Ternary Copolymer Gel Electrolyte for Battery Leakage Prevention
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Solution Overview
Problem
The challenge is to enhance the liquid retaining characteristics of gel electrolytes in batteries to improve battery performance, particularly when the salt concentration is increased, leading to weaker interactions between the solvent and polymer compounds, which affects the battery's capacity, cycle characteristics, and load characteristics.
Innovation Solution
A battery design incorporating a ternary system copolymer containing vinylidene fluoride, hexafluoropropylene, and monomethylmaleic acid ester, with specific copolymerization amounts and weight average molecular weights, along with a cathode binder containing vinylidene fluoride and an anode binder with a binary system copolymer, to stabilize the electrolyte and maintain effective contact with electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the salt concentration in the electrolytic solution is increased to improve battery capacity, then the battery capacity is improved, but the interaction between the solvent and polymer compound becomes weaker, leading to poorer liquid retaining characteristics
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer compound by introducing a specific copolymer containing vinylidene fluoride, hexafluoropropylene, and monomethylmaleic acid ester in controlled ratios. This compositional parameter change enhances the polymer's ability to retain electrolyte even at high salt concentrations, resolving the contradiction between battery capacity and liquid retaining characteristics
Solution Approach 2:
The patent uses a composite polymer material combining three different monomer units (vinylidene fluoride, hexafluoropropylene, and monomethylmaleic acid ester) to create a gel electrolyte with optimized properties. This composite structure provides both high electrolyte retention capability and compatibility with high salt concentration electrolytes, simultaneously achieving improved battery capacity and reliable liquid retention
2Volume of stationary object
If the distance between the cathode and the anode is designed small to reduce battery volume, then the battery volume is reduced, but the internal short circuit between the electrodes is easily generated
Solution Approach 1:
The patent employs a gel electrolyte formed by polymer compound that acts as a flexible, thin separating layer between the electrodes. This gel structure provides adequate electrical insulation to prevent internal short circuits while occupying minimal space, enabling small battery design with maintained safety
Solution Approach 2:
The gel electrolyte serves as an intermediary substance between the cathode and anode, providing both ionic conduction pathway for battery operation and physical separation to prevent direct contact and short circuiting of the electrodes. This mediator function allows close electrode spacing without compromising safety
3Reliability
If a liquid electrolyte is used to achieve good ionic conduction, then the ionic conduction is improved, but the electrolyte may be leaked, causing corrosion or dissolution of battery components
Solution Approach 1:
The patent utilizes the phase transition concept by transforming the electrolyte from a free-flowing liquid state to a gel state through polymerization. This phase change maintains the ionic conduction properties of the liquid electrolyte while adding the structural integrity and leakage prevention characteristics of a semi-solid gel material
Solution Approach 2:
The patent replaces the need for mechanical containment structures (such as metal cans and complex sealing mechanisms) by using the gel electrolyte's inherent semi-solid structure. The gel's viscoelastic properties provide self-containing capability, eliminating or reducing the need for robust mechanical packaging while preventing electrolyte leakage
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
This configuration improves the liquid retaining characteristics of the electrolyte, enhancing battery capacity, cycle characteristics, and load characteristics, while preventing electrolyte leakage even with defects in the film package member.
Implementation Method 1
a method for gelating an electrolytic solution by using a polymer compound has been suggested
Implementation Method 2
an electrolyte working as ion conduction path between the electrodes
Data Source
AI summary
A battery capable of obtaining the superior battery performance is provided. An electrolyte is a gel electrolyte containing an electrolytic solution and a polymer compound. The polymer compound contains a ternary system copolymer containing vinylidene fluoride, hexafluoropropylene, and monomethylmaleic acid ester as a component. The copolymerization amounts of hexafluoropropylene and monomethylmaleic acid ester in the ternary system copolymer are respectively in the range from 4 wt % to 7.5 wt %, and in the range from 0.3 wt % to 2 wt %. Further, the weight average molecular weight of the ternary system copolymer is in the range from 0.6 million to 1.5 million. The liquid retaining characteristics of the electrolyte are improved. Therefore, the contact characteristics of the electrolyte to a cathode, an anode, and a separator are improved.