Gel Polymer Battery Separator With Interconnected Pores
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Solution Overview
Problem
Conventional lithium polymer battery separators with dense gel polymer layers have complex manufacturing processes and can degrade due to residual plasticizers, and exhibit poor adhesion to electrodes, limiting their performance.
Innovation Solution
A battery separator with a gel polymer layer featuring three-dimensional open pores is created by adding a non-solvent to a gel polymer solution, causing phase separation and forming interconnected pores, which enhances ion conductivity and adhesion to electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense gel polymer layer is formed by dissolving polymer into solvent and dipping separator, then the separator provides basic separation function, but the manufacturing process becomes complex and residual plasticizer degrades battery quality
Solution Approach 1:
The invention extracts and eliminates the plasticizer component from the gel polymer electrolyte system. Instead of using a plasticizer-polymer-electrolyte complex that requires extraction steps, the patent uses a gel polymer solution with controlled solvent content that directly forms the desired porous structure upon drying, removing the harmful plasticizer entirely while maintaining electrolyte function
Solution Approach 2:
The invention intentionally creates a porous structure in the gel polymer layer by controlling the solvent content and drying conditions. The pores formed by solvent evaporation provide both mechanical integrity and ion transport pathways, eliminating the need for plasticizers to maintain structure while improving battery quality and simplifying the manufacturing process
2Strength
If a dense gel polymer layer is coated on separator, then the separator maintains structural integrity, but adhesion to electrode deteriorates
Solution Approach 1:
The gel polymer layer is designed with a controlled porous structure formed during drying. This porous architecture provides mechanical strength through the gel polymer network while the pores enable intimate contact with the electrode surface, dramatically improving adhesion. The pores allow the electrolyte to penetrate and form strong interfacial contact between the separator and electrode
Solution Approach 2:
The invention creates a composite structure combining the polyolefin separator base layer with a gel polymer coating layer containing dispersed inorganic particles. This composite approach provides both structural integrity from the separator and improved adhesion from the gel polymer matrix that can conform to electrode surfaces while maintaining mechanical strength
3Strength
If PVdF-based polymer electrolyte with nanopores is formed using plasticizer, then mechanical strength is improved, but additional extraction step is required and process becomes complicated
Solution Approach 1:
The invention completely removes the plasticizer extraction step by not using plasticizers at all. The gel polymer electrolyte is formed directly from a solution containing gel polymer and solvent in specific ratios, where the solvent acts as a porogen that evaporates to create pores without leaving harmful residues requiring extraction
Solution Approach 2:
The invention changes the fundamental parameters of the electrolyte formulation by using a gel polymer-solvent system instead of a plasticizer-polymer system. By controlling the solvent content (5-50 wt%) and drying conditions, the desired porous structure and mechanical properties are achieved directly without subsequent extraction steps, dramatically improving manufacturing efficiency
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 with interconnected three-dimensional open pores improves ion conductivity, swelling capacity, and cycle stability, leading to enhanced battery performance and manufacturing efficiency.
Implementation Method 1
when a non-solvent is added to a gel polymer solution and the resultant solution is dried under a controlled temperature, the solution undergoes phase separation into a gel polymer-rich phase and a gel polymer-poor phase, so that a plurality of three-dimensional open pores are formed
Implementation Method 2
when a non-solvent is added to a gel polymer solution and the resultant solution is dried under a controlled temperature
Data Source
AI summary
Disclosed are a separator for a battery, which comprises a gel polymer layer formed on a substrate, the gel polymer layer including a plurality of three-dimensional open pores interconnected with each other, and an electrochemical device comprising the same separator. Also, disclosed is a method for preparing the gel polymer layer including a plurality of three-dimensional open pores interconnected with each other on a substrate.