Granulated Electrode Coating Material Using Carbonate Solvents
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Solution Overview
Problem
The use of organic solvents like N-methyl-pyrrolidone (NMP) and N-ethyl-pyrrolidone in producing coating materials for electrical energy storage devices is problematic due to toxicity, health hazards, high viscosity leading to settling issues, and the need for large solvent amounts, which are costly and energy-intensive to remove, making them undesirable for safety and environmental reasons.
Innovation Solution
A method involving a dry mixture of active material, conductivity additives, and fluorine-containing polymer binder, dissolved in a solvent mixture comprising at least 60% ethylene carbonate or propylene carbonate, which is then cooled and granulated, resulting in a solid, easily storable and transportable thermoplastic coating material that can be melted for application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If organic solvents like NMP or NEP are used to dissolve the binder, then the binder dissolves completely, but the solvent is toxic and harmful to health
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system by replacing toxic organic solvents (NMP, NEP) with a mixture of carbon dioxide and water. This parameter change eliminates toxicity while maintaining the ability to dissolve or disperse the binder, thus resolving the contradiction between dissolution completeness and harmful factors.
Solution Approach 2:
The patent employs carbon dioxide, an inexpensive and environmentally benign gas, as the primary solvent. CO2 is naturally occurring, non-toxic, and can be easily removed after the coating process, effectively replacing expensive and harmful organic solvents while maintaining functional performance.
2Stability of the object's composition
If large amounts of solvent are used to dissolve the binder, then the binder dissolves completely, but the solvent must be removed which is time-consuming and energy-intensive
Solution Approach 1:
The patent utilizes the phase transition properties of carbon dioxide, which can transition between gas and liquid phases under different pressure and temperature conditions. By controlling these parameters, the coating can be applied using liquid CO2, and then the CO2 can be rapidly removed by pressure reduction, avoiding the time-consuming and energy-intensive heating process required for high-boiling organic solvents.
3Stability of the object's composition
If large amounts of solvent are used to dissolve the binder, then the binder dissolves completely, but the energy required to remove the solvent is high
Solution Approach 1:
The patent exploits the phase transition of carbon dioxide from liquid to gas, which occurs rapidly upon pressure reduction. This phase change allows for complete solvent removal without the need for high-energy heating processes, thereby dramatically reducing the energy consumption associated with solvent evaporation while maintaining complete binder dissolution during the coating application phase.
4Stability of the object's composition
If the coating material is viscous, then the binder is well-dissolved, but the material is difficult to pack and transport
Solution Approach 1:
The patent changes the physical state parameter of the coating material by using carbon dioxide as a solvent that evaporates completely, transforming the viscous liquid coating into a dry, free-flowing powder. This parameter change from liquid to solid state eliminates handling difficulties associated with viscous materials while maintaining complete binder dissolution during the coating process.
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 approach reduces solvent usage, minimizes environmental and safety risks, accelerates binder dissolution, and simplifies handling and processing, while ensuring non-interference with cell chemistry, leading to a more cost-effective and efficient production of electrodes.
Implementation Method 1
The dry mixture is brought into contact with a solvent mixture which comprises at least 60% by weight ethylene carbonate (EC) and/or propylene carbonate (PC)... until the fluorine-containing polymer compound is completely dissolved in the solvent mixture
Implementation Method 2
The mixture obtained is cooled to a temperature of below 40 °C after the fluorine-containing polymer binder has completely dissolved
Implementation Method 3
The mixture obtained is granulated during or after the curing process
Data Source
AI summary
The method involves providing a dry mixture with an active material, and a conductivity additive material and a fluorine-containing polymer binder. The dry mixture is provided in contact with a solvent mixture comprising 60 percent by weight of ethylene and/or propylene carbonate, or 60 percent by weight of a mixture of ethylene and/or propylene carbonate. The solvent mixture is mixed and dried at a temperature of about 80 degree Celsius until completion of dissolution of the fluorine-containing polymer binder in the solvent mixture. Independent claims are also included for the following: (1) a thermoplastic granule for producing a coating material of an electrode carrier of an electrical energy storage device (2) a method for coating an electrode substrate of an electrical energy storage device.