Separator Air Permeability for Battery Output and Heat Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional energy storage devices with multilayer structured separators experience transient output degradation during high-rate cycles, which is difficult to suppress without reducing battery performance.
Innovation Solution
An energy storage device with a separator having a base material layer and a coating layer, where the base material layer has an air permeability of 25-250 s/100 ml, porosity of 45-80%, and the interface and coating layer air permeabilities are 1-15 s/100 ml, using resin porous films with polymer, natural, hydrocarbon, glass, or ceramic fibers, and a heat-resistant coating layer with uniform distribution of particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer structured separator with heat resistant coating layer is used, then heat resistance is improved, but transient output degradation occurs during high-rate cycles
Solution Approach 1:
The separator is designed with different layers having different air permeability characteristics. The base material layer has higher air permeability (25-250 s/100ml) to facilitate ion transport and maintain output performance, while the heat resistant coating layer has lower air permeability to provide thermal stability. This local differentiation of properties allows each layer to perform its specific function optimally without compromising the other.
Solution Approach 2:
The separator combines multiple materials with complementary properties: a porous base material layer (polymer, natural, hydrocarbon, glass, or ceramic fibers) providing high air permeability and ion conductivity, and a heat resistant coating layer providing thermal stability. The composite structure integrates the advantages of both materials, achieving both high output performance and heat resistance simultaneously.
2Productivity
If air permeability of the separator is reduced to suppress transient output degradation, then output performance is improved, but battery performance is reduced
Solution Approach 1:
The separator is divided into functionally distinct segments: the base material layer segment responsible for ion transport with optimized air permeability (25-250 s/100ml), and the coating layer segment responsible for heat resistance with controlled air permeability (1-15 s/100ml). This segmentation allows independent optimization of each function without compromising the other, resolving the contradiction between output performance and battery performance.
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
Significantly improves transient output degradation and suppresses micro-short circuit occurrence while maintaining battery performance, enhancing both output and capacity.
Implementation Method 1
the separator has an air permeability of the base material layer of 25 s/100 ml (sec /100cc) or greater and 250 s/100 ml (sec /100cc) or less, a porosity of the base material layer in the range of 45% or greater and 80% or less, an air permeability of an interface between the base material layer and the coating layer of 1 s/100 ml (sec /100cc) or greater and 15 s/100 ml (sec /100cc) or less, and an air permeability of the coating layer of 1 s/100 ml (sec /100cc) or greater and 15 s/100 ml (sec /100cc) or less
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In an energy storage device (10) including a positive electrode plate (410) and a negative electrode plate (420) that are insulated from each other with a separator (430) interposed therebetween, and a non-aqueous electrolyte, the separator (430) includes a base material layer (431) and a coating layer (432) that is disposed on at least one surface of the base material layer (431), and the separator has an air permeability of the base material layer (431) of 25 (sec/100 cc) or greater and 250 (sec/100 cc) or less, a porosity of the base material layer (431) of 45% or greater, an air permeability of an interface (433) between the base material layer (431) and the coating layer (432) of 15 (sec/100 cc) or less, and an air permeability of the coating layer (432) of 15 (sec/100 cc) or less.