Dry Electrode Pore Structure for Fast Lithium-Ion Transport
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Solution Overview
Problem
Existing dry electrode manufacturing processes face issues with non-uniform solvent evaporation leading to defects like pinholes and cracks, and the use of expensive dryers for uniform drying is inefficient, resulting in poor electrode quality and performance.
Innovation Solution
A dry electrode structure with a uniform binder/conductive material distribution and controlled pore size and porosity, achieved through a method involving kneading, grinding, and calendering of electrode powder, to enhance lithium ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a drying process is used to remove solvent from electrode mixture, then the electrode active layer is formed, but defects such as pin holes or cracks occur and non-uniform drying leads to poor electrode quality
Solution Approach 1:
The invention extracts and removes the solvent from the electrode mixture before electrode formation, creating a dry electrode structure. This eliminates the drying process that causes pin holes and cracks, while maintaining uniform binder distribution through the extracted solvent-free structure
Solution Approach 2:
Instead of forming a wet electrode and then drying it (conventional approach), the invention inverts the process by forming a dry electrode structure from the beginning without solvent. This reversal prevents drying-related defects while achieving uniform binder distribution through the inverted manufacturing sequence
2Manufacturing precision
If expensive dryers are used to uniformly dry the active layer, then drying uniformity is improved, but manufacturing cost and process time increase
Solution Approach 1:
The invention extracts and eliminates the drying step entirely by removing the solvent before electrode formation. This eliminates the need for expensive drying equipment while achieving uniform electrode structure through the solvent-free manufacturing process
Solution Approach 2:
Instead of using complex drying equipment to achieve uniform drying of wet electrodes, the invention inverts the approach by forming dry electrodes without solvent from the start. This simplification removes the need for expensive drying infrastructure while maintaining manufacturing precision
3Manufacturing precision
If binder resin is fibrillated too finely in dry electrode manufacturing, then uniform distribution is achieved, but pore size becomes too small impeding Li ion migration
Solution Approach 1:
The invention applies local quality control by creating different pore size zones within the electrode structure. The binder is fibrillated to achieve uniform distribution in certain regions while maintaining larger pores in other regions to facilitate Li ion migration, optimizing both uniformity and ion transport speed
Solution Approach 2:
The invention utilizes porous material structure with controlled pore sizes and distributions. The pore structure is engineered to have appropriate size and connectivity that simultaneously achieves uniform binder distribution and maintains sufficient pore volume for fast Li ion migration through the porous network
Data Source
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AI summary
A dry electrode according to the present disclosure has an electrode active material layer including large diameter pores, leading to easy lithium (Li) migration, low Li diffusion resistance and fast lithium movement, thereby reducing or suppressing overvoltage, and improving high rate charge/discharge characteristics.