Polyurethane Gel Electrolyte for Battery Leakage and Conductivity
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Solution Overview
Problem
Current electrolyte systems for electrochemical cells face challenges such as leakage with liquid electrolytes and poor ionic conductivity with solid electrolytes, necessitating a solution that combines mechanical stability with high ionic conductivity.
Innovation Solution
A poly(dialkylene ester) thermoplastic polyurethane composition is used to create a polymer gel electrolyte system, incorporating an alkali metal salt and an aprotic organic solvent, which is processed by reacting a poly(dialkylene ester) polyol intermediate with a diisocyanate and a chain extender, providing a homogenous polymer gel electrolyte for electrochemical cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in electrochemical cells, then acceptable ionic conductivity is achieved, but leakage occurs and safety risks increase
Solution Approach 1:
The patent employs a composite gel electrolyte system combining poly(dialkylene ester) thermoplastic polyurethane polymer matrix with liquid electrolyte components (alkali metal salt and aprotic organic solvent). This composite structure integrates the high ionic conductivity of liquid electrolytes with the mechanical stability and leakage-free properties of solid polymers, resolving the contradiction between conductivity and safety.
Solution Approach 2:
The patent modifies the physical state of the electrolyte by transforming it from a free-flowing liquid into a gel state through incorporation into the polymer matrix. This parameter change maintains the ionic conductivity characteristics of liquid electrolytes while eliminating leakage and enhancing safety, directly addressing the technical contradiction.
2Object-affected harmful factors
If solid electrolytes are used in electrochemical cells, then leakage is eliminated, but ionic conductivity deteriorates
Solution Approach 1:
The patent creates a composite gel electrolyte system that combines solid polymer matrix (providing leakage-free structure) with liquid electrolyte components (providing high ionic conductivity). This composite approach allows the electrolyte to exhibit both the mechanical stability of solids and the ionic transport properties of liquids, resolving the contradiction between leakage prevention and conductivity.
Solution Approach 2:
The polymer gel acts as an intermediary phase between solid and liquid states. It provides the structural framework of a solid material while incorporating liquid electrolyte components that enable efficient ion transport, thus mediating between the conflicting requirements of leakage prevention and high conductivity.
3Ease of manufacture
If homopolymer-based gel electrolytes are used, then ease of manufacture is improved, but mechanical integrity is lost due to dissolution in electrolyte solvent
Solution Approach 1:
The patent employs a copolymer system comprising at least two different polymer components with distinct functions: one polymer provides mechanical strength and structural integrity, while the other facilitates electrolyte compatibility and ionic conductivity. This composite polymer architecture prevents dissolution in electrolyte solvent while maintaining ease of manufacture through established copolymerization techniques.
Solution Approach 2:
The copolymer structure assigns different local functions to different polymer segments or components. One segment or polymer provides mechanical reinforcement, while another segment or polymer provides electrolyte compatibility. This local differentiation of properties allows the material to simultaneously achieve mechanical integrity and electrolyte stability.
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 offers improved charge/discharge cycle life, high charge/discharge efficiency, and operational stability across a wide temperature range, eliminating the need for rigid metallic casings and reducing leakage risks, while maintaining mechanical integrity.
Implementation Method 1
reacting (i) at least one poly(dialkylene ester) polyol intermediate with (ii) at least one diisocyanate and (iii) at least one chain extender
Implementation Method 2
an alkali metal salt; and (C) an aprotic organic solvent, characterized in that the poly(dialkylene ester) thermoplastic polyurethane composition
Data Source
AI summary
The invention relates to a polymer gel electrolyte system for use in an electrochemical cell having positive and negative electrodes, said electrolyte system comprising: (A) a poly(dialkylene ester) thermoplastic polyurethane composition; (B) an alkali metal salt; and (C) an aprotic organic solvent. The invention also provides an electrochemical cell comprising a positive electrode, a negative electrode, and (I) a polymer electrolyte disposed between said positive and negative electrodes, wherein the polymer electrolyte comprises (A) the poly(dialkylene ester) thermoplastic polyurethane composition; (B) an alkali metal salt; and (C) an aprotic organic solvent.