Multilayer Inorganic Separator Electrode for Low-Resistance Li-Ion Cells
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Solution Overview
Problem
Conventional separator-composite electrodes using inorganic coatings on electrode active material layers suffer from increased resistance due to blocked pores, leading to decreased battery capacity and lifespan, and lack adequate safety at high temperatures.
Innovation Solution
A method of manufacturing a separator-composite electrode with a multilayer structure comprising a first inorganic layer with larger particles and a second inorganic layer with smaller particles, where the first layer has higher viscosity, ensuring the second layer does not penetrate the pores of the electrode active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer with inorganic material is added to the porous substrate, then thermal shrinkage resistance is improved, but adhesion to the electrode becomes weak and the non-reactive portion increases
Solution Approach 1:
The patent combines the separator function and electrode function into a single integrated structure. The porous substrate serves as both the separator and the electrode base, with inorganic coating layers applied only to specific regions. This merging eliminates the need for separate separator and electrode components, improving adhesion while maintaining thermal shrinkage resistance.
Solution Approach 2:
The inorganic coating layers are applied selectively to specific regions of the porous substrate rather than uniformly across the entire surface. This local application ensures that the coating provides thermal shrinkage resistance where needed while minimizing interference with electrode adhesion and chemical reaction areas.
2Reliability
If inorganic particles with small diameter are used in the inorganic layer, then separator performance is improved, but pores of the electrode active material layer are blocked increasing resistance
Solution Approach 1:
The patent applies different particle sizes in different layers and regions. The first inorganic layer uses particles with a first diameter range optimized for separator performance, while the second inorganic layer uses particles with a second diameter range that prevents pore blocking. This local differentiation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The inorganic coating is divided into multiple distinct layers (first inorganic layer and second inorganic layer) with different particle size characteristics. This segmentation allows the system to achieve both fine separator performance and adequate pore permeability by distributing different functional requirements across separate layers.
3Strength
If binder is added to adhere the inorganic layer, then adhesion is improved, but pores of the electrode active material layer are blocked increasing resistance
Solution Approach 1:
The binder is applied locally and selectively in the coating process rather than uniformly across all surfaces. This localized binder application ensures adequate adhesion of the inorganic layers to the porous substrate while minimizing binder intrusion into the electrode pores, thereby maintaining low resistance.
Data Source
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AI summary
The present invention relates to a method of manufacturing a separator-composite electrode having a multilayer-structured inorganic layer and a separator-composite electrode manufactured thereby. The present invention provides a method of manufacturing a separator-composite electrode and a separator-composite electrode using the same, wherein there is no separator substrate by forming an inorganic layer serving as an insulating layer in multiple layers, thereby safety is improved and the capacity of a battery is not reduced compared to a conventional battery.