Polyether Polyol Cathode Slurry for High-Mass Coating Stability
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Solution Overview
Problem
Increasing the energy density of lithium-ion batteries while avoiding the risks of cracking and material inefficiencies in the manufacturing of positive electrode plates, which are exacerbated by high coating masses.
Innovation Solution
A positive electrode slurry containing polyether polyol, which improves the flexibility and stability of the electrode plates, allowing for increased coating mass without cracking, and reduces material costs by optimizing the molecular weight and ratio of polyether polyol to active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the coating mass of positive electrode plates is increased to improve energy density, then the energy density of lithium-ion batteries is improved, but the risk of cracking and manufacturing difficulties increase
Solution Approach 1:
The patent changes the chemical composition parameters of the slurry by incorporating polyether polyol with specific molecular weight (1000-50000) and specific structural parameters (formula with defined R groups and X moieties). This parameter change in slurry composition improves the coating's mechanical properties, allowing higher coating mass without cracking, thus resolving the contradiction between energy density improvement and cracking risk
Solution Approach 2:
The patent creates a composite slurry system combining positive electrode active material with polyether polyol binder. This composite material approach enhances the overall performance of the coating, enabling it to withstand higher stresses from increased coating mass while maintaining flexibility and preventing cracking, thereby allowing energy density improvement without compromising reliability
2Use of energy by moving object
If the coating mass of positive electrode plates is increased to improve energy density, then the energy density of lithium-ion batteries is improved, but manufacturing precision and fabrication difficulty worsen
Solution Approach 1:
The patent optimizes slurry parameters including polyether polyol molecular weight (1000-50000) and compositional ratios to achieve optimal coating properties. These parameter adjustments ensure uniform coating quality and prevent defects even at high coating masses, thereby maintaining manufacturing precision while enabling energy density improvement through increased coating mass
3Stability of the object's composition
If polyether polyol with small molecular weight is used, then the flexibility of electrode plate is improved, but physical gelation occurs and sheet resistance deteriorates
Solution Approach 1:
The patent establishes an optimal molecular weight range (1000-50000) for polyether polyol to balance flexibility and electrical properties. This parameter optimization prevents physical gelation that occurs with small molecular weights while avoiding the rigidity issues of large molecular weights, thus maintaining both flexibility and acceptable sheet resistance
Solution Approach 2:
The patent uses polyether polyol as a binder material that replicates the desired mechanical flexibility properties in the electrode plate structure. The polyether polyol molecules form a network that copies the flexibility characteristics needed for the electrode to withstand manufacturing and operating stresses without compromising electrical conductivity
4Stability of the object's composition
If polyether polyol with large molecular weight is used, then the stability of slurry is improved, but dispersion becomes poor
Solution Approach 1:
The patent optimizes the molecular weight parameter of polyether polyol to fall within the range of 1000-50000, balancing slurry stability and dispersion characteristics. This parameter control ensures that the polyether polyol provides sufficient stability to prevent settling while maintaining adequate dispersibility for uniform coating formation
Data Source
AI summary
A positive electrode slurry contains polyether polyol, where the polyether polyol has the following constitutional formula:where R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and Y are as defined in the specification.