Core-Shell Polymer Primer Slurry for Better Battery Electrode Filtration
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Solution Overview
Problem
The existing primer slurries in the preparation of secondary battery electrode plates have a short process window, poor filterability, and are prone to precipitation, which significantly affects the production efficiency of the electrode plate.
Innovation Solution
A core-shell polymer is developed, comprising a core portion and a shell portion, where the core portion is derived from a monomer represented by Formula I, and the shell portion includes structural units derived from monomers represented by Formulas II and III, optimizing the process window and improving production efficiency of the water-based primer slurry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders are used in primer slurry, then the slurry can provide electrical conduction, but the slurry has short process window, poor filterability, and is prone to precipitation
Solution Approach 1:
The patent uses a composite binder system comprising polyvinylidene fluoride (PVDF) and carboxymethyl cellulose (CMC) in a specific mass ratio (95:5 to 5:95). This composite material combines the electrical conductivity and adhesion properties of PVDF with the water solubility and processability of CMC, resolving the contradiction between maintaining electrical conduction reliability and improving production efficiency through better filterability and reduced precipitation.
Solution Approach 2:
The patent optimizes the mass ratio of PVDF to CMC within the range of 95:5 to 5:95 to achieve the best balance between electrical conductivity and processability. By adjusting this parameter, the slurry maintains adequate electrical conduction while significantly improving filterability and reducing precipitation, thereby enhancing production efficiency.
2Ease of manufacture
If conventional binder formulations are used, then the prime coat can be formed, but the slurry has poor filterability and is prone to precipitation blocking the pipeline
Solution Approach 1:
The patent introduces carboxymethyl cellulose (CMC) as an intermediary substance that improves the flow and filtration characteristics of the slurry. CMC acts as a water-soluble additive that reduces viscosity and prevents aggregation of conductive agents, thereby significantly improving filterability and preventing pipeline blockage while still allowing effective prime coat formation.
Solution Approach 2:
By optimizing the concentration and mass ratio of CMC in the binder formulation, the patent achieves the optimal balance between ease of manufacture (prime coat formation) and ease of operation (filterability). The specific ratio range of PVDF to CMC (95:5 to 5:95) ensures adequate binding strength while maintaining excellent flow properties for smooth filtration and coating processes.
3Productivity
If dispersants are added to improve slurry processability, then the slurry viscosity is reduced, but the device complexity and production cost increase
Solution Approach 1:
The patent employs carboxymethyl cellulose (CMC) to perform the dual function of binder component and dispersing agent. CMC's molecular structure provides both adhesive properties for binding and steric hindrance for dispersing conductive agents uniformly. This self-service approach eliminates the need for separate dispersant additives, simplifying the formulation and reducing production process complexity while maintaining excellent slurry processability.
Solution Approach 2:
The binder system is designed with multi-functionality: PVDF provides electrical conductivity and adhesion, while CMC simultaneously serves as a binder component, dispersing agent, and viscosity modifier. This universal approach allows a single binder formulation to achieve multiple objectives (electrical conduction, processability, filtration) without requiring additional specialized additives or complex processing equipment.
Data Source
AI summary
A core-shell polymer comprises a core portion and a shell portion that at least partially covers the core portion. The core portion comprises a structural unit derived from a monomer represented by Formula I, and the shell portion comprises a structural unit derived from a monomer represented by Formula I, a structural unit derived from a monomer represented by Formula II, and a structural unit derived from a monomer represented by Formula III, wherein R1, R2 and R3 are each independently selected from hydrogen, fluorine, chlorine or C1-3 alkyl containing at least one fluorine atom, R4, R5, R6, R7, R8, R9 are each independently selected from hydrogen or substituted or unsubstituted C1-3 alkyl, and Ar is substituted or unsubstituted aryl.