Battery Slurry Premixing to Prevent SBR Emulsion Demulsification
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Solution Overview
Problem
The existing method of adding a plasticizer to a battery slurry after the styrene-butadiene rubber (SBR) emulsion can lead to demulsification, damaging the SBR structure and deteriorating battery performance due to molecular dipole forces between the plasticizer and sodium alkyl sulfonate in the SBR emulsion.
Innovation Solution
Premixing a plasticizer with an additive containing specific functional groups, such as hydroxyl, carbonate, or ketone groups, before mixing with the SBR emulsion to form an intermolecular dipole force, which reduces the force applied on the SBR emulsion and prevents demulsification, thereby stabilizing the slurry and enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a plasticizer is added to a battery slurry after the SBR emulsion, then the plasticity of the polymer is improved and flexibility is enhanced, but demulsification occurs in the SBR emulsion and battery performance deteriorates
Solution Approach 1:
The patent applies preliminary action by adding the plasticizer to the slurry before adding the SBR emulsion, rather than after. This preliminary addition allows the plasticizer to be distributed throughout the slurry matrix first, and when the SBR emulsion is subsequently added, the plasticizer is already in position to interact with the polymer chains as they form, preventing demulsification while still providing the desired plasticity and flexibility improvements.
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 maintains the structural stability of the SBR emulsion, improves slurry performance, and enhances the cycle performance of the battery by preventing demulsification and ensuring stable coating processes.
Implementation Method 1
the step of adding a plasticizer is usually performed after the SBR emulsion is added, or the plasticizer and the SBR emulsion are added together for stirring. In other words, no attention is given to the influence of the addition step of the plasticizer and the SBR emulsion on the slurry properties. This process makes it easy to generate a molecular dipole force between the polar plasticizer and the sodium alkyl sulfonate in the SBR emulsion.
Implementation Method 2
When a plasticizer (e.g., ethylene carbonate (EC), propylene carbonate (PC), 1,3-butanediol, nitrogen methyl pyrrolidone (NMP), and other small molecule solvents) is added to a battery slurry, the plasticizer enters the molecular chains of the adhesive polymer.
Data Source
AI summary
A preparation method of a cathode slurry and a battery are provided. The preparation method includes: S1, mixing materials containing a plasticizer and an additive to form a premixed slurry A; and S2, mixing a styrene-butadiene rubber emulsion with the premixed slurry A. The plasticizer includes a first functional group including at least one of a hydroxyl group, a carbonate group, and a ketone group. The additive includes a second functional group including at least one of a carboxyl group, a nitrile group, and an amide group.