layer due to uneven solvent evaporation, high costs and complexity of drying devices, and the use of toxic solvents like N-methyl-2-pyrrolidone (NMP), which is harmful and environmentally unfriendly. Additionally, dry electrodes struggle with dispersing conductive materials like carbon nanotubes, leading to increased conductive material usage and reduced active material loading.
Innovation Solution
The development of an electrode mixture film with a conductive path connectivity index (CPCI) of 0.09 to 0.45, achieved by using an electrode active material with a carbon coating layer and a fiberized binder. This film ensures excellent conductive path connectivity even with insufficient conductive material, allowing for increased active material loading and improved battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a solvent-based slurry is used to manufacture electrodes, then the electrode active material layer can be formed, but defects such as pinholes or cracks are generated due to uneven solvent evaporation
Solution Approach 1:
The patent removes the solvent component from the electrode manufacturing process entirely, transitioning from a wet slurry process to a dry process. This extraction of the harmful solvent eliminates the root cause of uneven evaporation, pinholes, and cracks, directly resolving the contradiction between layer formation capability and structural integrity.
Solution Approach 2:
The patent changes the fundamental parameter of the manufacturing process from wet to dry state. By using dry electrode materials and dry binding methods instead of solvent-based slurries, the evaporation parameter is completely eliminated, preventing defects while maintaining layer formation capability.
2Manufacturing precision
If expensive drying devices are used to control solvent evaporation rate, then uniform drying can be achieved, but manufacturing cost and operation time increase significantly
Solution Approach 1:
The patent extracts and eliminates the solvent evaporation step entirely from the manufacturing process. By adopting a dry electrode approach, the complex drying devices and associated high costs and long operation times are completely removed, achieving both uniformity and ease of manufacture.
Solution Approach 2:
The patent replaces expensive, complex drying equipment with simple, inexpensive dry processing methods. The dry electrode materials and binding techniques require minimal equipment, dramatically reducing manufacturing cost and simplifying the process while maintaining product quality.
3Ease of manufacture
If N-methyl-2-pyrrolidone (NMP) is used as solvent in electrode slurry, then the slurry can be prepared, but high heat energy is required for drying and the process becomes unsuitable for mass production
Solution Approach 1:
The patent removes NMP and all solvents from the electrode preparation process. By using dry mixing and dry binding techniques, the high heat energy requirement for drying is eliminated, making the process suitable for mass production while maintaining slurry-like workability through alternative mechanisms.
Solution Approach 2:
The patent replaces the expensive, energy-intensive NMP solvent system with inexpensive, energy-efficient dry processing methods. This substitution dramatically reduces heat energy requirements and enables scalable mass production while maintaining the ability to prepare and process electrode materials effectively.
4Ease of manufacture
If N-methyl-2-pyrrolidone (NMP) is used as solvent, then the electrode slurry can be formed, but the toxic and harmful nature of NMP makes the process environmentally unfriendly
Solution Approach 1:
The patent extracts and eliminates NMP and all organic solvents from the electrode manufacturing process. By using dry processing methods, the toxic and harmful environmental factors associated with NMP are completely removed, achieving environmentally friendly production while maintaining the ability to form and process electrode materials.
5Quantity of substance
If linear conductive materials such as CNT are used in dry electrodes, then the amount of conductive material can be reduced, but the materials are not dispersed well without solvents and dispersants
Solution Approach 1:
The patent introduces a binder that acts as an intermediary substance to facilitate the dispersion and distribution of conductive materials in the dry electrode mixture. This binder enables uniform distribution of CNT and other conductive materials without requiring external solvents or dispersants, resolving the contradiction between reduced conductive material quantity and uniform distribution.
Solution Approach 2:
The patent creates a composite material system where the binder and conductive materials are integrated into a unified dry mixture. This composite approach allows conductive materials to be evenly distributed throughout the electrode structure through the binder matrix, achieving uniform dispersion without solvents while maintaining reduced conductive material content.
Data Source
AI summary
An electrode mixture film includes an electrode active material containing a carbon coating layer, and a fiberized binder, and has a conductive path connectivity index (CPCI) defined by factors such as degree of agglomeration of the binder, volume cumulative average particle diameter D50 of the electrode active material, and thickness of the carbon coating layer of the electrode active material. The CPCI may be in a range from 0.9 to 0.45 and the dry electrode includes no conductive material but still has excellent resistance characteristics due to excellent connectivity of a conductive path. A dry electrode and a lithium secondary battery including the same are also provided.