Gel Polymer Battery Electrolyte for Selective Lithium-Ion Isolation
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Solution Overview
Problem
Existing secondary batteries face issues with solvent or additive decomposition due to high or low potential side reactions, leading to battery performance deterioration and limited operating voltage range.
Innovation Solution
A gel polymer secondary battery design with distinct gel polymers in the cathode, anode, and electrolyte layer, utilizing a third gel polymer with a higher content in the electrolyte layer to selectively permeate lithium ions, while suppressing electrolyte flowability and maintaining a wide operating voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrolyte is used in secondary batteries, then the battery structure is simple, but the operating voltage range is limited due to decomposition or unwanted byproduct formation at high or low potentials
Solution Approach 1:
The patent divides the single electrolyte system into multiple segmented electrolytes with different gel polymers. Each electrolyte is assigned to specific voltage ranges based on its stability characteristics, allowing the battery to operate across a wider voltage range without decomposition or unwanted byproduct formation.
Solution Approach 2:
The patent applies different gel polymer types to different regions (electrolytes) based on their electrochemical stability characteristics. Each electrolyte is optimized for specific voltage ranges, with high-potential stable gel polymers used in electrolytes exposed to higher potentials and low-potential stable gel polymers used elsewhere, achieving local optimization of voltage range.
2Reliability
If gel polymer content is increased in the electrolyte layer, then electrolyte flowability is suppressed and ion selectivity is improved, but electrolyte viscosity increases
Solution Approach 1:
The patent uses composite gel polymer materials combining different polymer types with complementary properties. This allows the electrolyte to achieve both high ion selectivity through sufficient gel polymer content and acceptable viscosity by selecting polymers with appropriate molecular weight and chain flexibility.
Solution Approach 2:
The patent optimizes gel polymer content as a controllable parameter, finding the balance point where ion selectivity is sufficiently improved while viscosity remains acceptable for ion transport. The specific gel polymer content is adjusted based on the required performance characteristics.
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 design enhances battery performance by preventing unwanted byproduct formation and maintaining a wide operating voltage range, improving safety and efficiency through selective ion permeation and reduced electrolyte flowability.
Implementation Method 1
the third gel polymer content of the electrolyte layer is larger than the first gel polymer content of the catholyte and the second gel polymer content of the anolyte... selectively permeate lithium ions while suppressing electrolyte flowability
Data Source
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AI summary
A gel polymer secondary battery that can selectively permeate only lithium ions within a cell and maintain a state in which a heterogenous electrolyte is isolated. Thegel polymer secondary battery includes: a cathode impregnated with a catholyte containing a first gel polymer; an anode impregnated with an anolyte containing a second gel polymer; and an electrolyte layer interposed between the cathode and anode and including a third gel polymer. The third gel polymer content of the electrolyte layer is larger than the first gel polymer content of the cathode and the second gel polymer content of the anode.