Ceramic-Coated Battery Separator for Adhesion and Thermal Stability
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Solution Overview
Problem
The existing lithium-ion battery separators face issues with thermal contraction and deformation leading to short circuits, poor adhesive force between electrodes and separator, and reduced cycle life due to gaps formation during charging and discharging cycles, which affect safety and performance.
Innovation Solution
A battery separator with a polymer layer coated on a substrate, incorporating ceramic particles of different sizes (0.01-1 μm) and specific surface area ≥50 m2/g, forming raised island structures to enhance adhesion and thermal stability, using a mixture of high-adhesive and heat-resistant polymers to improve compatibility and adhesive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the separator uses conventional polymer coating, then the manufacturing process is simple, but the adhesive force between electrodes and separator is insufficient
Solution Approach 1:
The patent applies composite materials by combining multiple polymers (PVDF-HFP copolymer, CMC, PMMA) with ceramic particles (alumina, silica) in the coating layer. This composite structure enhances adhesive force through synergistic effects: PVDF-HFP provides baseline adhesion, CMC adds polar groups for stronger electrode bonding, and ceramic particles create rough surface topography that mechanically interlocks with electrodes, achieving ≥20 N/m dry-press adhesive force.
Solution Approach 2:
The patent applies local quality by creating a multi-component polymer system where each polymer serves a specific function: PVDF-HFP copolymer provides fundamental adhesive properties, CMC contributes polar groups for enhanced electrode interaction, and PMMA adds structural support. This localized functional distribution within the coating layer optimizes overall adhesive performance while managing complexity through functional specialization.
2Temperature
If the separator uses single-polymer coating, then the manufacturing process is simple, but the heat resistance is insufficient
Solution Approach 1:
The patent applies composite materials for heat resistance by combining polymers with different thermal properties: PVDF-HFP copolymer (melting point 125-150°C) provides baseline thermal stability, while CMC and PMMA contribute additional heat resistance. The ceramic particles (alumina, silica) with high melting points further enhance thermal stability, creating a composite coating that maintains structural integrity at elevated temperatures during battery operation.
3Strength
If the separator uses smooth surface coating, then the manufacturing process is simple, but the adhesive force with electrodes is reduced
Solution Approach 1:
The patent applies local quality by creating surface heterogeneity through ceramic particle distribution. The coating layer contains regions with varying topography: peaks formed by ceramic particles provide mechanical interlocking points, while valleys allow polymer infiltration. This localized surface variation enhances adhesive force through both mechanical interlocking and increased surface area, achieving ≥20 N/m dry-press adhesive force while maintaining manufacturing feasibility.
4Strength
If the separator coating is too thick, then the adhesive force is improved, but the electrolyte permeability is reduced
Solution Approach 1:
The patent applies porous materials by incorporating ceramic particles (alumina, silica) with inherent porosity into the polymer coating. These ceramic particles create a porous network structure that allows electrolyte penetration while maintaining coating integrity. The porous structure provides channels for ion transport, ensuring adequate electrolyte permeability even with thicker coatings, while the polymer matrix maintains adhesive bonding to electrodes.
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 solution enhances adhesive force and thermal stability, reducing thermal shrinkage, improving safety, and extending cycle life by ensuring strong engagement with electrodes and uniform heat distribution, while maintaining electrolyte wettability and permeability.
Implementation Method 1
the first ceramic particle has a strong surface activity having a specific surface area ≥50 m2/g
Implementation Method 2
forming raised island structures to enhance adhesion and thermal stability
Implementation Method 3
using a mixture of high-adhesive and heat-resistant polymers to improve compatibility and adhesive force
Data Source
AI summary
A battery separator and a preparation method therefor, and a battery. The battery separator includes a substrate; one side or two sides of the substrate are coated with a polymer layer, the polymer layer is mainly formed by mixing a first polymer, a second polymer, first ceramic particles and second ceramic particles, the particle size of the first ceramic particles is 0.01-0.3 μm; the first ceramic particles have higher surface activity; the specific surface area of the first ceramic particles is larger than or equal to 50 m2/g.