Composite Separator Hydrogen Bond Adhesion
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Solution Overview
Problem
The existing lithium-ion battery separators face issues with poor cohesion and adhesion of inorganic ceramic coatings, leading to detachment, surface cracking, and potential short circuits, which compromise safety and product quality.
Innovation Solution
A composite separator is developed using inorganic particles with -OH functional groups and a binder containing -CO- or -CN functional groups, forming hydrogen bonds to enhance the adhesion force of the coating layer, thereby reducing detachment and peeling problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a layer of inorganic ceramic particles is coated on a porous polyolefin substrate to improve high-temperature resistance and safety performance, then thermal stability is improved, but the cohesion force of the coating layer deteriorates due to poor surface compatibility between hydrophilic ceramic particles and hydrophobic substrate
Solution Approach 1:
The patent introduces a binder as an intermediary substance between the hydrophilic inorganic ceramic particles and the hydrophobic polyolefin substrate. This binder mediates the interface between the two incompatible materials, enabling effective coating formation and improving both cohesion force and adhesion to the substrate, thereby resolving the contradiction between thermal stability improvement and coating layer integrity
Solution Approach 2:
The patent creates a composite coating structure consisting of inorganic ceramic particles, binder, and polyolefin substrate. This composite material approach combines the high-temperature resistance of ceramic particles with the adhesive properties of the binder and the substrate compatibility, achieving both thermal stability and coating strength simultaneously
2Reliability
If inorganic ceramic particles are coated on the separator surface to prevent thermal runaway, then safety performance is improved, but powder detachment occurs during subsequent winding causing low finished product rate
Solution Approach 1:
The binder serves as a mediator that anchors the inorganic ceramic particles to the polyolefin substrate, preventing powder detachment during winding and handling. This intermediary substance ensures that the safety-enhancing ceramic particles remain firmly attached, thereby maintaining both safety performance and manufacturing yield
Solution Approach 2:
The patent modifies the surface properties and bonding parameters of the coating system by introducing a binder with appropriate adhesive characteristics. This parameter change in the coating formulation enables the ceramic particles to remain firmly attached during subsequent processing, improving finished product rate while maintaining safety performance
3Object-affected harmful factors
If inorganic ceramic particles are coated on the separator to prevent short circuit, then thermal safety is improved, but ceramic particles detach and get sandwiched between separator and electrode causing micro-short circuit
Solution Approach 1:
The binder acts as a mediator that secures inorganic ceramic particles to the separator substrate, preventing their detachment and sandwiching between separator and electrode. This intermediary substance eliminates the harmful effect of particle detachment while preserving the thermal safety benefits of the ceramic coating
Solution Approach 2:
The patent converts the potential harm of loose ceramic particles (which could cause micro-short circuits) into a benefit by using the binder to firmly attach them. The same ceramic particles that provide thermal safety when properly attached are prevented from becoming a source of micro-short circuits, transforming a potential harm into a purely beneficial component
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 enhanced adhesion force improves the safety and quality of lithium-ion batteries by reducing the risk of short circuits and self-discharging, as demonstrated by improved cohesion force and lower self-discharging rates compared to existing separators.
Implementation Method 1
a hydrogen bond is formed between the binder and the inorganic particles
Data Source
Figure 1
AI summary
There is provided a composite separator for a lithium-ion battery, including a polyolefin substrate and a coating layer containing a binder and inorganic particles formed on a surface of the polyolefin substrate, a hydrogen bond being formed between the binder and the inorganic particles. Also provided are a method for preparing the composite separator for a lithium-ion battery and a lithium-ion battery using the composite separator. The composite separator of the present application increases adhesion force between the substrate and the inorganic particles, thereby reducing detachment of the inorganic particles. By using the composite separator, the product quality of the battery is improved, and the risk of influencing the safety performance of the battery caused by the detachment of the inorganic particles in a production process is reduced.