Binder-Free Composite Separator for Battery Safety
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Solution Overview
Problem
Conventional polyolefin-based separators in batteries face issues with organic binder degradation, leading to performance deterioration, such as clogging, gas generation, and increased volume due to chemical reactions with electrolyte solutions, which compromise safety and efficiency.
Innovation Solution
A composite separator is developed using a multi-dimensional heterogeneous material-containing composite layer with inorganic particles and one-dimensional inorganic materials like nanowires, eliminating the need for an organic binder to enhance adhesive strength, thermal stability, and wettability, thereby preventing binder elution and pore clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an organic binder is used to adhere the ceramic layer to the porous sheet, then adhesive strength is improved, but chemical stability deteriorates due to reactions with electrolyte solution causing elution, swelling, and gas generation
Solution Approach 1:
The patent removes the organic binder component from the ceramic layer composition entirely. The ceramic layer is formed by coating a slurry containing inorganic particles and drying it without adding any organic binder, thereby eliminating the source of chemical reactions with the electrolyte solution while maintaining structural integrity through the inorganic particle network itself
Solution Approach 2:
The patent creates a composite structure where the ceramic layer consists of inorganic particles embedded in a porous substrate. This composite of inorganic materials provides both the necessary adhesive strength and chemical stability, as inorganic materials do not react with or dissolve in the electrolyte solution like organic binders do
2Temperature
If a ceramic layer is introduced onto the porous sheet to improve safety, then thermal stability is improved, but device complexity increases due to additional coating and binder components
Solution Approach 1:
The patent simplifies the device structure by removing the organic binder component from the ceramic layer. The ceramic layer is applied as a simple inorganic particle coating without additional binder materials, reducing the number of components and simplifying the overall device structure while maintaining thermal stability
Solution Approach 2:
The patent uses a porous substrate as the base for the ceramic layer, which maintains the porous structure necessary for electrolyte penetration and ion transport. This porous architecture allows the ceramic layer to provide thermal stability without blocking the functional pathways needed for battery operation
3Strength
If organic binder is used in the ceramic layer, then adhesion is improved, but performance deteriorates due to pore clogging and electrolyte solution degradation
Solution Approach 1:
The patent eliminates the organic binder from the ceramic layer composition, removing the source of pore clogging and electrolyte degradation. The ceramic layer is formed solely from inorganic particles that do not dissolve or react with the electrolyte, thereby maintaining open pores and preventing performance deterioration
Solution Approach 2:
The patent applies the ceramic layer with specific control over particle size distribution and coating thickness to ensure proper adhesion to the porous substrate. The inorganic particles are sized and distributed to provide sufficient mechanical anchoring and adhesion without requiring organic binders, while maintaining adequate pore openness for electrolyte flow
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 solution significantly improves the battery's electrical characteristics, thermal stability, and safety by ensuring stable performance over time, reducing resistance, and maintaining dimensional integrity even after long-term use.
Implementation Method 1
wettability with the electrolyte solution is improved by the one-dimensional inorganic material
Implementation Method 2
adhesive strength between the porous substrate and the composite layer is sufficient
Data Source
AI summary
The present disclosure relates to an organic/inorganic composite porous separator that has excellent thermal stability, improved wettability with an electrolyte solution, an excellent adhesive property between a porous substrate and a porous active layer, excellent electrochemical stability, excellent lithium ion conductivity, and a low resistance increase rate in comparison to a polyolefin-based separator according to the related art, and an electrochemical device capable of implementing both securing of safety and performance improvement by including the separator.