Positive Electrode Slurry Cooling for High-Solid Viscosity Stability
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Solution Overview
Problem
The existing methods for preparing positive electrode slurries with high solid content face issues with rapid viscosity increase, leading to gelation and difficulties in forming uniform electrode layers, which affects the quality and efficiency of the positive electrode preparation process.
Innovation Solution
A method involving mixing a positive electrode active material, conductive agent, and binder in a non-aqueous solvent to create a mixture with a solid content greater than 60 wt%, followed by cooling to -30°C to 15°C to prepare a slurry precursor, and maintaining the precursor at a controlled temperature to suppress viscosity increase, thereby stabilizing the slurry composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solid content of the positive electrode slurry is increased to improve productivity and electrode drying efficiency, then the viscosity of the slurry increases rapidly over storage time, causing quality problems and making it difficult to use the slurry
Solution Approach 1:
The patent changes the temperature parameter to control viscosity. By cooling the slurry to -30°C to 15°C during preparation and maintenance, the viscosity increase over storage time is suppressed, allowing high solid content (greater than 60%) slurry to maintain stable viscosity characteristics
Solution Approach 2:
The patent applies preliminary cooling action before the slurry is stored or used. By cooling the slurry to -30°C to 15°C in advance, the viscosity increase that would normally occur over storage time is prevented, allowing the slurry to maintain usable properties throughout storage
2Quantity of substance
If lithium nickel composite metal oxide is used to achieve high reversible capacity, then thermal stability deteriorates, causing decomposition and battery rupture when internal short circuit occurs
Solution Approach 1:
The patent uses composite materials by substituting nickel with cobalt, manganese, or aluminum in the lithium transition metal oxide. This creates a composite structure that maintains high reversible capacity while improving thermal stability and preventing decomposition under short circuit conditions
Solution Approach 2:
The patent applies local quality by selectively substituting nickel atoms with cobalt, manganese, or aluminum at specific positions in the crystal structure. This localized substitution maintains the high capacity characteristics while providing thermal stability at critical locations
3Quantity of substance
If lithium cobalt composite metal oxide is used to achieve high operating voltage and excellent capacity, then thermal properties deteriorate due to unstable crystal structure caused by delithiation
Solution Approach 1:
The patent creates composite materials by combining lithium cobalt oxide with other transition metal oxides (nickel, manganese, aluminum). This composite structure stabilizes the crystal structure during delithiation while maintaining high operating voltage and excellent capacity characteristics
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 effectively suppresses viscosity growth over time, allowing for the preparation of high-solid-content positive electrode slurries, enhancing energy density and improving the quality and efficiency of the positive electrode production process.
Implementation Method 1
cooling the mixture to -30°C to 15°C to prepare a positive electrode slurry composition precursor
Data Source
AI summary
The present invention relates to a method of preparing a positive electrode slurry composition, which includes steps of (S1) mixing a positive electrode active material, a conductive agent, and a binder in a non-aqueous solvent to prepare a mixture having a solid content of greater than 60 wt%; (S2) cooling the mixture to -30°C to 15°C to prepare a positive electrode slurry composition precursor; and (S3) maintaining a temperature of the positive electrode slurry composition precursor to prepare a positive electrode slurry composition having a V72 of 0% to 50%, wherein Vn is a viscosity increase rate when the temperature of the positive electrode slurry composition precursor is maintained for n hours, and the viscosity increase rate is represented by Equation 1, and a method of preparing a positive electrode.