Electrochemical battery comprising a separator with a porous substrate and a heat-resistant porous layer and process for the production thereof
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Solution Overview
Problem
Large electrochemical batteries face challenges with heat dissipation, leading to internal temperatures exceeding 200°C, causing separator meltdown and short circuits, which existing heat-meltable resin separators cannot adequately prevent.
Innovation Solution
A separator with a porous substrate and a heat-resistant porous layer formed by curing a composition including a monomer, oligomer, or polymer, with a crosslinkable binder, providing enhanced tensile strength and adhesion to prevent fracture at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is formed of a heat-meltable resin to provide shutdown properties, then the separator can stop reactions in a battery at predetermined temperature, but the separator suffers meltdown and loses mechanical strength at temperatures of 200°C or more
Solution Approach 1:
The separator is divided into two functional layers: a heat-meltable resin layer (first layer) that provides shutdown properties, and a heat-resistant porous layer (second layer) that maintains mechanical strength. This segmentation allows each layer to specialize in one function without compromising the other.
Solution Approach 2:
The separator uses a composite structure combining heat-meltable resin and heat-resistant porous material. The heat-resistant porous layer serves as a skeleton that prevents meltdown while the heat-meltable layer provides shutdown functionality, creating a material system with both required properties.
2Volume of moving object
If the separator is made thinner to improve battery energy density, then the battery size is reduced, but the separator becomes more prone to fracture at high temperatures
Solution Approach 1:
The heat-resistant porous layer provides a three-dimensional skeletal structure with high specific strength. The porous architecture maintains mechanical integrity and fracture resistance while minimizing material usage and thickness, allowing thin separator design without sacrificing strength.
3Strength
If a heat-resistant porous layer is added to prevent meltdown, then the separator maintains form at high temperature, but the device complexity increases
Solution Approach 1:
The heat-resistant porous layer is applied only on the outer surfaces of the heat-meltable resin layer, not throughout the entire separator thickness. This extraction approach provides heat resistance where it is most needed (at the interfaces with electrodes) while minimizing the amount of additional material and structural complexity.
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 maintains its form and prevents short circuits at high temperatures, ensuring high-efficiency charge/discharge properties and improved battery reliability by maintaining tensile strength and adhesion, even after prolonged use.
Implementation Method 1
a heat resistant porous layer formed on one or both surfaces of the porous substrate by curing a composition comprising: a monomer, oligomer, polymer or a combination thereof, wherein the monomer is represented by Formula 1, and the oligomer and polymer are polymerized from the monomer
Data Source
Figure 1
AI summary
Disclosed herein is a separator of an electrochemical battery and an electrochemical battery including the same. In one emobodiment, the composition for obtaining the separator includes a monomer, oligomer, or polymer represented by Formula 1, an initiator, and a solvent. In another emobodiment, the separator includes a porous substrate and a heat resistant porous layer formed on one or both surfaces of the porous substrate, wherein the heat resistant porous layer includes a crosslinkable binder, and the separator has a tensile strength of ≥ 50 kgf/cm2 to ≤ 350 kgf/cm2, as measured after being left at 200°C for 10 minutes.