Silane-Coated Battery Separator for Low Heat Shrinkage
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Solution Overview
Problem
Current secondary battery separators lack sufficient thermal stability when exposed to electrolyte solutions, leading to varying heat shrinkage behaviors that differ from those in real battery conditions, posing a risk of internal short circuits and fires.
Innovation Solution
A separator with an inorganic particle layer formed using a hydrolytic condensate of a silane compound, applied on a porous substrate, which has a heat shrinkage rate of 8% or less and maintains heat resistance when exposed to 150°C for 60 minutes, with a TMA melt fracture temperature of 180°C or higher, ensuring improved thermal stability both within the battery and as a standalone component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an organic-inorganic composite porous separator with inorganic particle layer is used, then heat resistance of the separator itself is improved, but thermal stability inside the battery with electrolyte solution is insufficient
Solution Approach 1:
The patent uses a composite structure consisting of a porous substrate and an inorganic particle layer. The inorganic particle layer contains inorganic particles (such as metal oxides or metal hydroxides) dispersed in a binder, creating a composite material that combines the heat resistance of inorganic materials with the porosity and flexibility of the substrate, thereby achieving both improved heat resistance and thermal stability in the battery environment
Solution Approach 2:
The patent optimizes specific parameters including the weight ratio of inorganic particles to binder (95:5 to 50:50), particle size distribution (0.1 to 10 μm), and layer thickness (1 to 10 μm) to achieve the desired balance between heat resistance and thermal stability. The binder's glass transition temperature is specifically controlled to ensure proper thermal behavior in the battery
2Measurement precision
If conventional evaluation method (cutting separator and heating) is used, then heat shrinkage rate can be measured, but it does not reflect real battery conditions
Solution Approach 1:
The patent creates a simplified battery model that copies the essential features of a real battery (electrolyte solution, electrodes, separator assembly) to evaluate thermal stability. This model system replicates the actual battery environment without requiring a complete battery, allowing for controlled measurement of heat shrinkage behavior under conditions that accurately reflect real battery operation
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 separator exhibits excellent heat resistance and adhesive strength, reducing the risk of thermal instability and internal short circuits, while maintaining performance in batteries with electrolyte solutions, and demonstrates improved thermal stability and safety.
Implementation Method 1
a hydrolytic condensate of a silane compound
Implementation Method 2
a hydrolytic condensate of a silane compound
Implementation Method 3
heat shrinkage rate S of the separator in a battery... allowing a secondary battery including a negative electrode, a positive electrode, an electrolyte solution, and the separator to stand at 150°C for 60 minutes
Data Source
AI summary
Provided are a separator for a secondary battery, a method of manufacturing the separator, and a secondary battery including the separator. According to an exemplary embodiment of the present disclosure, a separator including: a porous substrate and an inorganic particle layer formed on at least one surface of the porous substrate, wherein a heat shrinkage rate S of the separator in a battery, represented by the following Equation (1) is 8% or less may be provided: S=A1−A2/A1∗100 wherein A1 is a length in a width direction of the separator, and A2 is a length in a width direction of a separator, the separator being obtained by allowing a secondary battery including a negative electrode, a positive electrode, an electrolyte solution, and the separator to stand at 150°C for 60 minutes, cooling the secondary battery to room temperature, and then disassembling the secondary battery.