Coated Battery Separator With Organic Protrusions for Thin Cells
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Solution Overview
Problem
Existing secondary batteries face challenges in achieving high energy density while maintaining good cycling performance and safety performance.
Innovation Solution
A separator is developed with a coating comprising inorganic particles and first organic particles, where the first organic particles have a primary particle morphology and a number-average particle size of ≥2 μm, forming protrusions on the coating surface and enhancing air permeability and bonding with electrode plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of secondary batteries is increased, then the battery capacity is improved, but the cycling performance and safety performance deteriorate
Solution Approach 1:
The patent applies local quality by creating a coating layer with specific local characteristics on the separator surface. The coating contains inorganic particles (such as aluminum oxide, boehmite) with specific size ranges (0.5-2.5 μm) and organic particles (such as polyacrylonitrile, polyacrylic acid) that provide localized functional properties. This localized modification of the separator surface improves electrode plate bonding and maintains safety performance while allowing higher energy density battery design
Solution Approach 2:
The patent employs composite materials by combining inorganic particles and organic particles in a coating layer on the separator. The inorganic particles provide structural stability and thermal resistance, while the organic particles enhance bonding with electrode plates. This composite structure allows the separator to simultaneously support high energy density requirements and maintain good cycling and safety performance
2Length of stationary object
If the separator thickness is reduced, then the energy density is improved, but the air permeability and bonding performance may deteriorate
Solution Approach 1:
The patent applies porous materials by incorporating inorganic particles with specific size ranges (0.5-2.5 μm) into the coating layer. These particles create a porous structure that maintains air permeability even with reduced separator thickness. The porous structure allows electrolyte penetration and ion transport while the inorganic particles provide structural support to prevent collapse
Solution Approach 2:
The patent uses local quality by concentrating functional particles (inorganic and organic) in a coating layer on the separator surface. This localized functional zone provides enhanced bonding performance and maintains air permeability without requiring increased overall separator thickness. The coating layer thickness is controlled at 1-5 μm to balance these requirements
Data Source
AI summary
The present application relates to a separator, comprising a substrate and a coating formed on at least one surface of the substrate, wherein the coating comprises inorganic particles and first organic particles embedded in the inorganic particles and forming protrusions on the surface of the coating, and the first organic particles have a primary particle morphology and a number-average particle size of ≥2 μm. The present application also relates to a secondary battery comprising the separator, a device comprising the secondary battery and a method for preparing the separator.