Battery Separator Coating for Thin Heat-Resistant Li-Ion Cells
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Solution Overview
Problem
Conventional separators for lithium secondary batteries face challenges in achieving high mechanical strength, heat resistance, and permeability at thin thicknesses, leading to safety issues such as short circuits and overheating due to decreased mechanical strength and heat resistance, which limits their suitability for high-capacity/high-output batteries.
Innovation Solution
A separator with an inorganic particle layer comprising inorganic particles and a metal silicate binder, where the organic compound content is lower than the inorganic binder, providing excellent adhesion and heat resistance even at small thicknesses by connecting inorganic particles and anchoring them to a porous substrate, preventing heat shrinkage and maintaining ion movement efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the separator is thinned to achieve high capacity and high output characteristics, then the capacity and output are improved, but the mechanical strength and heat resistance are decreased
Solution Approach 1:
The separator is constructed as a composite material consisting of a porous substrate layer and an inorganic particle layer. The inorganic particle layer contains inorganic particles (such as metal oxides or metal hydroxides) dispersed in a binder polymer, creating a composite structure that combines the porosity needed for ion transport with the thermal stability and mechanical strength provided by the inorganic components. This composite architecture enables the thin separator to maintain both high capacity/output performance and adequate mechanical strength and heat resistance.
2Productivity
If the separator is thinned to improve capacity and output, then the capacity and output increase, but safety problems such as short circuit and overheating become more likely
Solution Approach 1:
The composite structure of porous substrate plus inorganic particle layer provides enhanced safety characteristics. The inorganic particles (metal oxides or hydroxides) offer high thermal stability and can act as heat sinks, while the binder polymer provides mechanical integrity. This composite design prevents the safety issues of thin separators by maintaining structural stability and thermal resistance even at reduced thickness, thereby preventing short circuits and overheating while preserving high capacity and output.
Solution Approach 2:
The separator utilizes a porous structure in both the substrate and particle layer, which allows efficient ion transport necessary for high capacity and output. The controlled porosity ensures that the thin separator does not compromise ion conductivity while the inorganic particles provide structural support and thermal stability, thereby maintaining safety during manufacturing and use.
3Temperature
If the organic compound content in the inorganic particle layer is reduced, then the heat resistance is improved, but the adhesion and permeability may be compromised
Solution Approach 1:
The patent optimizes the composition parameters of the inorganic particle layer by carefully controlling the ratio of organic compound to inorganic particles, and selecting specific types of inorganic particles and binder polymers. By adjusting these parameters, the separator achieves the desired balance where reduced organic content improves heat resistance while the inorganic particles and binder polymer combination maintains adequate adhesion and permeability for 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
The separator exhibits improved heat resistance, adhesion, and permeability, preventing ignition and rupture from temperature rises, making it suitable for high-capacity/high-power batteries while maintaining battery performance and lifespan.
Implementation Method 1
the inorganic binder includes a metal silicate... the metal silicate may connect and fix the inorganic particles together and the inorganic particle layer and the porous substrate together
Implementation Method 2
providing excellent adhesion and heat resistance even at small thicknesses by connecting inorganic particles and anchoring them to a porous substrate, preventing heat shrinkage
Implementation Method 3
maintaining ion movement efficiency... improved adhesion and permeability even at a thin thickness
Data Source
AI summary
Provided are a separator and an electrochemical device including the same. According to an embodiment of the present disclosure, a separator is provided which includes a porous substrate; and an inorganic particle layer which is placed on one or both surfaces of the porous substrate and includes inorganic particles and an inorganic binder, wherein the inorganic particle layer includes an organic compound having a lower content than the inorganic binder and the inorganic binder includes a metal silicate.