Dual Porous Coating Layer Separator for Secondary Battery Safety
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Solution Overview
Problem
Secondary battery separators face safety concerns due to thermal instability and excessive metal ion deposition, leading to overheating, fires, or explosions, as existing coatings fail to effectively manage metal ions and maintain pore structure during high temperatures.
Innovation Solution
A dual porous coating layer separator is developed, with a first layer of inorganic particles having a low BET surface area for uniform dispersion and bonding, and a second layer with higher BET surface area and specific pore size for enhanced metal ion adsorption, ensuring safety by maintaining pore structure and adsorbing excess metal ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a porous coating layer is formed from a mixture of insulating filler particles and binder polymer, then thermal stability is improved, but metal ion adsorption capability deteriorates
Solution Approach 1:
The coating layer is divided into two distinct layers: a lower porous coating layer with insulating filler particles for thermal stability, and an upper porous coating layer with metal ion adsorbent particles for metal ion removal. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The invention uses composite materials by combining different types of particles (insulating filler particles and metal ion adsorbent particles) in separate layers. The lower layer uses insulating fillers like alumina or silica for thermal resistance, while the upper layer uses metal ion adsorbents for selective metal ion capture, creating a composite structure that addresses multiple safety concerns simultaneously.
2Temperature
If inorganic particles are added to porous coating layer, then thermal stability is improved, but pore structure maintenance deteriorates
Solution Approach 1:
Different regions of the coating layer have different qualities: the lower layer contains insulating filler particles optimized for thermal stability, while the upper layer contains metal ion adsorbent particles optimized for ion capture. Each layer's particle composition is locally optimized for its specific function while maintaining overall pore structure through controlled porosity (30-80%).
3Ease of manufacture
If single porous coating layer is used, then manufacturing simplicity is maintained, but metal ion adsorption capability deteriorates
Solution Approach 1:
The coating layer is divided into two distinct layers: a lower porous coating layer with insulating filler particles and an upper porous coating layer with metal ion adsorbent particles. This segmentation allows each layer to perform its specific function - thermal stability from the lower layer and metal ion adsorption from the upper layer.
Solution Approach 2:
The invention uses composite materials by combining different types of particles (insulating filler particles and metal ion adsorbent particles) in separate layers. The lower layer uses insulating fillers like alumina or silica for thermal resistance, while the upper layer uses metal ion adsorbents for selective metal ion capture.
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 dual-layer separator effectively maintains pore structure and adsorbs excess metal ions, enhancing safety by preventing thermal instability and reducing the risk of overheating, fires, or explosions in secondary batteries.
Implementation Method 1
a second porous coating layer formed by coating on the first porous coating layer, and including second inorganic particles having a Brunauer, Emmett & Teller (BET) surface area in a range of 12 to 30 m2/g
Data Source
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AI summary
The present disclosure relates to a separator for a secondary battery including a dual porous coating layer of inorganic particles with different surface characteristics, a secondary battery including the same, and a method of manufacturing the separator. According to an exemplary embodiment of the present disclosure, a separator for a secondary battery including a porous substrate, a first porous coating layer, and a second porous coating layer is provided. According to another exemplary embodiment of the present disclosure, a method of manufacturing a separator for a secondary battery including forming a first slurry, forming a second slurry, forming a first porous coating layer, and forming a second porous coating layer is provided. A separator according to an aspect of the present disclosure has uniform dispersion of inorganic particles in a coating layer of the separator, and adsorbs an excess of metal ions generated in the battery when the battery is out of a normal operating temperature range, thereby ensuring safety of the battery.