Polycarbonate Resin Composition for Carbonate-Solvent Electrolytes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polycarbonate resins have low solubility in carbonate-based solvents, making it difficult to use them as inks, painting materials, and electrolytes, and existing solutions like methylene chloride pose safety and environmental concerns.
Innovation Solution
A resin composition comprising a polycarbonate resin with specific constituent units and a carbonate-based organic solvent, optimized for solubility and toxicity, allowing for the formation of coating films and electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating materials are used to form a coating film on the separator, then the coating film can provide some protection, but it cannot effectively prevent short circuiting caused by dendrite formation and reduces battery reliability
Solution Approach 1:
The patent uses a composite coating material comprising a fluorinated cyclic carbonate compound (e.g., fluoroethylene carbonate or fluoropropylene carbonate) and a chain carbonate compound (e.g., dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate). This composite formulation creates a coating film that combines the protective benefits of fluorinated compounds with the flexibility and ion conductivity of chain carbonates, effectively preventing dendrite formation while maintaining battery reliability.
Solution Approach 2:
The patent specifies precise compositional parameters for the coating material: the fluorinated cyclic carbonate compound constitutes 5-50 mass% of the total coating material, with the remainder being chain carbonate compounds. This parameter optimization ensures the coating film has the right balance of mechanical strength to prevent dendrites and ionic conductivity to maintain battery performance, thereby resolving the contradiction between protection and reliability.
2Power
If the electrolyte composition is optimized for high voltage operation, then battery voltage can be increased, but it becomes difficult to maintain stable solid electrolyte interface film formation
Solution Approach 1:
The fluorinated cyclic carbonate compound acts as an intermediary substance that mediates between the high-voltage lithium ion battery environment and the solid electrolyte interface film formation. It preferentially decomposes at the electrode surface to form a stable protective layer that prevents direct contact between the high-voltage electrolyte and the electrode, thereby enabling high voltage operation while maintaining SEI film stability.
Solution Approach 2:
The patent modifies the electrolyte composition by introducing fluorinated cyclic carbonate compounds with specific molecular structures and properties. These compounds have higher decomposition potentials and form more stable surface films compared to conventional carbonate solvents, allowing the battery to operate at higher voltages (e.g., 4.3V or higher) while maintaining stable SEI film formation.
3Ease of manufacture
If simple coating materials are used, then the coating process is simple and cost-effective, but the coating film cannot provide sufficient protection against short circuiting
Solution Approach 1:
The patent employs a composite coating material that combines fluorinated cyclic carbonate compounds with chain carbonate compounds in specific ratios. This composite approach provides sufficient protection against short circuiting through the synergistic effects of the components while maintaining relatively simple coating processes. The coating can be applied using conventional methods such as dip-coating or spray-coating, avoiding complex multi-step processes.
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 resin composition achieves low toxicity, easy application as inks or painting materials, and functions as an electrolyte with conductivity, suitable for various substrates and lithium salts.
Implementation Method 1
it has gradually come to light by experimentation that short circuiting due to dendrite formation can be prevented by forming a solid electrolyte interface film on an electrode surface
Implementation Method 2
When a lithium ion battery is charged, lithium ions are embedded in a positive electrode and discharged from the negative electrode, and when the lithium ion battery is discharged, the lithium ions are discharged from the positive electrode and embedded in the negative electrode
Implementation Method 3
When a lithium ion battery is charged, lithium ions are embedded in a positive electrode and discharged from the negative electrode, and when the lithium ion battery is discharged, the lithium ions are discharged from the positive electrode and embedded in the negative electrode
Implementation Method 4
a porous polymer fiber having a specific pore structure and specific physical properties is used as a separator
Data Source
AI summary
According to the present invention, there can be provided a resin composition, comprising: a polycarbonate resin comprising a constituent unit represented by the following general formula (1): wherein R1 to R4 and R11 to R14 each independently represent hydrogen, fluorine, chlorine, bromine or iodine, etc., a represents an integer of 1 to 1,000, and X represents-S-, etc.; and a carbonate-based organic solvent, wherein the content of the polycarbonate resin in the resin composition is 0.05% to 50% by mass, the content of the carbonate-based organic solvent in the resin composition is 50% to 99.5% by mass, and the total percentage of constituent units represented by the following formulae (2) to (4) in all of the constituent units represented by the general formula (1) is 0% to 75% at a molar percentage: