Multi-Layer Battery Separator for Puncture-Resistant Ion Transport
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Solution Overview
Problem
Commercial separators made of single-layer polyolefin films are prone to puncture due to poor mechanical properties, posing safety hazards in batteries.
Innovation Solution
A separator comprising at least three layers of stacked base films with a first bonding layer between each two layers, enhancing support and stability, and incorporating a solid particle bonding layer, such as an inorganic particle bonding layer, to improve puncture resistance and ion permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer polyolefin base film is used as separator, then the separator structure is simple and manufacturing is easy, but the mechanical properties are poor and puncture resistance is insufficient
Solution Approach 1:
The separator is divided into multiple base film layers (at least three layers) stacked together, with bonding layers between adjacent layers. This segmentation approach transforms a single thin film with poor mechanical properties into a multi-layer structure where each layer contributes to overall strength, solving the puncture resistance problem while maintaining manufacturing feasibility through standardized lamination processes.
Solution Approach 2:
The separator combines multiple base film materials (such as PE and PP) with different properties into a composite structure. The bonding layers (solid particle bonding layers or gel bonding layers) create strong interfaces between layers. This composite material approach achieves superior puncture resistance and mechanical properties compared to single-layer films, while the modular design keeps manufacturing processes manageable.
2Strength
If multiple layers of base films are stacked with bonding layers, then puncture resistance and mechanical properties are improved, but the separator structure becomes complex
Solution Approach 1:
The multi-layer structure is segmented into functional modules: base film layers for mechanical strength, solid particle bonding layers for inter-layer adhesion, and gel bonding layers for additional bonding. This functional segmentation makes the complexity manageable by assigning specific roles to each layer, allowing the separator to achieve high puncture resistance without overwhelming structural complexity.
Solution Approach 2:
Different bonding layers are strategically placed at different locations within the separator structure. Solid particle bonding layers are positioned between certain base film layers, while gel bonding layers are placed between other layers. This local quality approach optimizes the bonding characteristics in different regions, achieving overall structural integrity without requiring uniform complexity throughout the entire separator.
3Strength
If solid particle bonding layer is used to bond base films, then mechanical strength is improved, but ion permeability may be affected
Solution Approach 1:
The solid particle bonding layer is designed with a porous structure containing inorganic particles (such as氧化铝 particles) distributed within a polymer matrix. This porous architecture provides channels for ion transport while the polymer matrix maintains mechanical bonding between layers. The result is a bonding layer that simultaneously improves mechanical strength and preserves ion permeability, resolving the contradiction between these two critical properties.
Solution Approach 2:
The bonding layer is formulated as a composite material combining inorganic particles (for structural integrity and porosity) with polymer binder (for adhesion). This composite approach allows optimization of both mechanical properties and ion transport characteristics, achieving strong bonding while maintaining high ion permeability necessary for battery performance.
4Strength
If gel bonding layer is used between base films, then inter-layer bonding is enhanced, but the thickness and potential ion transport resistance increase
Solution Approach 1:
The gel bonding layer parameters are precisely controlled, including thickness (kept minimal), composition (gel polymer electrolyte with specific Li salt content), and porosity. By optimizing these parameters, the gel layer provides sufficient inter-layer bonding strength while maintaining thin dimensions that minimize ion transport resistance, thus resolving the contradiction between bonding enhancement and ion conduction preservation.
Data Source
AI summary
A separator, a battery, and a power consuming apparatus are disclosed. The separator includes at least three layers of stacked base films. A first bonding layer bonded to at least two adjacent layers of the base films is arranged therebetween. The separator is arranged to include at least three layers of the stacked base films, and the first bonding layer is arranged between at least two layers of the base films. The base films on two sides of the first bonding layer are bonded by the first bonding layer. The base films bonded together provide support to each other, thereby making the single-layer base film not prone to be punctured, and further reducing a risk of the separator being punctured, so as to improve safety performance of a battery to which the separator is applied.