Polymer Electrolyte Crosslinking for Battery Safety
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Solution Overview
Problem
Pouch-type lithium rechargeable batteries using liquid electrolytes are prone to deformation and safety issues due to external impacts and high temperatures, and uniform electrolyte impregnation is crucial for preventing capacity reduction and lithium precipitation.
Innovation Solution
A polymer electrolyte composition with a pre-gel formulation including specific monomers, a lithium salt, and a non-aqueous organic solvent, which reduces viscosity for improved electrode impregnation and polymerization, enhancing thermal stability and safety by forming a cured product with increased crosslinking density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid electrolyte solution is used in pouch-type lithium rechargeable batteries, then the battery can be manufactured with flexible shape and increased size, but the battery becomes easily deformed and damaged by external physical impact and swells when exposed to high temperatures
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to gel polymer form, fundamentally altering the parameters of viscosity, flow characteristics, and thermal stability. This transformation maintains the electrolyte's ionic conductivity while eliminating the problems of leakage, deformation, and swelling associated with liquid electrolytes in pouch-type batteries
Solution Approach 2:
The patent employs composite gel polymer electrolytes formed by combining polymer matrices with electrolyte solutions and crosslinking agents. This composite structure integrates the flexibility and ionic conductivity of liquid electrolytes with the structural stability and thermal resistance of polymer gels, resolving the contradiction between adaptability and reliability
2Manufacturing precision
If the viscosity of pre-gel composition is reduced to improve electrode impregnation, then uniform electrolyte distribution is achieved, but the crosslinking density and thermal stability of the polymer matrix may be compromised
Solution Approach 1:
The patent applies preliminary action by injecting the pre-gel composition in a low-viscosity state to ensure complete and uniform impregnation of electrodes and separators before polymerization occurs. This preliminary fluid state allows the electrolyte to penetrate all porous structures, after which polymerization locks in this uniform distribution while building the crosslinked network structure
Solution Approach 2:
The patent utilizes dynamics by controlling the viscosity transition of the pre-gel composition from a fluid state during injection to a gel state after polymerization. This dynamic property change enables the system to exhibit low viscosity temporarily for impregnation, then transforms to a high-viscosity gel structure that provides thermal stability and crosslinking density
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 polymer electrolyte composition ensures uniform electrolyte distribution, reducing lithium precipitation, improving battery capacity, reliability, and safety against physical impacts and high temperatures, while preventing leaks and maintaining performance.
Implementation Method 1
the viscosity of the pre-gel is greatly affected by the amount and molecular weight of the monomer of the pre-gel... by polymerization after the polymer electrolyte composition is injected
Data Source
AI summary
A polymer electrolyte having improved reliability and safety by increasing thermal stability of a polymer of the polymer electrolyte and crosslinking density of a matrix of the polymer while improving electrode impregnation capability by inducing low viscosity in a pre-gel composition, and a lithium rechargeable battery including the same are disclosed. The polymer electrolyte is a cured product of a polymer electrolyte composition including a lithium salt, a non-aqueous organic solvent, and a pre-gel composition including a first monomer represented by Chemical Formula 1, a second monomer represented by Chemical Formula 2 and a third monomer represented by Chemical Formula 3.